Bath hot water supply device

Abstract

To provide a bath hot water supply device capable of achieving both functional improvement and water saving in cleaning after drain discharge via a reheating passage.SOLUTION: A bath hot water supply device (1) includes a hot water supply passage (22) for heating clean water by a hot water supply heat exchanger (14) with heat of combustion gas to supply hot water, a reheating passage (32) having a reheating heat exchanger (15) for heating hot water in a bathtub and a circulation pump (31), a hot water supply passage (25) branched from the hot water supply passage to supply hot water to the bathtub through the reheating passage, a hot water supply valve (26) for opening and closing the hot water supply passage, flow rate detection means (27) for the hot water supply passage, and a flow rate adjustment valve (24) for the hot water supply passage. The hot water supply device includes a control means (20) of drain discharge operation for discharging combustion gas drain, a flow passage switching valve (28) of a hot water supply passage, and a bypass passage (29) branched from the hot water supply passage at the flow passage switching valve and having an ozone water generator (30) connected to the downstream thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hot water supply device for a bath that supplies hot water heated by using the heat of combustion gas to a hot water supply destination including a bathtub. [Background technology]

[0002] Bath water heaters equipped with the functions of using the heat of combustion gas to supply hot water and reheat bathwater have been widely used. The reheating function involves returning bathwater water to the bathwater heater, heating it, and then returning the heated water to the bathtub. Because the reheating passages used for this reheating function tend to become contaminated with dirt and bacteria from the human body, and because the temperature of bathwater water is suitable for the growth of bacteria, it is preferable to clean the reheating passages after draining the bathtub to keep them clean. For this reason, bath water heaters are known that automatically circulate clean water, such as clean water, through the reheating passages after draining the bathtub.

[0003] A widely used hot water heater for baths is a highly efficient combustion-type bath heater that uses the heat (sensible heat and latent heat) of combustion gases generated by burning fuel to heat tap water and bathtub water. The combustion gas used for heating cools down, and the moisture contained in the combustion gas condenses, producing condensed water (drain). The drain is acidic because components of the combustion gas are dissolved in it, so it is designed to be neutralized before being discharged.

[0004] Depending on the installation environment of the bath water heater, such as a pipe shaft in an apartment building, there may be no nearby drainage channel through which the drain can be discharged. In such cases, as in Patent Documents 1 and 2, for example, the bath water heater is equipped with a drain tank to store the neutralized drain, and when the water level in the drain tank exceeds a predetermined level, the drain is discharged from the drain tank through the reheating passage when there is no hot or cold water in the bathtub. After the drain is discharged, the reheating passage is cleaned in the same way as after draining the bathtub. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-21707 [Patent Document 2] Patent No. 5727584 Summary of the Invention [Problem to be solved by the invention]

[0006] The frequency of draining the drain tank varies depending on the usage of the bath water heater, but since the bath water heater is cleaned every time the drain is discharged, a large amount of hot water is used, and if high-temperature hot water is used for cleaning to sterilize the bath water, the amount of fuel used also increases.

[0007] On the other hand, there is a known bath water heater that circulates ozone water with a bactericidal effect through a reheating passage after draining the bathtub, sterilizing the passage, and then circulates hot water through the reheating passage to drain and clean the remaining ozone water. The ozone water is circulated without heating so that the ozone concentration is sufficient for sterilization. However, there has been no technology to circulate ozone water through the reheating passage after draining the bathtub through the reheating passage for sterilization and cleaning.

