Bath system

Abstract

To provide a bath system capable of detecting a water level in a bathtub with high reliability when a plurality of water heaters supplies hot water to the bathtub, and thereby capable of appropriately achieving hot water supply to a set water level.SOLUTION: A hot water supply operation process of a bath system 1 comprises a first process of pouring a predetermined amount of hot water from a plurality of water heaters 2A, 2B into a bathtub BT; a second process of, after all the water heaters 2A, 2B have finished pouring hot water into the bathtub BT in the first process, detecting a water level in the bathtub BT in a state in which all the water heaters 2A, 2B have stopped pouring hot water; and a third process of pouring an amount of hot water to be poured into the bathtub BT from the water level detected in the second process to a set water level from the water heaters 2A, 2B into the bathtub.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bath system that fills a bathtub with hot water using a plurality of water heaters.

Background Art

[0002] Conventionally, as disclosed in, for example, Patent Document 1, a system for filling a large bathtub with hot water using a plurality of water heaters is known. In this system, hot water is filled up to a water level immediately before the set water level for filling with a plurality of water heaters (two water heaters), and after reaching the water level immediately before the set water level, hot water is filled only with one water heater (main unit).

[0003] Also, during the hot water filling up to the water level immediately before the set water level, the hot water injection operation of one water heater (main unit) is temporarily stopped, the water level in the bathtub is confirmed by the water level sensor of the one water heater, and the subsequent hot water injection amount is appropriately corrected according to the confirmation result.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the system disclosed in Patent Document 1 above, when detecting the water level with one water heater, although the hot water injection operation of the water heater is stopped, the hot water injection operation of the other water heater continues. For this reason, when detecting the water level with one water heater, the water level in the bathtub changes due to the hot water injection by the other water heater, and the hot water in the bathtub is likely to sway along with the hot water injection by the other water heater.

[0006] For this reason, an error in the detected water level is likely to occur in a water heater in which hot water supply is temporarily stopped. As a result, the amount of hot water poured into the bathtub after detecting the water level becomes inaccurate, and variations in the water level at the completion of hot water filling are likely to occur.

[0007] The present invention has been made in view of such a background, and an object thereof is to provide a bath system that can detect the water level in a bathtub with high reliability when pouring hot water into the bathtub by a plurality of water heaters, and thus can appropriately realize pouring hot water up to a set water level.

Means for Solving the Problems

[0008] The bath system of the present invention includes a plurality of water heaters connected to be able to pour hot water into one bathtub, and when receiving an instruction for hot water filling operation, it is configured to execute a hot water filling operation process of filling the bathtub with hot water from the plurality of water heaters until the set water level of the bathtub, and is a bath system, The hot water filling operation process includes a first process of pouring a predetermined amount of hot water into the bathtub from the plurality of water heaters once or a plurality of times, a second process of detecting the water level in the bathtub in a state where all the hot water pouring operations of the plurality of water heaters are stopped after the pouring of hot water into the bathtub in the first process has ended for all of the plurality of water heaters, and a third process of pouring hot water into the bathtub from the plurality of water heaters in an amount of hot water to be poured into the bathtub from the detected water level to the set water level (characteristic of the first invention).

[0009] In the present invention, pouring a predetermined amount of hot water into the bathtub from a plurality of water heaters means pouring a predetermined amount of hot water set for each of the plurality of water heaters into the bathtub from each water heater, or pouring hot water into the bathtub so that the total amount of hot water poured into the bathtub for each of the plurality of water heaters (the total amount of hot water poured in the whole of the plurality of water heaters) becomes a predetermined amount.

[0010] According to the first invention, the second process of detecting the water level in the bathtub is performed after the hot water supply to the bathtub in the first process has ended for all of the plurality of water heaters and in a state where the hot water supply operations of all of the plurality of water heaters have been stopped. Therefore, the water level can be detected in a static state of the hot water in the bathtub. For this reason, a highly reliable water level detection value can be obtained.

[0011] And in the third process, since the amount of hot water to be poured into the bathtub from the plurality of water heaters up to the set water level from the water level detected in the second process is poured into the bathtub, it is possible to appropriately specify the amount of hot water required up to the set water level and pour hot water into the bathtub.

[0012] Therefore, according to the first invention, when pouring hot water into the bathtub by a plurality of water heaters, the water level in the bathtub can be detected with high reliability, and thus it is possible to appropriately realize the hot water pouring up to the set water level.

[0013] In the first invention described above, the plurality of water heaters perform hot water supply to the bathtub in an operation mode for the first hot water supply when performing the first hot water supply to the bathtub, and acquire bathtub characteristic data regarding the relationship between the amount of hot water supplied to the bathtub for each water heater and the water level of the bathtub. The hot water supply operation process is a process executed during a hot water supply operation other than the first hot water supply. The predetermined amount of hot water poured from the plurality of water heaters into the bathtub in the first process of the hot water supply operation process is the amount of hot water set for each water heater according to the bathtub characteristic data acquired by each water heater. In the second process, the water level is detected for each water heater. In the third process, each water heater is configured to pour the amount of hot water determined for each water heater based on the water level detected in the second process in the water heater, the set water level, and the bathtub characteristic data acquired in the water heater from each water heater into the bathtub (second invention).

[0014] According to this, a plurality of water heaters can pour hot water into the bathtub with the same or similar sequence operations to each other when filling the bathtub. Therefore, it is possible to easily make many specifications regarding the hardware and software of each of the plurality of water heaters common among the plurality of water heaters. As a result, it is possible to reduce the development cost and manufacturing cost of the water heaters constituting the bath system.

[0015] In the second invention above, it is preferable that the plurality of water heaters are configured to detect the water level in the second process in parallel with each other (third invention). According to this, in the second process, the time required for all the water heaters to complete the water level detection can be made as short as possible. As a result, it is possible to shorten the time required to complete the hot water filling of the bathtub and improve the comfort of the user.

[0016] In the first invention above, when the bathtub is filled with hot water for the first time, the plurality of water heaters pour hot water into the bathtub in an operation mode for the first hot water filling operation, and a main water heater, which is a specific one of the plurality of water heaters, is configured to acquire bathtub characteristic data regarding the relationship between the amount of hot water poured into the bathtub and the water level of the bathtub. The hot water filling operation process is a process executed during the hot water filling operation other than the first hot water filling. The predetermined amount of hot water poured from the plurality of water heaters into the bathtub in the first process of the hot water filling operation process is the amount of hot water obtained by distributing, at a predetermined distribution ratio, the amount of hot water set according to the bathtub characteristic data acquired by the main water heater to each of the plurality of water heaters. In the second process, only one of the plurality of water heaters executes the water level detection. In the third process, each water heater is configured to pour hot water from each water heater into the bathtub in an amount of hot water obtained by distributing, at a predetermined distribution ratio, the amount of hot water determined based on the water level detected in the second process, the set water level, and the bathtub characteristic data acquired by the main water heater to each of the plurality of water heaters (fourth invention).

[0017] According to this, in each of the first process and the third process, the amount of hot water poured from the plurality of water heaters into the bathtub is set according to the bathtub characteristic data acquired by the main water heater, and the set amount of hot water is distributed to each water heater. Therefore, for example, even if one water heater other than the main water heater fails, it is possible to perform hot water pouring up to the set water level by setting the amount of hot water to be distributed to the water heaters other than the failed water heater and pouring the hot water into the bathtub.

[0018] In the fourth invention described above, the hot water pouring operation process further includes, before the execution of the first process, a fourth process of pouring a predetermined amount of hot water for priming into the hot water supply water channels connected to the bathtub corresponding to each of the plurality of water heaters from each water heater, and a fifth process of measuring the hot water pouring flow rate from each water heater to the bathtub in the fourth process for each water heater. In each of the first process and the third process, the predetermined distribution ratio may adopt a mode in which the ratio is determined according to the measured value of the hot water pouring flow rate for each water heater in the fifth process (the fifth invention).

[0019] According to this, the hot water pouring flow rate in the fourth process immediately after the start of the hot water pouring operation is measured for each water heater by the fifth process. And in each of the first process and the third process, the predetermined distribution ratio as the distribution ratio of the amount of hot water poured into the bathtub to each water heater is determined according to the measured value of the hot water pouring flow rate obtained in the fifth process for each water heater.

[0020] Therefore, each time the hot water pouring operation is executed, it is possible to determine the predetermined distribution ratio in each of the first process and the third process by reflecting the difference in the hot water pouring flow rate for each water heater measured immediately after the start of the hot water pouring operation. For example, it is possible to determine the distribution ratio so that the distribution ratio is larger for a water heater with a larger measured value of the hot water pouring flow rate. Thereby, in each of the first process and the third process, it is possible to realize pouring the required amount of hot water from the plurality of water heaters into the bathtub in a short time.

[0021] Further, in the fourth invention, the hot water filling operation process includes a sixth process of measuring the hot water filling flow rate from each water heater to the bathtub for each water heater immediately after the start of hot water filling from each water heater to the bathtub in the first process, and a seventh process of measuring the hot water filling flow rate from each water heater to the bathtub for each water heater immediately after the start of hot water filling from each water heater to the bathtub in the third process. It is also possible to adopt an aspect in which the predetermined distribution ratio in the first process is a ratio determined according to the measured value of the hot water filling flow rate for each water heater in the sixth process, and the predetermined distribution ratio in the third process is a ratio determined according to the measured value of the hot water filling flow rate for each water heater in the seventh process (sixth invention).

[0022] According to this, in each hot water filling operation, in the sixth process, the hot water filling flow rate is measured immediately after the start of hot water filling into the bathtub in the first process, and in the seventh process, the hot water filling flow rate is measured immediately after the start of hot water filling into the bathtub in the third process. And in each of the first process and the third process, the predetermined distribution ratio as the distribution ratio of the amount of hot water filled into the bathtub to each water heater is determined according to the measured value of the hot water filling flow rate obtained in the sixth process in the first process and according to the measured value of the hot water filling flow rate obtained in the seventh process in the third process.

[0023] Therefore, in each hot water filling operation, for each of the first process and the third process, by reflecting the difference in the hot water filling flow rate for each water heater measured immediately after the start of hot water filling in each of the first process and the third process, the predetermined distribution ratio in each of the first process and the third process can be determined. For example, in each of the first process and the third process, it is possible to determine the distribution ratio so that the distribution ratio is increased for the water heater with a larger measured value of the hot water filling flow rate immediately after the start of hot water filling. As a result, in each of the first process and the third process, it is possible to realize filling the required amount of hot water into the bathtub from the entire plurality of water heaters in a short time.

[0024] In the first invention described above, when the bathtub is filled with hot water for the first time, the plurality of water heaters perform pouring hot water into the bathtub in an operation mode for the first hot water pouring operation, and a main water heater, which is a specific one of the plurality of water heaters, is configured to acquire bathtub characteristic data regarding the relationship between the amount of hot water poured into the bathtub and the water level of the bathtub. The hot water pouring operation process is a process executed during the hot water pouring operation other than the first hot water pouring. The predetermined amount of hot water poured from the plurality of water heaters into the bathtub in the first process of the hot water pouring operation process is an amount of hot water that is the sum of the amounts of hot water poured from each of the plurality of water heaters into the bathtub and is set according to the bathtub characteristic data acquired by the main water heater. In the first process, when pouring the predetermined amount of hot water from the plurality of water heaters into the bathtub, while pouring hot water from each of the plurality of water heaters into the bathtub, the amount of hot water poured from each water heater into the bathtub is sequentially measured, and when the sum of the measured values of the amount of hot water poured reaches the predetermined amount, the pouring of hot water from each water heater into the bathtub is stopped. In the second process, only one of the plurality of water heaters performs water level detection. In the third process, while pouring hot water from each of the plurality of water heaters into the bathtub, the amount of hot water poured from each water heater into the bathtub is sequentially measured, and when the sum of the measured values of the amount of hot water poured reaches the amount of hot water determined based on the water level detected in the second process, the set water level, and the bathtub characteristic data acquired by the main water heater, the pouring of hot water from each water heater into the bathtub is stopped. It is also possible to adopt an aspect in which it is configured in this way (the seventh invention).

[0025] According to this, in each of the first process and the third process, the amount of hot water poured into the bathtub from the entire plurality of water heaters is set according to the bathtub characteristic data acquired by the main water heater, and the pouring of hot water into the bathtub is performed so that the sum of the amounts of hot water poured from each of the plurality of water heaters into the bathtub becomes the set amount of hot water. For this reason, for example, even when one water heater other than the main water heater fails, by appropriately pouring hot water from the water heaters other than the failed water heater, it is possible to perform hot water pouring up to the set water level without determining the amount of hot water poured for each water heater.

Brief Description of the Drawings

[0026]

Figure 1

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Figure 15

Embodiments for Carrying Out the Invention

[0027] [First Embodiment] The first embodiment of the present invention will be described below with reference to FIGS. 1 to 5. Referring to FIG. 1, the bath system 1 of the present embodiment includes a plurality of (for example, two) water heaters 2A and 2B connected to be able to pour hot water into a single bathtub BT. Each of the water heaters 2A and 2B includes a heat source machine 3 having the same configuration as each other as a heat source for heating hot water for hot water supply and the hot water in the bathtub BT (hereinafter referred to as bathtub water). In the following description, when there is no need to distinguish between the water heaters 2A and 2B, they are simply referred to as the water heater 2.

[0028] The heat source machine 3 of each water heater 2 includes a water supply path 10 to which hot water for hot water supply is supplied from a water supply source (not shown), a first heating unit 11 for heating the hot water supplied from the water supply path 10, a hot water supply path 12 for supplying the heated hot water to a hot water supply target location (not shown) such as a kitchen (or cooking room), a bathroom, or a washroom, a second heating unit 13 for heating the bathtub water, a circulation water path 14 for circulating the bathtub water between the second heating unit 13 and the bathtub BT, and a hot water pouring water path 15 for supplying the hot water heated by the first heating unit 11 from the hot water supply path 12 to the bathtub BT via the circulation water path 14.

[0029] The water supply paths 10 of each of the water heaters 2A and 2B are branched from a single upstream water supply path 4, and hot water for hot water supply is supplied from the upstream water supply path 4 to each water supply path 10. Also, the downstream sides of the hot water supply paths 12 of each of the water heaters 2A and 2B merge into a single downstream hot water supply path 5, and hot water for hot water supply is supplied from each hot water supply path 12 to the hot water supply target location via the downstream hot water supply path 5.

[0030] Although detailed illustration of the first heating unit 11 is omitted, for example, it is constituted by a known combustion type heating device including a burner and a heat exchanger. In this case, the first heating unit 11 heats the hot water supply water flowing through the heat exchanger from the water supply path 10 to the hot water supply path 12 while allowing the hot water supply water flowing through the heat exchanger to be heated by the combustion heat generated by the combustion operation of the burner.

[0031] In addition, the first heating unit 11 may be provided with a bypass path for allowing the hot water supply water to flow from the water supply path 10 to the hot water supply path 12 without passing through the heat exchanger, and a bypass ratio adjustment valve for adjusting the bypass ratio which is the ratio of the flow rate of the hot water supply water flowing through the bypass path to the flow rate of the hot water supply water flowing through the heat exchanger.

[0032] A water supply amount adjustment valve 16 for adjusting the water supply amount which is the flow rate of the hot water supply water flowing through the water supply path 10 and a flow rate sensor 17 for detecting the water supply amount are assembled in the water supply path 10, and a temperature sensor 18 for detecting the hot water supply temperature which is the temperature of the hot water supply water supplied to the downstream hot water supply target location through the hot water supply path 12 is assembled in the hot water supply path 12. The water supply amount adjustment valve 16 is constituted by, for example, an electric servo valve and can also close the water supply path 10. However, among the water heaters 2A and 2B, the water supply amount adjustment valve 16 of the main water heater (the water heater 2A in this embodiment) described later does not necessarily need to have a function of closing the water supply path 10.

[0033] The circulation water path 14 includes a return path side water path 14a for flowing the bathtub water from inside the bathtub BT to the second heating unit 13 and a forward path side water path 14b for flowing the bathtub water from the second heating unit 13 into the bathtub BT. An electric pump 19 as a power source for circulating the bathtub water in the circulation water path 14 is assembled in one of the return path side water path 14a and the forward path side water path 14b, for example, the return path side water path 14a.

[0034] And the ends of the return water channel 14a and the forward water channel 14b on the bathtub BT side are each connected to a hot water pouring port Ba formed on the side wall near the bottom surface of the bathtub BT. In this case, in the present embodiment, the bathtub BT is provided with separate hot water pouring ports Ba for each of the water heaters 2A and 2B, and the respective circulation water channels 14 of the water heaters 2A and 2B are connected to separate hot water pouring ports Ba. Note that the circulation water channel 14 is a water channel corresponding to the hot water pouring water channel in the present invention.

[0035] Although detailed illustration of the second heating unit 13 is omitted, for example, similar to the first heating unit 11, it is constituted by a known combustion type heating device including a burner and a heat exchanger. In this case, the heat exchanger of the second heating unit 13 is connected to the return water channel 14a and the forward water channel 14b so that bathtub water flows from the return water channel 14a to the forward water channel 14b. And the second heating unit 13 is configured to heat the bathtub water flowing through the circulation water channel 14 by the combustion heat generated by the combustion operation of the burner in the heat exchanger by the operation of the pump 19.

[0036] Supplementally, each of the first heating unit 11 and the second heating unit 13 of the heat source machine 3 of each water heater 2 is not limited to a combustion type heating device. For example, each of the first heating unit 11 and the second heating unit 13 may be provided with an electric heating device or a heat pump type heating device instead of or in addition to the combustion type heating device.

[0037] One of the return water channel 14a and the forward water channel 14b, for example, the return water channel 14a, is assembled with a temperature sensor 20 for detecting the temperature of the bathtub water, a water flow switch 21 for detecting the presence or absence of water flow in the circulation water channel 14, and a water level sensor 22 for detecting the water level of the bathtub water in the bathtub BT.

[0038] The water level sensor 22 is a known water pressure detection type sensor. When there is bathtub water at a level equal to or higher than the height of the hot water injection port Ba (the hot water injection port Ba corresponding to the water heater 2A or 2B equipped with the water level sensor 22) in the bathtub BT (and thus when the bathtub water fills the circulation water path 14), it is configured to detect the water level in the bathtub BT according to the water pressure acting on the water level sensor 22. Note that each of the temperature sensor 20, the water flow switch 21, and the water level sensor 22 may be provided in the forward path side water path 14b.

