JP5657325B2 - Bath water heater - Google Patents

Description

  The present invention relates to a bath water heater equipped with a latent heat recovery type hot water supply heat exchanger.

  Conventionally, in a hot water supply apparatus having a reheating circulation path connected to a bathtub and a hot water supply side circuit provided with a hot water supply heat exchanger, the apparatus provided with a hot water supply heat exchanger for latent heat recovery in the hot water supply side circuit has high thermal efficiency. Is widely used. However, if a hot water supply heat exchanger for latent heat recovery is provided to form a bath water heater, water vapor containing nitrogen oxides (NOx) in the combustion gas is cooled by water passing through the heat exchanger for latent heat recovery, and condensation occurs. Since drain (drain water) is generated, it is necessary to collect the drain and discharge it to the outside of the bath water heater. Therefore, it is detected by the detecting means that the collected drain has been stored in a predetermined amount, and the drain is sent to the water distribution pipe side to be drained (discharged) or led to the recirculation circuit, and the bathtub is taken from the recirculation circuit. The structure which drains to a bathroom or a bathroom is proposed (for example, refer to patent documents 1).

Japanese Patent No. 3153361

  By the way, since the recirculation circuit is a circulation path for circulating the hot water in the bathtub, in the configuration in which the drain is guided to the recirculation circuit and drained, if the drain is mixed into the hot water, the formaldehyde contained in the drain However, there is a possibility of adversely affecting the body of a person who bathes in the bath water, and it is necessary to provide a drain cleaning function for cleaning the drain passage by flowing water into the recirculation circuit after draining the drain.

  However, even if a drain cleaning function is provided, the bath water heater operates when the power is turned off due to a power failure or the like during drain drain cleaning or after drain drain channel cleaning of the recirculation circuit. If this happens, there is a possibility that the drain remains in the recirculation circuit. In addition, for example, when installing a bath hot water supply device, even during a completion inspection (combustion test) to confirm that normal operation is performed by performing hot water supply operation, etc., during the drainage drainage or after drainage In some cases, the energization may be stopped during the drain water passage cleaning of the circulation path, and even in such a case, there is a possibility that the drain remains in the recirculation circulation path. In such a state, if an operation such as hot water filling is performed through the recirculation circuit, drainage enters the bathtub, and as described above, it adversely affects the body of the person bathing in the bathtub hot water. turn into.

  The present invention has been made in order to solve the above-mentioned problems, and the purpose of the present invention is to cause a power failure or failure during drain drainage or drain cleaning through a recirculation circuit, or by a combustion test when installing the device. Even if drainage and cleaning of the generated drain is not done properly, the next hot water filling will be performed with the dirt of the drain attached to the recirculation circuit so that the human body will not be adversely affected. The object is to provide a bath water heater that can be used.

In order to achieve the above object, the present invention has the following configuration as means for solving the problems. That is, the first invention is a burner, a main hot water supply heat exchanger that absorbs sensible heat in the combustion gas of the burner, and a downstream of the flow of the combustion gas from the main hot water supply heat exchanger. And a hot water supply side circuit provided with a latent heat recovery hot water supply heat exchanger for recovering exhaust latent heat, and has a recirculation circuit connected to the bathtub, and the recirculation circuit is connected via the connection path The hot water supply side circuit communicates with the hot water side, drain recovery means for recovering the drain generated in the latent heat recovery hot water supply heat exchanger, drain storage means for storing the drain recovered by the drain recovery means, A drain lead-out path that guides the drain stored by the drain storage means to the recirculation circulation path side; Drain to drain Waterway is connected, a drain draining function for discharging the drain in the bathroom through said drain drainage channel and the reheating circulation path and the drain lead-out path, through the connection path from the previous SL hot water supply side circuit side A bath hot water supply device having a drain cleaning function for cleaning a water passage through which the drain passes in the recirculation circuit with water passed through the reheating circuit, and after turning on the power of the bath water supply device Is always a means for solving the problem with a structure having a drain cleaning control means for performing the operation of the drain cleaning function.

