water heater

Abstract

To provide a water heater which can accurately determine if a circulation abnormality occurs in a bath circulation circuit.SOLUTION: A water heater according to the disclosure includes: a bath circulation circuit including a circulation passage for taking out hot water in a bathtub to the outside of the bathtub and returning the hot water into the bathtub; a bath circulation pump which circulates hot water in the bath circulation circuit; pressure sensors which are provided at several positions of the bath circulation circuit and detect pressure in the bath circulation circuit at installation positions; and a control unit which acquires detection values of the pressure sensors and controls the bath circulation pump. The control unit acquires a difference between the detection values of the pressure sensors when the bath circulation pump is driven at a predetermined rotation number to circulate the hot water in the bath circulation circuit in predetermined reference conditions as a reference value and determines that a circulation abnormality occurs in the bath circulation pump when a value of a difference between detection values of the pressure sensors when the bath circulation pump is driven at the predetermined rotation number to circulate the hot water in the bath circulation circuit after acquisition of the reference value is different from the reference value by a specified or larger value.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] <7>The present disclosure relates to a water heater.

Background Art

[0002] In a conventional water heater disclosed in Patent Document 1 below, when circulating the hot water in the bathtub, a device has been proposed that uses a plurality of pressure sensors to calculate the flow rate from their pressure difference to detect the presence or absence of circulation (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when clogging occurs between the pressure sensors in the device proposed in Patent Document 1, the pressure difference increases, so it is determined that there is a flow rate, and there is a problem that it is determined that circulation is possible even though circulation is not possible.

[0005] The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide a water heater that can accurately determine an abnormal circulation of a bathtub circulation circuit.

Means for Solving the Problems

[0006] The water heater according to the present disclosure includes a bathtub circulation circuit having a circulation flow path for taking out the hot water in the bathtub to the outside of the bathtub and then returning it to the bathtub, a bathtub circulation pump for circulating the hot water in the bathtub circulation circuit, A hot water storage tank for storing hot water, a bath heat exchanger installed in the bath circulation circuit for exchanging heat between the hot water in the storage tank and the bath water, and at least one on the upstream and downstream side of the bath heat exchanger.The system includes pressure sensors installed at multiple locations in the bath circulation circuit to detect the pressure within the bath circulation circuit at those locations, and a control unit that acquires the detected values ​​from the pressure sensors and controls the bath circulation pump. The control unit acquires the difference between the detected values ​​from the multiple pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed to circulate hot water in the bath circulation circuit under predetermined reference conditions. After acquiring the reference value, if the difference between the detected values ​​from the multiple pressure sensors when the bath circulation pump is driven at a predetermined rotational speed to circulate hot water in the bath circulation circuit is greater than or equal to a predetermined value compared to the reference value, the control unit determines that a circulation abnormality has occurred in the bath circulation circuit. Furthermore, the water heater according to this disclosure includes a bath circulation circuit equipped with a circulation channel that takes the hot water from the bathtub out of the bathtub and returns it to the bathtub, a bath circulation pump that circulates the hot water in the bath circulation circuit, pressure sensors installed at multiple locations in the bath circulation circuit that detect the pressure in the bath circulation circuit at the installation locations, and a control unit that acquires the detected values ​​of the pressure sensors and controls the bath circulation pump. The control unit is configured to acquire the difference between the detected values ​​of the multiple pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit under a predetermined reference state, and after acquiring the reference value, if the difference between the detected values ​​of the multiple pressure sensors when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit is greater than or equal to a predetermined value compared to the reference value, it determines that a circulation abnormality has occurred in the bath circulation circuit. When the control unit determines that there is a circulation abnormality in the bath circulation circuit, it is equipped with a notification means that stops the bath circulation pump and notifies the user, and when notifying the user with the notification means, it identifies the location of the circulation abnormality based on the numerical value of the pressure difference acquired by the control unit and notifies the user with the notification means. Furthermore, the water heater according to this disclosure includes a bath circulation circuit equipped with a circulation channel that takes the hot water in the bathtub out of the bathtub and returns it to the bathtub, a bath circulation pump that circulates the hot water in the bath circulation circuit, pressure sensors installed at multiple locations in the bath circulation circuit that detect the pressure in the bath circulation circuit at the installation locations, and a control unit that acquires the detected values ​​of the pressure sensors and controls the bath circulation pump. The control unit is configured to acquire the difference between the detected values ​​of the multiple pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit under a predetermined reference state, and after acquiring the reference value, if the difference between the detected values ​​of the multiple pressure sensors when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit is greater than or equal to a predetermined value compared to the reference value, it determines that a circulation abnormality has occurred in the bath circulation circuit. The water heater further includes a bubble injection means for injecting bubbles into the bath circulation circuit, and the control unit is configured not to perform a pressure difference determination of the pressure sensors if bubbles are injected into the circulating hot water by the bubble injection means while the bath circulation pump is circulating the hot water in the bath circulation circuit. Furthermore, the water heater according to this disclosure includes a bath circulation circuit equipped with a circulation channel that takes the hot water in the bathtub out of the bathtub and returns it to the bathtub, a bath circulation pump that circulates the hot water in the bath circulation circuit, pressure sensors installed at multiple locations in the bath circulation circuit that detect the pressure in the bath circulation circuit at the installation locations, and a control unit that acquires the detected values ​​of the pressure sensors and controls the bath circulation pump. The control unit is configured to acquire the difference between the detected values ​​of the multiple pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit under a predetermined reference state, and after acquiring the reference value, if the difference between the detected values ​​of the multiple pressure sensors when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit is greater than or equal to the reference value, it determines that a circulation abnormality has occurred in the bath circulation circuit. Before acquiring the reference value, the control unit determines that a circulation abnormality has occurred in the bath circulation circuit if the difference between the detected values ​​of the pressure sensors when the bath circulation pump is driven at a predetermined rotational speed to circulate the hot water in the bath circulation circuit is greater than or equal to a predetermined value compared to a pre-stored initial value. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a water heater that can accurately detect circulation abnormalities in the bath circulation circuit. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing a water heater according to Embodiment 1. [Figure 2] This is a diagram illustrating the flow of hot and cold water when bath circulation operation is performed in the storage-type hot water heater of Embodiment 1. [Figure 3] This is a flowchart of the control for determining a circulation abnormality in the bath circulation circuit in Embodiment 1. [Modes for carrying out the invention]

