Water heater

Abstract

To provide a water heater equipped with a sterilization device for sterilizing bath water in a bathtub, which can prevent dirt of the bath water from adhering to the sterilization device.SOLUTION: A hot water device 1 comprises: a bath circulation circuit 2 through which bath water in a bathtub 11 circulates between the bathtub 11 and a heating unit 3; a sterilization device 7 that is provided in the bath circulation circuit 2, and sterilizes the bath water circulating through the bath circulation circuit 2; a branch flow path 8 through which the bath water bypasses the sterilization device 7 in the bath circulation circuit 2; and a switching valve 9 that switches whether the bath water circulating through the bath circulation circuit 2 passes through the sterilization device 7 or the branch flow path 8.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hot water system equipped with a sterilization device that sterilizes bath water in a bathtub. [Background technology]

[0002] Conventionally, there is a water heater that has the function of sterilizing bath water in the bathtub (Patent Document 1). This water heater is equipped with a bath circulation circuit that circulates the bath water in the bathtub while heating it with a heat exchanger. The bath circulation circuit has a bath return pipe that supplies the bath water in the bathtub to the heat exchanger, and a bath supply pipe that discharges the bath water heated by the heat exchanger into the bathtub. By installing a sterilization device that sterilizes the bath water in the bathtub return pipe, the bath water passes through the sterilization device before being heated by the heat exchanger, preventing damage to the sterilization device from heat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-54144 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional hot water system, the sterilization device is installed in the bath circulation circuit, so the bath water passes through the sterilization device every time it is reheated.In particular, since bath water contains a lot of dirt from bathing, there is a risk that the bath water will become contaminated with dirt from the bath water over time and the sterilization ability will deteriorate relatively quickly as a result.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a hot water device that can prevent dirt from adhering to the sterilization device from bath water. [Means for solving the problem]

[0006] The hot water device according to the present invention comprises: a bath circulation circuit in which bath water in the bath tub circulates between the bathtub and a heating unit; a sterilization device provided in the bath circulation circuit for sterilizing bathtub water circulating through the bath circulation circuit; A branch flow path that bypasses the sterilization device in the bath circulation circuit and allows bathwater to flow; The bathtub water circulating in the bath circulation circuit is provided with a switching valve that switches whether to pass through the sterilization device or the branch flow path.

[0007] With this configuration, during the bathtub water reheating operation, the switch valve directs the bathwater circulating through the bath circulation circuit through the branch flow path and prevents it from passing through the sterilization device, preventing the bathwater from becoming soiled on the sterilization device. Furthermore, since the high-temperature bathwater during the reheating operation can be prevented from passing through the sterilization device, the sterilization device is protected from damage by heat. Furthermore, when performing bathwater sterilization operation when a user uses leftover bathwater, the switch valve directs the bathwater circulating through the bath circulation circuit through the sterilization device, thereby sterilizing the bathwater. In this way, the bathwater circulating through the bath circulation circuit is passed through the sterilization device only when sterilization operation is performed, making it difficult for the bathwater to become soiled on the sterilization device, and the sterilization capability of the sterilization device can be maintained at a high level for a long period of time without prematurely deteriorating.

[0008] In the water heating device, The bath circulation circuit downstream of the heating unit is provided with a temperature sensor that detects the temperature of the bath water flowing through the bath circulation circuit. During sterilization operation in which bathtub water circulating through the bath circulation circuit is passed through the sterilization device, if the temperature of the bathtub water detected by the temperature sensor is above a predetermined temperature, the switching valve can be configured to pass the bathtub water through a branch flow path, thereby canceling the sterilization operation.

[0009] This configuration prevents high-temperature bath water from passing through the sterilization device, making the sterilization device less susceptible to damage from heat and extending the life of the sterilization device.

[0010] In the water heating device, A check valve can be provided in the bath circulation circuit in the flow path from the sterilization device to the junction of the branch flow paths to prevent bath water from flowing back upstream.

[0011] According to the above configuration, the check valve prevents high-temperature bath water that has passed through the branch flow path during reheating operation from flowing into the sterilization device, thereby preventing the sterilization device from being damaged by heat.

[0012] In the water heating device, a hot water supply circuit that heats water from a water supply source in a hot water supply heating unit and supplies hot water; a conveying path for connecting the hot water supply circuit and the bath circulation circuit and supplying hot water or water from the hot water supply circuit to the bath circulation circuit; After the sterilization operation in which bathtub water is passed through the sterilization device, a cleaning operation can be performed in which a predetermined amount of hot water or water is supplied from the hot water supply circuit to the bath circulation circuit through the conveying path and passed through the sterilization device.