[0008] Therefore, an object of the present invention is to provide a bath water heater that achieves both improved cleaning performance and water conservation during cleaning operation after drain discharge through a reheating passage. [Means for solving the problem]

[0009] The bath water heater of the invention of claim 1 comprises a hot water heat exchanger that heats tap water using the heat of combustion gas, a reheating heat exchanger that heats hot water in a bathtub using the heat of combustion gas, a hot water supply passage that supplies the hot water heated by the hot water heat exchanger, a reheating passage equipped with a circulation pump that circulates the hot water in the bathtub between the reheating heat exchanger and the hot water supply passage, a hot water supply passage that branches off from the hot water supply passage and supplies hot water to the bathtub through the reheating passage, a hot water supply valve that opens and closes the hot water supply passage, a flow rate detection means provided in the hot water supply passage, a flow rate adjustment valve provided in the hot water supply passage, and a flow rate adjustment valve that adjusts the flow rate of the hot water supply passage. A bath water heater having a control means for controlling the drain discharge operation in which drain is discharged through the reheating passage, the bath water heater comprises a flow path switching valve installed in the hot water supply passage, a bypass passage branched from the hot water supply passage at the flow path switching valve and connected to the hot water supply passage downstream of the flow path switching valve, and an ozone water generator installed in the bypass passage, and the control means is configured to switch the flow path switching valve to the bypass passage side and open the hot water supply valve after drain discharge is complete, thereby performing ozone water cleaning by circulating ozone water generated by the ozone water generator through the reheating passage.

[0010] According to the above configuration, the bath water heater circulates ozone water through the reheating passage that has become dirty due to drainage. Ozone water has a bactericidal effect, which improves the cleaning function of the reheating passage after drainage. Furthermore, it can clean the reheating passage with a small amount of ozone water, thereby saving water.

[0011] The bath water heater of the invention of claim 2 is characterized in that, in the invention of claim 1, the control means is configured to switch the flow path switching valve to the hot water supply passage side before and after the ozone water cleaning, and to pass clean water for a predetermined amount or for a predetermined period of time, respectively. According to the above configuration, dirt caused by drain discharge is washed away with tap water before the ozone water is circulated, so the reheating passage can be effectively sterilized with the ozone water, and any stagnant ozone water can be washed away with tap water after the ozone water is circulated. [Effects of the Invention]

[0012] According to the bath water heater of the present invention, it is possible to achieve both improved cleaning performance and water conservation during the cleaning operation after drain discharge through the reheating passage. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a configuration diagram of a hot water supply system in which a bath hot water supply device according to an embodiment of the present invention is installed. [Figure 2] 10 is a flowchart of a cleaning operation control according to an embodiment. [Figure 3] 4 is a flowchart of drain discharge operation control according to the embodiment. [Figure 4] 10 is a flowchart of a cleaning operation control after drain discharge according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the mode for carrying out the present invention will be described based on examples. [Example]

[0015] First, the configuration of a bath hot water supply device 1 will be described with reference to FIG. Bath water heater 1 is a combustion-type water heater that uses combustion heat to heat clean water supplied through water supply pipe 2 (as indicated by arrow W), and supplies hot water adjusted to a predetermined temperature to the outside through hot water supply pipe 3 (as indicated by arrow HW). This bath water heater 1 performs a hot water supply operation that supplies hot water at a preset hot water supply temperature. Bath water heater 1 also performs a bath filling operation that fills a bathtub 4 installed in the bathroom with hot water at a preset bath temperature up to a preset water level, and a reheating operation that heats the hot water in bathtub 4 and returns it to bathtub 4 to bring the water to the preset bath temperature.

[0016] The bath water heater 1 includes a fuel gas supply unit 10, a blower fan 11 that supplies air for combustion, a hot water burner 12 and a reheating burner 13 that burn the fuel gas, a hot water heat exchanger 14 that uses the heat of the high-temperature combustion gas generated by combustion to heat tap water, and a reheating heat exchanger 15 that heats the hot water in the bathtub 4. The hot water heat exchanger 14 includes a primary heat exchanger 14a that recovers the sensible heat of the combustion gas and a secondary heat exchanger 14b that recovers the latent heat of the combustion gas. Similarly, the reheating heat exchanger 15 includes a primary heat exchanger 15a and a secondary heat exchanger 15b.

[0017] A water supply temperature sensor 17 for detecting the temperature of the clean water and a water supply flow rate sensor 18 for detecting the flow rate of the clean water are disposed in a water supply passage 16 that supplies clean water from the water supply pipe 2 to the hot water heat exchanger 14. A distribution valve 19 capable of adjusting the distribution ratio is disposed in the water supply passage 16 upstream of the water supply flow rate sensor 18.

