Water heater

Abstract

To more reliably suppress resonance sound in a case where any one combustion unit is being burned and the other combustion units in a cold state are burned at a specific heating power or more.SOLUTION: A hot water supply heater 1 comprises a hot water combustion unit 4A, a heating combustion unit 5A, and a control board 79. When a state in which a combustion unit stops being burned is defined as a cold state, the control board 79 temporarily stops combustion of a heating combustion unit 5A when the hot water combustion unit 4A in the cold state is burned in four or more stages while the heating combustion unit 5A is being burned.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The technology disclosed in this specification relates to a water heater.

Background Art

[0002] When a water heater having a plurality of combustion parts burns the plurality of combustion parts simultaneously, combustion vibration may occur, and a resonance sound may be generated due to the combustion vibration (see, for example, Patent Document 1).

[0003] The composite heat source machine described in Patent Document 1 includes a first burner for hot water supply and a second burner for heating or supplementary heating for a bath. When a combustion instruction for the second burner is issued during combustion at the maximum combustion capacity of the first burner, the composite heat source machine starts the combustion of the second burner and adjusts the rotation speed of the combustion fan to a rotation speed for preventing a resonance sound generated due to the combustion vibration. Furthermore, the same document describes that when an instruction to switch from a state where the first burner burns with a combustion capacity other than the maximum combustion capacity to a state where it burns with the maximum combustion capacity is issued during simultaneous combustion of the first burner and the second burner, the combustion capacity of the first burner is switched to the maximum combustion capacity, and the rotation speed of the combustion fan is adjusted to a rotation speed for preventing a resonance sound generated due to the combustion vibration.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the invention described in Patent Document 1 has room for improvement in preventing resonance sound. One aspect of the present invention aims to more reliably suppress resonance sounds when any combustion part is burning and another combustion part in a cold state is burned at a specific heating power or more.

Means for Solving the Problems

[0006] The water heater of the present disclosure includes two or more combustion parts having gas burners and a controller. When a state where the combustion of the combustion part has stopped is defined as a cold state, the controller temporarily stops the combustion of any one of the combustion parts when burning another combustion part in the cold state at a specific heating power or more.

Effects of the Invention

[0007] According to the above configuration, resonance sounds can be more reliably suppressed when any combustion part is burning and another combustion part in a cold state is burned at a specific heating power or more.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] [Overview of Embodiment] First, an overview of the embodiments of the present disclosure will be enumerated and described.

[0010] (1) The water heater according to the embodiment includes two or more combustion units having gas burners and a controller. When the state in which the combustion of the combustion unit has stopped is defined as a cold state, when the controller causes the other combustion unit in the cold state to burn at a specific heating power or more while any one of the combustion units is burning, the controller temporarily stops the combustion of any one of the combustion units.

[0011] According to the water heater described in (1) above, when causing the other combustion unit in the cold state to burn at a specific heating power or more while any one of the combustion units is burning, the combustion of any one of the combustion units is temporarily stopped. Therefore, combustion vibration when causing the other combustion unit in the cold state to burn at a specific heating power or more can be suppressed.

[0012] According to the water heater described in (1) above, after causing the other combustion unit in the cold state to burn at a specific heating power or more, the combustion of any one of the combustion units is restarted. When restarting the combustion of any one of the combustion units, both the temperature of any one of the combustion units and the temperature of the other combustion unit are somewhat high. Here, the temperature of the combustion unit refers to, for example, the ambient temperature in the combustion chamber in which the combustion unit is housed. Combustion vibration is likely to occur when the combustion unit is cold (in other words, when the ambient temperature in the combustion chamber is low). Therefore, when both temperatures are somewhat high, combustion vibration is less likely to occur. For this reason, combustion vibration when restarting the combustion of any one of the combustion units is also suppressed.

[0013] Therefore, according to the water heater described in (1) above, combustion vibration when causing the other combustion unit in the cold state to burn at a specific heating power or more while any one of the combustion units is burning can be suppressed. Since combustion vibration can be suppressed, resonance sound can be more reliably suppressed compared to the case of simply adjusting the rotation speed of the combustion fan as in the prior art.

[0014] "Temporarily stopping the combustion of any of the combustion units" described in (1) above includes both the case where the combustion of any of the combustion units is stopped first and then the other combustion units are combusted at a specific thermal power or higher, and the case where the combustion of any of the combustion units is stopped and at the same time the other combustion units are combusted at a specific thermal power or higher.