In addition, the second invention is a burner, a main hot water supply heat exchanger that absorbs sensible heat in the combustion gas of the burner, and a downstream of the flow of the combustion gas from the main hot water supply heat exchanger. And a hot water supply side circuit provided with a latent heat recovery hot water supply heat exchanger for recovering exhaust latent heat, and has a recirculation circuit connected to the bathtub, and the recirculation circuit is connected via the connection path The hot water supply side circuit communicates with the hot water side, drain recovery means for recovering the drain generated in the latent heat recovery hot water supply heat exchanger, drain storage means for storing the drain recovered by the drain recovery means, A drain lead-out path that guides the drain stored by the drain storage means to the recirculation circulation path side, and the drain led to the recirculation circulation path is branched from the recirculation circulation path to the recirculation circulation path. Drain drainage to drain A drain drainage function for discharging the drain to the bathroom via the drain lead-out path, the reheating circulation path and the drain drainage path, and the hot water supply side circuit side via the connection path to the drain A bath water heater having a drain cleaning function for cleaning a water passage through which the drain of the recirculation circuit passes with water passed through the recirculation circuit, the failure being caused by the failure of the drain drain function or the drain cleaning function Regardless of whether or not to operate the drain drainage function after the error signal output at the time of stoppage is canceled, the problem is solved by the configuration having the drain cleaning control means for performing the drain cleaning function. As a means. Further, in addition to the configuration of the first or second invention, the third invention is characterized in that the drain cleaning control means is configured to turn on the power supply of the bath hot water supply device of the first invention and the drain of the second invention. After the error signal output at the time of stoppage due to failure of the drainage function or drain cleaning function is released, the drain cleaning function is not immediately operated, but the hot water circulation operation for circulating the bath water through the recirculation circuit and the additional operation are performed. The drain cleaning function is operated when at least one recirculation water passage operation of the water injection operation of pouring hot water into the bathtub through the water circulation circuit.

  The present invention relates to a drain drain function for draining drain generated in a hot water supply heat exchanger for latent heat recovery to a bathroom through a drain outlet path, a recirculation circuit, and a drain drain path, and after drain drain by the drain drain function. The bath water heater has a drain cleaning function for cleaning the drain passage of the recirculation circuit with water passed from the hot water supply circuit side through the connection passage to the recirculation circuit. The drain cleaning function is always operated after the power is turned on and after the error signal output at the time of stoppage due to failure of the drain drain function or the drain cleaning function is canceled.

  Therefore, for example, even if a power failure or failure occurs during the operation of the drain drain function or the drain cleaning function, it is possible to prevent the cleaning circuit from being left uncleaned. It is possible to prevent the human body from being adversely affected by the next hot water filling with adhering and draining into the bath water. Moreover, the same effect can be produced also when the drain which generate | occur | produces at the time of the combustion test at the time of attachment of the bath hot water supply apparatus cannot be cleaned, for example.

  Also, the hot water circulation that circulates the hot water in the bathtub through the recirculation circuit, not immediately after the bath water heater is turned on and immediately after the error signal output when the drain drainage function or the drain cleaning function is stopped due to a failure The drain cleaning control means performs the operation of the drain cleaning function when performing the drain cleaning function when at least one of the operation and the water injection operation of pouring hot water into the bathtub through the recirculation circuit is performed. Operation of the drain cleaning function is performed immediately after turning on the power supply of the hot water supply device or immediately after the error signal is canceled, and it is possible to prevent the user of the bath water supply device and the operator of the repair from being surprised by the sound. it can.

  In other words, the recirculation circulation passage water flow operation is performed, for example, when bath water is reheated, automatic hot water filling, additional hot water, additional water, etc. are started. Since the remote control device connected to the signal is operated by the user of the bath water heater or the operator for repairing the trouble, even if there is a sound that the drain cleaning function is activated at that time, it is suspicious There is no. Further, if the drain cleaning function is operated before the recirculation circulation passage water passing operation, the drain is not properly drained before the operation or the drain cleaning is not performed accurately. Even if drainage is attached to the circulating circuit, the draining water is operated after the drain has been washed, so the next hot water filling can be done while the drainage dirt remains attached to the circulating circuit. It is possible to prevent the drain from being mixed into the bath water and adversely affecting the human body.

  In addition, for example, when repairing a failure, the recirculation circuit may be disconnected, and if the drain cleaning function is operated at such time, the drain or drain cleaning water will be supplied to the bath hot water. There will be problems such as splashing in the device, but when the recirculation circuit water flow operation is performed, the piping is not removed, and at that time the operation of the drain cleaning function is performed , It is possible to prevent the occurrence of the above problems.