[0009] Embodiments will be described below with reference to the drawings. Common or corresponding elements in each drawing are denoted by the same reference numerals, and their descriptions are simplified or omitted. In the following description, terms such as "water," "hot water," "warm water," and "hot water" generally refer to liquid water, and may include water ranging from cold to boiling. Furthermore, the configurations shown in the embodiments below are examples of the technical ideas related to this disclosure and can be combined with other known technologies, or multiple technical ideas described in this disclosure can be combined. In addition, it is possible to omit or modify parts of the configuration without departing from the gist of this disclosure.

[0010] Embodiment 1. Figure 1 shows a water heater according to Embodiment 1. In this embodiment, the case in which the water heater of this disclosure is applied to a storage-type water heater will be described as an example, but the water heater of this disclosure can also be applied to water heaters that are not of the storage type. As shown in Figure 1, the storage-type water heater 35 of this embodiment includes a tank unit 33, an HP unit 7 that utilizes a heat pump cycle, and a remote control 44 for issuing operation commands or changing set values. The HP unit 7 and the tank unit 33 are connected via HP supply piping 14, HP return piping 15, and electrical wiring (not shown). A control unit 36 ​​is built into the tank unit 33. The operation of various valves, pumps, etc., provided in the tank unit 33 and the HP unit 7 is controlled by the control unit 36, which is electrically connected to them. The control unit 36 ​​and the remote control 44 are connected to communicate with each other. The remote control 44 is equipped with a display unit that displays information such as the status of the storage-type water heater 35, an operating unit such as switches for the user to operate, a speaker, a microphone, etc. (not shown). The display unit of the remote control 44 functions as a means of informing the user of information.

[0011] The HP unit 7 functions as a heating means for heating the low-temperature water supplied from the hot water storage tank 8 located in the tank unit 33. The HP unit 7 consists of a compressor 1, a water-refrigerant heat exchanger 3, an expansion valve 4, and an air heat exchanger 6, all connected in a ring shape by refrigerant piping 5 to form a heat pump cycle. The water-refrigerant heat exchanger 3 is used for heat exchange between the refrigerant flowing through the refrigerant piping 5 and the low-temperature water supplied from the tank unit 33.