[0015] (2) The water heater according to (1) above, wherein the cold state may include a state where the combustion unit is combusting at less than the specific thermal power.

[0016] According to the water heater described in (2) above, when any of the combustion units is combusting and another combustion unit that is combusting at less than the specific thermal power is combusted at a specific thermal power or higher, the combustion of any of the combustion units is also temporarily stopped, so combustion vibration can be suppressed.

[0017] (3) The water heater according to (2) above, wherein when any of the combustion units is combusting and another combustion unit that is combusting at a specific thermal power or higher changes to the cold state where it combusts at less than the specific thermal power, and if the other combustion unit is combusted at a specific thermal power or higher again within a first specified time from when it changes to the cold state, it is not necessary to temporarily stop the combustion of any of the combustion units.

[0018] Even if another combustion unit that is combusting at a specific thermal power or higher changes to the cold state (here, a state where it combusts at less than the specific thermal power), when the elapsed time from when it changes to the cold state is short, the temperature is still high. So when another combustion unit is combusted at a specific thermal power or higher again later, the temperatures of both any of the combustion units and the other combustion units are somewhat high. According to the water heater described in (3) above, when another combustion unit is combusted at a specific thermal power or higher again within a first specified time from when it changes to the cold state, it is not necessary to temporarily stop the combustion of any of the combustion units, so it is possible to prevent the combustion of any of the combustion units from being stopped unnecessarily.

[0019] (4) The water heater according to any one of (1) to (3) above, wherein when the controller temporarily stops the combustion of any one of the combustion units, when the combustion of any one of the combustion units is stopped or when the other combustion unit is combusted at a specific firing rate or higher, the combustion of any one of the combustion units may be restarted after a second specified time has elapsed.

[0020] When a certain amount of time has elapsed since the combustion of any one of the combustion units was stopped or when the other combustion unit was combusted at a specific firing rate or higher, the temperature of the other combustion unit exceeds the temperature at which combustion vibration is likely to occur. For this reason, when a certain amount of time has elapsed, combustion vibration is less likely to occur when restarting the combustion of any one of the combustion units. According to the water heater described in (4) above, by measuring in advance the time until the temperature of the other combustion unit exceeds the temperature at which combustion vibration is likely to occur and setting it as the second specified time, combustion vibration when restarting the combustion of any one of the combustion units can be more reliably suppressed. As described above, the temperature of the combustion unit here refers to, for example, the ambient temperature in the combustion chamber in which the combustion unit is housed.

[0021] Incidentally, it is also possible to provide a temperature sensor for detecting the temperature of the combustion unit and determine by the temperature sensor whether the temperature of the other combustion unit in the cold state exceeds the temperature at which combustion vibration is likely to occur. However, in that case, a temperature sensor is required, so the number of parts increases. According to the water heater described in (4) above, there is also an advantage that it is not necessary to provide a temperature sensor by measuring in advance the time until the temperature exceeds the temperature at which combustion vibration is likely to occur and setting it as the second specified time. There is also an advantage that the control program can be simplified because it is not necessary to detect the temperature.

[0022] (5) The water heater according to any one of (1) to (3) above, wherein any one of the combustion units may be for heating or for reheating a bath.

[0023] In the case of a combustion unit for heating or reheating, if the temperature of the heat medium does not drop significantly, it is difficult for the user to notice the change in temperature. According to the water heater described in (5) above, although the combustion of the combustion part for heating or supplementary heating is temporarily stopped, as long as it is temporary, the temperature of the heat medium will not drop significantly due to the residual heat of the combustion part, so the usability of the user is not impaired.

[0024] [Details of Embodiment] Details of the embodiments of the present disclosure will be described. The present disclosure is not limited to these examples, and is shown by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. Embodiments of the present disclosure can be realized in various forms such as devices, methods, computer programs for realizing the functions of these devices or methods, and recording media on which the computer programs are recorded.

[0025] <Embodiment 1> Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 5. In the following description, reference numerals of the drawings may be omitted for some of the same components.

[0026] (1) Overall Structure of the Water Heater and Heater Referring to FIG. 1, an outline of a water heater and heater 1 as a water heater according to Embodiment 1 will be described. The water heater and heater 1 has a water heating function of heating the supplied tap water and supplying hot water to the outside, and a heating function of supplying hot water to radiators installed outside the room or under the floor to heat the room or the floor. The water heater and heater 1 includes a front cover 72. The front cover 72 has an exhaust port 73 for accommodating an exhaust pipe 16 described later, an air supply port 74 for taking in outside air, and the like.

