JP2021101148A - Bath hot water supply unit - Google Patents

Abstract

To reduce a risk of a heat shock when getting into a bathtub.SOLUTION: A controller of a bath hot water supply unit starts hot water supply at a target temperature set by a hot water supply remote controller, etc. in S45 if a room temperature detected by a room temperature thermistor is a temperature for which heat shock countermeasures are required (e.g., 15°C or lower) in the discrimination in S41. When a set water amount is reached in S46 and hot water supply is finished in S47, hot water in the bathtub is circulated and agitated in S48. When it is confirmed that the temperature is lowered to a low target temperature lower than the target temperature in S49, agitation is finished in S50. Then, when bathing is detected in S51, reheating is executed in S54 and the temperature is kept at the target temperature.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a bath water heater including a hot water supply heating unit and a bath heating unit.

Conventionally, a bath water heater having a function of heating hot water in a bathtub has been widely put into practical use. As disclosed in Patent Document 1, for example, this bath water heater has passed through a hot water supply side combustion chamber provided with a hot water supply side heat exchanger and a hot water supply side burner for heating the heat exchanger, and a hot water supply side heat exchanger. A bath-side combustion chamber equipped with a hot-water supply circuit (hot water supply heating unit) including a hot water outlet pipe for discharging hot water, a bath-side heat exchanger, and a bath-side burner for heating the heat exchanger, and a bath-side heat exchanger. It is known that a bath circuit (bath heating unit) that forms a bath circulation path including a return pipe and a going pipe connected between the water heater and the water heater is provided. The bath circuit is connected to the hot water supply circuit, and in addition to being able to fill the bathtub with hot water discharged from the hot water supply circuit, the hot water in the bathtub is supplied to the bathtub side heat exchanger by the pump of the bath circulation path. By burning the burner on the bath side while circulating between the bathtubs, it is possible to boil the hot water in the bathtub or keep it warm by reheating.

Japanese Unexamined Patent Publication No. 2013-170794

By the way, in recent years, it has been pointed out that there is a danger of so-called heat shock, in which fluctuations in blood pressure and fluctuations in pulse rate occur due to sudden changes in temperature. This heat shock can also occur in winter when entering a cold dressing room or bathroom from a heated room, or entering a hot tub in a cold bathroom. Therefore, measures have been taken to mitigate temperature changes by installing a heating function in the dressing room and bathroom, but since the temperature filled in the bathtub is often higher than the heating temperature (40 ° C or higher), the bathtub is used. Changes in the sensible temperature before and after use are inevitable.

Therefore, an object of the present disclosure is to provide a bath water heater capable of reducing the risk of heat shock when immersed in a bathtub.

In order to achieve the above object, the present disclosure includes a hot water supply heating unit including a hot water supply side burner, a hot water supply side heat exchanger that heats water passing through the inside by combustion exhaust of the hot water supply side burner, and a bath side. It is equipped with a burner and a bath-side heat exchanger that heats the hot water passing through the inside by the combustion exhaust of the bath-side burner, and provides a bath circulation path connected to the hot water supply heating unit between the bath-side heat exchanger and the bathtub. The bath heating unit to be formed, the hot water temperature detecting means for detecting the temperature of the hot water in the bathtub, the bathing detecting means for detecting the bathing in the bathtub, the combustion of the hot water supply side burner and the bath side burner are controlled, and the hot water supply heating is performed. A bath water heater that includes a controller that executes hot water filling from the unit to the bathtub and / or reheating of hot water in the bathtub, and a target temperature setting means that sets a target temperature for hot water filling and / or reheating. There,
The controller executes hot water filling and / or reheating at the target temperature set by the target temperature setting means, and then circulates the hot water in the bathtub in the bath circulation path to make the hot water in the bathtub lower than the target temperature. On the other hand, when the bathing is detected by the bathing detection means after the hot water in the bathtub is circulated, the reheating is executed until the target temperature is reached.
In another aspect of the present disclosure, in the above configuration, if the controller detects a drop in the temperature of the hot water in the bathtub by the hot water temperature detecting means after the hot water filling and / or reheating and before the detection of bathing by the bathing detecting means. It is characterized by performing reheating to a low target temperature.

According to the present disclosure, until bathing is detected, hot water filling and / or reheating is performed in which a low target temperature lower than the target temperature is maintained, so that the hot water at the low target temperature is immersed at the time of bathing. , The change in sensible temperature before and after bathing can be reduced. Therefore, it is possible to reduce the risk of heat shock when submerged in the bathtub.
According to another aspect of the present disclosure, in addition to the above effects, if the temperature drop of the hot water in the bathtub is detected before the detection of bathing, the temperature is kept at a low target temperature, so that the hot water temperature does not drop too much.