[0012] The tank unit 33 incorporates the following various components and piping. The hot water storage tank 8 is for storing hot water. The third water supply pipe 9c is connected to the water inlet 8a located at the bottom of the hot water storage tank 8. Water supplied from a water source such as a water supply is regulated to a predetermined pressure by the pressure reducing valve 31 before flowing into the hot water storage tank 8 through the third water supply pipe 9c. The hot water inlet outlet 8d located at the top of the hot water storage tank 8 is connected to the hot water supply pipe 21 for supplying the hot water stored in the hot water storage tank 8 to the outside of the hot water storage type water heater 35, and to the upper hot water supply pipe 13b. High-temperature hot water heated by the HP unit 7 flows into the hot water storage tank 8 from the hot water inlet outlet 8d, and low-temperature water from the third water supply pipe 9c flows in from the water inlet 8a, so that a temperature difference is created between the upper and lower parts of the hot water storage tank 8. In addition, multiple hot water storage temperature sensors 41, 42, and 43 are mounted on the surface of the hot water storage tank 8 at different heights. By detecting the temperature distribution of the hot water in the hot water storage tank 8 using these hot water temperature sensors 41, 42, and 43, the amount of remaining hot water in the hot water storage tank 8 is determined, and the HP unit 7 controls the start and stop of the hot water heating operation in the hot water storage tank 8.

[0013] The tank unit 33 contains a heat source pump 12 and a bath heat exchanger 20. The heat source pump 12 is a pump for circulating hot water through various pipes in the tank unit 33, which will be described later, and is installed on the HP supply pipe 14. The bath heat exchanger 20 is a heat exchanger for heating the bath water, which is the water to be heated on the secondary side, using high-temperature hot water supplied from the hot water storage tank 8 or the HP unit 7. In this embodiment, the bath supply pipe 27a and the bath return pipe 28, which form a bath circulation circuit that circulates the hot water in the bath 30, are illustrated and described as examples of the configuration on the secondary side of the bath heat exchanger 20. The bath heat exchanger 20 is installed in the middle of the bath supply pipe 27a and the bath return pipe 28. Furthermore, a bath circulation pump 29 for circulating bath water, a bath return temperature sensor 38 for detecting the temperature of bath water coming out of the bath 30, and a bath supply temperature sensor 37 for detecting the temperature of the heat-exchanged water coming out of the bath heat exchanger 20 are installed in the middle of the bath supply pipe 27a and the bath return pipe 28.

[0014] The inlet three-way valve 11a is a flow path switching means having ports a and b through which hot water flows in, and port c through which hot water flows out. The medium-temperature three-way valve 11b is a flow path switching means having ports a and b through which hot water flows in, and port c through which hot water flows out. The medium-temperature four-way valve 18a is a flow path switching means having ports b and c through which hot water flows in, and ports a and d through which hot water flows out, and is configured to allow switching of flow paths between four paths, ab, ac, bd, and cd. The tank unit 33 also has a water outlet pipe 10, a hot water introduction pipe 20a, a first bypass pipe 16, a hot water outlet pipe 20b, and a second bypass pipe 17. The water outlet pipe 10 connects the water outlet 8b located at the bottom of the hot water storage tank 8 to port a of the inlet three-way valve 11a. The HP supply pipe 14 connects port c of the inlet three-way valve 11a to the inlet side of the HP unit 7. The HP return pipe 15 connects the outlet side of the HP unit 7 to the c port of the medium-temperature four-way valve 18a. The lower hot water supply pipe 13a connects the d port of the medium-temperature four-way valve 18a to the a port of the medium-temperature four-way valve 18b. The first bypass pipe 16 connects the a port of the medium-temperature four-way valve 18a to the hot water inlet 8c located between the center and the bottom of the hot water storage tank 8. The hot water supply pipe 20a connects the c port of the medium-temperature four-way valve 18b to the primary side inlet of the bath heat exchanger 20. The hot water outlet pipe 20b connects the primary side outlet of the bath heat exchanger 20 to the b port of the inlet three-way valve 11a. The second bypass pipe 17 branches off from between the heat source pump 12 and the inlet side of the HP unit 7 in the HP supply pipe 14 and connects to the b port of the medium-temperature four-way valve 18a.

[0015] The upper hot water supply piping 13b connects the d port of the medium-temperature four-way valve 18a to the hot water inlet outlet 8d at the top of the hot water storage tank 8. The first medium-temperature piping 19a connects the b port of the medium-temperature four-way valve 18b to the medium-temperature water inlet 8e located in the middle of the hot water storage tank 8.