[0027] As shown in FIG. 2, the water heater and heater 1 includes a housing 70, an inner cylinder 2 accommodated in the housing 70, a control board 79 (an example of a controller), and the like. The housing 70 includes a box-shaped housing main body 71 having an opening 71A on the front surface, and a front cover 72 (see FIG. 1) that closes the opening 71A of the housing main body 71. The housing body 71 includes a bottom plate 71B positioned on the lower side in a front view, a left side plate 71C positioned on the left side in a front view, a right side plate 71D positioned on the right side in a front view, a top plate 71E positioned on the upper side in a front view, and a rear wall 71F positioned on the rear side.

[0028] The inner cylinder 2 includes a hot water supply combustion chamber 4, a heating combustion chamber 5, a hot water supply primary heat exchanger 11, a heating primary heat exchanger 13, a hot water supply secondary heat exchanger 12, a heating secondary heat exchanger 14, an exhaust hood 15, etc. The inner cylinder 2 is partitioned into left and right by a partitioning member 3 (see FIG. 3) to be described later. A hot water supply combustion chamber 4, a hot water supply primary heat exchanger 11, and a hot water supply secondary heat exchanger 12 are provided on the right side, and a heating combustion chamber 5, a heating primary heat exchanger 13, and a heating secondary heat exchanger 14 are provided on the left side.

[0029] As shown in FIG. 3, the hot water supply and heating machine 1 has a hot water supply circuit A, a heating circuit B, and a bath circuit C. The hot water supply and heating machine 1 has a hot water supply combustion chamber 4 and a heating combustion chamber 5 formed by partitioning within the inner cylinder 2 by a partitioning member 3, and a gas burner 6. The gas burner 6 includes a hot water supply burner 6A arranged at the lower part of the hot water supply combustion chamber 4 and a heating burner 6B arranged at the lower part of the heating combustion chamber 5. An ignition plug 8 and a flame rod 9 are respectively provided in each combustion chamber 4, 5. A combustion fan 10 for supplying combustion air to each gas burner 6A, 6B is provided at the lower part of the inner cylinder 2.

[0030] A hot water supply primary heat exchanger 11 and a hot water supply secondary heat exchanger 12 through which the combustion exhaust of the hot water supply burner 6A passes are provided at the upper part within the hot water supply combustion chamber 4. A heating primary heat exchanger 13 and a heating secondary heat exchanger 14 through which the combustion exhaust of the heating burner 6B passes are provided at the upper part of the heating combustion chamber 5. Each secondary heat exchanger 12, 14 is accommodated in an exhaust hood 15 provided at the upper part of the inner cylinder 2. An exhaust pipe 16 for discharging the combustion exhaust that has passed through each secondary heat exchanger 12, 14 is formed in the exhaust hood 15.

[0031] In the following description, the hot water supply burner 6A, the hot water supply primary heat exchanger 11, and the hot water supply secondary heat exchanger 12 are referred to as the hot water supply combustion section 4A, and the heating burner 6B, the heating primary heat exchanger 13, and the heating secondary heat exchanger 14 are referred to as the heating combustion section 5A. The hot water supply combustion section 4A and the heating combustion section 5A are examples of the combustion section. The heating combustion section 5A is an example of one of the combustion sections, and the hot water supply combustion section 4A is an example of the other combustion section.

[0032] A gas pipe 17 to which an external gas pipe is connected is connected to the gas inlet provided in the bottom plate 71B of the housing 70. Gas branch pipes 18, 18... branched from the gas pipe 17 are respectively connected to each of the hot water supply burner 6A and the heating burner 6B, and a gas solenoid valve 19 for opening and closing the gas flow path is provided in each gas branch pipe 18. Further, an original gas solenoid valve 20 and a gas proportional valve 21 are respectively provided in the gas pipe 17 before branching.

[0033] A water supply pipe 22 connected to the water inlet 78 of the bottom plate 71B is connected to the inlet of the heat absorption pipe of the hot water supply secondary heat exchanger 12. In the water supply pipe 22, from the upstream side, a strainer 23 provided with a drain plug, a hot water supply water volume sensor 24 for detecting the water volume flowing through the water supply pipe 22, a hot water supply inlet thermistor 25 for detecting the temperature of the water (inlet water temperature) supplied from the water inlet 78, and a water volume control valve 26 for controlling the water volume flowing through the water supply pipe 22 are provided.