[0013] According to the above configuration, the cleaning operation can wash away dirt adhering to the sterilization apparatus, thereby further suppressing adhesion of dirt to the sterilization apparatus. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing the overall configuration of a hot water device according to an embodiment. [Figure 2] 2(a) and 2(b) are schematic diagrams for explaining the operation during reheating operation (FIG. 2(a)) and sterilization operation (FIG. 2(b)). [Figure 3] FIG. 10 is a schematic diagram for explaining the operation of the sterilization device during cleaning operation in the hot water system of another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the hot water device 1 according to the embodiment includes a bath circulation circuit 2, a bath heat exchanger 3 (heating section), a hot water supply circuit 5, and a hot water supply heat exchanger 4 (hot water heating section). The hot water supply circuit 5 has a water supply passage 51 and a hot water outlet passage 52 connected to the hot water heat exchanger 4. The water supply passage 51 is a passage that supplies water from a water supply source to the hot water heat exchanger 4, and the hot water outlet passage 52 is a passage that supplies hot water heated by the hot water heat exchanger 4 to a predetermined hot water supply location. The hot water heat exchanger 4 is equipped with a main heat exchanger 41 and a sub-heat exchanger 42 for heating the water supplied from the water supply passage 51. A hot water burner 43 is installed below the hot water heat exchanger 4, and the hot water heat exchanger 4 absorbs heat from the combustion exhaust generated by combustion in the hot water burner 43. A gas pipe 44 for supplying fuel gas to the hot water burner 43 is connected to the hot water burner 43, and the gas pipe 44 is equipped with a main gas solenoid valve 45 that opens and closes the passage, a gas proportional valve 46 that adjusts the opening degree of the passage, and a gas solenoid valve 47 that opens and closes the passage. A fan 48 is provided on the underside of the boiler body that houses hot water burner 43, supplying combustion air to hot water burner 43. A water volume sensor 53 that detects the flow rate of water flowing through water supply passage 51 is provided in water supply passage 51, and hot water burner 43 ignites and burns when water volume sensor 53 detects a predetermined ignition water volume. A hot water outlet passage 52 is provided with a hot water temperature sensor 54 that detects the temperature of the hot water flowing through passage 52 and a check valve 55 that prevents the hot water from flowing back upstream, and the combustion amount of hot water burner 43 is adjusted so that the hot water temperature detected by hot water temperature sensor 54 becomes a predetermined set temperature.

[0016] In the hot water supply operation, when a hot water tap (not shown) at a hot water supply location is opened and water volume sensor 53 detects that water is flowing into water supply path 51, hot water burner 43 is ignited and combusted, the water supplied from water supply path 51 to hot water heat exchanger 4 is heated in hot water heat exchanger 4, and the hot water heated in hot water heat exchanger 4 flows through hot water outlet path 52 and is supplied to the hot water supply location. The operation of the hot water supply operation is controlled by a control device (not shown).

[0017] The hot water device 1 also has a water filling path 6 that connects the hot water supply circuit 5 and the bath circulation circuit 2 and is used to fill the bathtub 11 with hot water. The water filling path 6 is connected between the hot water outlet path 52 of the hot water supply circuit 5 and the bath return flow path 21 of the bath circulation circuit 2. The water filling path 6 is equipped with a water filling solenoid valve 61 that opens and closes the water filling path 6, a check valve 62 that prevents hot water from flowing back into the hot water outlet path 52, and a water volume sensor 63 that detects the flow rate of hot water or cold water flowing through the water filling path 6. In the filling operation, when the water volume sensor 53 detects that water has flowed into the water supply line 51 due to the opening of the water filling solenoid valve 61, the hot water burner 43 is ignited and combusted, causing the water supplied from the water supply line 51 to the hot water heat exchanger 4 to be heated by the hot water heat exchanger 4. The hot water heated by the hot water heat exchanger 4 flows from the hot water outlet line 52 through the hot water filling line 6 and is supplied to the bath return line 21 of the bath circulation circuit 2, and a predetermined amount of hot water is supplied into the bathtub 11 from the bath supply line 22 and the bath return line 21. The operation of the filling operation is controlled by a control device (not shown). The hot water filling line 6 serves as a transport line for supplying hot water or water from the hot water supply circuit 5 to the bath circulation circuit 2 during the cleaning operation of the sterilization device 7, which will be described later.