It is a schematic circuit diagram of a bath water heater. It is a flowchart of automatic hot water filling operation. It is a flowchart of automatic reheating operation. It is a flowchart of the automatic hot water filling operation of the modification example.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
FIG. 1 is a schematic circuit diagram of a bath water heater. In the bath water heater 1, the hot water supply side burners 5, 5, ... And the primary heat exchangers 6 and 2 as hot water supply side heat exchangers are installed in the hot water supply side combustion chamber 4. A hot water supply heating unit 2 equipped with a secondary heat exchanger 7 to heat tap water to discharge hot water, and a bath side burner 21 and a bath side heat exchanger 22 provided in the bath side combustion chamber 20 to re-cook the bath, etc. It is composed of a bath heating unit 3 used for the above.
First, in the hot water supply heating unit 2, a water supply pipe 8 provided with a hot water supply water amount sensor 9 and supplying tap water from the water supply is connected to the inlet of the secondary heat exchanger 7, and the outlet of the secondary heat exchanger 7 and the primary heat are connected. A connecting pipe 10 for supplying hot water heated by the secondary heat exchanger 7 to the primary heat exchanger 6 is connected to the inlet of the exchanger 6, and a hot water supply thermista is connected to the outlet of the primary heat exchanger 6. A hot water discharge pipe 11 which is provided with 12 and discharges hot water heated by a primary heat exchanger is connected. Reference numeral 13 denotes a hot water tap outside the appliance.

Further, in the hot water supply side combustion chamber 4, the primary heat exchanger 6 is arranged on the upstream side of the combustion exhaust path of the hot water supply side burner 5, and the secondary heat exchanger 7 is arranged on the downstream side of the combustion exhaust path. The water flow in the heat tube is heat-exchanged with the combustion exhaust. The gas pipe 14 that supplies gas to the hot water supply side burner 5 includes a gas source solenoid valve 15 and a hot water supply gas proportional control valve 16 from the upstream side, and a hot water supply switching solenoid valve 17 for each branch pipe to each hot water supply side burner 5. 17 ... are provided respectively. Below the hot water supply side combustion chamber 4, a fan 18 for supplying combustion air to each hot water supply side burner 5 and a bath side burner 21 is provided. Reference numeral 19 is an igniter for ignition.

On the other hand, in the bath heating unit 3, a return pipe 24 provided with a circulation pump 25 and a bath thermista 26 as a hot water temperature detecting means and an outgoing pipe 27 are connected between the bath side heat exchanger 22 and the bathtub 23. Has been done. A hot water supply electromagnetic valve 29 branched from the hot water discharge pipe 11 and a drop pipe 28 provided with a drop water amount sensor 30 are connected to the return pipe 24, and the hot water supply electromagnetic valve 29 provided on the drop pipe 28 is opened. The hot water heated by the hot water supply heating unit 2 can be supplied to the bathtub 23. The bath side heat exchanger 22, the return pipe 24, and the forward pipe 27 form a bath circulation path for circulating hot water in the bathtub 23.

Further, a switching solenoid valve 31 is provided in the branch pipe from the gas pipe 14 connected to the bath side burner 21. Reference numerals 32 and 33 are check valves provided on the downstream side of the hot water supply solenoid valve 29 in the drop pipe 28, and the return pipe 24 is opened and closed on the upstream side of the connection portion with the drop pipe 28 in the return pipe 24. A control motor 34 for driving a possible valve body is provided. 35 is a controller, 36 is a hot water supply remote controller, 37 is a bath remote controller, and the return pipe 24 is provided with a water pressure sensor 38 as a bathing detection means for detecting the water level in the bathtub 23. A room temperature thermistor 39 is provided as a temperature detecting means for detecting the temperature in the field. However, the temperature detecting means is not limited to the thermistor of the dressing room, and if it is outside the bathtub, a thermistor or the like provided indoors such as a bathroom or a living room may be used, or a thermistor or the like that detects the outside air temperature outdoors may be used. You may.