[0039] The hot water injection water path 15 branches from the hot water supply path 12 and joins one of the return path side water path 14a and the forward path side water path 14b of the circulation water path 14, for example, the return path side water path 14a. And, assembled to the hot water injection water path 15 are a hot water injection solenoid valve 23 capable of opening and closing the hot water injection water path 15, and a flow rate sensor 24 for detecting the flow rate of the hot water supply water (the hot water injection flow rate to the bathtub BT) supplied from the hot water supply path 12 through the hot water injection water path 15 to the bathtub BT.

[0040] Each of the water heaters 2A and 2B further includes control devices 31A and 31B each having a function of performing operation control and the like of its respective heat source machine 3. The control devices 31A and 31B are respectively mounted on the respective heat source machines 3 of the water heaters 2A and 2B. Also, the water heater 2A includes, as its operation remote control, a kitchen (or cooking room) remote control 32A installed in the kitchen (or cooking room) or in the vicinity thereof, and a bathroom remote control 33A installed in the bathroom. Also, the water heater 2B includes, as its operation remote control, a kitchen (or cooking room) remote control 32B installed in the kitchen (or cooking room) or in the vicinity thereof.

[0041] Although detailed illustrations of the kitchen remote controls 32A and 32B of the water heaters 2A and 2B are omitted, they each include an operation unit including a switch (on / off switch) for on / off operation of the hot water supply operation of the corresponding water heater 2, an operation switch for setting the target value of the hot water supply temperature, an operation switch for instructing execution of the hot water injection operation for hot water injection into the bathtub BT, etc., a display unit for displaying various information related to the operation of each of the water heaters 2A and 2B, and a sound emitting unit for outputting an alarm sound and voice information.

[0042] Further, although detailed illustration is omitted, the bathroom remote controller 33A of the water heater 2A includes an operation unit including operation switches for setting a target value of the bath temperature which is the temperature of the bath water in the bathtub BT and a target value of the water level of the bath water, an operation switch for instructing execution of the hot water supply operation, etc., a display unit for displaying various information regarding the hot water supply, etc., and a sound emitting unit for outputting an alarm sound and voice information.

[0043] The control devices 31A and 31B are each composed of one or more electronic circuit units including a processor such as a microcomputer, a memory, an interface circuit, etc., and can communicate with each other. Further, the control device 31A of the water heater 2A can communicate with the kitchen remote controller 32A and the bathroom remote controller 33A, and the control device 31B of the water heater 2B can communicate with the kitchen remote controller 32B.

[0044] And each of the control devices 31A and 31B has a function of controlling the operation of the heat source machine 3 of the corresponding water heaters 2A and 2B by functions realized by the mounted hardware configuration and program (software configuration). In the following description, when there is no need to distinguish between the control devices 31A and 31B, each is simply referred to as the control device 31.

[0045] Next, regarding the operation when hot water is supplied to the bathtub BT in the bath system 1 of the present embodiment, it will be described with reference to FIGS. 2 to 5. In the bath system 1 of the present embodiment, among the water heaters 2A and 2B, the water heater 2A functions as the main water heater, and the water heater 2B functions as the auxiliary water heater. And in the standby state of the bath system 1 (a state where neither the hot water supply operation for supplying hot water to the hot water supply target location nor the hot water supply operation for supplying hot water to the bathtub BT is being executed), the water supply amount adjustment valve 16 of the water heater 2A (hereinafter sometimes referred to as the main water heater 2A) is held in the open valve state, and the water supply amount adjustment valve 16 of the water heater 2B (hereinafter sometimes referred to as the auxiliary water heater 2B) is held in the closed valve state.

[0046] When the hot water filling operation is to be executed for the bathtub system 1, the user performs an operation to start the hot water filling operation using the kitchen remote controller 32A or the bathroom remote controller 33A of the main water heater 2A. In response to this, the start of the hot water filling operation is instructed from the kitchen remote controller 32A or the bathroom remote controller 33A to the control device 31A of the main water heater 2A.

[0047] Alternatively, the user can reserve in advance the start time of the hot water filling operation using the timer function provided in the kitchen remote controller 32A or the bathroom remote controller 33A. In this case, at the start time of the hot water filling operation, the start of the hot water filling operation is instructed from the kitchen remote controller 32A or the bathroom remote controller 33A to the control device 31A of the main water heater 2A.

[0048] Note that the kitchen remote controller 32B of the auxiliary water heater 2B may also be able to perform an operation to start the hot water filling operation or reserve the start time. And the start of the hot water filling operation may be instructed from the kitchen remote controller 32B to the control device 31A of the main water heater 2A via the control device 31B of the auxiliary water heater 2B.

[0049] When the start of the hot water filling operation is instructed as described above, the control device 31A of the main water heater 2A, if the hot water filling operation is the first hot water filling operation after the installation of the bathtub system 1 (specifically, if performing the hot water filling operation in the operation mode for the first hot water filling operation is specified in advance by a predetermined operation of the kitchen remote controller 32A or the bathroom remote controller 33A), executes control processing (control processing in the operation mode for the first hot water filling operation) as shown in the flowchart of FIG. 2. Note that the first hot water filling operation is a hot water filling operation started with the bathtub BT being empty.

[0050] In the first hot water filling operation, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the hot water filling operation (the first hot water filling operation) in STEP1. And the control device 31A executes the control processing of STEP2 to 20 regarding the operation control of the main water heater 2A.

[0051] Also, upon receiving a notification of the start of warm-up operation (the first warm-up operation) from the control device 31A of the main water heater 2A, the control device 31B of the auxiliary water heater 2B executes control processing (control processing in the operation mode for the first warm-up operation) as shown in the flowchart of FIG. 3. In this case, first, in STEP1a, the control device 31B of the auxiliary water heater 2B performs opening control of the water supply amount adjustment valve 16 of the heat source machine 3 of the auxiliary water heater 2B, and then executes the control processing of STEP2 to 20a regarding the operation control of the auxiliary water heater 2B. In this case, the control processing of STEP2 to 19 shown in FIGS. 2 and 3 is control processing separately executed by the main water heater 2A and the auxiliary water heater 2B, but is control processing of the same content for the main water heater 2A and the auxiliary water heater 2B.

[0052] In STEP2, the control device 31 of each water heater 2 operates the heat source machine 3 of each water heater 2 so as to pour a predetermined amount V0 (for example, 6 liters) of hot water into the bathtub BT. Specifically, in the main water heater 2A, the control device 31A performs opening control of the hot water pouring solenoid valve 23 and starts the operation of the first heating unit 11 (heating of the hot water for supplying hot water). Then, the control device 31A controls the heating amount of the first heating unit 11 so that the temperature of the hot water for supplying hot water (hot water pouring temperature) detected by the temperature sensor 18 matches or substantially matches the set temperature, which is the target value of the bathtub temperature preset by the bathroom remote control 33A.

[0053] Also, from the start of pouring a predetermined amount V0 of hot water, the control device 31A sequentially integrates the hot water pouring flow rate (the flow rate of the hot water for supplying hot water to the bathtub BT) detected by the flow rate sensor 24 in the hot water pouring water channel 15, and when the integrated value reaches the predetermined amount V0, performs closing control of the hot water pouring solenoid valve 23 and stops the operation of the first heating unit 11. As a result, in the main water heater 2A, a predetermined amount V0 of hot water is poured into the bathtub BT. Here, the predetermined amount V0 of hot water is the so-called calling water, and by pouring the predetermined amount V0 of hot water, the water channel near the pump 19 in the circulation water channel 14 of the main water heater 2 is filled with the hot water for supplying hot water.

[0054] In the auxiliary water heater 2B as well, pouring of hot water in a predetermined amount V0 is performed in the same manner as in the main water heater 2A. As a result, pouring of hot water in the predetermined amount V0 is performed in parallel in each of the main water heater 2A and the auxiliary water heater 2B. In this case, the set temperature of the bath water temperature for controlling the heating amount of the first heating unit 11 of the auxiliary water heater 2B is notified from the control device 31A of the main water heater 2A to the control device 31B of the auxiliary water heater 2B.

[0055] When the pouring of hot water in the predetermined amount V0 in each water heater 2 is completed, the control device 31 of the water heater 2 then repeats the processes of STEP3 to 5 until the determination result in STEP5 becomes affirmative. In this case, in the main water heater 2A, in STEP3, the control device 31A operates the heat source machine 3 of the main water heater 2A so as to pour hot water in a predetermined amount V1 (for example, 10 liters) into the bathtub BT. Pouring of hot water in this predetermined amount V1 is performed in the same manner as pouring of hot water in the predetermined amount V0 in STEP2.

[0056] Then, when the pouring of hot water in the predetermined amount V1 is completed, the control device 31A performs a water flow check in the circulation water path 14 of the main water heater 2A in STEP4. Specifically, the control device 31A operates the pump 19 for a predetermined time, and during the operation, based on the output signal of the water flow switch 21 (a detection signal indicating the presence or absence of water flow), it checks whether continuous water flow occurs in the circulation water path 14.

[0057] Then, after the operation of the pump 19 stops, the control device 31A then determines in STEP5 whether pouring into the bathtub BT has ended up to the water level equal to or higher than the height of the hot water pouring port Ba corresponding to the main water heater 2A (specifically, the water level slightly above the hot water pouring port Ba) based on the water flow check result in STEP4. And if this determination result is negative, the control device 31A repeats the processes from STEP3 (pouring of hot water in the predetermined amount V1 and the subsequent water flow check). For the auxiliary water heater 2B as well, the processes of STEP3 to 5 are repeated in the same manner as in the main water heater 2A.

[0058] Here, by repeatedly pouring a predetermined amount V1 of hot water in each of the main water heater 2A and the auxiliary water heater 2B, the water level of the bath water in the bathtub BT eventually reaches a water level above the water injection port Ba corresponding to each of the main water heater 2A and the auxiliary water heater 2B (the water level at which the water injection port Ba is submerged in the bath water in the bathtub BT). And in this state, since almost the entire circulation water passage 14 of each of the main water heater 2A and the auxiliary water heater 2B is filled with bath water, in STEP4, the generation of a continuous water flow is confirmed during the operation of the pump 19.

[0059] In this embodiment, in STEP5, in order to repeatedly pour a predetermined amount V1 of hot water until the water level in the bathtub BT surely reaches a water level above the water injection port Ba, the control device 31A of the main water heater 2A determines whether, for example, the generation of a continuous water flow in the circulation water passage 14 of the main water heater 2A is confirmed twice continuously after pouring a predetermined amount V1 of hot water. That is, the control device 31A determines whether the generation of a continuous water flow in the circulation water passage 14 of the main water heater 2A is confirmed during the operation of the pump 19 after pouring a predetermined amount V1 of hot water at a certain number of times and after pouring a predetermined amount V1 of hot water at the next number of times.

[0060] And when the generation of a continuous water flow is confirmed twice continuously after pouring a predetermined amount V1 of hot water, the control device 31A determines in STEP5 that the pouring of hot water into the bathtub BT has ended up to a water level equal to or higher than the height of the water injection port Ba corresponding to the main water heater 2A in the bathtub BT (decides that the judgment result of STEP5 is affirmative). The same applies to the auxiliary water heater 2B.

[0061] However, even if the generation of a continuous water flow is not confirmed after the previous pouring of hot water, when the generation of a continuous water flow is confirmed after pouring a predetermined amount V1 of hot water at a certain number of times, the control device 31 of each water heater 2 may immediately determine in STEP5 that the pouring of hot water into the bathtub BT has ended up to a water level equal to or higher than the height of the water injection port Ba corresponding to the main water heater 2A in the bathtub BT (decide that the judgment result of STEP5 is affirmative).

[0062] Supplementary note: In each water heater 2, the predetermined amount V1 of hot water poured into the bathtub BT in STEP3 may be changed according to, for example, the number of times of hot water pouring in STEP3. For example, after the generation of continuous water flow is confirmed for the first time in STEP4, the predetermined amount V1 of hot water poured in the next STEP3 may be made larger than the predetermined amount V1 of hot water poured in the previous STEP3.

[0063] In each water heater 2, when the judgment result in STEP5 is affirmative, the control device 31 of each water heater 2 then sequentially repeats in STEP6 to judge whether the hot water pouring up to the water level above the height of the hot water pouring port Ba corresponding to each water heater 2 has ended in all the water heaters 2A and 2B until the judgment result becomes affirmative.

[0064] This judgment is made through communication between the control devices 31 of each water heater 2. For example, when the control device 31A of the main water heater 2A has completed the processing of STEP3 to 5 in the main water heater 2A and has received a notice from the control device 31B of another water heater 2B (auxiliary water heater 2B) indicating that the processing of STEP3 to 5 has been completed, it is determined that the hot water pouring up to the water level above the height of the hot water pouring port Ba corresponding to each water heater 2 has ended in all the water heaters 2A and 2B (it is determined that the judgment result in STEP6 is affirmative). In this case, the notice indicating that the processing of STEP3 to 5 has been completed in the auxiliary water heater 2B is transmitted from the control device 31B to the control device 31A at a predetermined timing such as in response to a request from the control device 31A of the main water heater 2A to the control device 31B of the auxiliary water heater 2B or immediately after the completion of the processing of STEP3 to 5 in the auxiliary water heater 2B. The judgment process of STEP6 in the auxiliary water heater 2B is also performed in the same manner as above.

[0065] Supplementary note: If the number of times of pouring hot water of the predetermined amount V1 exceeds the predetermined upper limit number of times in either or both of the main water heater 2A and the auxiliary water heater 2B, there may be a possibility that the bathtub water in the bathtub BT leaks from the drain port or the like. Therefore, in this case, the hot water pouring operation is stopped in all the water heaters 2A and 2B.

[0066] In each water heater 2, when the determination result in STEP6 is affirmative, the control device 31 of each water heater 2 executes the processes in STEP7 to 9. In the main water heater 2A, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 in STEP7 and calculates the current amount of bathtub water in the bathtub BT.

[0067] In this case, since the detection of the water level by the water level sensor 22 is performed in a state where the pouring of water into the bathtub BT in all the water heaters 2A and 2B has stopped, the water level can be detected in a static state of the bathtub water in the bathtub BT. Therefore, a highly reliable water level detection value can be obtained.

[0068] Also, in the main water heater 2A, the current amount of bathtub water in the bathtub BT calculated in STEP7 is, more specifically, the amount of water poured by the main water heater 2A (the amount of bathtub water for the portion in charge of the main water heater 2A) among the actual amount of bathtub water in the bathtub BT. And this amount of bathtub water is calculated based on the amount of water poured by the main water heater 2A.

[0069] Specifically, the control device 31A of the main water heater 2A calculates the total amount of water poured, which is the sum of the amount of water poured in STEP2 (=predetermined amount V0) in the main water heater 2A and the amount of water poured by repeating STEP3 (=predetermined amount V1×number of repetitions), as the current amount of bathtub water in the bathtub BT (the amount of bathtub water for the portion in charge of the main water heater 2A). In other words, the control device 31A calculates the amount of bathtub water in the bathtub BT by assuming that the pouring of water into the bathtub BT is carried out only by the main water heater 2A. Therefore, the amount of bathtub water calculated by the control device 31A in STEP7 is the amount of water obtained by excluding the amount of water poured by the other water heater 2B (auxiliary water heater 2B) from the actual amount of bathtub water in the bathtub BT.

[0070] Next, in STEP8, the control device 31A of the main water heater 2A stores the water level detected in STEP7 as the reference water level H0 of the bathtub BT and stores the amount of bathtub water calculated in STEP7 as the reference amount of bathtub water W0 of the bathtub BT.

[0071] Next, in STEP9, the control device 31A of the main water heater 2A operates the heat source machine 3 of the main water heater 2A so as to pour a predetermined amount V2 (for example, 40 liters) of hot water into the bathtub BT. The pouring of this predetermined amount V2 of hot water is performed in the same manner as the pouring of the predetermined amount V0 of hot water in STEP2.

[0072] Also in the auxiliary water heater 2B, the processes of STEP7 to 9 are executed by the control device 31B in the same manner as in the main water heater 2A. In this case, in STEP7, the control device 31B calculates the current amount of water in the bathtub (the amount of water in the bathtub for which the auxiliary water heater 2B is responsible), assuming that the pouring of hot water into the bathtub BT is carried out only by the auxiliary water heater 2B.

[0073] Next, in STEP10, the control device 31 of each water heater 2 sequentially repeats determining whether the pouring of the predetermined amount V2 of hot water has ended in all the water heaters 2A and 2B until the determination result becomes affirmative.

[0074] This determination is made through communication between the control devices 31 of each water heater 2 in the same manner as in STEP6. That is, the control device 31A of the main water heater 2A determines that the pouring of the predetermined amount V2 of hot water has ended in all the water heaters 2A and 2B (decides that the determination result in STEP10 is affirmative) when the process of STEP9 in the main water heater 2A is completed and a notification indicating that the process of STEP9 has ended is received from the control device 31B of the other water heater (auxiliary water heater 2B). The same applies to the auxiliary water heater 2B.

[0075] When the determination result in STEP10 becomes affirmative in each water heater 2, the control device 31 of each water heater 2 executes the processes of STEP11 and 12. In the main water heater 2A, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 in STEP11. In this case, since the detection of the water level by the water level sensor 22 is performed in a state where the pouring of hot water into the bathtub BT by all the water heaters 2A and 2B has stopped, a highly reliable water level detection value can be obtained in the same manner as in the case of STEP7.

[0076] In STEP11, the control device 31A further calculates and stores the bathtub reference cross-sectional area WH as the cross-sectional area of the bathtub BT near the height of the reference water level H0, and further calculates the shortage hot water volume V3 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs, which is the target value of the water level preset by the bathroom remote control 33A.

[0077] Here, the bathtub reference cross-sectional area WH is calculated by the following formula (1) from the reference water level H0 stored in STEP8, the current water level Hnow detected in STEP11, and the predetermined volume V2 of hot water poured in STEP9. WH = V2 / (Hnow - H0) ……(1)

[0078] Therefore, the control device 31A calculates the bathtub reference cross-sectional area WH assuming that only the main water heater 2A has poured the hot water of the predetermined volume V2 into the bathtub BT (assuming that no hot water of the predetermined volume V2 has been poured by the other water heater 2B (auxiliary water heater 2B)). The bathtub reference cross-sectional area WH calculated in this way is a cross-sectional area smaller than the actual cross-sectional area of the bathtub BT.