[0018] The bath circulation circuit 2 has a bath return flow path 21 and a bath forward flow path 22 connected between the bath heat exchanger 3 and the circulation adapter 12 of the bathtub 11, and serves as a flow path for circulating the bathwater in the bathtub 11 while heating it in the bath heat exchanger 3. The bath return flow path 21 is a flow path that supplies the bathwater in the bathtub 11 to the bath heat exchanger 3, and the bath forward flow path 22 is a flow path that supplies the bathwater heated by the bath heat exchanger 3 back into the bathtub 11. The bath heat exchanger 3 is equipped with a main heat exchanger 31 and a sub-heat exchanger 32 for heating the bathwater circulating through the bath circulation circuit 2. A bath burner 33 is installed below the bath heat exchanger 3, and the bath heat exchanger 3 absorbs heat from the combustion exhaust generated by the combustion of the bath burner 33. A gas pipe 44 that also supplies fuel gas to the hot water supply burner 43 is connected to the bath burner 33, and the gas pipe 44 extended to the bath burner 33 is equipped with a gas solenoid valve 34 that opens and closes the flow path. The bath return flow path 21 is provided with, in order from the upstream side in the direction of circulation of the bath water, a bath return temperature sensor 23 that detects the temperature of the bath water flowing out from the bathtub 11 to the bath return flow path 21, a circulation pump 24 that circulates the bath water in the bath circulation circuit 2, and a bath water flow switch 25 that detects the flow rate of the bath water flowing through the bath return flow path 21.

[0019] The bath-going flow path 22 is equipped with a sterilization device 7 that sterilizes the bathwater circulating through the bath circulation circuit 2. The sterilization device 7 has a housing 71 and a sterilization treatment unit 72 housed within the housing 71. The sterilization treatment unit 72 is composed of LEDs (light-emitting diodes) that emit ultraviolet light to sterilize the bathwater. By operating the sterilization device 7 and illuminating the LED of the sterilization treatment unit 72, the bathwater flowing within the housing 71 is irradiated with ultraviolet light, sterilizing the bathwater. The recommended operating temperature for this sterilization device 7 is 10°C to 60°C, and it is preferable not to pass bathwater hotter than 60°C. Furthermore, as the sterilization device 7 is used, the sterilization performance will decrease if a large amount of dirt contained in the bathwater adheres to the LED that serves as the sterilization treatment unit 72. In addition, the sterilization device 7 may be a sterilization device having a UV lamp that emits ultraviolet light, other than the LED type sterilization device, or any other sterilization device such as an ozone generator that generates ozone for sterilization or an ion generator that generates metal ions (e.g., silver ions) for sterilization, may be used.

[0020] The bath-bound flow path 22 has a branch flow path 8 that branches off from a position upstream of the sterilization device 7 in the bathwater circulation direction and merges with the branch flow path 8 downstream, bypassing the sterilization device 7. The flow path section of the bath-bound flow path 22 that is connected in parallel to the branch flow path 8 and where the sterilization device 7 is installed is called the sterilization flow path 27. A switching valve 9 is provided at the branch point where the sterilization flow path 27 and the branch flow path 8 branch off. The switching valve 9 switches the flow path between connecting the bath-bound flow path 22 upstream of the branch point with the sterilization flow path 27 and connecting the bath-bound flow path 22 upstream of the branch point with the branch flow path 8, thereby switching whether the bathwater circulating through the bath circulation circuit 2 passes through the sterilization device 7 or the branch flow path 8. The branch flow path 8 and the sterilization flow path 27 are two parallel flow paths that are part of the bath-bound flow path 22, one of which constitutes the branch flow path 8 and the other constitutes the sterilization flow path 27.