In the bath water heater 1 configured as described above, first, normal hot water supply is performed as follows.
When the hot water supply plug 13 provided in the hot water outlet pipe 11 is opened and water is passed through the appliance, and the water flow is detected by the hot water supply water amount sensor 9, the controller 35 rotates the fan 18 for a predetermined time to burn the hot water supply side. The combustion exhaust stored in the chamber 4 and the combustion chamber 20 on the bath side is discharged (prepurge). After that, the gas source solenoid valve 15 of the gas pipe 14 and each hot water supply switching solenoid valve 17 are opened, the hot water supply gas proportional control valve 16 is opened at a predetermined opening degree, and gas is supplied to each hot water supply side burner 5. , The igniter 19 is operated to ignite the hot water supply side burners 5, 5 ...

Then, the combustion exhaust of the hot water supply side burner 5 first passes through the primary heat exchanger 6 to exchange heat with the water flow of the heat transfer tube, and then passes through the secondary heat exchanger 7 to exchange heat with the water flow of the heat transfer tube. And it is discharged to the outside. As a result, the sensible heat is recovered by the primary heat exchanger 6 and the latent heat is recovered by the secondary heat exchanger 7, and the heated hot water is discharged from the hot water tap 13.

The controller 35 monitors the hot water discharge temperature by the hot water supply thermista 12 of the hot water supply pipe 11, controls the opening and closing of the hot water supply switching electromagnetic valve 17 and hot water supply so that the hot water discharge temperature becomes the set temperature instructed by the hot water supply remote controller 36 or the bath remote controller 37. The opening degree of the gas proportional control valve 16 is adjusted, and the amount of air is continuously changed by controlling the rotation speed of the fan 18. When the hot water supply tap 13 is closed, the controller 35 confirming that the signal of the hot water supply water amount sensor 9 is stopped closes the gas source solenoid valve 15 and the hot water supply switching solenoid valve 17, extinguishes the hot water supply side burner 5, and rotates the fan 18 for a predetermined time. Post-purge.

(Explanation of automatic hot water filling operation)
Then, the controller 35 can automatically fill the bathtub 23 with the hot water discharged from the hot water supply and heating unit 2. Hereinafter, this automatic hot water filling operation will be described with reference to the flowchart of FIG.
When the hot water filling switch provided on the hot water supply remote controller 36 or the bath remote controller 37 is pressed, the controller 35 first determines that the room temperature of the dressing room detected from the room temperature thermistor 39 in S1 is the temperature at which heat shock countermeasures are required (for example, 15 ° C.). It is determined whether or not it is (below).
Here, if the room temperature requires measures against heat shock, the hot water outlet temperature is set to a temperature lower than the hot water filling temperature (target temperature (for example, 40 ° C.)) set in the hot water supply remote controller 36 or the bath remote controller 37 in S2 (target temperature (for example, 40 ° C.)). The hot water filling is started by setting the target temperature), and the hot water supply remote controller 36 and / or the bath remote controller 37 as the notification means notifies that the target temperature has been lowered (for example, synthetic voice or character display).

This low target temperature may be arbitrarily set by the hot water supply remote controller 36 or the bath remote controller 37 as the target temperature setting means. Further, a temperature table set in advance based on the temperature detected from the room temperature thermistor 39 (for example, if the detected temperature is 15 ° C. to 10 ° C., the temperature is -1 ° C. To -2 ° C temperature, if it is 5 ° C or less, the temperature is set to -3 ° C from the target temperature), or by calculating from a function using the detected temperature, the hot water supply remote control 36 or the bath remote control 37 May be set automatically in. By changing the low target temperature according to the temperature detected by the room temperature thermistor 39 in this way, it is possible to set an appropriate low target temperature according to the air temperature outside the bathtub.

On the other hand, if the room temperature is not the temperature at which heat shock countermeasures are required according to the determination in S1, the hot water outlet temperature is set to the target temperature in S3 and the hot water filling is started.
In the hot water filling of S2 and S3, the hot water supply solenoid valve 29 of the drop pipe 28 is opened to allow water to pass through the hot water supply heating unit 2 to burn the hot water supply side burner 5, and the hot water from the hot water outlet pipe 11 is discharged from the hot water supply pipe 28. And by supplying to the bathtub 23 via the return pipe 24. At this time, the flow path of the return pipe 24 is opened by the control motor 34.

In the case of hot water filling at the target temperature, when it is confirmed in S4 that the amount of water detected by the drop water amount sensor 30 provided in the drop pipe 28 has reached the set amount of water, the hot water supply solenoid valve 29 is closed in S5. Water flow is stopped, the hot water supply side burner 5 is extinguished to end the hot water filling, and the circulation pump 25 is operated to circulate the hot water in the bathtub 23 in the bath heating unit 3. Further, the end of hot water filling is notified by the hot water supply remote controller 36 or the bath remote controller 37.
After that, the hot water temperature is monitored by the bath thermistor 26 provided in the return pipe 24, and when the hot water temperature drops, the bath side burner 21 is ignited and the circulation pump 25 is operated to circulate the hot water in the bathtub 23 for reheating. Then, the heat retention control for keeping the heat at the target temperature is executed.