[0034] The outlet of the heat absorption pipe is connected to the inlet of the heat transfer pipe of the hot water supply primary heat exchanger 11, and a hot water supply pipe 27 connected to the hot water outlet of the bottom plate 71B is connected to the outlet of the heat transfer pipe. In the hot water supply pipe 27, a hot water supply heat exchanger thermistor 28 for detecting the outlet temperature from the hot water supply primary heat exchanger 11 and a hot water supply outlet thermistor 29 for detecting the hot water outlet temperature from the appliance downstream of the hot water supply heat exchanger thermistor 28 are provided. A bypass pipe 30 that bypasses the hot water supply primary and secondary heat exchangers 11, 12 is connected between the upstream side of the hot water supply outlet thermistor 29 in the hot water supply pipe 27 and the downstream side of the water volume control valve 26 in the water supply pipe 22, and a bypass valve 31 for controlling the bypass flow rate is provided in the bypass pipe 30.

[0035] In this way, in the housing 70, water from the water supply pipe 22 passes through the secondary hot water heat exchanger 12 and the primary hot water heat exchanger 11 in this order, exchanges heat with the combustion exhaust gas of the hot water burner 6A and is heated, and then a hot water supply circuit A that discharges hot water from the hot water outlet pipe 27 is formed.

[0036] On the other hand, at the inlet of the heat absorption pipe of the secondary heating heat exchanger 14, a heating return pipe 32 connected to the heating return port 76 of the bottom plate 71B is connected. The heating return port 76 is connected to the downstream ends of the pipes extending from the high-temperature radiator 33 and the low-temperature radiator 34 outside the hot water heater 1. The high-temperature radiator 33 is, for example, a heating blower that blows warm air into the room. The low-temperature radiator 34 is, for example, floor heating. The outlet of the heat absorption pipe of the secondary heating heat exchanger 14 is connected to an intermediate pipe 35 (intermediate pipes 35A and 35B). The intermediate pipe 35 is provided with a heating tank 69 and a heating circulation pump 36.

[0037] The downstream end of the intermediate pipe 35 is connected to the inlet of the heat transfer pipe of the primary heating heat exchanger 13 and the heating low-temperature forward pipe 38. A thermostatic valve 39 is arranged on the downstream side of the heating low-temperature forward pipe 38, branching the heating low-temperature forward pipe 38. The downstream end of the thermostatic valve 39 serves as a heating low-temperature forward port 77. The heating low-temperature forward port 77 is connected to the low-temperature radiator 34.

[0038] The outlet of the heat transfer pipe of the primary heating heat exchanger 13 is connected to a heating high-temperature forward pipe 40. The downstream end of the heating high-temperature forward pipe 40 serves as a heating high-temperature forward port 75 provided on the bottom plate 71B. The heating high-temperature forward port 75 is connected to the high-temperature radiator 33. A heating high-temperature thermistor 41 is provided on the heating high-temperature forward pipe 40. The heating high-temperature forward pipe 40 and the heating return pipe 32 are connected by a bath heating pipe 42. A supplementary boiling flow control valve 43 is provided on the bath heating pipe 42. Between the upstream side of the heating tank 69 in the intermediate pipe 35 and the heating high-temperature forward pipe 40, a heating bypass pipe 44 that bypasses the primary and secondary heating heat exchangers 13 and 14 is connected, and a bypass thermostatic valve 45 for controlling the bypass flow rate is provided on the heating bypass pipe 44.

[0039] Therefore, in the heating circuit B, the hot water heated by the heating secondary heat exchanger 14 circulates through the intermediate pipe 35, the heating tank 69, the heating low-temperature supply pipe 38, and the low-temperature radiator 34 to the heating return pipe 32, and at the same time, it flows into the heating primary heat exchanger 13 through the intermediate pipe 35. The hot water heated by the heating primary heat exchanger 13 returns to the heating return pipe 32 through the heating high-temperature supply pipe 40 and the high-temperature radiator 33, and circulates through the heating secondary heat exchanger 14, the intermediate pipe 35, and the heating tank 69 to the heating primary heat exchanger 13.

[0040] The bath circuit C is provided with a bath heat exchanger 46 through which a bath heating pipe 42 is inserted. The inlet of the bath heat exchanger 46 is connected to a bath return pipe 47 connected to the bath return port of the bottom plate 71B. The bath return port is connected to the bathtub 49 through an external bath return pipe 48. A bath circulation pump 50 is provided on the downstream side of the bath return pipe 47. A bath return thermistor 51 for detecting the bath return temperature is provided on the upstream side of the bath circulation pump 50. A water flow switch 52 and a water level sensor 53 are provided on the downstream side of the bath circulation pump 50. The outlet of the bath heat exchanger 46 is connected to a bath supply pipe 54 connected to the bath supply port of the bottom plate 71B. The bath supply port is connected to the bathtub 49 through an external bath supply pipe 55. A bath supply thermistor 56 for detecting the bath supply temperature is provided on the bath supply pipe 54.