[0018] The bath water heater 1 has a control unit 20 (control means) to control various operations based on the temperature detected by the water supply temperature sensor 17 and the flow rate detected by the water supply flow rate sensor 18. When the water supply flow rate sensor 18 detects a flow rate equal to or higher than a preset minimum operating flow rate, the control unit 20 activates the hot water burner 12 to heat the clean water supplied to the hot water heat exchanger 14. The heated hot water is supplied to the hot water supply passage 22 and mixed with clean water from a water supply bypass passage 23 that is branched off from the water supply passage 16 by the distribution valve 19 and connected to the hot water supply passage 22, where the temperature is adjusted.

[0019] The hot water supply passage 22 is equipped with a hot water temperature sensor 22a that detects the temperature of the adjusted hot water, and a hot water flow rate adjustment valve 24 (flow rate adjustment valve) that adjusts the flow rate of the hot water supplied from the hot water supply passage 22. The hot water flow rate adjustment valve 24 is normally fully open, and the flow rate is adjusted as needed. A hot water pouring passage 25 branches off from the hot water supply passage 22 via the hot water flow rate adjustment valve 24. The hot water pouring passage 25 is equipped with a hot water pouring valve 26 that opens and closes the hot water pouring passage 25, and a hot water pouring flow rate sensor 27 (flow rate detection means).

[0020] A flow path switching valve 28 is provided midway along the molten metal pouring passage 25. A molten metal pouring bypass passage 29 (bypass passage) branches off from the molten metal pouring passage 25 at this flow path switching valve 28, and this molten metal pouring bypass passage 29 is connected to the molten metal pouring passage 25 downstream of the flow path switching valve 28. The flow path switching valve 28 is switched to either the molten metal pouring passage 25 side or the molten metal pouring bypass passage 29 side so as to select the molten metal pouring passage 25 or the molten metal pouring bypass passage 29 as the flow path for the molten metal pouring. The molten metal pouring bypass passage 29 has an ozone water generator 30 that electrolyzes the molten metal pouring passage 29 and produces ozone water when the flow path switching valve 28 is switched to the molten metal pouring bypass passage 29 side.

[0021] A reheating passage 32 equipped with a circulation pump 31 is connected to the reheating heat exchanger 15 to circulate the hot water in the bathtub 4. The bathtub 4 and the reheating passage 32 are connected by a reheating piping 8 connected to the circulation adapter 4a of the bathtub 4. The reheating passage 32 is composed of a return passage 32a equipped with a circulation pump 31 that returns the hot water in the bathtub 4 to the bath hot water supply device 1 and sends it to the reheating heat exchanger 15, and a bathtub forward passage 32b that returns the hot water that has circulated through the reheating heat exchanger 15 to the bathtub 4. The hot water pouring passage 25 is connected to the return passage 32a via the circulation pump 31. Alternatively, the hot water pouring passage 25 may be connected to the return passage 32a, and a circulation pump 31 may be installed in the return passage 32a downstream of this connection (on the reheating heat exchanger 15 side).

[0022] A water level sensor 33, for example, a water pressure sensor, is disposed in the reheating passage 32 as a water level detection means for detecting the water level in the bathtub 4. A bath temperature sensor 34 for detecting the temperature of the water in the bathtub 4 and a water flow switch 35 as a water flow detection means for detecting the water flow in the reheating passage 32 are provided downstream of the circulation pump 31 in the return passage 32a. The water temperature in the bathtub 4 is detected when the circulation pump 31 is driven, the water in the bathtub 4 flows through the reheating passage 32, and the water flow is detected by the water flow switch 35.

[0023] When the hot water supply destination of the bath water heater 1 is, for example, a bathroom faucet 5 or shower 6, hot water adjusted to the set hot water supply temperature is supplied via the hot water supply pipe 3. When the bathtub 4 is being filled with water, hot water adjusted to the set bath temperature is supplied to the bathtub 4 via the hot water supply passage 25, the reheating passage 32, and the reheating pipe 8. At this time, the hot water from the hot water supply passage 25 is divided into the upstream and downstream sides of the circulation pump 31 and flows through the reheating passage 32, respectively, before being supplied to the bathtub 4.