[0079] Also, the shortage hot water volume V3 is calculated by the following formula (2) from the current water level Hnow (the detected value in STEP11), the bathtub reference cross-sectional area WH, and the set water level Hs, assuming that the cross-sectional area of the bathtub BT at a height above the reference water level H0 is a constant value that matches the bathtub reference cross-sectional area WH calculated as described above. V3 = WH × (Hs - Hnow) ……(2)

[0080] In this case, since the bathtub reference cross-sectional area WH is smaller than the actual cross-sectional area, the shortage hot water volume V3 calculated by formula (2) is the amount of hot water corresponding to the share borne by the main water heater 2A among the actual shortage hot water volume (the shortage hot water volume when assuming that the cross-sectional area of the bathtub BT at a height above the reference water level H0 is constant).

[0081] Next, in STEP12, the control device 31A of the main water heater 2A activates the heat source unit 3 of the main water heater 2A so as to pour the hot water corresponding to the insufficient hot water volume V3 calculated in STEP11 into the bathtub BT. The pouring of the hot water corresponding to this insufficient hot water volume V3 is performed in the same manner as the pouring of the predetermined amount V0 of hot water in STEP2.

[0082] Also in the auxiliary water heater 2B, the processes of STEP11 and 12 are executed by the control device 31B in the same manner as in the main water heater 2A. In this case, in STEP11, the control device 31B calculates the bathtub reference cross-sectional area WH by regarding the pouring of the predetermined amount V2 of hot water into the bathtub BT as being performed only by the auxiliary water heater 2B, and calculates the insufficient hot water volume V3 (the insufficient hot water volume for the share borne by the auxiliary water heater 2B) using this bathtub reference cross-sectional area WH. The set water level Hs used for calculating the insufficient hot water volume V3 in the control device 31B is notified from the control device 31A of the main water heater 2A to the control device 31B of the auxiliary water heater 2B.

[0083] Next, in STEP13, the control device 31 of each water heater 2 sequentially repeats determining whether the pouring of the hot water corresponding to the insufficient hot water volume V3 has ended for all the water heaters 2A and 2B until the determination result becomes affirmative.

[0084] This determination is made through communication between the control devices 31 of each water heater 2 in the same manner as in STEP6. That is, the control device 31A of the main water heater 2A determines that the pouring of the hot water corresponding to the insufficient hot water volume V3 has ended for all the water heaters 2A and 2B (decides that the determination result of STEP13 is affirmative) when the process of STEP12 in the main water heater 2A is completed and a notification indicating that the process of STEP12 has ended is received from the control device 31B of the other water heater (auxiliary water heater 2B). The same applies to the auxiliary water heater 2B.

[0085] In each water heater 2, when the determination result in STEP13 is affirmative, the control device 31 of each water heater 2 executes the processes of STEP14 and 15. In the main water heater 2A, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 in STEP14. In this case, since the detection of the water level by the water level sensor 22 is performed in a state where the pouring of water into the bathtub BT has stopped in all the water heaters 2A and 2B, a highly reliable water level detection value can be obtained as in the case of STEP7.

[0086] In STEP14, the control device 31A further calculates and stores the bathtub cross-sectional area increase rate ΔWH, which is the increase amount per unit height of the cross-sectional area of the bathtub BT at a height above the reference water level H0, and further calculates the shortage water volume V4 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs.

[0087] Here, the bathtub cross-sectional area increase rate ΔWH is calculated by the following formula (3) from the reference water level H0 stored in STEP8, the current water level Hnow detected in STEP14, the bathtub reference cross-sectional area WH calculated in STEP11, and the set water level Hs. ΔWH = 2×WH×(Hs - Hnow) / (Hnow - H0) 2 ……(3)

[0088] Also, the shortage water volume V4 is calculated by the following formulas (4a) and (4b) from the set water level Hs, the current water level Hnow (detection value), the reference bathtub water level H0, the bathtub reference cross-sectional area WH, and the bathtub cross-sectional area increase rate ΔWH, assuming that the cross-sectional area of the bathtub BT at a height above the reference water level H0 increases from the bathtub reference cross-sectional area WH at a constant bathtub cross-sectional area increase rate ΔWH calculated as above. V4 = (Hs - Hnow)×average cross-sectional area ……(4a) average cross-sectional area = WH + ((Hs - Hnow) / 2 + (Hnow - H0))×ΔWH ……(4b) Note that the above average cross-sectional area is the average value of the cross-sectional area of the bathtub BT between the current water level Hnow and the set water level Hs.

[0089] As described above, by calculating the bathtub cross-sectional area increase rate ΔWH, the hot water injection of the insufficient hot water volume V3 into the bathtub BT in STEP12 is regarded as being carried out only by the main water heater 2A, and the bathtub cross-sectional area increase rate ΔWH is calculated. Then, by calculating the insufficient hot water volume V4 using this bathtub cross-sectional area increase rate ΔWH, the insufficient hot water volume V4 corresponds to the amount of hot water that is the share of the burden of the main water heater 2A among the actual insufficient hot water volume required to increase the water level in the bathtub BT from the current water level Hnow to the set water level Hs.

[0090] As a supplement, in the present embodiment, in each water heater 2, the reference water level H0 and the reference bathtub water volume W0 stored in STEP8, the reference bathtub cross-sectional area WH stored in STEP11, and the bathtub cross-sectional area increase rate ΔWH stored in STEP14 correspond to bathtub characteristic data regarding the relationship between the hot water injection amount into the bathtub BT and the water level of the bathtub BT (bathtub characteristic data for each water heater 2).

[0091] Next, in STEP15, the control device 31A of the main water heater 2A operates the heat source machine 3 of the main water heater 2A so as to inject the hot water of the insufficient hot water volume V4 calculated in STEP14 into the bathtub BT. The injection of the hot water of this insufficient hot water volume V4 is performed in the same manner as the injection of the hot water of the predetermined volume V0 in STEP2.

[0092] Also in the auxiliary water heater 2B, the processes of STEP14 and 15 are executed by the control device 31B in the same manner as the main water heater 2A. In this case, in STEP14, the control device 31B calculates the bathtub cross-sectional area increase rate ΔWH by regarding the injection of the insufficient hot water volume V3 into the bathtub BT in STEP12 as being carried out only by the auxiliary water heater 2B, and calculates the insufficient hot water volume V4 using this bathtub cross-sectional area increase rate ΔWH. The insufficient hot water volume V4 corresponds to the amount of hot water that is the share of the burden of the auxiliary water heater 2B among the actual insufficient hot water volume required to increase the water level in the bathtub BT from the current water level Hnow to the set water level Hs.

[0093] Next, the control device 31 of each water heater 2 sequentially repeats, in STEP16, determining whether the pouring of hot water with the shortage hot water volume V4 has ended in all the water heaters 2A and 2B until the determination result becomes affirmative.

[0094] This determination is made through communication between the control devices 31 of each water heater 2 in the same manner as in STEP6. That is, the control device 31A of the main water heater 2A determines that the pouring of hot water with the shortage hot water volume V4 has ended in all the water heaters 2A and 2B (decides that the determination result in STEP16 is affirmative) when the processing in STEP15 in the main water heater 2A is completed and the control device 31A of the main water heater 2A can receive a notification indicating that the processing in STEP15 has ended from the control device 31B of the other water heater (auxiliary water heater 2B). The same applies to the auxiliary water heater 2B.

[0095] When the determination result in STEP16 becomes affirmative in each water heater 2, the control device 31 of each water heater 2 executes the processing from STEP17. In the main water heater 2A, the control device 31A determines, in STEP17, whether the bath temperature (the temperature of the bath water in the bathtub BT) detected by the temperature sensor 20 is equal to or higher than the set temperature. When the determination result in STEP17 is negative (when the bath temperature (detected value) < the set temperature), the control device 31A operates the heat source machine 3 of the main water heater 2A to boil the bath water in STEP18 until the determination result in STEP17 becomes affirmative.

[0096] Specifically, in STEP18, the control device 31A starts the operation of the second heating unit 13 (heating of the bath water) while operating the pump 19. Then, the control device 31A controls so that the heating amount of the second heating unit 13 becomes a predetermined heating amount. Thereby, in the main water heater 2A, the bath water is boiled. The above-mentioned predetermined heating amount may be a constant heating amount, or may be changed stepwise according to, for example, the detected value of the bath temperature.

[0097] Also in the auxiliary water heater 2B, similar to the main water heater 2A, by the processes of STEP17 and 18, the boiling of the bathtub water is carried out until the detected value of the bath temperature becomes equal to or higher than the set temperature. In this case, the set temperature of the bath temperature is notified from the control device 31A of the main water heater 2A to the control device 31B of the auxiliary water heater 2B.

[0098] In each water heater 2, when the determination result of STEP17 is affirmative, the control device 31 of each water heater 2 stops the operation of the pump 19 and the second heating unit 13 of each water heater 2 to end the boiling of the bathtub water, and then, in STEP19, sequentially repeats determining whether the bath temperature has become "OK" in all the water heaters 2A and 2B (specifically, whether the detected value of the bath temperature has become equal to or higher than the set temperature) until the determination result becomes affirmative.

[0099] This determination is made through communication between the control devices 31 of each water heater 2, similar to STEP6 and the like. That is, the control device 31A of the main water heater 2A determines that the bath temperature is "OK" in all the water heaters 2A and 2B when the boiling of the bathtub water in the main water heater 2A ends and it can receive a notification from the control device 31B of the other water heater (auxiliary water heater 2B) indicating that the boiling of the bathtub water has ended. The same applies to the auxiliary water heater 2B.

[0100] Then, in the main water heater 2A, when the determination result of STEP19 is affirmative, the control device 31A of the main water heater 2A causes the kitchen remote controller 32A and the bathroom remote controller 33A of the main water heater 2A to give a notification indicating that the hot water supply has been completed in STEP20. This notification is made by outputting display information or voice information on the kitchen remote controller 32A and the bathroom remote controller 33A.

[0101] Also, in the auxiliary water heater 2B, when the determination result in STEP19 is affirmative, the control device 31B of the auxiliary water heater 2B causes the kitchen remote controller 32B of the auxiliary water heater 2B to give a notification indicating that the water filling has been completed in STEP20a. This notification is made by the display information on the kitchen remote controller 32B or the output of voice information. Further, in STEP20a, the control device 31B closes the water supply amount adjustment valve 16 of the auxiliary water heater 2B.

[0102] Here, since the notifications indicating the completion of water filling in each water heater 2 are made when the boiling of the bathtub water is completed in all the water heaters 2A and 2B, it is possible to give notifications indicating the completion of water filling almost simultaneously in the main water heater 2A and the auxiliary water heater 2B. In the bathtub system 1 of the present embodiment, the first water filling operation (the water filling operation in the operation mode for the first water filling operation) is performed as described above.

[0103] Next, the operations related to the water filling operations after the first water filling operation (hereinafter referred to as normal water filling operations) will be described. When the control device 31A of the main water heater 2A is instructed to start the water filling operation as described above, if the water filling operation is a normal water filling operation after the first water filling operation (specifically, a water filling operation in a state where the execution of the water filling operation in the operation mode for the first water filling operation is not specified), it executes control processing (control processing for normal water filling operations) as shown in the flowchart of FIG. 4. Note that in the normal water filling operation, the bathtub BT is not necessarily empty at the start, and there may be bathtub water already present in the bathtub BT.

[0104] In the normal water filling operation, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the water filling operation (normal water filling operation) in STEP31. Then, the control device 31A executes the control processing of STE32 to 47 regarding the operation control of the main water heater 2A.

[0105] Also, upon receiving a notification of the start of normal hot water supply operation from the control device 31A of the main water heater 2A, the control device 31B of the auxiliary water heater 2B executes control processing (control processing for normal hot water supply operation) as shown in the flowchart of FIG. 5. In this case, the control device 31B of the auxiliary water heater 2B first performs opening control of the water supply amount adjustment valve 16 of the heat source machine 3 of the auxiliary water heater 2B in STEP31a, and then executes the control processing of STEP32 to 47a regarding the operation control of the auxiliary water heater 2B. In this case, the control processing of STEP32 to 46 shown in FIGS. 4 and 5 is control processing separately executed by the main water heater 2A and the auxiliary water heater 2B, but is control processing with the same content for the main water heater 2A and the auxiliary water heater 2B.

[0106] In STEP32, the control device 31 of each water heater 2 operates the heat source machine 3 of each water heater 2 so as to pour a predetermined amount V0 (for example, 6 liters) of hot water as call water into the bathtub BT. This process is the same as the process of STEP2 in the first hot water supply operation.

[0107] Next, the control device 31 of each water heater 2 checks the water flow in the circulation water path 14 of each water heater 2 in STEP33. This water flow check is performed in the same manner as STEP4 in the first hot water supply operation.

[0108] Next, the control device 31 of each water heater 2 determines in STEP34 whether or not the generation of water flow (continuous generation of water flow) is detected by the water flow switch 21 during the operation of the pump 19 based on the water flow check in STEP33. Here, if there is already remaining hot water, which is bathtub water with a water level equal to or higher than the reference water level H0 in the bathtub BT, the determination result in STEP34 is affirmative.

[0109] And when the determination result in STEP34 is affirmative, the control device 31 of each water heater then sequentially repeats in STEP35 to determine whether or not the pouring of the predetermined amount V0 has ended for all the water heaters 2A and 2B until the determination result becomes affirmative.

[0110] This determination is made through communication between the control devices 31 of each water heater 2, similar to STEP6 in the initial water filling operation. That is, the control device 31A of the main water heater 2A finishes the processes of STEP32 and 33 in the main water heater 2A and, when it can receive information indicating that the processes of STEP32 and 33 have been completed from the control device 31B of another water heater (auxiliary water heater 2B), it determines that the pouring of hot water of a predetermined amount V0 has ended in all water heaters 2A and 2B (decides that the determination result of STEP35 is affirmative). The same applies to the auxiliary water heater 2B. Then, when the determination result of STEP35 becomes affirmative, the control device 31 of each water heater 2 executes the processes starting from STEP41 described later.

[0111] On the other hand, when the determination result of STEP34 is negative, that is, when there is no remaining hot water in the bathtub BT (including the case where bathtub water exists at a level lower than the pouring port Ba in the bathtub BT), in the next STEP36, the heat source machine 3 of each water heater 2 is operated to pour hot water into the bathtub BT in an amount obtained by adding a predetermined amount ΔV to the reference bathtub water volume W0 (reference bathtub water volume W0 for each water heater 2) memorized during the initial water filling operation.

[0112] In this case, the predetermined amount ΔV is calculated as the amount of water required to increase the bathtub water level from the reference water level H0 to a water level that is a predetermined value ΔH (for example, 5 cm) higher. The predetermined amount ΔV is calculated from the bathtub reference cross-sectional area WH and the bathtub cross-sectional area increase rate ΔWH memorized and held during the initial water filling operation for each water heater 2 and the water level difference of the above-mentioned predetermined value ΔH. Specifically, for each water heater 2, ΔV is calculated by a formula in which Hs and Hnow in the formulas (4a) and (4b) are replaced with H0 + ΔH and H0, respectively. Note that the predetermined amount ΔV calculated in this way corresponds to the amount of water for the share of the burden of each water heater 2 among the amount of water actually required to increase the bathtub water level in the bathtub BT from the reference water level H0 to a water level that is a predetermined value ΔH higher.

[0113] Then, the pouring of hot water in the amount of W0+ΔV in each water heater 2 is carried out in the same manner as the pouring of a predetermined amount V0 of hot water in STEP2 during the first hot water filling operation. As a supplement, the predetermined amount ΔV may be a fixed value determined in advance, or may be a value determined by a map or the like from the bathtub reference cross-sectional area WH, for example.

[0114] When the control device 31 of each water heater 2 finishes the hot water pouring in STEP36, next, in STEP37, it determines whether or not the pouring of hot water in the amount of W0+ΔV has been completed in all the water heaters 2A and 2B. This determination is made through communication between the control devices 31 of each water heater 2 in the same manner as in STEP6 or the like during the first hot water filling operation. That is, the control device 31A of the main water heater 2A finishes the process of STEP36 in the main water heater 2A, and when it can receive a notification from the control device 31B of another water heater (auxiliary water heater 2B) indicating that the process of STEP36 has been completed, it determines that the pouring of hot water in the amount of W0+ΔV has been completed in all the water heaters 2A and 2B (decides that the determination result of STEP37 is affirmative). The same applies to the auxiliary water heater 2B.

[0115] When the determination result of STEP37 becomes affirmative in each water heater 2, the control device 31 of each water heater 2 performs a water flow check in the circulation water path 14 of each water heater 2 in STEP38. This water flow check is carried out in the same manner as in STEP4 during the first hot water filling operation.

[0116] Next, the control device 31 of each water heater 2 determines in STEP39 whether or not the generation of continuous water flow during the operation of the pump 19 has been detected by the water flow check in STEP38 in all the water heaters 2A and 2B.

[0117] This determination is made based on the result of water flow confirmation in each water heater 2 and the communication between the control device 31 of each water heater 2. That is, the control device 31 of the main water heater 2A detects the generation of continuous water flow during the operation of the pump 19 through the water flow confirmation in STEP38 in the main water heater 2A, and when it can receive a notification indicating that the generation of continuous water flow during the operation of the pump 19 has been detected from the control device 31B of the other water heater 2B (auxiliary water heater 2B), it determines that continuous water flow has been detected in all water heaters 2A and 2B (decides that the determination result of STEP39 is affirmative). When the determination result of STEP39 is affirmative, the control device 31 of each water heater 2 executes the processing starting from STEP41 described later.

[0118] Here, by performing the hot water injection in STEP36 in each water heater 2, when the hot water injection has ended in all water heaters 2A and 2B, the water level in the bathtub BT basically becomes higher than the reference water level H0.