[0016] The water inlet three-way valve 11a is used by switching the flow path of the hot and cold water in the tank unit 33 between two flow path forms: a form in which the water outlet pipe 10 and the HP forward pipe 14 communicate, and a form in which the hot water outlet pipe 20b and the HP forward pipe 14 communicate. The second medium-temperature pipe 19b is connected between the medium-temperature water outlet 8f provided in the middle part of the hot water storage tank 8 and the b port of the medium-temperature three-way valve 11b. The medium-temperature three-way valve 11b is used by switching the flow path of the hot and cold water in the tank unit 33 between two flow path forms: a form in which the second water supply pipe 9b and the fourth water supply pipe 9d communicate, and a form in which the second medium-temperature pipe 19b and the fourth water supply pipe 9d communicate. The four-way valve 18a for medium temperature uses four flow path forms, namely, a form in which the HP return pipe 15 and the lower hot water supply pipe 13a communicate, a form in which the HP return pipe 15 and the first bypass pipe 16 communicate, a form in which the first bypass pipe 16 and the second bypass pipe 17 communicate, and a form in which the lower hot water supply pipe 13a and the second bypass pipe 17 communicate, to switch and use the flow path of the hot and cold water in the tank unit 33.

[0017] The water inlet three-way valve 11a conducts the a port and the c port, the four-way valve 18a for medium temperature conducts the c port and the d port, and the four-way valve 18b for medium temperature conducts the a port and the d port to form a flow path for flowing the hot and cold water at the lower part of the hot water storage tank 8 to the upper hot water supply pipe 13b. An intermediate hot water storage temperature sensor 42 is installed in the middle part of the hot water storage tank 8, and a lower hot water storage temperature sensor 43 is installed at the lower part thereof, and the temperatures of the respective hot and cold waters can be measured.

[0018] Furthermore, the tank unit 33 has a first water supply pipe 9a, a second water supply pipe 9b, a mixing valve 22 for hot water supply, a mixing valve 23 for bath use, a first hot water supply pipe 24, and a second hot water supply pipe 25. One end of the first water supply pipe 9a is connected to a water source such as a water supply, and the second water supply pipe 9b and the third water supply pipe 9c are connected to the other end of the first water supply pipe 9a via a pressure reducing valve 31. The fourth water supply pipe 9d branches off midway and is connected to the mixing valve 22 for hot water supply and the mixing valve 23 for bath use, respectively. Also, the hot water supply pipe 21 branches off midway and is connected to the mixing valve 22 for hot water supply and the mixing valve 23 for bath use, respectively. In the middle of the second hot water supply pipe 25, a solenoid valve 26 for bath use for opening and closing the second hot water supply pipe 25 and a flow sensor 45 for bath use for detecting the flow rate of the hot water passing through the second hot water supply pipe 25 are provided.

[0019] The hot water mixing valve 22 for hot water supply and the hot water mixing valve 23 for bath adjust the flow rate ratio between the high-temperature hot water supplied from the hot water supply pipe 21 and the low-temperature water supplied from the fourth water supply pipe 9d, thereby generating hot water at the set temperature set by the user with the remote control 44 and flowing it into the first hot water supply pipe 24 and the second hot water supply pipe 25 respectively. The hot water whose temperature is adjusted by the hot water mixing valve 22 is supplied from the first hot water supply pipe 24 via the hot water faucet 34 to a faucet (not shown) such as a shower or a faucet that the user uses. On the other hand, the hot water adjusted to the set temperature by the hot water mixing valve 23 for bath is supplied from the second hot water supply pipe 25 to the bathtub 30 through the electromagnetic valve 26 for bath, the flow sensor 45 for bath, the bath forward pipe 27a, and the bath return pipe 28.

[0020] Also, a first pressure sensor 39a is provided in the bath forward pipe 27a, and a second pressure sensor 39b is provided in the bath return pipe 28. At this time, each pressure sensor is installed so as to sandwich the heat exchanger 20 for bath. This is because a pressure difference is likely to occur when the bath circulation circuit is circulated by sandwiching a component such as the heat exchanger 20 for bath that is likely to cause a pressure loss.

[0021] Also, the first pressure sensor 39a and the second pressure sensor 39b are both arranged to be located downstream of the bath circulation pump 29. In this way, it is desirable to install both the first pressure sensor 39a and the second pressure sensor 39b either upstream or downstream of the bath circulation pump 29. This is because if they are installed straddling the bath circulation pump 29, it becomes difficult to obtain an accurate pressure difference ΔP because the pressure fluctuates due to the drive of the bath circulation pump 29.