[0041] Between the downstream side of the bypass pipe 30 in the hot water outlet pipe 27 and the upstream side of the bathtub return pipe 47 from the bathtub circulation pump 50, a drop pipe 57 is connected. In this drop pipe 57, from the upstream side (hot water outlet pipe 27 side), a drop water solenoid valve 58 for opening and closing the drop pipe 57 and a bathtub water volume sensor 59 for detecting the amount of water flowing through the drop pipe 57 are respectively provided. The drop pipe 57 enables the hot water heated in the hot water supply circuit A to be supplied to the bathtub 49. On the downstream side of the bathtub water volume sensor 59, three check valves 60, 60, 60 are provided. An edge cut-off valve 61 is connected between these check valves 60. This edge cut-off valve 61 is connected to a drain pipe 62 connected to an overflow discharge port provided on the bottom plate 71B and an introduction pipe 63 connected to the downstream side of the strainer 23 in the water supply pipe 22. When the internal pressure of the hot water (an example of a heat medium) in the drop pipe 57 increases due to the back pressure from the bathtub return pipe 47 and becomes larger than the back pressure from the introduction pipe 63, the edge cut-off valve 61 discharges the hot water flowing back from the drop pipe 57 to the overflow discharge port via the drain pipe 62. In this way, a bathtub circuit C for circulating the hot water in the bathtub 49 is formed by the bathtub heat exchanger 46, the bathtub forward pipe 54, the bathtub return pipe 47, and the like.

[0042] Inside the housing 70, a neutralizer 64 for neutralizing the drain generated in the hot water supply secondary heat exchanger 12 and the heating secondary heat exchanger 14 is provided. This neutralizer 64 is connected to a drain receiver 66 provided on the bottom surface of the exhaust hood 15 via a drain introduction pipe 65 and is connected to the drain pipe 62 of the edge cut-off valve 61 via a drain discharge pipe 67. The neutralizer 64 is provided with a water level electrode 68 for detecting the water level.

[0043] Referring to FIG. 2, the control board 79 will be described. The control board 79 has a control unit and various electronic components mounted thereon. The control unit is, for example, a CPU, a microcomputer (so-called microcontroller), an FPGA (Field Programmable Gate Array), etc. The control board 79 receives detection signals from various thermistors, sensors, etc. and operates respective valves, etc. to perform hot water temperature control, hot water filling control for the bathtub 49, temperature control related to heating, etc. Although not shown, the water heater 1 includes a remote control or the like that is communicably connected to the control board 79.

[0044] (2) Control to ignite the hot water combustion section when the heating combustion section is burning Referring to FIG. 4, the cold state of the hot water combustion section 4A will be described. The hot water combustion section 4A has five hot water burners 6. The magnitude of the heating power of the hot water combustion section 4A is represented by the number of hot water burners 6 that are burning (hereinafter referred to as the combustion stage number). Here, when the combustion stage number is 4 or more, it is defined as a state of burning at a specific heating power or more, and when the combustion stage number is less than 4, it is defined as a cold state. The cold state includes a state of burning at stages 1 to 3 and a state where combustion has stopped (i.e., a state where the combustion stage number is 0).

[0045] When the control board 79 is to burn the cold hot water combustion section 4A at 4 or more stages when the heating combustion section 5A is burning, the control board 79 temporarily stops the combustion of the heating combustion section 5A. Then, when a second specified time (for example, 15 seconds) has elapsed since the hot water combustion section 4A was burned at 4 or more stages (or when the combustion of the heating combustion section 5A was stopped), the control board 79 resumes the combustion of the heating combustion section 5A. This will be specifically described below.

[0046] (2-1) When burning the hot water combustion section from stages 1 to 3 to 4 or more Referring to Fig. 4, the case where the water heating combustion section 4A, which is burning in 1 to 3 stages, is made to burn in 4 or more stages when the heating combustion section 5A is burning will be described. In Fig. 4, ON indicates combustion and OFF indicates combustion stop. In Fig. 4, the time point T1 is the time when the combustion of the water heating combustion section 4A is started. Since the water heating combustion section 4A is determined to be in a cold state when the previous combustion stage number changes from 4 or more stages to less than 4 stages, the water heating combustion section 4A immediately before the time point T1 is in a cold state. In the example shown in Fig. 4, although the combustion of the water heating combustion section 4A is started at the time point T1, since the combustion stage number is 2 stages, the water heating combustion section 4A remains in a cold state even at the time point T1.