[0119] Therefore, basically, the determination result of STEP39 becomes affirmative in each water heater 2. However, when the bathtub water is leaking from the drain outlet or the like of the bathtub BT, in one or more water heaters 2, the water level in the bathtub BT may be lower than the hot water injection port Ba. In such a case, the determination result of STEP39 becomes negative. And when the determination result of STEP39 becomes negative, the control device 31 of each water heater 2 executes, in STEP40, to error-stop each water heater 2 (stop the hot water supply operation of each water heater 2 in response to the occurrence of an abnormality).

[0120] When the determination result of STEP35 is affirmative or the determination result of STEP39 is affirmative, the control device 31 of each water heater 2 then executes the processing of STEP41 and 42. In the main water heater 2, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 in STEP41. In this case, since the detection of the water level by the water level sensor 22 is performed in a state where the hot water injection into the bathtub BT in all water heaters 2A and 2B has stopped, a highly reliable water level detection value can be obtained.

[0121] In STEP41, the control device 31A further calculates the insufficient hot water volume V5 required to increase the water level of the bath water in the bathtub BT from the current water level to the set water level Hs. In this case, the insufficient hot water volume V5 is calculated by the same calculation as the above formulas (4a) and (4b) using the bathtub reference cross-sectional area WH in the main water heater 2A and the bathtub cross-sectional area increase rate ΔWH. Therefore, the insufficient hot water volume V5 corresponds to the amount of water that is the share of the main water heater 2A among the actual insufficient hot water volume required to increase the water level of the bath water in the bathtub BT from the current water level to the set water level Hs.

[0122] Next, in STEP42, the control device 31A of the main water heater 2A operates the heat source machine 3 of the main water heater 2A so as to pour the hot water of the insufficient hot water volume V5 calculated in STEP41 into the bathtub BT. The pouring of the hot water of this insufficient hot water volume V5 is performed in the same manner as the pouring of the predetermined amount V0 of hot water in STEP2 in the first hot water filling operation.

[0123] Also in the auxiliary water heater 2B, the processes of STE41 and 42 are executed by the control device 31B in the same manner as in the main water heater 2A. In this case, in STEP41, the control device 31B calculates the insufficient hot water volume V5 by the same calculation as the above formulas (4a) and (4b) using the bathtub reference cross-sectional area WH in the auxiliary water heater 2B and the bathtub cross-sectional area increase rate ΔWH. The insufficient hot water volume V5 corresponds to the amount of water that is the share of the auxiliary water heater 2B among the actual insufficient hot water volume required to increase the water level of the bath water in the bathtub BT from the current water level to the set water level Hs.

[0124] Next, in STEP43, the control device 31 of each water heater 2 sequentially repeats determining whether or not the pouring of the hot water of the insufficient hot water volume V5 has ended in all the water heaters 2A and 2B until the determination result becomes affirmative.

[0125] This determination is made through communication between the control devices 31 of each water heater 2, similar to STEP6 etc. in the initial water filling operation. That is, the control device 31A of the main water heater 2A finishes the process of STEP42 in the main water heater 2A and, when it can receive a notification from the control device 31B of another water heater (auxiliary water heater 2B) indicating that the process of STEP42 has been completed, determines that the pouring of hot water with the insufficient hot water volume V5 has ended in all water heaters 2A and 2B (decides that the determination result of STEP43 is affirmative). The same applies to the auxiliary water heater 2B.

[0126] Here, since the insufficient hot water volume V5 is determined in each water heater 2 as described above, when the pouring of hot water with the insufficient hot water volume V5 in all water heaters 2A and 2B ends (when the determination result of STEP43 becomes affirmative), the water level in the bathtub BT reaches the set water level Hs.

[0127] When the determination result of STEP43 becomes affirmative in each water heater 2, the control device 31 of each water heater 2 executes the process from STEP44. In the main water heater 2A, the control device 31A executes the same processes as STEP17 - 20 in the initial water filling operation in STEP44 - 47. Thereby, the boiling of the bathtub water in the bathtub BT and the notification indicating the completion of water filling are performed by the main water heater 2A.

[0128] Also, in the auxiliary water heater 2B, the control device 31B executes the same processes as STEP17 - 20a in the initial water filling operation in STEP44 - 47a. Thereby, the boiling of the bathtub water in the bathtub BT and the notification indicating the completion of water filling are performed by the auxiliary water heater 2B, and furthermore, the water supply adjustment valve 16 of the auxiliary water heater 2B is finally controlled to close. Note that the notification indicating the completion of water filling is performed almost simultaneously by the main water heater 2A and the auxiliary water heater 2B, similar to the case of the initial water filling operation.

[0129] In the bathtub system 1 of the present embodiment, the normal hot water filling operation after the execution of the first hot water filling operation is performed as described above. To supplement, the entire control process of the control devices 31A and 31B in the normal hot water filling operation corresponds to the hot water filling operation process in the present invention. And the process of STEP36 (hot water pouring process of W0 + ΔV) in each water heater 2 corresponds to the first process in the present invention, the process of STEP41 (water level detection process) in each water heater 2 corresponds to the second process in the present invention, and the process of STEP42 (hot water pouring process of V5) in each water heater 2 corresponds to the third process in the present invention.

[0130] According to the first embodiment described above, in either the first hot water filling operation or the normal hot water filling operation, the water level detection in each water heater 2 is performed in a state where the hot water pouring into the bathtub BT by each water heater 2 has stopped in all the water heaters 2A and 2B. Therefore, a highly reliable water level detection value (a highly accurate detection value) can be obtained. As a result, it is possible to appropriately realize pouring hot water into the bathtub BT up to the set water level Hs after the detection of the water level, and the water level in the bathtub BT at the end of the hot water filling operation can be made to coincide with or almost coincide with the set water level Hs with high reliability.

[0131] Also, in either the first hot water filling operation or the normal hot water filling operation, the operation control of the plurality of water heaters 2A and 2B is executed by control processes with substantially the same content for the main water heater 2A and the auxiliary water heater B. For this reason, most of the specifications of each water heater 2 constituting the bathtub system 1 can be made common, and thus the development cost and manufacturing cost of the bathtub system 1 can be reduced. In addition, each water heater 2 constituting the bathtub system 1 can also be easily manufactured from an existing water heater 2 that performs hot water pouring into the bathtub alone.

[0132] [Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. 1 and 6 to 10. Note that since only the control process by the control device of each water heater 2 is different from that of the first embodiment in the present embodiment, the description of the same matters as those in the first embodiment will be omitted.

[0133] In this embodiment, the control device 31A of the main water heater 2A is instructed to start the hot water supply operation in the same manner as in the first embodiment. At this time, when the hot water supply operation for which the start is instructed is the first hot water supply operation (specifically, when performing the hot water supply operation in the operation mode for the first hot water supply operation has been previously specified by a predetermined operation of the kitchen remote controller 32A or the bathroom remote controller 33A), the control process (control process in the operation mode for the first hot water supply operation) shown in the flowcharts of FIGS. 6 and 7 is executed.

[0134] In this case, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the hot water supply operation (first hot water supply operation) in STEP51. Then, the control device 31A executes the control processes of STEP52 to 78 regarding the operation control of the main water heater 2A.

[0135] Also, the control device 31B of the auxiliary water heater 2B that has received the notification of the start of the hot water supply operation (first hot water supply operation) from the control device 31A of the main water heater 2A executes the control process (control process in the operation mode for the first hot water supply operation) shown in the flowchart of FIG. 8. In this case, in this embodiment, the control device 31B of the auxiliary water heater 2B first performs opening valve control on the water supply amount adjustment valve 16 of the heat source machine 3 of the auxiliary water heater 2B in STEP81, and then executes the control processes of STEP82 to 105 regarding the operation control of the auxiliary water heater 2B. Also, in this embodiment, the control process of the control device 31B of the auxiliary water heater 2B is executed according to an instruction from the control device 31A of the main water heater 2A.

[0136] In the main water heater 2A, in STEP52 following STEP51, the control device 31A operates the heat source machine 3 of the main water heater 2A so as to pour a predetermined amount V0 (for example, 6 liters) of hot water as call water into the bathtub BT. The pouring of this predetermined amount V0 of hot water is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0137] In STEP52, the control device 31A further measures the pouring flow rate of hot water of a predetermined amount V0 through the flow rate sensor 24 in the hot water pouring water channel 15 of the water heater 2A when pouring the hot water. For example, the control device 31A obtains, as the measured value of the pouring flow rate in the water heater 2A, the average value of the flow rates sequentially detected by the flow rate sensor 24 during the entire period or a part of the period when pouring the hot water of the predetermined amount V0.

[0138] In the auxiliary water heater 2B, in STEP82 following STEP81, the control device 31B performs the pouring of hot water of a predetermined amount V0 as the called water and the measurement of the pouring flow rate in the same manner as in STEP52 in the main water heater 2.

[0139] Then, when the pouring of hot water of the predetermined amount V0 and the measurement of the pouring flow rate in the auxiliary water heater 2B are completed, the control device 31B notifies the control device 31A of the main water heater 2A of the measured value of the pouring flow rate in the auxiliary water heater 2B in STEP83, and also notifies the control device 31A of the main water heater 2A that the pouring of hot water of the predetermined amount V0 has ended. Note that the notification of the measured value of the pouring flow rate does not have to be performed simultaneously with the notification that the pouring has ended. For example, the notification of the measured value of the pouring flow rate may be performed immediately after the measurement of the pouring flow rate is completed.

[0140] In the main water heater 2A, when the pouring of hot water of the predetermined amount V0 and the measurement of the pouring flow rate are completed, the control device 31A obtains the measured values of the pouring flow rates in each water heater 2 (2A, 2B) in STEP53. Further, the control device 31A determines the distribution ratio of the water heater 2 (specifically, the sharing ratio of each water heater 2 among the fixed amount of hot water to be poured into the bathtub BT) when pouring a fixed amount of hot water into the bathtub BT according to the obtained measured values of the pouring flow rates.

[0141] In this case, the distribution ratio of each water heater 2 is determined such that the water heater 2 with a larger pouring flow rate has a larger distribution ratio. For example, when the measured value of the pouring flow rate in the main water heater 2A is Qa and the measured value of the pouring flow rate in the auxiliary water heater 2B is Qb, the distribution ratio of the main water heater 2A is determined as Qa / (Qa + Qb), and the distribution ratio of the auxiliary water heater is determined as Qb / (Qa + Qb). Note that the process of STEP53 is not limited to being executed after the pouring of a predetermined amount V0 of hot water in the main water heater 2A is completed, and it may be executed before the end of the pouring.

[0142] Next, in STEP54, the control device 31A of the main water heater 2A sequentially repeats determining whether the pouring of a predetermined amount V0 of hot water has been completed in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of a predetermined amount V0 of hot water in the main water heater 2A is completed and the control device 31A receives a notification from the control device 31B of the other water heater 2B (auxiliary water heater 2B) indicating that the pouring of a predetermined amount V0 of hot water has been completed, it is determined that the pouring of a predetermined amount V0 of hot water has been completed in all the water heaters 2A and 2B (the determination result of STEP54 is determined to be affirmative).

[0143] When the determination result of STEP54 becomes affirmative, next, in STEP55, the control device 31A determines the distribution amount (share) of each water heater 2 of the pouring amount of the predetermined amount V6 by distributing the pouring amount of the predetermined amount V6 (for example, 20 liters) to be newly poured into the bathtub BT to each water heater 2 (2A, 2B) at the distribution ratio determined in STEP53. In this case, the pouring amount of the value obtained by multiplying the distribution ratio of each water heater 2 by the predetermined amount V6 is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 of the pouring amount of the predetermined amount V6 is simply referred to as the distribution amount of V6.

[0144] Next, in STEP56, the control device 31A operates the heat source machine 3 of the main water heater 2A to pour the hot water of the distribution amount of V6 corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to pour the hot water of the distribution amount of V6 corresponding to the water heater into the bathtub BT. In this case, the pouring of the hot water of the distribution amount of V6 in the main water heater 2A is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0145] On the other hand, in the auxiliary water heater 2B, after the execution of the process of STEP83 described above, in STEP84, the control device 31B sequentially repeats determining whether or not it has received an instruction from the control device 31A of the main water heater 2A to pour hot water in the allocated amount of V6 until the determination result becomes affirmative.

[0146] And when the determination result of STEP84 becomes affirmative (when an instruction to pour hot water in the allocated amount of V6 is received), the control device 31B of the auxiliary water heater 2B operates the heat source machine 3 of the auxiliary water heater 2B so as to pour hot water in the allocated amount of V6 into the bathtub BT. In this case, the pouring of hot water in the allocated amount of V6 by the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0147] And when the pouring of hot water in the allocated amount of V6 by the auxiliary water heater 2B is completed, the control device 31B of the auxiliary water heater 2B notifies the control device 31A of the main water heater 2A in STEP86 that the pouring has been completed.

[0148] In the main water heater 2A, after the execution of the process of STEP56 described above, in STEP57, the control device 31A sequentially repeats determining whether or not the pouring of hot water in the allocated amount of V6 has been completed in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of hot water in the allocated amount of V6 by the main water heater 2A is completed and the control device 31A has received a notification indicating that the pouring of hot water in the allocated amount of V6 by the control device 31B of the other water heater 2B (auxiliary water heater 2B) has been completed, it is determined that the pouring of hot water in the allocated amount of V6 has been completed in all the water heaters 2A and 2B (the determination result of STEP57 is determined to be affirmative).

[0149] When the determination result in STEP57 is affirmative, the control device 31A, in STEP58, checks for water flow in the circulation water path 14 of the main water heater 2A (a process of checking whether continuous water flow occurs in the circulation water path 14 during the operation of the pump 19 based on the output signal of the water flow switch 21), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to execute water flow confirmation in the circulation water path 14 of the water heater. In this case, the water flow confirmation in the main water heater 2 is performed in the same manner as the water flow confirmation in STEP4 in the first embodiment.

[0150] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP86 described above, the control device 31B sequentially repeats, until the determination result becomes affirmative, the process of determining in STEP8Y whether it has received an instruction to execute water flow confirmation from the control device 31A of the main water heater 2A.

[0151] When the determination result in STEP87 becomes affirmative, the control device 31B, in STEP88, performs water flow confirmation in the circulation water path 14 of the auxiliary water heater 2B in the same manner as the main water heater 2A. Further, when the water flow confirmation is completed, the control device 31B, in STEP89, notifies the control device 31A of the main water heater 2A of the result of the water flow confirmation.

[0152] After executing the process of STEP58 described above, the control device 31A of the main water heater 2A, in STEP59, acquires the result of the water flow confirmation from the control device 31B of the other water heater 2B (auxiliary water heater 2B). Subsequently, in STEP60, the control device 31A determines, based on the result of the water flow confirmation in the main water heater 2A and the result of the water flow confirmation in the other water heater 2B (auxiliary water heater 2B), whether the hot water injection into the bathtub BT has ended up to the water level equal to or higher than the height of the hot water injection port Ba corresponding to each of all the water heaters 2A and 2B (specifically, the water level slightly above the hot water injection port Ba). When the determination result in STEP60 is negative, the control device 31A repeats the process from STEP58.

[0153] Further, in the auxiliary water heater 2B, after the execution of the process of STEP89 described above, in STEP90, the control device 31B determines whether the pouring of the water with the distribution amount of V6 is instructed again from the control device 31A of the main water heater 2A. If the determination result is affirmative, the process from STEP85 is repeated.

[0154] Here, in STEP60, the control device 31A of the main water heater 2A, in the same manner as the determination process of STEP5 in the first embodiment, for each water heater 2, after the pouring of the water with the distribution amount of V6, when it is confirmed that the continuous water flow is generated in the circulation water path 14, for example, when it is continuous twice, it is determined that the pouring of the water up to the water level above the height of the pouring port Ba is completed in each water heater 2.

[0155] However, in each water heater 2, when it is confirmed that the continuous water flow is generated during the operation of the pump 19 after the pouring of the water with the distribution amount of V6 a certain number of times, even if the water flow was not confirmed after the previous pouring, it may be determined that the pouring into the bathtub BT up to the water level above the height of the pouring port Ba is completed in the water heater 2.

[0156] Supplementally, in each water heater 2, the predetermined amount V6 distributed to each water heater 2 in STEP55 may be changed according to, for example, the number of repetitions of STEP56. For example, after the generation of the water flow is confirmed for the first time in all the water heaters 2A and 2B, the predetermined amount V6 distributed in STEP56 next may be made larger than the previous predetermined amount V6.

[0157] As described above, by repeating the pouring of the water with the distribution amount of V6 into the bathtub BT in each water heater 2, eventually, the determination result of STEP60 becomes affirmative. In this case, the control device 31A of the main water heater 2A, in the next STEP61, detects the current water level in the bathtub BT by the water level sensor 22 of the main water heater 2A and calculates the current amount of water in the bathtub BT.

[0158] In this case, since the water level detection by the water level sensor 22 is performed with the hot water pouring into the bathtub BT stopped in all the water heaters 2A and 2B, the water level can be detected in the static state of the bathtub water in the bathtub BT. Therefore, a highly reliable water level detection value can be obtained.

[0159] Also, the current amount of bathtub water in the main water heater 2A is calculated as the total amount of hot water poured into the bathtub BT from all the water heaters 2A and 2B. Specifically, the amount of hot water obtained by multiplying the predetermined amount V0 by the total number of water heaters 2 (two in this embodiment) and the amount of hot water obtained by multiplying the predetermined amount V6 by the number of repetitions of hot water pouring in STEP56 are added together to calculate the current amount of bathtub water. The amount of bathtub water calculated in this way substantially matches the actual amount of hot water in the bathtub BT.

[0160] Next, the control device 31A of the main water heater 2 stores the water level detected in STEP61 as the reference water level H0 of the bathtub BT and stores the amount of bathtub water calculated in STEP61 as the reference amount of bathtub water W0 of the bathtub BT in STEP62.

[0161] Next, in STEP63, the control device 31A determines the distribution amount (burden share) of each water heater 2 in the amount of hot water to be newly poured into the bathtub BT, which is a predetermined amount V7 (for example, 80 liters), by distributing the amount of hot water of the predetermined amount V7 to each water heater 2 (2A and 2B) at the distribution ratio determined in STEP53. In this case, the amount of hot water obtained by multiplying the predetermined amount V7 by the distribution ratio of each water heater 2 is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 in the amount of hot water of the predetermined amount V7 is simply referred to as the distribution amount of V7.