[0022] In this embodiment, an example is described in which two pressure sensors, a first pressure sensor 39a and a second pressure sensor 39b, are provided. However, three or more pressure sensors may be provided in the bath circulation circuit. In that case, it is desirable that the pressure sensors be installed so that there is at least one on the upstream side and one on the downstream side of the bath heat exchanger 20. Furthermore, it is desirable that all pressure sensors be installed on the upstream side of the bath circulation pump 29, or that all pressure sensors be installed on the downstream side of the bath circulation pump 29.

[0023] The remote control 44 is equipped with an automatic bath operation function. When automatic bath operation is set, the system fills the bathtub with water to the temperature and volume set on the remote control 44. After that, the system maintains the set temperature and water level by keeping the bathwater warm and adding more hot water as needed. When filling the bathtub with water, the system drives the bath circulation pump 29 to check for the presence of water in the bathtub 30 when filling the bathtub with the volume set on the remote control 44. At this time, the bath circulation pump 29 is driven at a predetermined rotation speed (for example, 6000 rpm) to obtain values ​​from the first pressure sensor 39a and the second pressure sensor 39b, thereby obtaining the pressure difference in the bathtub 30 when there is bathwater in it, when the bath circulation pump 29 is driven at a predetermined rotation speed under standard conditions. Using this value as a reference value, the system checks the pressure difference when the bath circulation pump 29 is driven at a predetermined rotation speed when determining the presence or absence of water in the bath circulation circuit or when detecting pipe blockages, and determines whether circulation is occurring in the bath circulation circuit. By pre-acquiring reference values ​​for the rotational speed of the bath circulation pump 29 at multiple different predetermined rotational speeds, it is possible to determine whether there is an abnormality in the circulation state under different operating conditions where the rotational speed of the bath circulation pump 29 is different.

[0024] Figure 2 is a diagram illustrating the flow of hot and cold water when bath circulation operation is performed in the storage-type water heater 35 of Embodiment 1. Thick lines in the figure indicate the circuits through which hot and cold water flows, and arrows indicate the flow of hot and cold water. Figure 3 is a flowchart of the control for determining circulation abnormalities in the bath circulation circuit in Embodiment 1. The determination of whether or not circulation is occurring in the bath circulation circuit is explained using the flowchart.

[0025] In step S1, the bath circulation pump 29 is driven at a predetermined rotational speed to detect whether or not circulation is occurring in the bath circulation circuit. In step S2, the values ​​P1 and P2 from the first pressure sensor 39a and the second pressure sensor 39b are obtained, and the pressure difference ΔP between P1 and P2 is calculated. In step S3, a waiting time of 1 minute is provided to allow for the discharge of any remaining water in the bath piping. In step S4, if ΔP is less than a first predetermined value ΔP1 (e.g., 5kPa), it is determined that there is no bath water, or that there is a blockage in the piping on the secondary side of the first pressure sensor 39a or the primary side of the second pressure sensor 39b in the bath circulation circuit. Then, in step S5, the bath circulation pump 29 is stopped, and in step S6, the remote control 44 is displayed indicating that there is no bath water or that there is a blockage in the bath piping, i.e., that there is a circulation abnormality in the bath circulation circuit. At this time, it may also be announced that there is a possibility of a blockage in the piping on the secondary side of the first pressure sensor 39a or the primary side of the second pressure sensor 39b in the bath circulation circuit. In this way, the control unit 36 ​​identifies the location of the circulation abnormality based on the pressure difference value it acquires, and notifies the system via the notification means, thereby improving convenience.

[0026] If ΔP is greater than or equal to the first predetermined value ΔP1 in step S4, then in step S7, if ΔP is greater than or equal to the second predetermined value ΔP2 (for example, 15 kPa), it is determined that a blockage has occurred between the first pressure sensor 39a and the second pressure sensor 39b. The second predetermined value ΔP2 is the value calculated by the following formula. ΔP2 = Reference value + Specific value If ΔP is greater than or equal to the second predetermined value ΔP2 in step S7, this corresponds to a case where ΔP differs from the reference value by a predetermined value or more.

[0027] After step S7, step S8 stops the bath circulation pump 29, and step S9 displays on the remote control 44 that a blockage has occurred in the product, i.e., a circulation abnormality has occurred in the bath circulation circuit. At this time, it may also be announced that a blockage has occurred between the first pressure sensor 39a and the second pressure sensor 39b. In this way, convenience is improved by identifying the location of the circulation abnormality based on the pressure difference value acquired by the control unit 36 ​​and notifying it with the notification means.