[0021] A check valve 28 is provided in the sterilization flow path 27 between the sterilization device 7 and the junction of the branch flow paths 8 (the flow path portion downstream of the sterilization device 7) to prevent bathwater from flowing back from downstream to upstream. A bath-outflow temperature sensor 26 is provided in the bath-outflow flow path 22 downstream of the sterilization flow path 27. The bath-outflow temperature sensor 26 detects the temperature of bathwater heated by the bath heat exchanger 3 and flowing from the bath-outflow flow path 22 into the bathtub 11 (bath-outflow temperature). When the flow path is switched to the sterilization flow path 27 side by the switching valve 9, it can also detect the temperature of the bathwater water passing through the sterilization device 7. In this embodiment, the bath-outflow temperature sensor 26 detects the bath-outflow temperature and the temperature of the bathwater water passing through the sterilization device 7. However, a temperature sensor separate from the bath-outflow temperature sensor 26 may be provided in the sterilization flow path 27 (for example, downstream of the sterilization device 7) or at any position in the bath-outflow flow path 22 downstream of the bath heat exchanger 3 to detect the temperature of the bathwater flowing to the sterilization device 7.

[0022] Next, the operation during reheating operation will be described. This reheating operation is controlled by a control device (not shown). When the user operates the remote control (not shown) to perform the reheating operation, the switch valve 9 is switched to the branch flow path 8 side (see Figure 2(a)) so that the bath water circulating through the bath circulation circuit 2 passes through the branch flow path 8, and the circulation pump 24 is operated. When the circulation pump 24 is operated, the bath water in the bathtub 11 flows into the bath return flow path 21 from the suction port of the circulation adapter 12, flows through the bath return flow path 21, and is supplied to the bath heat exchanger 3. When the bath water flow switch 25 is turned on by the bath water flowing through the bath return flow path 21, the bath burner 33 is ignited and burns. The bath water supplied to the bath heat exchanger 3 is heated by the bath heat exchanger 3 and flows out into the bath supply flow path 22.

[0023] As shown in Figure 2(a), during reheating operation, the bath water flowing into the bath-bound flow path 22 passes through the branch flow path 8 via the switching valve 9, flows through the bath-bound flow path 22 without passing through the sterilization device 7, and flows into the bathtub 11 from the outlet of the circulation adapter 12.

[0024] In this way, during reheating operation, the switching valve 9 is switched to the branch flow path 8 side, and the bath water circulates through the bath circulation circuit 2 so that it passes through the branch flow path 8 without passing through the sterilization device 7. This prevents the bath water from passing through the sterilization device 7 every time reheating operation is performed, preventing dirt contained in the bath water, such as from bathing, from adhering to the sterilization device 7. Furthermore, during reheating operation, the high-temperature bath water heated by the bath heat exchanger 3 does not pass through the sterilization device 7, preventing damage to the sterilization device 7 from heat. Furthermore, the check valve 28 located downstream of the sterilization device 7 in the sterilization flow path 27 prevents high-temperature bath water that passes through the branch flow path 8 from flowing into the sterilization device 7 during reheating operation, preventing damage to the sterilization device 7 from heat.

[0025] Next, the operation during the sterilization operation will be described. This sterilization operation is controlled by a control device (not shown). When a user operates a remote control (not shown) to sterilize bathwater, such as when using leftover bathwater in the bathtub 11, the switch valve 9 is switched to the sterilization flow path 27 side (see Figure 2(b)) so that the bathwater circulating through the bath circulation circuit 2 passes through the sterilization device 7, the sterilization device 7 is activated, and the circulation pump 24 is operated. When the circulation pump 24 is activated, the bathwater in the bathtub 11 flows from the suction port of the circulation adapter 12 into the bath return flow path 21, flows through the bath return flow path 21, passes through the bath heat exchanger 3, and flows out into the bath supply flow path 22. During sterilization operation, even if the bath water flow switch 25 for the bath return flow path 21 is turned on, the bath burner 33 is not ignited, and the bathwater is not heated by the bath heat exchanger 3.

[0026] As shown in Figure 2(b), during sterilization operation, bath water flowing from the bath heat exchanger 3 into the bath-going flow path 22 flows into the sterilization flow path 27 via the switching valve 9, passes through the sterilization device 7, flows through the bath-going flow path 22, and flows into the bathtub 11 from the outlet of the circulation adapter 12. Then, after a predetermined sterilization operation time (e.g., 6 hours) has elapsed, the circulation pump 24 and sterilization device 7 are stopped, and the sterilization operation is terminated. In this way, during sterilization operation, the switching valve 9 is switched to the sterilization flow path 27 side, and the bath water is circulated through the bath circulation circuit 2 so that it passes through the sterilization device 7, allowing the sterilization device 7 to sterilize the bath water.