[0162] Next, in STEP64, the control device 31A operates the heat source machine 3 of the main water heater 2A to pour the hot water of the distribution amount of V7 corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to pour the hot water of the distribution amount of V7 corresponding to the water heater into the bathtub BT. In this case, the pouring of the hot water of the distribution amount of V7 in the main water heater 2A is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0163] On the other hand, in the auxiliary water heater 2B, when the determination result in the above-described STEP90 is negative (when the pouring of hot water with the distribution amount of V6 is not instructed), in STEP91, the control device 31B determines whether or not it has received an instruction to pour hot water with the distribution amount of V7 from the control device 31A of the main water heater 2A. If the determination result is negative, the process from STEP90 is repeated.

[0164] When the determination result in STEP91 becomes positive (when an instruction to pour hot water with the distribution amount of V7 is received), the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B so as to pour the hot water with the instructed distribution amount of V7 into the bathtub BT in STEP92. In this case, the pouring of hot water with the distribution amount of V7 in the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0165] When the pouring of hot water with the distribution amount of V7 in the auxiliary water heater 2B is completed, the control device 31B of the auxiliary water heater 2B notifies the control device 31A of the main water heater 2A that the pouring has been completed in STEP93.

[0166] In the main water heater 2A, after executing the process in the above-described STEP64, the control device 31A sequentially repeats determining whether or not the pouring of hot water with the distribution amount of V7 has been completed in all the water heaters 2A and 2B until the determination result becomes positive in STEP65. In this case, when the pouring of hot water with the distribution amount of V7 in the main water heater 2A is completed and the control device 31A receives a notification indicating that the pouring of hot water with the distribution amount of V7 in another water heater (auxiliary water heater 2B) has been completed, it determines that the pouring of hot water with the distribution amount of V7 has been completed in all the water heaters 2A and 2B (determines that the determination result in STEP65 is positive).

[0167] When the determination result in STEP65 is affirmative, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 of the main water heater 2A in STEP66. In this case, since the detection of the water level by the water level sensor 22 is performed with the pouring of water into the bathtub BT stopped in all the water heaters 2A and 2B, a highly reliable detected value of the water level can be obtained.

[0168] In STEP66, the control device 31A further calculates and stores the bathtub reference cross-sectional area WH as the cross-sectional area of the bathtub BT in the vicinity of the height of the reference water level H0, and further calculates the shortage water volume V8 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs, which is the target value of the water level preset by the bathroom remote controller 33A.

[0169] Here, the bathtub reference cross-sectional area WH is calculated by the above-described formula (1) in the first embodiment from the reference water level H0 stored and held in STEP62, the current water level Hnow detected in STEP66, and the predetermined volume V7 distributed in STEP63. The bathtub reference cross-sectional area WH calculated in this way substantially coincides with the actual cross-sectional area in the vicinity of the reference water level H0 of the bathtub BT.

[0170] Further, the shortage water volume V8 is calculated by the above-described formula (2) in the first embodiment from the current water level Hnow (the detected value in STEP66), the bathtub reference cross-sectional area WH, and the set water level Hs, assuming that the cross-sectional area of the bathtub BT at a height above the reference water level H0 is a constant value that coincides with the bathtub reference cross-sectional area WH calculated as described above.

[0171] In this case, when the cross-sectional area of the bathtub BT at a height above the reference water level H0 is constant, the shortage water volume V8 calculated as described above substantially coincides with the actual shortage water volume from the current water level Hnow to the set water level Hs.

[0172] Next, in STEP67, the control device 31A of the main water heater 2A distributes the shortage hot water amount V8 calculated as described above to each water heater 2 (2A, 2B) at the distribution ratio determined in STEP53, thereby determining the distribution amount (burden share) of each water heater 2 in the shortage hot water amount V8. In this case, the pouring amount of hot water, which is the value obtained by multiplying the shortage hot water amount V8 by the distribution ratio of each water heater 2, is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 in the shortage hot water amount V8 is simply referred to as the distribution amount of V8.

[0173] Next, in STEP68, the control device 31A operates the heat source machine 3 of the main water heater 2A so as to pour the hot water of the distribution amount of V8 corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to pour the hot water of the distribution amount of V8 corresponding to the water heater into the bathtub BT. In this case, the pouring of the hot water of the distribution amount of V8 in the main water heater 2A is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0174] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP93 described above, the control device 31B sequentially repeats in STEP94 the determination of whether or not it has received an instruction to pour the hot water of the distribution amount of V8 from the control device 31A of the main water heater 2A until the determination result becomes affirmative.

[0175] When the determination result in STEP94 becomes affirmative (when it has received an instruction to pour the hot water of the distribution amount of V8), the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B so as to pour the hot water of the instructed distribution amount of V8 into the bathtub BT. In this case, the pouring of the hot water of the distribution amount of V8 in the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0176] When the pouring of the hot water of the distribution amount of V8 in the auxiliary water heater 2B is completed, the control device 31B of the auxiliary water heater 2B notifies the control device 31A of the main water heater 2A in STEP96 that the pouring has been completed.

[0177] In the main water heater 2A, after the execution of the process of STEP68 described above, in STEP69, the control device 31A sequentially repeats determining whether the pouring of the water with the distribution amount of V8 has ended in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of the water with the distribution amount of V8 in the main water heater 2A has ended and the control device 31A receives a notification indicating that the pouring of the water with the distribution amount of V8 has ended from the control device 31B of the other water heater (auxiliary water heater 2B), it determines that the pouring of the water with the distribution amount of V8 has ended in all the water heaters 2A and 2B (decides that the determination result of STEP69 is affirmative).

[0178] When the determination result of STEP69 becomes affirmative, the control device 31A detects the current water level in the bathtub BT by the water level sensor 22 of the main water heater 2A in STEP70. In this case, since the detection of the water level by the water level sensor 22 is performed in a state where the pouring of water into the bathtub BT in all the water heaters 2A and 2B has stopped, a highly reliable water level detection value can be obtained.

[0179] In STEP70, the control device 31A further calculates and stores the bathtub cross-sectional area increase rate ΔWH, which is the increase amount per unit height of the cross-sectional area of the bathtub BT at a height above the reference water level H0, and further calculates the shortage water amount V9 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs.

[0180] Here, the bathtub cross-sectional area increase rate ΔWH is calculated by the above formula (3) described in the first embodiment from the reference water level H0 stored and held in STEP62, the current water level Hnow detected in STEP70, the bathtub reference cross-sectional area WH calculated in STEP66, and the set water level Hs. The bathtub cross-sectional area increase rate ΔWH calculated in this way substantially coincides with the actual increase rate (increase amount per unit height) of the cross-sectional area of the bathtub BT at a height above the reference water level H0.

[0181] Further, the insufficient hot water volume V9 is calculated from the set water level Hs, the current water level Hnow (detected value), the reference bathtub water level H0, the reference bathtub cross-sectional area WH, and the bathtub cross-sectional area increase rate ΔWH by the above-described formulas (4a) and (4b) explained in the first embodiment, assuming that the cross-sectional area of the bathtub BT at a height above the reference water level H0 increases from the reference bathtub cross-sectional area WH at a constant bathtub cross-sectional area increase rate ΔWH calculated as described above. The insufficient hot water volume V9 calculated in this way will almost match the actual insufficient hot water volume from the current water level Hnow to the set water level Hs.

[0182] Supplementary note: In this embodiment, in the main water heater 2A, the reference water level H0 and the reference bathtub water volume W0 stored in STEP62, the reference bathtub cross-sectional area WH stored in STEP66, and the bathtub cross-sectional area increase rate ΔWH stored in STEP70 correspond to bathtub characteristic data regarding the relationship between the hot water injection volume into the bathtub BT and the water level of the bathtub BT.

[0183] Next, in STEP71, the control device 31A of the main water heater 2A distributes the insufficient hot water volume V9 calculated as described above to each water heater 2 (2A, 2B) at the distribution ratio determined in STEP53, thereby determining the distribution amount (burden share) of each water heater 2 in the insufficient hot water volume V9. In this case, the hot water injection volume of the value obtained by multiplying the insufficient hot water volume V9 by the distribution ratio of each water heater 2 is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 in the insufficient hot water volume V9 will simply be referred to as the distribution amount of V9.

[0184] Next, in STEP72, the control device 31A operates the heat source machine 3 of the main water heater 2A to inject the hot water of the distribution amount of V9 corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to inject the hot water of the distribution amount of V9 corresponding to the water heater into the bathtub BT. In this case, the hot water injection of the distribution amount of V9 in the main water heater 2A is performed in the same manner as the hot water injection in STEP2 in the first embodiment.

[0185] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP96 described above, in STEP97, the control device 31B sequentially repeats determining whether it has received an instruction from the control device 31A of the main water heater 2A to pour hot water in the allocated amount of V9 until the determination result becomes affirmative.

[0186] When the determination result in STEP97 becomes affirmative (when an instruction to pour hot water in the allocated amount of V9 is received), the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B in STEP98 so as to pour hot water in the allocated amount of V9 indicated into the bathtub BT. In this case, the pouring of hot water in the allocated amount of V9 by the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0187] When the pouring of hot water in the allocated amount of V9 by the control device 31B of the auxiliary water heater 2B is completed, in STEP99, the control device 31B notifies the control device 31A of the main water heater 2A that the pouring has ended.

[0188] In the main water heater 2A, after executing the process of STEP72 described above, in STEP73, the control device 31A sequentially repeats determining whether the pouring of hot water in the allocated amount of V9 has ended in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of hot water in the allocated amount of V9 in the main water heater 2A is completed and the control device 31A receives a notification indicating that the pouring of hot water in the allocated amount of V9 in another water heater (auxiliary water heater 2B) has ended from the control device 31B, it determines that the pouring of hot water in the allocated amount of V9 has ended in all the water heaters 2A and 2B (decides that the determination result in STEP73 is affirmative).

[0189] When the determination result in STEP73 becomes affirmative, the control device 31A of the main water heater 2 executes processes for boiling the bathtub water in the bathtub BT in STEP74 to 76. In STEP74, the control device 31A instructs the control device 31B of another water heater 2B (auxiliary water heater 2B) to execute the boiling process.

[0190] Furthermore, in STEP 75, the control device 31A determines whether the bath temperature detected by the temperature sensor 20 (the temperature of the bath water in the bathtub BT) is equal to or higher than the set temperature. When the determination result in STEP 75 is negative (when the bath temperature (detected value) < set temperature), the control device 31A operates the heat source machine 3 of the main water heater 2A to boil the bath water in STEP 76 until the determination result in STEP 75 becomes positive. The process of boiling the bath water in this way is performed in the same manner as STEP 18 in the first embodiment. When the determination result in STEP 75 becomes positive, the control device 31A stops the operation of the pump 19 of the main water heater 2A and the second heating unit 13 to end the boiling process in the main water heater 2A.

[0191] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP 99 described above, the control device 31B sequentially repeats, until the determination result becomes positive, the determination as to whether an instruction to execute the boiling process has been received from the control device 31A of the main water heater 2A in STEP 100.

[0192] When the determination result in STEP 100 becomes positive (when an instruction to execute the boiling process has been received), the control device 31B performs the same processes as STEP 75 and 76 in the main water heater 2A in STEP 101 and 102, and boils the bath water in STEP 102 until the determination result in STEP 101 becomes positive (until the bath temperature detected by the temperature sensor 20 of the auxiliary water heater 2B becomes equal to or higher than the set temperature).

[0193] When the determination result in STEP 101 becomes positive, the control device 31B stops the operation of the pump 19 and the second heating unit 13 of the auxiliary water heater 2B, and then, in STEP 103, notifies the control device 31A of the main water heater 2A that the bath temperature has become "OK" in the auxiliary water heater 2B (that the bath temperature detected by the temperature sensor 20 of the auxiliary water heater 2B has become equal to or higher than the set temperature).

[0194] In the main water heater 2A, when the determination result in STEP75 is affirmative (when the boiling of the bathtub water in the main water heater 2A ends), in STEP77, the control device 31A sequentially repeats determining whether the bath water temperature has become "OK" (whether the detected value of the bath water temperature is equal to or higher than the set temperature) in all water heaters 2A and 2B until the determination result becomes affirmative.

[0195] In this case, when the determination result in STEP75 in the main water heater 2A is affirmative and the control device 31A of the main water heater 2A receives a notification indicating that the bath water temperature has become "OK" from the control device 31B of another water heater (auxiliary water heater 2B), the control device 31A determines that the bath water temperature has become "OK" in all water heaters 2A and 2B (decides that the determination result in STEP77 is affirmative).

[0196] When the determination result in STEP77 becomes affirmative, the control device 31A of the main water heater 2A instructs the control device 31B of another water heater (auxiliary water heater 2B) to perform a notification indicating the completion of hot water supply in STEP78, and causes the kitchen remote controller 32A and the bathroom remote controller 33A of the main water heater 2A to perform a notification indicating that the hot water supply has been completed. This notification is performed by outputting display information or voice information on the kitchen remote controller 32A and the bathroom remote controller 33A.

[0197] Also, in the auxiliary water heater 2B, after executing the process in STEP103 described above, the control device 31B sequentially repeats determining whether it has received an instruction from the control device 31A of the main water heater 2A to execute a notification indicating the completion of hot water supply in STEP104 until the determination result becomes affirmative.

[0198] When the determination result in STEP 104 is affirmative (when receiving an instruction to execute the notification indicating the completion of hot water filling), the control device 31B causes the kitchen remote controller 32B of the auxiliary water heater 2B to perform a notification indicating that the hot water filling has been completed in STEP 105. This notification is performed by the display information on the kitchen remote controller 32B or by the output of voice information. Further, in STEP 105, the control device 31B performs a closing valve control on the water supply amount adjustment valve 16 of the auxiliary water heater 2B.

[0199] Here, the notification indicating the completion of hot water filling in the auxiliary water heater 2B is performed in parallel with the notification indicating the completion of hot water filling in the main water heater 2A in response to an instruction from the control device 31A of the main water heater 2A. Therefore, it is possible to perform notifications indicating the completion of hot water filling in the main water heater 2A and the auxiliary water heater 2B almost simultaneously. In the bath system 1 of the present embodiment, the first hot water filling operation (hot water filling operation in the operation mode for the first hot water filling operation) is performed as described above.

[0200] Next, the operations related to the hot water filling operations after the first hot water filling operation (normal hot water filling operations) will be described. When the control device 31A of the main water heater 2A is instructed to start the hot water filling operation as described above, when the hot water filling operation is a normal hot water filling operation after the first hot water filling operation (specifically, when the hot water filling operation is not specified to be executed in the operation mode for the first hot water filling operation), the control device 31A executes control processing as shown in the flowchart of FIG. 9.

[0201] In the normal hot water filling operation, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the hot water filling operation (normal hot water filling operation) in STEP 111. Then, the control device 31A executes the control processing of STE112 to 131 regarding the operation control of the main water heater 2A (control processing for the normal hot water filling operation).

[0202] Furthermore, upon receiving notification of the start of normal hot water filling operation from the control device 31A of the main hot water heater 2A, the control device 31B of the auxiliary hot water heater 2B executes control processing (control processing for normal hot water filling operation) as shown in the flowchart of Figure 10. In this case, the control device 31B of the auxiliary hot water heater 2B first controls the opening of the water supply amount adjustment valve 16 of the heat source unit 3 of the auxiliary hot water heater 2B in STEP 141, and then executes the control processing of STEPs 142 to 155 related to the operation control of the auxiliary hot water heater 2B. Furthermore, in this embodiment, the control processing of the control device 31B of the auxiliary hot water heater 2B is executed in accordance with instructions from the control device 31A of the main hot water heater 2A.

[0203] In main water heater 2A, control device 31A performs the same processing as steps 52 to 54 during the initial hot water filling operation in steps 112 to 114 following step 111. Also, in auxiliary water heater 2B, in steps 142 and 143 following step 141, it performs the same processing as steps 82 and 83 during the initial hot water filling operation. As a result, each water heater 2 pours a predetermined amount V0 of hot water into the bathtub BT as priming water, and the hot water pouring flow rate of each water heater 2 is measured. Furthermore, the distribution ratio of each water heater 2 when pouring a certain amount of hot water into the bathtub BT is determined according to the measured value of the hot water pouring flow rate of each water heater 2.

[0204] Then, when the determination result in STEP 114 becomes positive (when the pouring of the predetermined amount V0 of hot water has been completed in all water heaters 2A, 2B), the control device 31A of the main water heater 2A next checks the water flow in the circulation water path 14 of the main water heater 2 in STEP 115. This water flow check is performed in the same way as the water flow check in STEP 4 in the first embodiment. Then, in STEP 116, the control device 31A determines whether or not this water flow check has detected the generation of a continuous water flow while the pump 19 is operating.

[0205] In a normal bath filling operation, there may already be bath water (residual hot water) in the bathtub BT at a water level higher than the pouring spouts Ba of the bathtub BT when the operation starts, and in such a case, the determination result of STEP 116 becomes affirmative. In this case, the control device 31A executes the process from STEP 123 described below.

[0206] Also, when there is no bathtub water (remaining hot water) in the bathtub BT at a water level higher than each hot water pouring port Ba of the bathtub BT, the determination result in STEP116 becomes negative. In this case, the control device 31A, in the next STEP117, in order to pour hot water of an amount obtained by adding a predetermined amount ΔV to the reference bathtub water amount W0 memorized in the first hot water filling operation into the bathtub BT newly, distributes the hot water pouring amount of W0 + ΔV to each water heater 2 at the distribution ratio determined in STEP113, thereby determining the distribution amount (burden share) of each water heater 2 in the hot water pouring amount of W0 + ΔV. In this case, the hot water pouring amount obtained by multiplying the hot water pouring amount of W0 + ΔV by the distribution ratio of each water heater 2 is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 in the hot water pouring amount of W0 + ΔV is simply referred to as the distribution amount of W0 + ΔV.