[0024] Control unit 20 calculates the amount of hot water to be poured into bathtub 4 based on the flow rate detected by pouring flow rate sensor 27 and the pouring time, and ends the water filling operation when the calculated amount of poured hot water reaches the amount corresponding to the set water level. In addition, when reheating the bathtub 4, control unit 20 drives circulation pump 31 and burns the water in reheating burner 13 while water flow switch 35 detects water flow, so that the hot water in bathtub 4 circulated through reheating passage 32 is heated in reheating heat exchanger 15 and returned to bathtub 4.

[0025] During hot water supply operation, hot water filling operation, and reheating operation, the heat (sensible heat and latent heat) of the combustion gas is used for heating in the hot water supply heat exchanger 14 or the reheating heat exchanger 15. The bath water heater 1 has a neutralizer 40 containing a neutralizing agent to recover latent heat and neutralize and discharge the acidic condensed water (drain) formed by condensing moisture in the combustion gas. The drain flows into the neutralizer 40 through a drain passage 40a. The neutralizer 40 discharges the neutralized drain from a discharge passage 40b to maintain a constant water level and maintain a water-sealed state. The drain discharged through the drain discharge passage 40b is stored in a drain tank 41.

[0026] A drain discharge valve 42 is provided upstream of the circulation pump 31 in the return passage 32a to discharge drain water from the drain tank 41 through the reheating passage 32. The drain tank 41 and the drain discharge valve 42 are connected by a tank discharge passage 41a. The drain tank 41 is equipped with a pair of water level detection electrodes 41b for detecting when the drain water reaches a predetermined reference water level. The drain discharge valve 42 is a three-way valve with a flow path switching function and a closing function. The drain discharge valve 42 can be switched between a circulation side, which connects the return passage 32a to circulate hot and cold water in the bathtub 4 by driving the circulation pump 31, a discharge side, which connects the tank discharge passage 41a to the return passage 32a to discharge drain water from the drain tank 41 by driving the circulation pump 31, or a closed state, which isolates the bathtub 4, the circulation pump 31, and the drain tank 41 from each other.

[0027] The reheating pipe 8 on the bathtub supply passage 32b side is equipped with a reheating pipe discharge valve 43, and a drain passage 44 extends from this reheating pipe discharge valve 43 to drain water into the bathtub pan below the bathtub 4 or into the bathroom drain. The reheating pipe discharge valve 43 is a three-way valve with a flow path switching function, and can be switched to a circulation side that connects the bathtub supply passage 32b with the bathtub 4 to circulate hot and cold water in the bathtub 4, or a discharge side that connects the bathtub supply passage 32b with the drain passage 44 to drain water. If the reheating pipe discharge valve 43 and drain passage 44 are not installed, the drain will be drained into the bathtub 4 and from the bathtub 4 to the bathroom drain.

[0028] The bath water heater 1 has an operation terminal for starting the reheating operation and for various setting operations such as the hot water temperature setting, bath temperature setting, and water level setting. This operation terminal, for example, a bathroom remote control 7 installed in the bathroom, is communicatively connected to the control unit 20. In addition to multiple operation buttons, the bathroom remote control 7 is equipped with a display unit 7a that displays setting information related to various operations, an audio output unit 7b, and a human presence sensor 7c that detects people in the bathroom, allowing it to detect the presence of people in the bathroom and their entry and exit.

[0029] When the water level of bathtub 4 detected by water level sensor 33 drops below the height of circulation adapter 4a and becomes undetectable, control unit 20 detects this as bathtub 4 being drained. Then, for example, if the system is set to perform a pipe cleaning operation (hereinafter abbreviated as cleaning operation) in which cleaning water is circulated from hot water supply passage 25 to reheating passage 32 and discharged into bathtub 4 when bathtub 4 drainage is detected, control unit 20 executes the cleaning operation.