[0027] During sterilization operation, the bath burner 33 is not ignited, preventing damage to the sterilization device 7 from heat caused by high-temperature bathwater. Furthermore, if the bathwater temperature detected by the bath inlet temperature sensor 26 during sterilization operation is equal to or higher than a predetermined temperature (e.g., 60°C), the switching valve 9 is switched to the branch flow path 8, the circulation pump 24 and the sterilization device 7 are stopped, and the sterilization operation is canceled. This prevents high-temperature bathwater from passing through the sterilization device 7, preventing damage to the sterilization device 7 from heat. Alternatively, if the bathwater temperature detected by the bath inlet temperature sensor 26 during sterilization operation is equal to or higher than a predetermined temperature, the switching valve 9 may simply be switched to the branch flow path 8, and if the bathwater temperature falls below the predetermined temperature, the switching valve 9 may be switched to the sterilization flow path 27, allowing the bathwater to pass through the sterilization device 7. In this case, the counting of the sterilization operation time is stopped while the switching valve 9 is switched to the branch flow path 8.

[0028] As described above, according to this embodiment, during reheating operation, the switching valve 9 passes the bath water through the branch flow path 8, and during sterilization operation, the switching valve 9 passes the bath water through the sterilization device 7. Therefore, even if the sterilization device 7 is installed in the bath circulation circuit 2, the bath water passes through the sterilization device 7 only when sterilization operation is performed, making it difficult for dirt to adhere to the sterilization device 7, and the sterilization ability of the sterilization device 7 can be maintained at a high level for a long period of time without prematurely decreasing.

[0029] During reheating operation, high-temperature bathwater does not pass through the sterilization device 7, preventing the sterilization device 7 from being damaged by the heat of the high-temperature bathwater. Also, during sterilization operation, the bath heat exchanger 3 does not heat the bathwater, preventing the sterilization device 7 from being damaged by the heat of the high-temperature bathwater. Furthermore, if the temperature of the bathwater is above a predetermined temperature during sterilization operation, the switching valve 9 switches to the branch flow path 8, preventing the sterilization device 7 from being damaged by the heat of the high-temperature bathwater. Therefore, the sterilization device 7 is less susceptible to damage by heat, and the life of the sterilization device 7 can be extended.

[0030] Other embodiments In another embodiment, the hot water heater 1A is configured to perform a cleaning operation to clean the sterilization device 7 after the sterilization operation is completed. As shown in FIG. 3, in the hot water heater 1A, the cleaning operation is performed continuously after the sterilization operation is completed. The solenoid valve 61 of the hot water filling path 6, which serves as a conveying path, is opened to supply hot water from the hot water supply circuit 5 to the bath circulation circuit 2 through the hot water filling path 6. The switching valve 9 is held in a position on the sterilization flow path 27 side, where the bath circulation circuit 2 and the sterilization flow path 27 are connected. The hot water supplied to the bath circulation circuit 2 from the hot water supply circuit 5 through the hot water filling path 6 flows from the bath return flow path 21 through the bath heat exchanger 3, into the bath supply flow path 22, into the sterilization flow path 27, and through the sterilization device 7. Then, the hot water reaches the circulation adapter 12 of the bathtub 11 from the bath supply flow path 22 and flows into the bathtub 11. In this case, the bath burner 33 does not burn even if the bath water flow switch 25 provided in the bath return flow path 21 is turned on. When the hot water volume sensor 63 installed in the hot water filling path 6 detects that the amount of hot water supplied from the hot water supply circuit 5 to the bath circulation circuit 2 has reached a predetermined volume (for example, 10 liters), the hot water filling solenoid valve 61 is closed and the cleaning operation is terminated. By performing this cleaning operation, clean hot water supplied from the hot water supply circuit 5 is passed through the sterilization device 7, which washes away dirt adhering to the sterilization device 7, thereby further suppressing the adhesion of dirt to the sterilization device 7.

[0031] The cleaning operation is controlled by a control device (not shown) and is configured to be performed periodically, and is performed only after a certain number of sterilization operations have been performed. For example, the control device stores the number of times the sterilization operation has been performed, and performs the cleaning operation every time the sterilization operation has been performed a predetermined number of times (e.g., 10 times). Note that the cleaning operation may be performed whenever the sterilization operation has been performed.

[0032] Furthermore, a remote controller (not shown) may be provided with a wash operation switch for executing the wash operation, so that the wash operation can be manually executed at the user's discretion.