[0047] In the example shown in Fig. 4, at the time point T2 when 20 seconds have elapsed from the time point T1, the combustion stage number of the water heating combustion section 4A changes from 2 stages to 5 stages. When the water heating combustion section 4A, which is burning in 1 to 3 stages, is made to burn in 4 or more stages while the heating combustion section 5A is burning, the control board 79 temporarily stops the combustion of the heating combustion section 5A in order to suppress combustion vibration. Specifically, the control board 79 first stops the combustion of the heating combustion section 5A, and makes the water heating combustion section 4A burn in 4 or more stages in a state where the combustion of the heating combustion section 5A has stopped.

[0048] Even when the water heating combustion section 4A is made to burn in 4 or more stages, the control board 79 does not immediately cancel the determination of the cold state of the water heating combustion section 4A, and cancels the determination of the cold state when 15 seconds (the second specified time) have elapsed since the water heating combustion section 4A started burning in 4 or more stages. 15 seconds is a time measured in advance as the time until the temperature of the water heating combustion section 4A exceeds the temperature at which combustion vibration is likely to occur. Here, the temperature of the water heating combustion section 4A refers to the ambient temperature inside the water heating combustion chamber 4. The control board 79 resumes the combustion of the heating combustion section 5A on the condition that the determination of the cold state of the water heating combustion section 4A has been canceled. For this reason, the combustion of the heating combustion section 5A is resumed 15 seconds after the water heating combustion section 4A starts burning in 4 or more stages.

[0049] The time point T4 is the time when the combustion of the water heating combustion section 4A, which is burning in 4 or more stages, is stopped (that is, the time when the combustion stage number changes from 4 or more stages to 0 stages). The control board 79 determines the state of the water heating combustion section 4A to be in a cold state at the time point T4.

[0050] Figure 5 shows another example in which the hot water combustion unit 4A that is burning in 1 to 3 stages is burned in 4 or more stages when the heating combustion unit 5A is burning. In the example shown in Figure 5, the hot water combustion unit 4A is burned in 4 or more stages at time point T5 when 40 seconds have elapsed since the hot water combustion unit 4A was burned in 2 stages. Also in this case, the combustion of the heating combustion unit 5A resumes at time point T6 15 seconds later. That is, the time (second specified time) during which the combustion of the heating combustion unit 5A is temporarily stopped is 15 seconds regardless of the time during which the hot water combustion unit 4A was burning in 1 to 3 stages.

[0051] (2-2) When the hot water combustion unit is burned from 0 stage to 4 or more stages In Figure 6, time point T7 is the time when the hot water combustion unit 4A whose combustion has stopped (that is, the hot water combustion unit 4A with a combustion stage number of 0 stage) starts combustion in 4 or more stages. In this case, the control board 79 temporarily stops the combustion of the heating combustion unit 5A and ignites the hot water combustion unit 4A. Specifically, the control board 79 first stops the combustion of the heating combustion unit 5A and ignites the hot water combustion unit 4A while the combustion of the heating combustion unit 5A has stopped. Then, the control board 79 releases the determination of the cold state of the hot water combustion unit 4A at time point T8 15 seconds later. For this reason, the combustion of the heating combustion unit 5A resumes 15 seconds later.

[0052] (2-3) When the hot water combustion unit is burned from 4 or more stages to 1 to 3 stages With reference to Figure 6, the case where the hot water combustion unit 4A burning in 4 or more stages is burned in 1 to 3 stages will be described. As described above, the control board 79 determines that it is in a cold state when the combustion stage number of the hot water combustion unit 4A changes from 4 or more stages to less than 4 stages. However, when changing from 4 or more stages to 1 to 3 stages, the control board 79 does not immediately determine that it is in a cold state, but determines that it is in a cold state after the first specified time (for example, 30 seconds) has elapsed since the change to 1 to 3 stages.

[0053] In the example shown in FIG. 6, the combustion stage number of the hot water supply combustion unit 4A changes from 4 stages to 2 stages at time T9. In this case, it is determined to be in the cold state at time T10 when 30 seconds have elapsed from time T9. Between time T9 and time T10, although the combustion stage number is less than 4 stages, it is not determined to be in the cold state. Therefore, when the hot water supply combustion unit 4A is burned again at 4 stages or more during this period, the combustion of the heating combustion unit 5A is not temporarily stopped.