[0207] Here, the above-mentioned predetermined amount ΔV is calculated as the water amount necessary to increase the bathtub water to a water level that is a predetermined value ΔH (for example, 5 cm) higher than the reference water level H0. The predetermined amount ΔV is calculated from the bathtub reference cross-sectional area WH and the bathtub cross-sectional area increase rate ΔWH memorized and held by the control device 31A of the main water heater 2A during the first hot water filling operation, and the water level difference of the above-mentioned predetermined value ΔH. Specifically, ΔV is calculated by the formula obtained by replacing Hs and Hnow in the above formulas (4a) and (4b) with H0 + ΔH and H0, respectively. Note that the predetermined amount ΔV calculated in this way almost matches the actual water amount necessary to increase the water level in the bathtub BT from the reference water level H0 to a water level that is a predetermined value ΔH higher. Supplementary note: The above-mentioned predetermined amount ΔV may be a predetermined constant value, or may be a value determined by a map or the like from the bathtub reference cross-sectional area WH, for example.

[0208] Next, in STEP118, the control device 31A operates the heat source machine 3 of the main water heater 2A to pour hot water with a distribution amount of W0+ΔV corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to pour hot water with a distribution amount of W0+ΔV corresponding to the water heater into the bathtub BT. In this case, the pouring of hot water with a distribution amount of W0+ΔV by the main water heater 2A is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0209] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP143 described above, in STEP144, the control device 31B determines whether it has received an instruction from the control device 31A of the main water heater 2A to pour hot water with a distribution amount of W0+ΔV. If the determination result is negative, then in STEP147, it further determines whether it has received an instruction from the control device 31A of the main water heater 2A to pour hot water with a distribution amount of the insufficient hot water amount V10 (the hot water amount determined in STEP123 described later in the main water heater 2A). And if the determination results of both STEP144 and STEP147 are negative, the control device 31B repeats the process from STEP144.

[0210] When the determination result of STEP144 in the control device 31B of the auxiliary water heater 2B is affirmative (when it has received an instruction to pour hot water with a distribution amount of W0+ΔV), in STEP145, it operates the heat source machine 3 of the auxiliary water heater 2B to pour the instructed hot water with a distribution amount of W0+ΔV into the bathtub BT. In this case, the pouring of hot water with a distribution amount of W0+ΔV by the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment. Then, when the pouring of hot water with a distribution amount of W0+ΔV is completed, in STEP146, the control device 31B notifies the control device 31A of the main water heater 2A that the pouring has ended.

[0211] In the main water heater 2A, after the execution of the process of STEP118 described above, in STEP119, the control device 31A sequentially repeats determining whether the pouring of hot water with a distribution amount of W0 + ΔV has ended in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of hot water with a distribution amount of W0 + ΔV in the main water heater 2A has ended and the control device 31A of the other water heater (auxiliary water heater 2B) has received a notification that the pouring of hot water with a distribution amount of W0 + ΔV has ended, the control device 31A determines that the pouring of hot water with a distribution amount of W0 + ΔV has ended in all the water heaters 2A and 2B (decides that the determination result of STEP119 is affirmative).

[0212] When the determination result of STEP119 becomes affirmative, the control device 31A performs a water flow confirmation in the circulation water path 14 of the main water heater 2A in STEP120. This water flow confirmation is performed in the same manner as the water flow confirmation in STEP4 in the first embodiment. Then, the control device 31A determines in STEP121 whether the generation of continuous water flow has been detected by this water flow confirmation.

[0213] Here, when the pouring of hot water with a distribution amount of W0 + ΔV has ended in all the water heaters 2A and 2B, a larger amount of hot water than the reference water amount W0 has been poured into the bathtub BT. Therefore, basically, the water level of the bath water in the bathtub BT becomes higher than the water level at each pouring port Ba. And in this case, the determination result of STEP121 becomes affirmative.

[0214] However, when the bath water is leaking from the drain port or the like of the bathtub BT, the water level in the bathtub BT may become lower than the water level at the pouring port Ba, and the determination result of STEP121 may become negative. Therefore, when the determination result of STEP121 becomes negative, the control device 31A executes stopping all the water heaters 2A and 2B in error (stopping the hot water pouring operation of each water heater 2 in response to the occurrence of an abnormality) in STEP122.

[0215] When the determination result in STEP121 is affirmative, the control device 31A of the main water heater 2A then detects the current water level in the bathtub BT by the water level sensor 22 of the main water heater 2A in STEP123. In this case, since the detection of the water level by the water level sensor 22 is performed with the pouring of water into the bathtub BT stopped at all the water heaters 2A and 2B, a highly reliable water level detection value can be obtained.

[0216] In STEP123, the control device 31A further calculates the insufficient hot water volume V10 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs. This insufficient hot water volume V10 is calculated by the above-mentioned formulas (4a) and (4b) described in the first embodiment from the set water level Hs, the current water level Hnow (detection value), the reference bathtub water level H0, the reference bathtub cross-sectional area WH, and the bathtub cross-sectional area increase rate ΔWH. The insufficient hot water volume V10 calculated in this way will almost match the actual insufficient hot water volume from the current water level Hnow to the set water level Hs.

[0217] Next, the control device 31A of the main water heater 2A determines the distribution amount (burden share) of each water heater 2 in the insufficient hot water volume V10 by distributing the insufficient hot water volume V10 calculated as described above to each water heater 2 (2A, 2B) at the distribution ratio determined in STEP113. In this case, the pouring amount of the value obtained by multiplying the insufficient hot water volume V10 by the distribution ratio of each water heater 2 is determined as the distribution amount of the water heater 2. Hereinafter, the distribution amount of each water heater 2 in the insufficient hot water volume V10 will be simply referred to as the distribution amount of V10.

[0218] Then, in STEP125, the control device 31A operates the heat source machine 3 of the main water heater 2A to pour the water of the distribution amount of V10 corresponding to the main water heater 2A into the bathtub BT, and instructs the control device 31B of the other water heater (auxiliary water heater 2B) to pour the water of the distribution amount of V10 corresponding to the water heater into the bathtub BT. In this case, the pouring of the water of the distribution amount of V10 at the main water heater 2A is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0219] On the other hand, in the auxiliary water heater 2B, after the execution of the process of STEP146 described above, in STEP147, the control device 31B sequentially repeats determining whether it has received an instruction from the control device 31A of the main water heater 2A to pour hot water in the allocated amount of V10 until the determination result becomes affirmative. In this case, the determination process of STEP144 is also executed, but this determination result constantly becomes negative.

[0220] When the determination result of STEP147 becomes affirmative (when an instruction to pour hot water in the allocated amount of V10 is received), the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B in STEP148 so as to pour hot water in the allocated amount of V10 indicated into the bathtub BT. In this case, the pouring of hot water in the allocated amount of V10 by the auxiliary water heater 2B is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0221] When the pouring of hot water in the allocated amount of V10 by the auxiliary water heater 2B is completed, the control device 31B of the auxiliary water heater 2B notifies the control device 31A of the main water heater 2A in STEP149 that the pouring has been completed.

[0222] In the main water heater 2A, after the execution of the process of STEP125 described above, in STEP126, the control device 31A sequentially repeats determining whether the pouring of hot water in the allocated amount of V10 has been completed in all the water heaters 2A and 2B until the determination result becomes affirmative. In this case, when the pouring of hot water in the allocated amount of V10 in the main water heater 2A is completed and the control device 31A receives a notification from the control device 31B of another water heater (auxiliary water heater 2B) that the pouring of hot water in the allocated amount of V10 has been completed, it determines that the pouring of hot water in the allocated amount of V10 has been completed in all the water heaters 2A and 2B (decides that the determination result of STEP126 is affirmative).

[0223] When the determination result of STEP126 is affirmative, the control device 31A of the main water heater 2 executes the same processes as those in STEP74 to 78 in the first water filling operation in STEP127 to 131. Further, after executing the process of STEP149, the control device 31B of the auxiliary water heater 2B executes the same processes as those in STEP100 to 105 in the first water filling operation in STEP150 to 155.

[0224] As a result, the process of boiling the bathtub water is executed in each water heater 2, and after the completion of the boiling process, a notification indicating the completion of water filling is given. Also, in the auxiliary water heater 2B, the water supply amount adjustment valve 16 is controlled to close.

[0225] In the bathtub system 1 of the present embodiment, the normal water filling operation after the execution of the first water filling operation is performed as described above. As a supplement, in the present embodiment, the entire control processes of the control devices 31A and 31B in the normal water filling operation correspond to the water filling operation process in the present invention. And the process of STEP118 in the main water heater 2A (the process of pouring hot water with a distribution amount of W0 + ΔV) and the process of STEP145 in the auxiliary water heater 2B (the process of pouring hot water with a distribution amount of W0 + ΔV) correspond to the first process in the present invention.

[0226] Also, the process of STEP123 in the main water heater 2A (the process of detecting the water level) corresponds to the second process in the present invention. Also, the process of STEP125 in the main water heater 2A (the process of pouring hot water with a distribution amount of V10) and the process of STEP148 in the auxiliary water heater 2B (the process of pouring hot water with a distribution amount of V10) correspond to the third process in the present invention.

[0227] Also, the hot water pouring process in STEP112 in the main water heater 2A and the hot water pouring process in STEP142 in the auxiliary water heater 2B correspond to the fourth process in the present invention, and the measurement process of the hot water pouring flow rate in STEP112 in the main water heater 2A and the measurement process of the hot water pouring flow rate in STEP142 in the auxiliary water heater 2B correspond to the fifth process in the present invention.

[0228] According to the second embodiment described above, in any of the initial water filling operation and the normal water filling operation, the detection of the water level in each water heater 2 is performed in a state where the water pouring into the bathtub BT by each water heater 2 has stopped in all the water heaters 2A and 2B. Therefore, a highly reliable water level detection value (a highly accurate detection value) can be obtained. As a result, it is possible to appropriately realize pouring water into the bathtub BT up to the set water level Hs after the detection of the water level, and the water level in the bathtub BT at the end of the water filling operation can be made to coincide with or substantially coincide with the set water level Hs with high reliability.

[0229] Also, in the present embodiment, the control device 31A of the main water heater 2A stores and holds, as bathtub characteristic data, a reference water level H0, a reference bathtub water volume W0, a bathtub reference cross-sectional area WH, and a bathtub cross-sectional area increase rate ΔWH. And these bathtub characteristic data are data that conform to the actual shape and size of the bathtub BT. For this reason, for example, even when the auxiliary water heater 2B fails, the main water heater 2A can appropriately perform the water filling up to the set water level Hs in the normal water filling operation. Specifically, in this case, the main water heater 2A may execute the normal water filling operation with the distribution ratio to the auxiliary water heater 2B being zero.

[0230] Note that the above bathtub characteristic data may be stored and held not only in the control device 31A of the main water heater 2A but also in the control device 31B of the auxiliary water heater 2B. In this case, when the main water heater 2A fails, it is also possible to make the auxiliary water heater 2B execute the normal water filling operation instead of the main water heater 2A.

[0231] [Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. 1 and 11 to 15. Since only the control processing by the control device of each water heater 2 is different from that in the first embodiment or the second embodiment in this embodiment, the description of the same matters as those in the first embodiment or the second embodiment will be omitted.

[0232] In this embodiment, the control device 31A of the main water heater 2A is instructed to start the hot water supply operation, as in the first embodiment. At this time, when the hot water supply operation whose start is instructed is the first hot water supply operation, the control device 31A of the main water heater 2A executes control processing in the operation mode for the first hot water supply operation, as shown in the flowcharts of FIGS. 11 and 12.

[0233] In this case, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the hot water supply operation (the first hot water supply operation) in STEP161. Then, the control device 31A executes the control processing of STEP162 to 187 regarding the operation control of the main water heater 2A.

[0234] Also, the control device 31B of the auxiliary water heater 2B that has received the notification of the start of the hot water supply operation (the first hot water supply operation) from the control device 31A of the main water heater 2A executes control processing in the operation mode for the first hot water supply operation, as shown in the flowchart of FIG. 13. In this case, in this embodiment, the control device 31B of the auxiliary water heater 2B first performs opening control of the water supply amount adjustment valve 16 of the heat source machine 3 of the auxiliary water heater 2B in STEP191, and then executes the control processing of STEP192 to 207 regarding the operation control of the auxiliary water heater 2B. Also, in this embodiment, the control processing of the control device 31B of the auxiliary water heater 2B is executed according to an instruction from the control device 31A of the main water heater 2A.

[0235] In the main water heater 2A, in STEP162 following STEP161, the control device 31A operates the heat source machine 3 of the main water heater 2A so as to pour a predetermined amount V0 (for example, 6 liters) of hot water as called water into the bathtub BT. The pouring of this predetermined amount V0 of hot water is performed in the same manner as the pouring in STEP2 in the first embodiment.

[0236] In the auxiliary water heater 2B, in STEP192 following STEP191, the control device 31B performs the pouring of a predetermined amount V0 of hot water as called water in the same manner as in STEP162 in the main water heater 2.

[0237] Then, when auxiliary water heater 2B has finished pouring the predetermined amount V0 of hot water, control device 31B notifies control device 31A of main water heater 2A in STEP 193 that pouring of the predetermined amount V0 of hot water has finished.

[0238] When the main water heater 2A has finished pouring the predetermined amount of hot water V0, the control device 31A determines in STEP 163 whether all water heaters 2A, 2B have finished pouring the predetermined amount of hot water V0, and repeats this determination successively until the determination result becomes affirmative. In this case, when the main water heater 2A has finished pouring the predetermined amount of hot water V0 and the control device 31B of the other water heater 2B (auxiliary water heater 2B) has notified the control device 31A that the pouring of the predetermined amount of hot water V0 has finished, the control device 31A determines that all water heaters 2A, 2B have finished pouring the predetermined amount of hot water V0 (determines the determination result in STEP 163 to be affirmative).

[0239] Next, in STEP 164, the control device 31A starts operating the heat source unit 3 of the main water heater 2A to pour hot water into the bathtub BT, and also instructs the control device 31B of the other water heater (auxiliary water heater 2B) to start pouring hot water into the bathtub BT. In this case, the control device 31A starts pouring hot water into the bathtub BT in the same manner as the pouring in STEP 2 in the first embodiment. Furthermore, after starting to pour hot water into the bathtub BT, the control device 31A sequentially integrates the pouring flow rate (the flow rate of hot water supplied to the bathtub BT) detected by the flow sensor 24 of the water filling channel 15, thereby sequentially measuring the amount of hot water poured into the bathtub BT from the start of pouring.

[0240] Meanwhile, in auxiliary water heater 2B, after executing the processing of STEP 193 described above, control device 31B determines in STEP 194 whether or not it has received an instruction to start pouring hot water from control device 31A of main water heater 2A. If the determination result in STEP 194 is affirmative, control device 31B begins operating heat source unit 3 of auxiliary water heater 2B to pour hot water into bathtub BT in STEP 195. In this case, pouring of hot water from auxiliary water heater 2B into bathtub BT begins in the same manner as main water heater 2A.

[0241] Furthermore, like the main hot water heater 2A, the control device 31B successively measures the amount of hot water poured into the bathtub BT from the start of pouring by successively integrating the flow rate of hot water poured detected by the flow rate sensor 24 of the water filling channel 15 of the auxiliary hot water heater 2B. Then, in STEP 196, the control device 31B successively notifies the control device 31A of the main hot water heater 2A of the measured amount of hot water poured. If the judgment result of STEP 194 is negative, the control device 31B executes the judgment process of STEP 199 described below.

[0242] In the main water heater 2A, after starting to pour hot water into the bathtub BT as described above, the control device 31A repeats in STEP 165 the process of determining whether the sum of the amounts of hot water poured by all water heaters 2A, 2B (in other words, the increase in the amount of hot water in the bathtub BT) has reached a predetermined amount V6 (e.g., 20 liters) until the determination result becomes affirmative. In this case, the sum of the amount of hot water poured is sequentially calculated as the sum of the measured value of the amount of hot water poured in the main water heater 2A and the measured value of the amount of hot water poured notified by the control device 31 of the auxiliary water heater 2B.

[0243] Then, when the judgment result of STEP 165 becomes positive (when the total amount of hot water poured reaches a predetermined amount V6), in STEP 166, the control device 31A operates the heat source unit 3 of the main water heater 2A to stop pouring hot water from the main water heater 2A to the bathtub BT (controls the water filling solenoid valve 23 to close and stops the operation of the first heating section 11), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to stop pouring hot water.

[0244] In the auxiliary water heater 2B, while pouring hot water into the bathtub BT, the control device 31B notifies the control device 31A of the main water heater 2A of the measured value of the amount of hot water poured in STEP 196, and in STEP 197 determines whether or not it has received an instruction from the control device 31A to end pouring, repeatedly repeating this process until the determination result becomes positive.

[0245] When the determination result in STEP197 is affirmative, the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B so as to end the hot water pouring from the auxiliary water heater 2B into the bathtub BT in STEP198 (controls the hot water pouring electromagnetic valve 23 to close and stops the operation of the first heating unit 11). As a result, the pouring of a predetermined amount V6 of hot water from the main water heater 2A and the auxiliary water heater 2B into the bathtub BT is completed.

[0246] When the pouring of a predetermined amount V6 of hot water into the bathtub BT is completed, in the main water heater 2A, the control device 31A performs a water flow confirmation in the circulation water path 14 of the main water heater 2A in STEP167 (a process of confirming whether continuous water flow occurs in the circulation water path 14 during the operation of the pump 19 based on the output signal of the water flow switch 21), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to perform a water flow confirmation in the circulation water path 14 of the water heater. In this case, the water flow confirmation in the main water heater 2 is performed in the same manner as the water flow confirmation in STEP4 in the first embodiment.

[0247] On the other hand, in the auxiliary water heater 2B, after executing the process of STEP198 described above, the control device 31B determines in STEP199 whether it has received an instruction to execute a water flow confirmation from the control device 31A of the main water heater 2A. When the determination result in STEP199 is affirmative, the control device 31B performs a water flow confirmation in the circulation water path 14 of the auxiliary water heater 2B in STEP200 in the same manner as the main water heater 2A. Further, when the water flow confirmation is completed, the control device 31B notifies the control device 31A of the main water heater 2A of the result of the water flow confirmation in STEP201.

[0248] After executing the process of STEP167 described above, the control device 31A of the main water heater 2A acquires the result of water flow confirmation from the control device 31B of another water heater 2B (auxiliary water heater 2B) in STEP168. Subsequently, in STEP169, the control device 31A determines whether the pouring of hot water into the bathtub BT has ended up to the water level above the height of the pouring spout Ba corresponding to each of all the water heaters 2A and 2B based on the result of water flow confirmation in the main water heater 2A and the result of water flow confirmation in another water heater 2B (auxiliary water heater 2B). This determination is made in the same manner as STEP5 in the first embodiment (or STEP60 in the second embodiment). And when the determination result in STEP169 is negative, the control device 31A repeats the process from STEP164.