Then, in the case of hot water filling at a low target temperature, when it is confirmed in S6 that the detected water amount has reached the set water amount, the hot water filling is ended in S7, and the hot water filling is terminated by the hot water supply remote controller 36 or the bath remote controller. Notify at 37. At this time as well, a notification that the target temperature has been lowered may be given.
After that, in S8, bathing is detected by the water pressure sensor 38, and in S9, the decrease in hot water temperature is monitored by the bath thermistor 26 provided in the return pipe 24. When a decrease in hot water temperature is confirmed in S9 without detecting bathing in S8, the bath side burner 21 is ignited to operate the circulation pump 25 in S10 to move between the bath side heat exchanger 22 and the bathtub 23. Circulating bath The circulating water is reheated to keep it warm at a low target temperature. At this time as well, the notification that the target temperature is low may be given. After the decrease in hot water temperature is not confirmed in S9 or the temperature is kept in S10, the process returns to S8 and waits for the detection of bathing.

On the other hand, when bathing is detected by the water pressure sensor 38 in S8, the bath side burner 21 is ignited to operate the circulation pump 25 in S11, and the bath circulation circulates between the bath side heat exchanger 22 and the bathtub 23. Reheat the water to the target temperature. When the target temperature is reached, the combustion of the bath side burner 21 is stopped, the circulation pump 25 is stopped, and the temperature is kept at the target temperature.

(Explanation of automatic reheating operation)
Further, the controller 35 can automatically reheat (boil) the cold water stored in the bathtub 23, and in this case as well, heat shock countermeasures are taken. Hereinafter, this automatic reheating operation will be described with reference to the flowchart of FIG.
When the reheating switch provided on the hot water supply remote controller 36 or the bath remote controller 37 is pressed, the controller 35 determines that the room temperature of the dressing room detected from the room temperature thermistor 39 in S21 is the temperature at which heat shock countermeasures are required (for example, 15 ° C. or lower). ) Is determined.
Here, if the room temperature requires measures against heat shock, the reheating temperature is set to a low target temperature lower than the target temperature set by the hot water supply remote controller 36 or the bath remote controller 37 in S22, and the bath side burner. 21 is ignited, and the circulation pump 25 is operated to circulate the hot water in the bathtub 23 to start reheating. Then, the hot water supply remote controller 36 and / or the bath remote controller 37 notify that the target temperature has been lowered (for example, display of synthetic voice, characters, or marks). This low target temperature is set in the same manner as in the case of FIG.

On the other hand, if the room temperature is not the temperature at which heat shock countermeasures are required according to the determination in S21, the reheating temperature is set to the target temperature in S23 and the reheating is started.
In the case of reheating at the target temperature, when it is confirmed in S24 that the hot water temperature detected by the bath thermista 26 has reached the target temperature, in S25, the bath side burner 21 is extinguished and the circulation pump 25 is turned on. When the reheating is completed by stopping and the hot water temperature drops, the bath side burner 21 is ignited, and the circulation pump 25 is operated to circulate the hot water in the bathtub 23 to reheat and keep the temperature at the target temperature.

Then, in the case of reheating at a low target temperature, when it is confirmed in S26 that the hot water temperature detected by the bath thermistor 26 has reached the low target temperature, in S27, the bath side burner 21 is extinguished and the fire is extinguished. The circulation pump 25 is stopped to end the reheating, and the completion of the reheating is notified by the hot water supply remote controller 36 or the bath remote controller 37. At this time as well, a notification that the target temperature has been lowered may be given.
After that, in S28, bathing is detected by the water pressure sensor 38, and in S29, the decrease in hot water temperature is monitored by the bath thermistor 26. When a decrease in hot water temperature is confirmed in S29 without detecting bathing in S28, the bath side burner 21 is ignited to operate the circulation pump 25 in S30 to move between the bath side heat exchanger 22 and the bathtub 23. Circulating bath The circulating water is reheated to keep it warm at a low target temperature. At this time as well, the notification that the target temperature is low may be given. After the decrease in hot water temperature is not confirmed in S29 or the temperature is kept in S30, the patient returns to S28 and waits for the detection of bathing.