[0054] The reason for determining the cold state after 30 seconds (the first specified time) has elapsed is that when changing from 1 to 3 stages, the temperature drop of the hot water supply combustion unit 4A is smaller than when changing to 0 stages. Therefore, until a certain period of time (here, 30 seconds) has elapsed, the temperature of the hot water supply combustion unit 4A is high. 30 seconds is a time measured in advance or a time close to it as the time when combustion vibration does not occur even if the combustion of the hot water supply combustion unit 4A is not stopped. When the temperature of the hot water supply combustion unit 4A is high, since both the temperature of the hot water supply combustion unit 4A and the temperature of the heating combustion unit 5A are high, it is difficult for combustion vibration to occur even if the combustion of the heating combustion unit 5A is not temporarily stopped. For this reason, the control board 79 does not determine it to be in the cold state until 30 seconds have elapsed in order not to unnecessarily stop the combustion of the heating combustion unit 5A when the hot water supply combustion unit 4A is burned again at 4 stages or more within 30 seconds.

[0055] (3) Effects of the Embodiment According to the hot water supply and heating machine 1 according to Embodiment 1, when the hot water supply combustion unit 4A in the cold state is burned at 4 stages or more while the heating combustion unit 5A is burning, the combustion of the heating combustion unit 5A is temporarily stopped. Therefore, combustion vibration when the hot water supply combustion unit 4A in the cold state is burned at 4 stages or more can be suppressed. According to the hot water supply and heating machine 1, after the hot water supply combustion unit 4A in the cold state is burned at 4 stages or more, the combustion of the heating combustion unit 5A is restarted. When the combustion of the heating combustion unit 5A is restarted, both the temperature of the heating combustion unit 5A and the temperature of the hot water supply combustion unit 4A are somewhat high. Combustion vibration is likely to occur when the combustion unit is cold. Therefore, when both temperatures are somewhat high, combustion vibration is less likely to occur. For this reason, combustion vibration when the combustion of the heating combustion unit 5A is restarted is also suppressed. Therefore, according to the water heater 1, when the heating combustion part 5A is burning, combustion vibration can be suppressed when the cold water heating combustion part 4A is burned in four or more stages. Since the combustion vibration can be suppressed, the resonance sound can be more reliably suppressed than in the case of simply adjusting the rotation speed of the combustion fan as in the prior art.

[0056] According to the water heater 1, when the heating combustion part 5A is burning, even when the water heating combustion part 4A that is burning in stages 1 to 3 is burned in four or more stages, the combustion of the heating combustion part 5A is temporarily stopped, so combustion vibration can be suppressed.

[0057] According to the water heater 1, when the heating combustion part 5A is burning, when the water heating combustion part 4A that is burning in four or more stages changes to a cold state where it burns in stages 1 to 3, if the water heating combustion part 4A is burned in four or more stages again within 30 seconds (the first specified time) from when it changes to the cold state, the combustion of the heating combustion part 5A is not temporarily stopped, so it is possible to prevent the combustion of the heating combustion part 5A from stopping unnecessarily.

[0058] According to the water heater 1, by measuring in advance the time until the temperature of the water heating combustion part 4A exceeds the temperature at which combustion vibration is likely to occur and setting it as the second specified time (here 15 seconds), combustion vibration when restarting the combustion of the heating combustion part 5A can be more reliably suppressed. Furthermore, according to the water heater 1, since the time until the temperature of the water heating combustion part 4A exceeds the temperature at which combustion vibration is likely to occur is measured in advance and set as the second specified time, there is also an advantage that it is not necessary to provide a temperature sensor. Since it is not necessary to detect the temperature, there is also an advantage that the control program can be simplified.

[0059] According to the water heater 1, the combustion of the heating combustion part 5A is temporarily stopped, but as long as it is temporary, the temperature of the hot water does not drop significantly due to the residual heat of the heating combustion part 5A, so the usability of the user is not impaired.

[0060] <Other embodiments> (1) In the above embodiment, the case where the state in which the hot water supply combustion unit 4A burns in 1 to 3 stages is also included in the cold state was exemplified. On the contrary, the state of burning in 1 to 3 stages may not be included in the cold state. That is, only the state in which the combustion of the hot water supply combustion unit 4A has stopped may be regarded as the cold state.