[0249] Also, in the auxiliary water heater 2B, after executing the process of STEP201 described above, the control device 31B repeats the process from STEP194. Therefore, when receiving an instruction to start pouring hot water from the control device 31A of the main water heater 2A, the control device 31B starts pouring hot water from the auxiliary water heater 2B into the bathtub BT, and when receiving an instruction for water flow confirmation from the control device 31A of the main water heater 2A, the control device 31B executes the process of water flow confirmation in the auxiliary water heater 2B. When the determination result in STEP199 is negative, the control device 31B executes the determination process of STEP202 described later. Since the determination result of this STEP202 is negative until the pouring of hot water into the bathtub BT finally ends, the process from STEP194 is repeated.

[0250] By the above processes of the control devices 31A and 31B, the pouring of a predetermined amount V6 of hot water into the bathtub BT is repeated until the determination result in STEP169 becomes affirmative. Similar to the case of supplementing the second embodiment, in the repetition of pouring a predetermined amount V6 of hot water, the amount of hot water poured each time (V6) may be changed according to the number of repetitions and the like.

[0251] As described above, by repeatedly pouring a predetermined amount V6 of hot water into the bathtub BT, eventually, the determination result in STEP169 becomes affirmative. In this case, the control device 31A of the main water supply device 2A, in STEP170 next, detects the current water level in the bathtub BT by the water level sensor 22 of the main water supply device 2A and calculates the current bathtub water volume in the bathtub BT. The process of this STEP170 is the same as the process of STEP61 in the second embodiment.

[0252] Next, the control device 31A of the main water supply device 2 stores the water level detected in STEP170 as the reference water level H0 of the bathtub BT and stores the bathtub water volume calculated in STEP170 as the reference bathtub water volume W0 of the bathtub BT.

[0253] Next, the control device 31A starts operating the heat source machine 3 of the main water supply device 2A to pour hot water into the bathtub BT in STEP172 and instructs the control device 31B of the other water supply device 2B (auxiliary water supply device 2B) to start pouring hot water into the bathtub BT. The process of this STEP172 is the same as the process of STEP164, and the hot water pouring amount from the main water supply device 2A into the bathtub BT (the hot water pouring amount from the start of hot water pouring in STEP172) is also sequentially measured.

[0254] On the other hand, in the auxiliary water supply device 2B, since the control device 31B receives the instruction to start pouring hot water from the control device 31A of the main water supply device 2A and the determination result in the above STEP194 becomes affirmative, the process from the above STEP195 is executed. As a result, the pouring of hot water from the auxiliary water supply device 2B into the bathtub BT is started, and the measured value of the hot water pouring amount (the measured value of the hot water pouring amount from the start of hot water pouring in STEP195) is sequentially notified to the control device 31A of the main water supply device 2A.

[0255] After the start of hot water pouring by the process of STEP172, the control device 31A of the main water heater 2A determines in STEP173 whether or not the total sum of the hot water pouring amounts of all the water heaters 2A and 2B (in other words, the increased amount of the hot water amount in the bathtub BT) has reached a predetermined amount V7 (for example, 80 liters), and repeats this determination process until the determination result becomes affirmative. This determination process is performed in the same manner as the above-mentioned STEP165.

[0256] Then, when the determination result in STEP173 becomes affirmative (when the total sum of the hot water pouring amounts reaches the predetermined amount V7), the control device 31A operates the heat source machine 3 of the main water heater 2A so as to end the hot water pouring from the main water heater 2A to the bathtub BT in STEP174 (controls the hot water pouring solenoid valve 23 to close and stops the operation of the first heating unit 11), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to end the hot water pouring.

[0257] In the auxiliary water heater 2B, since the determination result in STEP197 becomes affirmative by receiving the instruction to end the hot water pouring from the control device 31A of the main water heater 2A, the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B so as to end the hot water pouring from the auxiliary water heater 2B to the bathtub BT in STEP198 (controls the hot water pouring solenoid valve 23 to close and stops the operation of the first heating unit 11). Thereby, the pouring of the predetermined amount V7 of hot water from the entire main water heater 2A and the auxiliary water heater 2B to the bathtub BT is completed.

[0258] Note that after the end of this hot water pouring, the control device 31B executes the process from the above-mentioned STEP199. Thereafter, until the hot water pouring into the bathtub BT is finally completed, the determination result in STEP199 becomes negative, and further, since the determination result in STEP202 described later becomes negative, the control device 31B repeats the determination process in STEP194 via the determination processes in STEP199 and 202.

[0259] When the pouring of a predetermined amount V7 of hot water into the bathtub BT is completed, the control device 31A of the main water heater 2A detects the current water level in the bathtub BT by the water level sensor 22 of the main water heater 2A in STEP175. In STEP175, the control device 31A further calculates and stores the bathtub reference cross-sectional area WH as the cross-sectional area of the bathtub BT in the vicinity of the height of the reference water level H0, and further calculates the shortage amount of hot water V8 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs, which is the target value of the water level set in advance by the bathroom remote control 33A. The processing of STEP175 is performed in the same manner as STEP66 in the second embodiment.

[0260] Next, the control device 31A of the main water heater 2A starts operating the heat source machine 3 of the main water heater 2A to pour hot water into the bathtub BT in STEP176, and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to start pouring hot water into the bathtub BT. The processing of this STEP176 is the same as the processing of STEP164, and the amount of hot water poured from the main water heater 2A into the bathtub BT (the amount of hot water poured from the start of pouring in STEP176) is also sequentially measured.

[0261] On the other hand, in the auxiliary water heater 2B, when the control device 31B repeatedly performs the determination process of STEP194 as described above and receives an instruction to start pouring hot water from the control device 31A of the main water heater 2A, the determination result of STEP194 becomes affirmative, so the process from STEP195 described above is executed. As a result, the pouring of hot water from the auxiliary water heater 2B into the bathtub BT is started, and the measured value of the pouring amount (the measured value of the pouring amount from the start of pouring in STEP195) is sequentially notified to the control device 31A of the main water heater 2A.

[0262] After the start of pouring hot water by the processing of STEP176, the control device 31A of the main water heater 2A repeatedly performs a process of determining whether or not the total of the pouring amounts of all the water heaters 2A and 2B (in other words, the increase amount of the hot water amount in the bathtub BT) has reached the shortage amount of hot water V8 calculated in STEP175 until the determination result becomes affirmative. This determination process is performed in the same manner as STEP165.

[0263] Then, when the determination result in STEP177 becomes affirmative (when the total amount of hot water injection reaches the insufficient hot water amount V8), in STEP178, the control device 31A operates the heat source machine 3 of the main hot water supply device 2A to end the hot water injection from the main hot water supply device 2A to the bathtub BT (controls the hot water injection solenoid valve 23 to close and stops the operation of the first heating unit 11), and instructs the control device 31B of the other hot water supply device 2B (auxiliary hot water supply device 2B) to end the hot water injection.

[0264] In the auxiliary hot water supply device 2B, since the determination result in STEP197 becomes affirmative by receiving the instruction to end the hot water injection from the control device 31A of the main hot water supply device 2A, the control device 31B operates the heat source machine 3 of the auxiliary hot water supply device 2B to end the hot water injection from the auxiliary hot water supply device 2B to the bathtub BT in STEP198 (controls the hot water injection solenoid valve 23 to close and stops the operation of the first heating unit 11). As a result, the injection of the insufficient hot water amount V8 of hot water from the entire main hot water supply device 2A and the auxiliary hot water supply device 2B to the bathtub BT ends.

[0265] When the injection of the insufficient hot water amount V8 of hot water into the bathtub BT ends, the control device 31A of the main hot water supply device 2A detects the current water level in the bathtub BT by the water level sensor 22 of the main hot water supply device 2A in STEP179. In STEP179, the control device 31A further calculates and stores the bathtub cross-sectional area increase rate ΔWH, which is the increase amount per unit height of the cross-sectional area of the bathtub BT at a height above the reference water level H0, and further calculates the insufficient hot water amount V9 required to increase the water level of the bathtub water in the bathtub BT from the current water level to the set water level Hs. The processing of STEP179 is performed in the same manner as STEP70 in the second embodiment.

[0266] Next, the control device 31A of the main water heater 2A starts operating the heat source machine 3 of the main water heater 2A to pour hot water into the bathtub BT in STEP180, and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to start pouring hot water into the bathtub BT. The process of this STEP180 is the same as that of STEP164, and the hot water pouring amount from the main water heater 2A into the bathtub BT (the hot water pouring amount from the start of hot water pouring in STEP180) is also sequentially measured.

[0267] On the other hand, in the auxiliary water heater 2B, since the control device 31B receives the instruction to start pouring hot water from the control device 31A of the main water heater 2A, the determination result of the above STEP194 becomes affirmative, and thus the process from the above STEP195 is executed. As a result, hot water pouring from the auxiliary water heater 2B into the bathtub BT is started, and the measured value of the hot water pouring amount (the measured value of the hot water pouring amount from the start of hot water pouring in STEP195) is sequentially notified to the control device 31A of the main water heater 2A.

[0268] After starting the hot water pouring by the process of STEP180, the control device 31A of the main water heater 2A repeats in STEP181 the process of determining whether the sum of the hot water pouring amounts of all the water heaters 2A and 2B (in other words, the increase amount of the hot water amount in the bathtub BT) has reached the shortage hot water amount V9 calculated in STEP179 until the determination result becomes affirmative. This determination process is performed in the same manner as the above STEP165.

[0269] When the determination result of STEP181 becomes affirmative (when the sum of the hot water pouring amounts reaches the shortage hot water amount V9), the control device 31A operates the heat source machine 3 of the main water heater 2A to end the hot water pouring from the main water heater 2A into the bathtub BT in STEP182 (controls the hot water pouring electromagnetic valve 23 to close and stops the operation of the first heating unit 11), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to end the hot water pouring.

[0270] In the auxiliary water heater 2B, since the control device 31A of the main water heater 2A receives an instruction indicating the end of hot water pouring, the determination result in STEP197 becomes affirmative. Therefore, in STEP198, the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B to end the hot water pouring from the auxiliary water heater 2B into the bathtub BT (closes the electromagnetic valve 23 for hot water pouring and stops the operation of the first heating unit 11). As a result, the pouring of the insufficient hot water volume V9 from the entire main water heater 2A and the auxiliary water heater 2B into the bathtub BT ends.

[0271] When the pouring of the insufficient hot water volume V9 into the bathtub BT ends, the control device 31A of the main water heater 2A executes the processes in STEP183 to 185 to boil the bath water in the bathtub BT. These processes in STEP183 to 185 are the same as the processes in STEP74 to 76 in the second embodiment, and the processes in STEP184 and 185 are executed until the determination result in STEP184 becomes affirmative (until the bath temperature detected by the temperature sensor 20 of the main water heater 2A reaches the set temperature or higher).

[0272] On the other hand, in the auxiliary water heater 2B, since the determination result in STEP199 becomes negative after the pouring of the insufficient hot water volume V9 ends, in STEP202, the control device 31B determines whether it has received an instruction to execute the boiling process from the control device 31A of the main water heater 2A. In this case, since the determination results of the STEP194 and 199 determination processes, which are executed when the determination result in STEP202 becomes negative after the pouring of the insufficient hot water volume V9 ends, become negative, the determination process in STEP202 is repeated through the determination processes in STEP194 and 199 until the determination result becomes affirmative.

[0273] When the determination result in STEP202 becomes affirmative (when an instruction to execute the boiling process is received), the control device 31B performs the same processes as in STEP184 and 185 in the main water heater 2A in STEP203 and 204 to boil the bath water until the determination result in STEP203 becomes affirmative (until the bath temperature detected by the temperature sensor 20 of the auxiliary water heater 2B reaches the set temperature or higher).

[0274] When the determination result in STEP203 is affirmative, the control device 31B stops the operation of the pump 19 of the auxiliary water heater 2B and the second heating unit 13, and then in STEP205, notifies the control device 31A of the main water heater 2A that the bath water temperature has become "OK" in the auxiliary water heater 2B (the bath water temperature detected by the temperature sensor 20 of the auxiliary water heater 2B has become equal to or higher than the set temperature).

[0275] In the main water heater 2A, when the determination result in STEP184 is affirmative (when the boiling of the bathtub water in the main water heater 2A is completed), in STEP186, the control device 31A of the main water heater 2A sequentially repeats determining whether the bath water temperature has become "OK" (whether the detected value of the bath water temperature has become equal to or higher than the set temperature) in all water heaters 2A and 2B until the determination result becomes affirmative. This determination process is performed in the same manner as STEP77 in the second embodiment.

[0276] When the determination result in STEP186 is affirmative, the control device 31A of the main water heater 2A instructs the control device 31B of the other water heater (auxiliary water heater 2B) to perform a notification indicating the completion of the hot water supply in STEP187, and causes the kitchen remote control 32A and the bathroom remote control 33A of the main water heater 2A to perform a notification indicating that the hot water supply is completed. This notification is performed by outputting display information or voice information on the kitchen remote control 32A and the bathroom remote control 33A.

[0277] Also, in the auxiliary water heater 2B, after executing the process of STEP205 described above, the control device 31B sequentially repeats determining whether it has received an instruction from the control device 31A of the main water heater 2A to execute a notification indicating the completion of the hot water supply until the determination result becomes affirmative.

[0278] When the determination result in STEP206 is affirmative (when receiving an instruction to execute the notification indicating the completion of water filling), the control device 31B causes the kitchen remote controller 32B of the auxiliary water heater 2B to give a notification indicating that the water filling is completed in STEP207. This notification is made by the display information on the kitchen remote controller 32B or by outputting voice information. Further, in STEP207, the control device 31B performs a closing control of the water supply amount adjustment valve 16 of the auxiliary water heater 2B. In the bath system 1 of this embodiment, the first water filling operation (the water filling operation in the operation mode for the first water filling operation) is performed as described above.

[0279] Next, the operations related to the water filling operations after the first water filling operation (ordinary water filling operations) will be described. When the control device 31A of the main water heater 2A is instructed to start the water filling operation as described above, if the water filling operation is an ordinary water filling operation after the first water filling operation (specifically, a water filling operation in a state where the execution of the water filling operation in the operation mode for the first water filling operation is not specified), it executes control processing as shown in the flowchart of FIG. 14.

[0280] In the ordinary water filling operation, the control device 31A of the main water heater 2A first notifies the control device 31B of another water heater 2B (auxiliary water heater 2B) of the start of the water filling operation (ordinary water filling operation) in STEP211. Then, the control device 31A executes the control processing of STE212 to 230 related to the operation control of the main water heater 2A (control processing for the ordinary water filling operation).

[0281] Also, upon receiving a notification of the start of normal hot water supply operation from the control device 31A of the main water heater 2A, the control device 31B of the auxiliary water heater 2B executes control processing (control processing for normal hot water supply operation) as shown in the flowchart of FIG. 15. In this case, first, in STEP241, the control device 31B of the auxiliary water heater 2B performs opening control of the water supply amount adjustment valve 16 of the heat source machine 3 of the auxiliary water heater 2B, and then executes the control processing of STEP242 to 254 regarding the operation control of the auxiliary water heater 2B. Also, in the present embodiment, the control processing of the control device 31B of the auxiliary water heater 2B is executed according to an instruction from the control device 31A of the main water heater 2A.

[0282] In the main water heater 2A, in STEP212 and 213 following STEP211, the control device 31A executes the same processing as STEP5162 and 163 during the first hot water supply operation. Also, in the auxiliary water heater 2B, in STEP242 and 243 following STEP241, the control device 31B executes the same processing as STEP192 and 193 during the first hot water supply operation. As a result, in each water heater 2, hot water of a predetermined amount V0 as called water is poured into the bathtub BT.

[0283] Then, when the determination result in STEP213 of the control device 31A of the main water heater 2A becomes affirmative (when the pouring of hot water of the predetermined amount V0 is completed in all water heaters 2A and 2B), next, in STEP214, the control device 31A of the main water heater 2 checks the water flow in the circulation water path 14. This water flow check is performed in the same manner as the water flow check in STEP4 in the first embodiment. Then, based on this water flow check, the control device 31A determines in STEP215 whether the occurrence of continuous water flow has been detected during the operation of the pump 19 (in other words, whether there is remaining hot water in the bathtub BT).

[0284] When the determination result of STEP215 is affirmative (when there is remaining hot water in the bathtub BT), the control device 31A executes the processing from STEP222 described later. When there is no remaining hot water in the bathtub BT and the determination result of STEP215 is negative, the control device 31A next starts operating the heat source machine 3 of the main water supply device 2A to pour hot water into the bathtub BT in STEP216, and instructs the control device 31B of the other water supply device 2B (auxiliary water supply device 2B) to start pouring hot water into the bathtub BT. The processing of this STEP216 is the same as the processing of the above-mentioned STEP164, and the amount of hot water poured from the main water supply device 2A into the bathtub BT (the amount of hot water poured from the start of pouring in STEP216) is also sequentially measured.

[0285] On the other hand, in the auxiliary water supply device 2B, after executing the processing of STEP243, the control device 31B determines in STEP244 whether it has received an instruction to start pouring hot water from the control device 31A of the main water supply device 2A. When the determination result of this STEP244 is affirmative, the control device 31B starts operating the heat source machine 3 of the auxiliary water supply device 2B to pour hot water into the bathtub BT in STEP245. In this case, hot water is poured from the auxiliary water supply device 2B into the bathtub BT in the same manner as the main water supply device 2A.

[0286] Furthermore, the control device 31B sequentially measures the amount of hot water poured into the bathtub BT from the start of pouring (the amount of hot water poured from the start of pouring in STEP245) by sequentially integrating the pouring flow rate detected by the flow rate sensor 24 in the hot water pouring water channel 15 of the auxiliary water supply device 2B. Then, in STEP246, the control device 31B sequentially notifies the control device 31A of the main water supply device 2A of the measured amount of hot water poured. When the determination result of STEP244 is negative, the control device 31B executes the determination processing of STEP249 described later.