[0030] The cleaning operation is performed, for example, in the order of a pre-cleaning process, an ozone water cleaning process, and a rinse-cleaning process. In the pre-cleaning process, high-temperature hot water is circulated to sterilize and wash away dirt. In the ozone water cleaning process, in order to achieve an ozone concentration that has sufficient sterilizing effect, the distribution valve 19 is adjusted so that the water supply bypass passage 23 side is at its maximum, the flow rate is narrowed by the hot water supply flow rate adjustment valve 24, and combustion is prevented by the hot water supply burner 12. The ozone water generated by the ozone water generator 30 is circulated, and bacteria that cannot be killed by high-temperature hot water are sterilized. In the rinse-cleaning process, the stagnant ozone water is washed away with tap water or high-temperature hot water.

[0031] Next, the cleaning operation control by the control unit 20 will be described based on the flowchart of Fig. 2. In the figure, Si (i = 1, 2, . . . ) represents a step.

[0032] When drainage of bathtub 4 is detected and cleaning operation control is started, a pre-clean is performed in S1, and when the pre-clean is finished, the process proceeds to S2. Specifically, hot water supply valve 26 is opened, combustion begins in hot water supply burner 12, and temperature-adjusted high-temperature hot water is supplied to hot water supply passage 25 as cleaning water. This high-temperature hot water is divided into the upstream and downstream sides (reheating heat exchanger 15 side) of circulation pump 31, flows through reheating passage 32 respectively, and is discharged into bathtub 4. The flow rate of cleaning water is calculated based on the flow rate detected by hot water supply flow rate sensor 27 and the flow time, and the pre-clean is finished when it reaches a preset flow rate of cleaning water that is sufficient to wash away dirt.

[0033] Next, in S2, flow path switching valve 28 is switched to the hot water supply bypass passage 29 side to perform ozonated water cleaning, and when ozonated water cleaning is completed, the process proceeds to S3. Specifically, combustion of hot water burner 12 is stopped, distribution valve 19 is adjusted so that the feed water bypass passage 23 side is fully open, and hot water supply flow rate adjustment valve 24 is adjusted so that the flow rate is reduced. Then, power for electrolysis is supplied to ozonated water generator 30 to generate ozonated water from the clean water flowing through hot water supply bypass passage 29, and this ozonated water is circulated through reheating passage 32.

[0034] Because the reheating passage 32 is filled with hot water by the pre-cleaning, even a low flow rate of ozone water can be circulated throughout the reheating passage 32. The flow rate of ozone water is calculated based on the flow rate detected by the hot water flow rate sensor 27 and the flow time, and ozone water cleaning ends when a preset flow rate of ozone water is reached. The flow rate of ozone water is, for example, an amount equivalent to the passage volume of the reheating passage 32 and the reheating piping 8.

[0035] In S3, flow path switching valve 28 is switched to the hot water supply passage 25 side, and a rinse is performed by circulating clean water, for example, and proceeds to S4 when the rinse is complete. At this time, hot water supply flow rate adjustment valve 24 is returned to full open. The amount of flush water flow is calculated based on the flow rate detected by hot water supply flow rate sensor 27 and the flow time, and when the flow of flush water reaches a preset flush water flow rate, the rinse is completed. Then, in S4, hot water supply valve 26 is closed, and flush operation control is completed.

[0036] Next, the drain discharge operation control by the control unit 20 will be described with reference to FIG. When the water level detection electrode 41b detects that the water level in the drain tank 41 has reached the reference water level, a determination is made in S11 as to whether drain discharge is possible. Specifically, if the water level in the bathtub 4 has not been detected and hot water is not being poured into the bathtub 4 through the hot water pouring passage 25, it is determined that drain discharge is possible. If the determination in S11 is No, the process returns to S11. In this case, a notification may be made, for example, from the bathroom remote control 7, to prompt the user to make the drain discharge possible. On the other hand, if the determination in S11 is Yes, the process proceeds to S12.