[0061] (2) In the above embodiment, when temporarily stopping the combustion of the heating combustion unit 5A and burning the hot water supply combustion unit 4A in 4 or more stages, the case of first stopping the combustion of the heating combustion unit 5A and then burning the hot water supply combustion unit 4A in 4 or more stages was exemplified. On the contrary, the hot water supply combustion unit 4A may be burned in 4 or more stages simultaneously with stopping the combustion of the heating combustion unit 5A. However, in order to suppress combustion vibration, it is preferable to first stop the combustion of the heating combustion unit 5A.

[0062] (3) In the above embodiment, the case where the combustion of the heating combustion unit 5A is restarted when the second specified time (for example, 15 seconds) has elapsed since the hot water supply combustion unit 4A was burned in 4 or more stages was exemplified. That is, the case where the start point of counting the second specified time is the time when the hot water supply combustion unit 4A is burned in 4 or more stages was exemplified. On the contrary, the start point of counting the second specified time may be the time when the combustion of the heating combustion unit 5A is stopped.

[0063] (4) In the above embodiment, the case where the combustion of the heating combustion unit 5A is restarted when 15 seconds (the second specified time) has elapsed since the hot water supply combustion unit 4A was burned in 4 or more stages was exemplified. On the contrary, after the hot water supply combustion unit 4A is burned in 4 or more stages, the combustion of the heating combustion unit 5A may be restarted immediately without a time delay.

[0064] (5) In the above embodiment, when the hot water supply combustion unit 4A that is burning in 4 or more stages changes to the cold state of burning in 1 to 3 stages while the heating combustion unit 5A is burning, and the hot water supply combustion unit 4A is burned in 4 or more stages again within 30 seconds (the first specified time), the case where the combustion of the heating combustion unit 5A is not temporarily stopped was exemplified. On the contrary, in this case, the combustion of the heating combustion unit 5A may also be temporarily stopped. That is, when the hot water supply combustion unit 4A is burned in 4 or more stages, the combustion of the heating combustion unit 5A may always be temporarily stopped.

[0065] (6) In the above embodiment, the heating combustion part 5A is an example of one of the combustion parts, and the case where the hot water supply combustion part 4A is an example of the other combustion part is illustrated. On the contrary, the hot water supply combustion part 4A may be an example of one of the combustion parts, and the heating combustion part 5A may be an example of the other combustion part.

[0066] (7) In the above embodiment, the case where the number of combustion parts is two (the hot water supply combustion part 4A and the heating combustion part 5A) is illustrated, but the number of combustion parts may be three or more.

[0067] (8) In the above embodiment, the case where the time until the temperature of the hot water supply combustion part 4A exceeds the temperature at which combustion vibration is likely to occur is measured in advance and set as the second specified time is illustrated. On the contrary, a temperature sensor for detecting the ambient temperature in the hot water supply combustion chamber 4 may be provided, and when the temperature detected by the temperature sensor exceeds the temperature at which combustion vibration is likely to occur, the combustion of the heating combustion part 5A may be restarted.

Explanation of reference numerals

[0068] 1: Hot water supply and heating machine (an example of a water heater) 4A: Hot water supply combustion part (an example of a combustion part) 5A: Heating combustion part (an example of a combustion part) 6: Gas burner 79: Control board (an example of a controller)

Claims

1. A water heater, comprising two or more combustion parts having gas burners, a controller, and when a state where combustion of the combustion part has stopped is defined as a cold state, if the controller causes the other combustion parts in the cold state to burn at a specific firing rate or higher when any one of the combustion parts is burning, the controller temporarily stops the combustion of any one of the combustion parts. A water heater.

2. The water heater according to Claim 1, wherein the cold state includes a state where the combustion part is burning at less than the specific firing rate. A water heater.

3. The water heater according to Claim 2, wherein when any one of the combustion parts is burning and another combustion part that is burning at the specific firing rate or higher changes to the cold state where it burns at less than the specific firing rate, if the controller causes the other combustion part to burn at the specific firing rate or higher again within a first specified time from when the change to the cold state occurs, the controller does not temporarily stop the combustion of any one of the combustion parts. A water heater.

4. The water heater according to any one of Claims 1 to 3, wherein when the controller temporarily stops the combustion of any one of the combustion parts, the controller resumes the combustion of any one of the combustion parts when a second specified time has elapsed from when the combustion of any one of the combustion parts was stopped or when the other combustion part was caused to burn at the specific firing rate or higher. A water heater.

5. The water heater according to any one of Claims 1 to 3, wherein any one of the combustion parts is for heating or for reheating a bath. A water heater. ​

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