On the other hand, when bathing is detected by the water pressure sensor 38 in S28, the bath side burner 21 is ignited in S31 to operate the circulation pump 25, and the bath circulation circulates between the bath side heat exchanger 22 and the bathtub 23. Reheat the water to the target temperature. When the target temperature is reached, the combustion of the bath side burner 21 is stopped, and the process of stopping the circulation pump 25 is repeated to keep the temperature at the target temperature.

As described above, according to the bath water heater 1 of the above-described embodiment, when the heat shock countermeasure is required, the controller 35 makes the hot water filling and reheating more than the target temperature set by the hot water supply remote control 36 or the bath remote control 37. On the other hand, when bathing is detected by the water pressure sensor 38 after hot water filling and reheating, the reheating is executed until the target temperature is reached, and the low target temperature is maintained until bathing is detected. It is possible to reduce the change in the perceived temperature before and after soaking in the bathtub 23 by soaking in hot water filled and reheated at a low target temperature. Therefore, it is possible to reduce the risk of heat shock when using the bathtub 23.

In particular, here, the controller 35 executes reheating to a low target temperature when the bath thermistor 26 detects a decrease in the temperature of the hot water in the bathtub 23 after the hot water filling and reheating and before the detection of bathing by the water pressure sensor 38. Therefore, it can be kept warm at a low target temperature, and the hot water temperature does not drop too much.
Further, since the controller 35 executes hot water filling and reheating at a low target temperature lower than the target temperature when the temperature detected by the room temperature thermistor 39 is 15 ° C. or lower, it is low only when heat shock countermeasures are required. Hot water filling and reheating can be performed at the target temperature.
Furthermore, by providing a notification means for notifying the hot water filling and reheating to be executed at a low target temperature, it is possible to notify the user that the hot water filling and reheating are performed by heat shock countermeasures, and it is possible to avoid misunderstanding as a failure. ..

In the above embodiment, heat shock countermeasures are taken to adopt a low target temperature for hot water filling and reheating (boiling), respectively, but heat shock countermeasures are taken only for either hot water filling or reheating. You may.
Further, heat shock countermeasures are required when the temperature detected by the room temperature thermistor is 15 ° C. or lower, but other detection temperatures may be used as a condition, and the temperature difference between the detected temperature and the target temperature is, for example, 10 ° C. If the above is the case, it may be determined that heat shock countermeasures are necessary.
Further, the bathing detection means is not limited to the water pressure sensor, and a water level sensor or the like may be adopted.

(Explanation of change example of automatic hot water filling operation)
In the bath water heater 1, when measures against heat shock are required, hot water filling and / or reheating is performed at a low target temperature, but after hot water filling and / or reheating at the target temperature, It is also conceivable to stir the hot water in the bathtub to lower the hot water temperature to a low target temperature. Hereinafter, the present invention will be described with reference to the flowchart of FIG. 4 by taking automatic hot water filling operation as an example.

When the hot water filling switch provided on the hot water supply remote controller 36 or the bath remote controller 37 is pressed, the controller 35 tells S41 that the room temperature of the dressing room detected from the room temperature thermistor 39 is the temperature at which heat shock countermeasures are required (for example, 15 ° C. or lower). ) Is determined.
Here, if the temperature does not require heat shock countermeasures, the hot water outlet temperature is set to the target temperature in S42, and hot water filling is started. When it is confirmed in S43 that the amount of water detected by the water amount sensor 30 has reached the set amount of water, in S44, the solenoid valve 29 for hot water supply is closed to stop the water flow, and the burner 5 on the hot water supply side is extinguished to fill the water. Is terminated, and the completion of hot water filling is notified by the hot water supply remote controller 36 or the bath remote controller 37. Further, the circulation pump 25 is operated to circulate and reheat the hot water in the bathtub 23 to keep the temperature at the target temperature.

On the other hand, even if the temperature is determined by S41 and measures against heat shock are required, similarly, in S45, the hot water outlet temperature is set to the target temperature and the hot water filling is started. When it is confirmed in S46 that the detected amount of water has reached the set amount of water, the hot water filling is finished in S47, and the hot water supply remote controller 36 or the bath remote controller 37 notifies the end of the hot water filling.
Next, in S48, the circulation pump 25 is operated without igniting the bath side burner 21, and the hot water in the bathtub 23 is circulated to start stirring. When it is confirmed in S49 that the hot water temperature detected by the bath thermistor 26 has dropped to a low target temperature, the circulation pump 25 is stopped in S50 to end the stirring.