[0028] If ΔP is less than the second predetermined value ΔP2 in step S7, step S10 is performed to check the elapsed time (e.g., 5 minutes) since the bath circulation pump 29 was started. If the predetermined elapsed time has not passed, steps S4 and S7 are repeated to check for any circulation abnormalities during bath circulation. If the bath circulation pump 29 has been run for the predetermined time, step S11 is performed to stop the bath circulation pump 29 and complete the determination of whether or not there is circulation in the bath circulation circuit.

[0029] In addition, when draining the bathtub 30, if a function is implemented to clean the inside of the bath supply pipe 27a and bath return pipe 28 by generating microbubbles using a bubble injection means (not shown), there is a possibility of false pressure detection due to the bubbles inside the pipes. Therefore, the determination of whether or not the bath circulation circuit is circulating is prohibited, and the pressure sensor does not perform pressure difference determination.

[0030] When performing a test run immediately after installing the product, before obtaining a baseline value at a predetermined rotation speed (e.g., 6000 rpm), the difference in the value detected by the pressure sensor is compared to a pre-stored initial value (e.g., 10 kPa) to see if the difference is greater than or equal to the predetermined value. For example, if there are problems such as blockages or crushing in the bathtub circulation piping in an existing house, and only the water heater is replaced, it would be impossible to determine the circulation abnormality without an initial value when the water heater is first circulated after installation. However, by comparing the current value with this initial value, the circulation abnormality can be determined, improving convenience.

[0031] Furthermore, if the water heater acquires an inappropriate reference value due to faulty plumbing work on the house side or incorrect connection of pipes or parts, even if the faulty work is corrected, the water heater may still incorrectly detect a circulation abnormality if the reference value is not appropriate. To address this, after correcting the faulty work, it may be advisable to operate the reset mechanism to reset the reference value and then acquire the reference value again. This makes it possible to avoid false detections caused by acquiring incorrect initial values ​​due to faulty work.

[0032] The various aspects of this disclosure are summarized below as an appendix.

[0033] (Note 1) A bath circulation circuit includes a circulation channel that takes the hot water from the bathtub out of the bathtub and then returns it to the bathtub, A bath circulation pump that circulates the hot water in the aforementioned bath circulation circuit, Pressure sensors are installed at multiple locations in the bath circulation circuit to detect the pressure within the bath circulation circuit at the installation locations, A control unit that acquires the detected value from the pressure sensor and controls the bath circulation pump, Equipped with, The control unit acquires the difference between the detected values ​​of a plurality of pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed and the hot water is circulated within the bath circulation circuit under a predetermined reference state. A water heater that, after obtaining the aforementioned reference value, drives the bath circulation pump at the predetermined rotational speed to circulate the hot water in the bath circulation circuit, and determines that a circulation abnormality has occurred in the bath circulation circuit if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the reference value. (Note 2) A hot water storage tank for storing hot water, A bath heat exchanger is provided in the bath circulation circuit for exchanging heat between the hot water in the hot water storage tank and the bath water, Furthermore, The water heater as described in Appendix 1, wherein the pressure sensors are installed so that there is at least one on the upstream side and one on the downstream side of the bath heat exchanger. (Note 3) The water heater according to Appendix 1 or Appendix 2, wherein all of the pressure sensors are installed upstream of the bath circulation pump, or all of the pressure sensors are installed downstream of the bath circulation pump. (Note 4) The water heater according to any one of the appendices 1 to 3, wherein the control unit determines that there is a circulation abnormality in the bath circulation circuit when the pressure difference between the two pressure sensors is less than a first predetermined value while the bath circulation pump is driven at the predetermined rotation speed. (Note 5) The control unit determines that there is a circulation abnormality in the bath circulation circuit when the bath circulation pump is driven at the predetermined rotational speed and the pressure difference between the two pressure sensors is greater than or equal to a second predetermined value, according to any one of the appendices 1 to 4 of the water heater. (Note 6) A water heater according to any one of the appendices 1 to 5, further comprising a notification means for stopping the bath circulation pump and notifying the user when the control unit determines that there is a circulation abnormality in the bath circulation circuit. (Note 7) The water heater described in Appendix 6, wherein when the notification means notifies the user, the control unit identifies the location of the circulation abnormality based on the pressure difference value acquired by the control unit and notifies the user via the notification means. (Note 8) The bath circulation circuit is further provided with a bubble injection means for injecting bubbles, The water heater according to any one of the appendices 1 to 7, wherein the control unit does not perform pressure difference determination of the pressure sensor when bubbles are injected into the circulating water by the bubble injection means while the bath circulation pump is circulating hot water in the bath circulation circuit. (Note 9) The control unit, before acquiring the reference value, drives the bath circulation pump at the predetermined rotational speed and circulates the hot water in the bath circulation circuit. If the difference in the value of the pressure sensor detected while circulating the hot water is greater than or equal to a predetermined value, the control unit determines that a circulation abnormality has occurred in the bath circulation circuit. This is the water heater according to any one of the appendices 1 to 8. (Note 10) A water heater according to any one of the appendices 1 to 9, comprising a reset means for clearing the reference value acquired by the control unit. (Note 11) The aforementioned predetermined rotation speeds have multiple types, The water heater according to any one of the appendices 1 to 10, wherein the control unit acquires the reference value corresponding to each of the predetermined rotation speeds, and after acquiring the reference value, drives the bath circulation pump at the predetermined rotation speed to circulate the hot water in the bath circulation circuit, and if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the respective reference value, it determines that a circulation abnormality has occurred in the bath circulation circuit. [Explanation of Symbols]