[0037] Next, in S12, the drain discharge valve 42 and the reheating pipe discharge valve 43 are each switched to the discharge side, and the process proceeds to S13. Then, in S13, the circulation pump 31 begins to operate, and the process proceeds to S14. The circulation pump 31 may be driven at any rotational speed that allows drain to be discharged from the drain tank 41 through the reheating passage 32, and may be driven at a rotational speed lower than the rotational speed during reheating operation. When the circulation pump 31 is driven, drain is introduced from the drain tank 41 through the tank discharge passage 41a into the return passage 32a, flows through the bathtub supply passage 32b, and is discharged from the drain passage 44 of the reheating pipe 8 to the bathtub pan or drain in the bathroom. If the reheating pipe discharge valve 43 and the drain passage 44 are not provided, the drain is discharged into the bathtub 4, and from the bathtub 4 to the bathroom drain.

[0038] In S14, it is determined whether drainage from the drain tank 41 has been completed. Specifically, if the water level detection electrode 41b does not detect the water level and the water flow switch 35 does not detect the water flow even if the circulation pump 31 is driven, it is determined that drainage has been completed. If the determination in S14 is No, the process returns to S14. If the determination in S14 is Yes, the process proceeds to S15, where the circulation pump 31 is stopped and the process proceeds to S16. Then, in S16, the ozone water cleaning operation is performed.

[0039] Unlike the cleaning operation of the reheating passage 32 in Fig. 2, the ozone water cleaning operation does not use heated hot water, but instead uses ozone water to improve cleaning performance and save water. When the ozone water cleaning operation is started, in S21 in Fig. 4, the drain discharge valve 42 is switched to the circulation side, and the process proceeds to S22. Then, in S22, the hot water supply valve 26 is opened to circulate clean water, and the process proceeds to S23. At this time, the distribution valve 19 is adjusted so that the water supply bypass passage 23 side is maximized to prevent combustion by the hot water supply burner 12. The clean water is divided into two parts and circulates upstream and downstream of the circulation pump 31, and is discharged into the bathtub 4 on the upstream side of the circulation pump 31, and into the drain passage 44 or the bathtub 4 on the downstream side.

[0040] Next, in S23, it is determined whether the flow of clean water has reached a predetermined clean water volume. The predetermined clean water volume is, for example, an amount that can flush out any drain remaining in the reheating passage 32. If the determination in S23 is No, the process returns to S23. If the determination in S23 is Yes, the process proceeds to S24, where the hot water supply valve 26 is closed to stop the flow of clean water, and the process proceeds to S25.

[0041] Next, in S25, flow path switching valve 28 is switched to the hot water supply bypass passage 29 side, and the process proceeds to S26. Then, in S26, hot water supply valve 26 is opened to supply clean water from hot water supply passage 25 to hot water supply bypass passage 29, and power for electrolysis is supplied to ozone water generator 30 to circulate ozone water through reheating passage 32, and the process proceeds to S27. At this time, hot water supply flow rate adjustment valve 24 is adjusted to throttle the flow rate. Because clean water was circulated immediately before and is accumulating in reheating passage 32, ozone water is divided into two and circulates on the upstream and downstream sides of circulation pump 31, even at a low flow rate.

[0042] In S27, it is determined whether the flow of ozone water has reached a predetermined amount of ozone water. The predetermined amount of ozone water is, for example, an amount corresponding to the passage volume of the drain discharge path. If the determination in S27 is No, the process returns to S27. If the determination in S27 is Yes, the process proceeds to S28, where the hot water supply valve 26 is closed to stop the flow of ozone water, and the process proceeds to S29. At this time, the hot water supply flow rate adjustment valve 24 is returned to full open.

[0043] Next, in S29, flow path switching valve 28 is switched to the side of pouring passage 25, and the process proceeds to S30. Then, in S30, pouring valve 26 is opened to allow clean water to circulate, and the process proceeds to S31. The clean water is divided into two parts, one upstream and one downstream of circulation pump 31, and is discharged into bathtub 4 on the upstream side of circulation pump 31, and into drain passage 44 or bathtub 4 on the downstream side.