[0287] In the main water heater 2A, after the control device 31A starts pouring hot water into the bathtub BT as described above, in STEP 217, it repeats the process of determining whether the sum of the amounts of hot water poured by all water heaters 2A, 2B (in other words, the increase in the amount of hot water in the bathtub BT) has reached a predetermined amount W0+ΔV until the result of the determination becomes positive. This determination process is performed in the same manner as in STEP 165 above. Here, the predetermined amount W0+ΔV is the amount of hot water obtained by adding a predetermined amount ΔV to the standard bathtub water amount W0 stored during the initial water filling operation, and is the amount of hot water set in the same manner as in STEP 117 in the second embodiment.

[0288] Then, when the judgment result of STEP 217 becomes positive (when the total amount of hot water poured reaches a predetermined amount W0+ΔV), in STEP 218, the control device 31A operates the heat source unit 3 of the main water heater 2A to stop pouring hot water from the main water heater 2A to the bathtub BT (controls the water filling solenoid valve 23 to close and stops the operation of the first heating section 11), and instructs the control device 31B of the other water heater 2B (auxiliary water heater 2B) to stop pouring hot water.

[0289] In the auxiliary water heater 2B, while pouring hot water into the bathtub BT, the control device 31B notifies the control device 31A of the main water heater 2A of the measured value of the amount of hot water poured in STEP 246, and in STEP 247 determines whether or not it has received an instruction from the control device 31A to end pouring, and repeats this process repeatedly until the determination result becomes positive.

[0290] Then, if the determination result in STEP 247 becomes positive, in STEP 248, the control device 31B operates the heat source unit 3 of the auxiliary water heater 2B to stop the supply of hot water from the auxiliary water heater 2B to the bathtub BT (controlling the bath filling solenoid valve 23 to close and stopping the operation of the first heating unit 11). This ends the supply of hot water of the predetermined amount W0+ΔV to the bathtub BT from the main water heater 2A and auxiliary water heater 2B as a whole.

[0291] In addition, when the control device 31B of the auxiliary water heater 2B finishes pouring hot water from the auxiliary water heater 2B into the bathtub BT in STEP 248, it determines in STEP 249 whether it has received an instruction to execute the boiling process from the control device 31A of the main water heater 2A. However, once the pouring of the predetermined amount of hot water W0+ΔV into the bathtub BT has finished, no instruction to execute the boiling process is issued, so the determination result in STEP 249 becomes negative. In this case, the control device 31B executes the determination process of STEP 244 described above.

[0292] When the pouring of the predetermined amount of hot water W0+ΔV into the bathtub BT is completed, in the main hot water heater 2A, the control device 31A checks the water flow in the circulation water path 14 of the main hot water heater 2A in STEP 219. This water flow check is performed in the same way as the water flow check in STEP 4 in the first embodiment. Then, in STEP 220, the control device 31A determines whether or not the generation of a continuous water flow has been detected by this water flow check.

[0293] If the judgment result of STEP 220 is negative, there is a possibility that bath water is leaking from the drain outlet of the bathtub BT, etc., so in STEP 221, the control device 31A performs an error stop on all water heaters 2A, 2B (stopping the water filling operation of each water heater 2 in response to the occurrence of an abnormality).

[0294] If the determination result in STEP 220 is affirmative, then in STEP 222, the controller 31A of the main water heater 2A detects the current water level in the bathtub BT using the water level sensor 22 of the main water heater 2A.

[0295] In STEP 222, the control device 31A further calculates the hot water shortage V10 required to increase the bathwater level in the bathtub BT from the current water level to the set water level Hs. This hot water shortage V10 is calculated in the same manner as in STEP 123 in the second embodiment.

[0296] The control device 31A of the main water supply heater 2A then starts, in STEP223, to operate the heat source machine 3 of the main water supply heater 2A to pour water into the bathtub BT, and instructs the control device 31B of the other water supply heater 2B (auxiliary water supply heater 2B) to start pouring water into the bathtub BT. The processing of this STEP223 is the same as the processing of the above-mentioned STEP164, and the amount of water poured from the main water supply heater 2A into the bathtub BT (the amount of water poured since the start of pouring in STEP223) is also sequentially measured.

[0297] On the other hand, in the auxiliary water supply heater 2B, since the control device 31B receives an instruction to start pouring water from the control device 31A of the main water supply heater 2A, the determination result of the above-mentioned STEP244 becomes affirmative, and thus the processing from the above-mentioned STEP245 is executed. As a result, pouring water from the auxiliary water supply heater 2B into the bathtub BT is started, and the measured value of the amount of water poured (the measured value of the amount of water poured since the start of pouring in STEP245) is sequentially notified to the control device 31A of the main water supply heater 2A.

[0298] After starting the pouring water by the processing of STEP223, the control device 31A of the main water supply heater 2A repeatedly performs, in STEP224, a process of determining whether or not the sum of the respective amounts of water poured from all the water supply heaters 2A and 2B (in other words, the increase amount of the amount of hot water in the bathtub BT) has reached the shortage amount of hot water V10 calculated in STEP222 until the determination result becomes affirmative. This determination process is performed in the same manner as the above-mentioned STEP165.

[0299] When the determination result of STEP224 becomes affirmative (when the sum of the amount of water poured reaches the shortage amount of hot water V10), the control device 31A operates, in STEP225, the heat source machine 3 of the main water supply heater 2A to end the pouring water from the main water supply heater 2A into the bathtub BT (controls the hot water discharge solenoid valve 23 to close and stops the operation of the first heating unit 11), and instructs the control device 31B of the other water supply heater 2B (auxiliary water supply heater 2B) to end the pouring water.

[0300] In the auxiliary water heater 2B, since the control device 31A of the main water heater 2A receives an instruction to end the pouring of hot water, the determination result of STEP247 becomes affirmative. Therefore, in STEP248, the control device 31B operates the heat source machine 3 of the auxiliary water heater 2B to end the pouring of hot water from the auxiliary water heater 2B into the bathtub BT (closes the electromagnetic valve 23 for pouring hot water and stops the operation of the first heating unit 11). As a result, the pouring of the insufficient hot water volume V10 from the entire main water heater 2A and the auxiliary water heater 2B into the bathtub BT ends.

[0301] When the pouring of the insufficient hot water volume V10 into the bathtub BT ends, the control device 31A of the main water heater 2 executes the same processes as those in STEP183 to 187 in the first pouring operation in STEP226 to 230. Also, the control device 31B of the auxiliary water heater 2B executes the same processes as those in STEP203 to 207 in the first pouring operation in STEP250 to 254 in response to the affirmative determination result of STEP249.

[0302] As a result, the process of boiling the bathtub water is executed in each water heater 2, and after the completion of the boiling process, a notification indicating the completion of the pouring of hot water is given. Also, in the auxiliary water heater 2B, the water supply adjustment valve 16 is controlled to be closed.

[0303] In the bathtub system 1 of the present embodiment, the normal pouring operation after the execution of the first pouring operation is performed as described above. As a supplement, in the present embodiment, the entire control processes of the control devices 31A and 31B in the normal pouring operation correspond to the pouring operation process in the present invention. And the processes in STEP216 to 218 in the main water heater 2A regarding pouring a predetermined amount W0 + ΔV of hot water into the bathtub BT and the processes in STEP245 to 248 first executed in the auxiliary water heater 2B correspond to the first process in the present invention.

[0304] In addition, the process of STEP222 (water level detection process) in the main water heater 2A corresponds to the second process in the present invention. Also, the processes of STEP223 to 225 in the main water heater 2A regarding pouring hot water with a shortage hot water amount V10 into the bathtub BT and the processes of STEP245 to 248 executed the second time in the auxiliary water heater 2B correspond to the third process in the present invention.

[0305] According to the third embodiment described above, the same effects as those of the second embodiment can be achieved. Also, pouring the required amount of hot water into the bathtub BT can be executed without setting the hot water pouring amount for each water heater 2. Therefore, even if any one of the water heaters 2 cannot pour hot water normally, the required amount of hot water can be poured into the bathtub BT.

[0306] [Other Embodiments] Note that the present invention is not limited to the embodiments described above, and other embodiments can also be adopted. Some other embodiments will be described below. In each of the above embodiments, in the normal hot water pouring operation, as a process corresponding to the first process in the present invention, the process of pouring hot water with W0 + ΔV into the bathtub BT by each water heater 2 (the process of STEP36 in the first embodiment, the processes of STEP118 and STEP145 in the second embodiment, and the processes of STEP216 to 218 and the processes of STEP245 to 248 executed first in the third embodiment) is executed.

[0307] However, in the first process, pouring a predetermined amount of hot water into the bathtub BT by each water heater 2 may be executed in multiple times. For example, in the first embodiment, for each water heater, the hot water amount that matches the reference bathtub water amount W0 or the hot water amount obtained by adding a predetermined amount ΔV to the reference bathtub water amount W0 may be divided into multiple portions, and the hot water amount of each division may be sequentially poured into the bathtub BT. And in this case, for example, each time the pouring of the hot water amount of each division is completed by each water heater 2, a water flow check is performed. When the generation of water flow is detected in all the water heaters 2A and 2B due to the remaining water existing in the bathtub BT, the pouring of the hot water amount of each division by each water heater 2 is stopped, and the shortage hot water amount from the current water level to the set water level is calculated for each water heater 2, and the hot water of the shortage hot water amount may be poured from each water heater 2 into the bathtub BT.

[0308] Also, for example, in the second or third embodiment, the amount of hot water that matches the reference bathtub water amount W0, or the amount of hot water obtained by adding a predetermined amount ΔV to the reference bathtub water amount W0, may be divided into a plurality of portions, and the hot water amount of each portion may be repeatedly poured from the entire hot water supply devices 2A and 2B into the bathtub BT. And in this case, for example, each time the pouring of the hot water amount of each portion from the entire hot water supply devices 2A and 2B is completed, the water flow is checked with the main hot water supply device 2A. When the generation of the water flow is detected by the main hot water supply device 2A due to the remaining water present in the bathtub BT, the pouring of the divided hot water amount into the bathtub BT is stopped, and the shortage hot water amount from the current water level to the set water level is calculated, and the hot water of the shortage hot water amount may be poured from the entire hot water supply devices 2A and 2B into the bathtub BT.

[0309] Also, in the second embodiment, the pouring distribution ratio for each hot water supply device 2 is determined according to the pouring flow rate of each hot water supply device 2 measured when pouring the hot water of a predetermined amount V0 immediately after the start of the pouring operation. However, for example, the pouring flow rate of each hot water supply device 2 is measured immediately after the start of the pouring in the first process (pouring of (W0 + ΔV)) and the pouring in the third process (pouring of the shortage hot water amount V10), and the distribution ratio of each hot water supply device 2 in each of the first process and the third process is determined according to the measured value of the flow rate. In this case, even when the pouring flow rate of each hot water supply device 2 fluctuates within the period of each pouring operation, it is possible to set a suitable distribution ratio to complete the pouring in each of the first process and the third process (pouring by all the hot water supply devices 2A and 2B) in a short time.

[0310] Also, the detection of the water level (second process) in STEP123 in the second embodiment or STEP222 in the third embodiment may be executed by the control device 31B of the hot water supply device 2B (auxiliary hot water supply device 2B) other than the main hot water supply device 2A in response to an instruction from the control device 31A of the main hot water supply device 2A, and the detected value of the water level thus obtained may be notified from the control device 31B to the control device 31A of the main hot water supply device 2A.

[0311] In the second embodiment, when the main water heater 2A performs the water flow check in STEP115 and 120, the auxiliary water heater 2B may also perform the water flow check. In the determination processes of STEP116 and 121, for example, when continuous water flow is detected in all the water heaters 2A and 2B, it may be determined that the respective determination results are affirmative. This also applies to the water flow check in STEP214 and 219 and the determination processes in STEP215 and 220 in the third embodiment.

[0312] Also, the water flow check in STEP4 or STEP33 in the first embodiment may be executed after confirming that the hot water pouring has stopped in all the water heaters 2A and 2B.

[0313] In the first embodiment or the second embodiment, the hot water boiling process for the bathtub water in each water heater 2 (the process from STEP17, the process from STEP44, the process from STEP75, the process from STEP101, the process from STEP128, the process from STEP151) is executed after the completion of the hot water pouring in all the water heaters 2A and 2B. However, the hot water boiling process for the bathtub water in each water heater 2 may be started after the completion of the hot water pouring in each water heater 2 (regardless of whether the hot water pouring in other water heaters 2 has ended). In that case, the processes in STEP16 and 43 in the first embodiment are unnecessary, and the processes in STEP73, 74, 99, 100, 126, 127, 149, and 150 in the second embodiment are unnecessary.

[0314] In each of the above embodiments, the bathtub system 1 including two water heaters 2A and 2B is exemplified. However, the bathtub system 1 of this embodiment may be a system including three or more water heaters.

Explanation of Reference Numerals

[0315] 1... Bathtub system, 2A... Water heater (main water heater),

Claims

1. A bathtub system comprising a plurality of water heaters connected to be able to pour hot water into a single bathtub, and configured to perform a hot water filling operation for filling the bathtub to a set water level by pouring hot water from the plurality of water heaters into the bathtub when receiving an instruction for a hot water filling operation, wherein the hot water filling operation includes a first process of performing, one or more times, pouring a predetermined amount of hot water from the plurality of water heaters into the bathtub, a second process of detecting the water level in the bathtub in a state where all the hot water pouring operations of the plurality of water heaters are stopped after the pouring of hot water into the bathtub in the first process has ended for all of the plurality of water heaters, and a third process of pouring, from the plurality of water heaters into the bathtub, an amount of hot water that should be poured into the bathtub from the detected water level in the second process up to the set water level. The bathtub system is characterized by including these processes.

2. In the bathtub system according to Claim 1, when performing the first hot water filling into the bathtub, the plurality of water heaters are configured to pour hot water into the bathtub in an operation mode for the first hot water filling operation and to acquire bathtub characteristic data regarding the relationship between the amount of hot water poured into the bathtub and the water level of the bathtub for each water heater, the hot water filling operation is a process executed during a hot water filling operation other than the first hot water filling operation. In the first process of the hot water filling operation, the predetermined amount of hot water poured from the plurality of water heaters into the bathtub is an amount of hot water set for each water heater according to the bathtub characteristic data acquired by each water heater. In the second process, the water level is detected for each water heater. In the third process, each water heater is configured to pour, from each water heater into the bathtub, an amount of hot water determined for each water heater based on the water level detected in the second process at the water heater, the set water level, and the bathtub characteristic data acquired at the water heater. The bathtub system is characterized by this configuration.

3. In the bathtub system according to Claim 2, the plurality of water heaters are configured to perform the detection of the water level in the second process in parallel with each other. The bathtub system is characterized by this configuration.

4. In the bathtub system according to Claim 1, when performing the first hot water filling into the bathtub, the plurality of water heaters are configured to pour hot water into the bathtub in an operation mode for the first hot water filling operation, and a main water heater, which is one specific water heater among the plurality of water heaters, is configured to acquire bathtub characteristic data regarding the relationship between the amount of hot water poured into the bathtub and the water level of the bathtub. The hot water filling operation process is a process executed during hot water filling operations other than the first hot water filling. Among the first processes in the hot water filling operation process, the predetermined amount of hot water poured from the plurality of water heaters into the bathtub is the amount of hot water set according to the bathtub characteristic data acquired by the main water heater, and is distributed to each of the plurality of water heaters at a predetermined distribution ratio, which is the amount of hot water for each water heater. In the second process, only one of the plurality of water heaters performs water level detection. In the third process, each water heater is configured to pour hot water into the bathtub from each water heater, where the amount of hot water is determined based on the water level detected in the second process, the set water level, and the bathtub characteristic data acquired by the main water heater, and is distributed to each of the plurality of water heaters at a predetermined distribution ratio. A bathtub system characterized by this.

5. In the bathtub system according to claim 4, Before the execution of the first process, the hot water filling operation process further includes a fourth process of pouring a predetermined amount of hot water for priming into the hot water supply water channels connected to the bathtub corresponding to each of the plurality of water heaters from each water heater, and a fifth process of measuring the hot water filling flow rate from each water heater to the bathtub for each water heater in the fourth process. A bathtub system characterized in that the predetermined distribution ratio in each of the first process and the third process is a ratio determined according to the measured value of the hot water filling flow rate for each water heater in the fifth process.

6. In the bathtub system according to claim 4, The hot water filling operation process further includes a sixth process of measuring the hot water filling flow rate from each water heater to the bathtub for each water heater immediately after the start of hot water filling from each water heater in the first process, and a seventh process of measuring the hot water filling flow rate from each water heater to the bathtub for each water heater immediately after the start of hot water filling from each water heater in the third process. A bathtub system characterized in that the predetermined distribution ratio in the first process is a ratio determined according to the measured value of the hot water filling flow rate for each water heater in the sixth process, and the predetermined distribution ratio in the third process is a ratio determined according to the measured value of the hot water filling flow rate for each water heater in the seventh process.

7. In the bathtub system according to claim 1, The plurality of water heaters perform pouring water into the bathtub in an operation mode for the first water pouring operation when initially pouring water into the bathtub, and a main water heater, which is one specific water heater among the plurality of water heaters, is configured to acquire bathtub characteristic data regarding the relationship between the amount of water poured into the bathtub and the water level of the bathtub. The water pouring operation process is a process executed during a water pouring operation other than the first water pouring operation. The predetermined amount of water for pouring water from the plurality of water heaters into the bathtub in the first process of the water pouring operation process is an amount of water set according to the bathtub characteristic data acquired by the main water heater as the total amount of water poured into the bathtub from each of the plurality of water heaters. In the first process, when pouring the predetermined amount of water from the plurality of water heaters into the bathtub, while pouring water from each of the plurality of water heaters into the bathtub, the amount of water poured from each water heater into the bathtub is sequentially measured, and when the sum of the measured values of the amount of water poured reaches the predetermined amount, the pouring of water from each water heater into the bathtub is stopped. In the second process, only one water heater among the plurality of water heaters performs water level detection. In the third process, while pouring water from each of the plurality of water heaters into the bathtub, the amount of water poured from each water heater into the bathtub is sequentially measured, and when the sum of the measured values of the amount of water poured reaches an amount of water determined based on the water level detected in the second process, the set water level, and the bathtub characteristic data acquired by the main water heater, the pouring of water from each water heater into the bathtub is stopped. A bathtub system characterized by being configured as described above.

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