[0034] 1 Compressor, 3 Water refrigerant heat exchanger, 4 Expansion valve, 5 Refrigerant piping, 6 Air heat exchanger, 7 HP unit, 8 Hot water storage tank, 8a Water inlet, 8b Water outlet, 8c Hot water inlet, 8d Hot water inlet / outlet, 8e Medium-temperature water inlet, 9a First water supply piping, 9b Second water supply piping, 9c Third water supply piping, 9d Fourth water supply piping, 10 Water outlet piping, 11a Water inlet three-way valve, 11b Medium-temperature three-way valve, 12 Heat source pump, 13a Lower hot water supply piping, 13b Upper hot water supply piping, 14 HP supply piping, 15 HP return piping, 16 First bypass piping, 17 Second bypass piping, 18a Medium-temperature four-way valve, 18b Medium-temperature four-way valve, 19a 19b First medium-temperature piping, 20 Second medium-temperature piping, 20 Heat exchanger for bath, 20a Hot water inlet piping, 20b Hot water outlet piping, 21 Hot water supply piping, 22 Hot water supply mixing valve, 23 Bath mixing valve, 24 First hot water supply piping, 25 Second hot water supply piping, 26 Solenoid valve for bath, 27a Bath supply piping, 28 Bath return piping, 29 Bath circulation pump, 30 Bathtub, 31 Pressure reducing valve, 33 Tank unit, 34 Hot water tap, 35 Storage-type water heater, 36 Control unit, 37 Bath supply temperature sensor, 38 Bath return temperature sensor, 39a First pressure sensor, 39b Second pressure sensor, 41 Storage temperature sensor, 42 Intermediate storage temperature sensor, 43 Lower storage temperature sensor, 44 Remote control, 45 Bath Flow Sensor

Claims

1. A bath circulation circuit includes a circulation channel that takes the hot water from the bathtub out of the bathtub and then returns it to the bathtub, A bath circulation pump that circulates the hot water in the aforementioned bath circulation circuit, A hot water storage tank for storing hot water, A bath heat exchanger is provided in the bath circulation circuit for exchanging heat between the hot water in the hot water storage tank and the bath water, A pressure sensor is installed at multiple locations in the bath circulation circuit, with at least one on the upstream and downstream sides of the bath heat exchanger, to detect the pressure in the bath circulation circuit at the installation location. A control unit that acquires the detected value from the pressure sensor and controls the bath circulation pump, Equipped with, The control unit acquires the difference between the detected values ​​of a plurality of pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed and the hot water is circulated within the bath circulation circuit under a predetermined reference state. A water heater that, after obtaining the aforementioned reference value, drives the bath circulation pump at the predetermined rotational speed to circulate the hot water in the bath circulation circuit, and determines that a circulation abnormality has occurred in the bath circulation circuit if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the reference value.