[0033] Furthermore, when water from the water supply source flows into the water supply passage 51 of the hot water supply circuit 5, the hot water burner 43 is ignited and hot water heated by the hot water heat exchanger 4 is supplied to the bath circulation circuit 2 through the hot water filling passage 6, but during cleaning operation, the hot water burner 43 may not be ignited and water from the water supply source may be supplied from the hot water supply circuit 5 to the bath circulation circuit 2 through the hot water filling passage 6. This prevents the sterilization device 7 from being damaged by heat even during cleaning operation, thereby extending the life of the sterilization device 7.

[0034] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, in the embodiment, the sterilization device 7 is provided in the bath-supply flow path 22, but it may also be provided in the bath-return flow path 21. In this case, the sterilization device 7, branch flow path 8, sterilization flow path 27, switching valve 9, and check valve 28 are provided in the bath-return flow path 21 so as to match the flow direction of bathwater in the bath-supply flow path 22. Furthermore, when filling the bathtub 11 with hot water, the switching valve 9 may be switched to the sterilization flow path 27 side so that the hot water passes through the sterilization device 7. In this case, dirt adhering to the sterilization device 7 can be washed away every time the bathtub 11 is filled with hot water. Instead of the switching valve 9 in the embodiment, a switching valve device may be provided that controls the opening and closing of the branch flow path 8 and the sterilization flow path 27. The switching valve device may be configured, for example, to have electromagnetic on-off valves provided in each of the branch flow path 8 and the sterilization flow path 27, and by controlling the opening and closing of these electromagnetic on-off valves, it is possible to switch between passing the bath water circulating through the bath circulation circuit 2 through the sterilization device 7 (opening the electromagnetic on-off valve of the sterilization flow path 27 and closing the electromagnetic on-off valve of the branch flow path 8) and passing the bath water through the branch flow path 8 (closing the electromagnetic on-off valve of the sterilization flow path 27 and opening the electromagnetic on-off valve of the branch flow path 8). [Explanation of symbols]

[0035] 1,1A water heater 2 Bath circulation circuit 3 Bath heat exchanger (heating section) 4. Hot water heat exchanger (hot water heating section) 5 Hot water circuit 6. Filling path (transport path) 7. Sterilization equipment 8 Branching Channel 9. Switching valve 11 Bathtub 12 Circulation adapter 21 Bath return channel 22 Bath route 23 Bath return temperature sensor 24 Circulation Pump 25 Bath water flow switch 26 Bath temperature sensor (temperature sensor) 27 Sterilization channel 28 Check valve 33 Bath Burner 43 Hot water burner 51 Water supply channel 52 Hot water outlet 53 Water volume sensor 54 Hot water temperature sensor 55 Check valve 61 Hot water filling solenoid valve 62 Check valve 63 Water volume sensor 71 Case 72 Sterilization treatment unit

Claims

1. a bath circulation circuit in which bath water in the bath tub circulates between the bathtub and a heating unit; a sterilization device provided in the bath circulation circuit for sterilizing bathtub water circulating through the bath circulation circuit; A branch flow path that bypasses the sterilization device in the bath circulation circuit and allows bathwater to flow; The hot water device is provided with a switching valve that switches whether the bathtub water circulating in the bath circulation circuit passes through the sterilization device or the branch flow path.

2. The hot water device according to claim 1, The bath circulation circuit downstream of the heating unit is provided with a temperature sensor that detects the temperature of the bath water flowing through the bath circulation circuit. This hot water device is configured so that, during sterilization operation in which bathtub water circulating in a bath circulation circuit is passed through a sterilization device, if the temperature of the bathtub water detected by a temperature sensor is equal to or higher than a predetermined temperature, the switching valve passes the bathtub water through a branch flow path, thereby canceling the sterilization operation.

3. The hot water device according to claim 1, A hot water device in which a check valve is provided in the flow path between the sterilization device and the junction of the branch flow paths in the bath circulation circuit to prevent bath water from flowing back upstream.

4. In the hot water device according to any one of claims 1 to 3, a hot water supply circuit that heats water from a water supply source in a hot water supply heating unit and supplies hot water; a conveying path for connecting the hot water supply circuit and the bath circulation circuit and supplying hot water or water from the hot water supply circuit to the bath circulation circuit; This hot water device is configured to perform a cleaning operation in which a predetermined amount of hot water or water is supplied from the hot water supply circuit to the bath circulation circuit through a conveying path and passed through the sterilization device after a sterilization operation in which bath water is passed through the sterilization device.

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