After that, in S51, bathing is detected by the water pressure sensor 38, and in S52, the decrease in hot water temperature is monitored by the bath thermistor 26. When a decrease in hot water temperature is confirmed in S52 without detecting bathing in S51, the bath side burner 21 is ignited to operate the circulation pump 25 in S53 to reheat the circulating water in the bath and keep it warm at a low target temperature. To do. After the decrease in hot water temperature is not confirmed in S52 or the temperature is kept in S53, the patient returns to S51 and waits for the detection of bathing.
Then, when bathing is detected by the water pressure sensor 38 in S51, the bath side burner 21 is ignited in S54 to operate the circulation pump 25, and the bath circulating water is reheated to the target temperature. When the target temperature is reached, the combustion of the bath side burner 21 is stopped, and the process of stopping the circulation pump 25 is repeated to keep the temperature at the target temperature.

Also in this modification example, the controller 35 executes hot water filling at the target temperature, and then circulates the hot water in the bathtub 23 in the bath circulation path to lower the hot water in the bathtub 23 to a low target temperature. By soaking in hot water of the target temperature, it is possible to reduce the change in the sensible temperature before and after soaking in the bathtub 23. Therefore, it is possible to reduce the risk of heat shock when using the bathtub 23. Further, if the bathtub 23 is not covered, the temperature in the bathroom can be expected to rise by stirring the hot water.

Even in the case of automatic reheating operation from cold water, if heat shock countermeasures are required, after reheating to the target temperature, the treatment after S48 in FIG. 4, that is, stirring to a low target temperature The temperature of the hot water may be lowered to keep the temperature warm, and when bathing is detected, the temperature may be reheated to the target temperature to keep the temperature warm. Further, in this modified example as well, heat shock countermeasures may be taken only by either filling with hot water or reheating.

In addition, in the above embodiment, the hot water supply heating unit is provided with a primary heat exchanger and a secondary heat exchanger as hot water supply side heat exchangers, but there is no secondary heat exchanger and only the primary heat exchanger is provided. It doesn't matter. The bath heating unit may also be provided with a primary heat exchanger and a secondary heat exchanger as bath side heat exchangers.

1 ・ ・ Bath water heater, 2 ・ ・ Hot water heating unit, 3 ・ ・ Bath heating unit, 4 ・ ・ Hot water supply side combustion chamber, 5 ・ ・ Hot water supply side burner, 6 ・ ・ Primary heat exchanger, 7 ・ ・ Secondary heat Exchanger, 8 ... water supply pipe, 11 ... hot water outlet pipe, 20 ... bath side combustion chamber, 21 ... bath side burner, 22 ... bath side heat exchanger, 23 ... bathtub, 24 ... return pipe, 27 ... going pipe, 35 ... controller, 36 ... hot water supply remote control, 37 ... bath remote control, 38 ... water pressure sensor, 39 ... room temperature thermistor.

Claims (2)

A hot water supply heating unit including a hot water supply side burner and a hot water supply side heat exchanger that heats water passing through the inside by combustion exhaust of the hot water supply side burner.
A bath-side burner and a bath-side heat exchanger that heats hot water passing through the inside by the combustion exhaust of the bath-side burner are provided, and the hot water supply and heating unit is connected between the bath-side heat exchanger and the bathtub. The bath heating part that forms the bath circulation path
A hot water temperature detecting means for detecting the temperature of hot water in the bathtub,
A bathing detection means for detecting bathing in the bathtub and
A controller that controls combustion of the hot water supply side burner and the bath side burner, and executes hot water filling from the hot water supply heating unit to the bathtub and / or reheating of hot water in the bathtub.
A bath water heater including a target temperature setting means for setting a target temperature for filling and / or reheating.
After executing the hot water filling and / or the reheating at the target temperature set by the target temperature setting means, the controller performs the hot water filling and / or the reheating at the target temperature set by the target temperature setting means.
While circulating the hot water in the bathtub in the bath circulation path to lower the hot water in the bathtub to a lower target temperature lower than the target temperature, while
A bath water heater characterized in that when bathing is detected by the bathing detecting means after circulation of hot water in the bathtub, the reheating is executed until the target temperature is reached. When the controller detects a decrease in the temperature of the hot water in the bathtub after the hot water filling and / or the reheating and before the detection of bathing by the bathing detecting means by the hot water temperature detecting means, the controller can reach the low target temperature. The bath water heater according to claim 1, wherein the reheating is performed.

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