2. A bath circulation circuit comprising a circulation channel that takes the hot water in the bathtub out of the bathtub and returns it to the bathtub, A bath circulation pump that circulates the hot water in the aforementioned bath circulation circuit, Pressure sensors are installed at multiple locations in the bath circulation circuit to detect the pressure within the bath circulation circuit at the installation locations, A control unit that acquires the detected value from the pressure sensor and controls the bath circulation pump, Equipped with, The control unit acquires the difference between the detected values ​​of a plurality of pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed and the hot water is circulated within the bath circulation circuit under a predetermined reference state. After obtaining the aforementioned reference value, when the bath circulation pump is driven at the predetermined rotational speed to circulate the hot water within the bath circulation circuit, if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the reference value, it is determined that a circulation abnormality has occurred in the bath circulation circuit. The control unit is equipped with a notification means that stops the bath circulation pump and notifies the user when it determines that there is a circulation abnormality in the bath circulation circuit. A water heater that, when notifying the user via the notification means, identifies the location of a circulation abnormality based on the pressure difference value acquired by the control unit and notifies the user via the notification means.

3. A bath circulation circuit comprising a circulation channel that takes the hot water from the bathtub out of the bathtub and returns it to the bathtub, A bath circulation pump that circulates the hot water in the aforementioned bath circulation circuit, Pressure sensors are installed at multiple locations in the bath circulation circuit to detect the pressure within the bath circulation circuit at the installation locations, A control unit that acquires the detected value from the pressure sensor and controls the bath circulation pump, Equipped with, The control unit acquires the difference between the detected values ​​of a plurality of pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed and the hot water is circulated within the bath circulation circuit under a predetermined reference state. After obtaining the aforementioned reference value, when the bath circulation pump is driven at the predetermined rotational speed to circulate the hot water within the bath circulation circuit, if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the reference value, it is determined that a circulation abnormality has occurred in the bath circulation circuit. The bath circulation circuit is further provided with a bubble injection means for injecting bubbles, The control unit, when circulating hot water in the bath circulation circuit with the bath circulation pump, injects bubbles into the circulating hot water using the bubble injection means, prevents the pressure sensor from determining the pressure difference.

4. A bath circulation circuit comprising a circulation channel that takes the hot water from the bathtub out of the bathtub and returns it to the bathtub, A bath circulation pump that circulates the hot water in the aforementioned bath circulation circuit, Pressure sensors are installed at multiple locations in the bath circulation circuit to detect the pressure within the bath circulation circuit at the installation locations, A control unit that acquires the detected value from the pressure sensor and controls the bath circulation pump, Equipped with, The control unit acquires the difference between the detected values ​​of a plurality of pressure sensors as a reference value when the bath circulation pump is driven at a predetermined rotational speed and the hot water is circulated within the bath circulation circuit under a predetermined reference state. After obtaining the aforementioned reference value, when the bath circulation pump is driven at the predetermined rotational speed to circulate the hot water within the bath circulation circuit, if the difference between the detected values ​​of the multiple pressure sensors is greater than or equal to the reference value, it is determined that a circulation abnormality has occurred in the bath circulation circuit. The control unit, before acquiring the reference value, drives the bath circulation pump at the predetermined rotational speed and circulates the hot water in the bath circulation circuit. If the difference in the value detected by the pressure sensor while circulating the hot water is greater than or equal to a predetermined value compared to a pre-stored initial value, the control unit determines that a circulation abnormality has occurred in the bath circulation circuit.

5. A water heater according to any one of claims 1 to 4, wherein all of the pressure sensors are installed upstream of the bath circulation pump, or all of the pressure sensors are installed downstream of the bath circulation pump.

6. The water heater according to any one of claims 1 to 4, wherein the control unit determines that there is a circulation abnormality in the bath circulation circuit when the pressure difference between the two pressure sensors is less than a first predetermined value while the bath circulation pump is driven at the predetermined rotation speed.

7. The water heater according to any one of claims 1 to 4, wherein the control unit determines that there is a circulation abnormality in the bath circulation circuit when the pressure difference between the two pressure sensors is greater than or equal to a second predetermined value while the bath circulation pump is driven at the predetermined rotation speed.

8. The water heater according to any one of claims 1 to 4, further comprising a reset means for clearing the reference value acquired by the control unit.

9. The aforementioned predetermined rotation speeds have multiple types, The water heater according to any one of claims 1 to 4, wherein the control unit acquires a reference value corresponding to each of the predetermined rotation speeds, and after acquiring the reference value, drives the bath circulation pump at the predetermined rotation speed to circulate the hot water in the bath circulation circuit, and if the difference between the detected values ​​of the plurality of pressure sensors is greater than or equal to the respective reference value, it is determined that a circulation abnormality has occurred in the bath circulation circuit.

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