[0044] In S31, it is determined whether the flow of clean water has reached a predetermined clean water volume. The predetermined clean water volume is the same as S23. If the determination in S31 is No, the process returns to S31. If the determination in S31 is Yes, the process proceeds to S32, where the hot water supply valve 26 is closed to stop the flow of clean water, thereby ending the ozone water cleaning operation control. Since S16 in FIG. 3 has now ended, the drain discharge operation control ends.

[0045] The operation and effects of the above-described hot water supply device for bath 1 will be described. The bath water heater 1 neutralizes drainage formed by condensation of moisture contained in combustion gas in the hot water heat exchanger 14 and the reheating heat exchanger 15, stores the neutralized drainage in the drain tank 41, and discharges the neutralized drainage from the drain tank 41 through the reheating passage 32. After the drainage is completed, ozone water is circulated through the reheating passage 32, which has become dirty due to the drainage, to clean it. Because ozone water has a bactericidal effect, it is possible to clean the reheating passage 32 with only a small amount of ozone water circulated, thereby achieving both improved cleaning performance and water conservation when cleaning the reheating passage 32 after drainage through the reheating passage 32.

[0046] The control unit 20 washes away dirt caused by drain discharge with clean water before the ozone water is circulated, so that the reheating passage 32 can be effectively sterilized with the ozone water, and after the ozone water is circulated, the stagnant ozone water can be washed away with clean water.

[0047] In addition, a person skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention, and the present invention includes such modifications. [Explanation of symbols]

[0048] 1: Bath water heater 2: Water supply piping 3: Hot water supply piping 4: Bathtub 5: Karan 6: Shower 7: Bathroom remote control 8: Reheating piping 10: Fuel gas supply unit 11: Blower fan 12: Hot water burner 13: Reheat burner 14: Hot water heat exchanger 15: Reheating heat exchanger 16:Water supply passage 17: Water supply temperature sensor 18: Water supply flow sensor 19: Distribution valve 20: Control unit (control means) 22: Hot water passage 23: Water supply bypass passage 24: Hot water flow control valve (flow control valve) 25: Pouring passage 26: Meltwater valve 27: Pouring flow rate sensor (flow rate detection means) 28: Flow path switching valve 29: Pouring bypass passage (bypass passage) 30: Ozone water generator 31: Circulation pump 32: Reburning passage 32a: Bathtub return passage 32b: Passage to the bathtub 33: Water level sensor 34: Bathtub temperature sensor 35: Water flow switch 40: Neutralizer 41b: Water level detection electrode 42: Drain discharge valve 43: Reheating piping discharge valve 44: Drain passage

Claims

1. a hot water supply passage for supplying the hot water heated by the hot water heat exchanger, a reheating passage provided with a circulation pump for circulating the hot water in the bathtub between the hot water supply passage and the reheating heat exchanger, a hot water supply passage branching from the hot water supply passage and supplying the hot water to the bathtub through the reheating passage, a hot water supply valve for opening and closing the hot water supply passage, a flow rate detection means provided in the hot water supply passage, a flow rate adjustment valve provided in the hot water supply passage, and a control means for controlling a drain discharge operation for discharging drain formed by condensation of moisture contained in the combustion gas in the hot water heat exchanger and the reheating heat exchanger through the reheating passage; The apparatus comprises a flow path switching valve provided in the molten metal pouring passage, a bypass passage branched from the molten metal pouring passage at the flow path switching valve and connected to the molten metal pouring passage downstream of the flow path switching valve, and an ozone water generating device provided in the bypass passage, The bath water heater is characterized in that the control means is configured to switch the flow path switching valve to the bypass passage side and open the hot water supply valve after the drain has been discharged, thereby performing ozone water cleaning by circulating the ozone water generated in the ozone water generation device through the reheating passage.

2. The bath water heater device described in claim 1, characterized in that the control means is configured to switch the flow path switching valve to the hot water supply passage side before and after the ozone water cleaning, and to pass clean water for a predetermined amount or for a predetermined period of time.

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