It is a block diagram which shows the control structure of one Example of the bath hot-water supply apparatus which concerns on this invention. It is explanatory drawing which shows typically the system configuration | structure of the bath hot-water supply apparatus of an Example. It is a system diagram for demonstrating the drainage path at the time of operation | movement of the drain drainage function in the bath hot-water supply apparatus of an Example. It is a system figure for demonstrating the water flow path | route at the time of operation | movement of the drain washing function in the bath hot-water supply apparatus of an Example. It is a system figure for demonstrating the water flow path | route at the time of hot water filling operation | movement in the bath hot-water supply apparatus of an Example. It is a system figure for demonstrating the water flow path | route at the time of the chasing operation | movement in the bath hot-water supply apparatus of an Example. In the bath hot-water supply apparatus of an Example, it is a flowchart which shows the operation example until it reaches drain drain operation and drain washing operation. It is a flowchart which shows the drain drainage operation example of the bath water heater of an Example. It is a flowchart which shows the drain cleaning operation example of the bath hot-water supply apparatus of an Example. FIG. 10 is a flowchart illustrating an example of a drain cleaning operation of the bath water heater of the embodiment, following FIG. 9. FIG. FIG. 10 is a flowchart illustrating an example of a drain cleaning operation of the bath water heater of the embodiment, following FIG. 9. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 schematically shows a system configuration of an embodiment of the bath water heater according to the present invention. In the figure, a combustion chamber 2 is provided in the instrument case 60, and a hot water supply side burner 1 (1 a, 1 b, 1 c) and a hot water replenishment burner 7 in the bathtub 14 are provided in the combustion chamber 2. Has been placed. These burners 1 and 7 are connected to gas pipes 55 for supplying fuel to the respective burners 1 and 7. The gas pipes 55 are used to control fuel supply / stop to the burners 1 and 7. On-off valves 51, 52, and 53, and a proportional valve 54 that can control the amount of fuel supplied to the burner 1 with the valve opening are interposed.

  A combustion fan 5 for supplying and exhausting the combustion of the burners 1 and 7 is provided below the burners 1 and 7, and the combustion fan 5 rotates through an intake port (not shown). Then, the air sucked from the outside is sent to the burners 1 and 7, and burner combustion is performed by this air and the gas supplied through the gas pipe 55. Combustion gas generated by burner combustion passes through the combustion chamber 2 and is exhausted from an exhaust port (not shown).

  A hot water supply heat exchanger (primary hot water supply heat exchanger) 4 that recovers sensible heat in the combustion gas of the burner 1 is disposed above the hot water supply side burner 1, and the combustion is performed more than the main hot water supply heat exchanger 4. A latent heat recovery hot water supply heat exchanger (secondary hot water supply heat exchanger) 6 for recovering sensible heat and latent heat of the combustion gas is provided on the downstream side of the gas flow. The main hot water supply heat exchanger 4 has a plurality of plate-like fins 3.

  A water supply pipe 8 for guiding water from a water supply source is connected to the inlet side of the latent heat recovery hot water supply heat exchanger 6, and the main hot water supply heat exchanger 4 is connected to the outlet side of the latent heat recovery hot water supply heat exchanger 6. The entrance side of is connected. A hot water supply pipe 9 is connected to the outlet side of the main hot water supply heat exchanger 4, and a hot water supply side circuit including the main hot water supply heat exchanger 4 and a hot water supply heat exchanger 6 for recovering latent heat is formed. Yes. This hot water supply side circuit preheats the water passing through the latent heat recovery hot water supply heat exchanger 6 with the heat of latent heat recovery, supplies the preheated water to the water inlet of the main hot water supply heat exchanger 4, and It has a hot water supply function of supplying hot water heated by the hot water supply heat exchanger 4 and supplying hot water from the hot water supply passage 9 to the hot water supply destination. By providing the hot water supply heat exchanger 6 for recovering latent heat, efficient heating can be performed.

  The water supply pipe 8 includes a flow rate sensor (flow sensor) 10 for detecting the flow rate of water supplied from the water supply pipe 8 and flowing into the latent heat recovery hot water supply heat exchanger 6 side, water amount control valves 11 and 56, and An incoming water thermistor (not shown) for detecting the incoming water temperature of the water flowing into the latent heat recovery hot water supply heat exchanger 6 is provided. Further, the hot water supply pipe 9 is provided with a hot water thermistor (not shown) that can detect the temperature of the hot water flowing out. The hot water supply pipe 9 and the water supply pipe 8 include a pipe 12 and a water amount control valve 11. Connected through.

  Further, a reheating heat exchanger 13 for reheating the bath water is provided above the reheating burner 7, and the reheating heat exchanger 13 is connected to the bathtub 14. 15 is provided. In this example, the reheating heat exchanger 13 is also a main heat exchanger 13a that recovers sensible heat of the combustion gas of the burner 7, and a latent heat recovery heat exchanger 13b that recovers sensible heat and latent heat in the combustion gas. The main heat exchanger 13a has a plurality of plate-like fins 3 and is formed.

  The recirculation circulation path 15 has an outward pipe 16 (16 a, 16 b) leading to the bathtub 14, a return pipe 17 from the bathtub 14, and pipe lines 18, 19, 20, 21. In addition, the inside of the instrument case 60 of these pipe lines 18, 19, 20, 21 and the forward pipe 16 and the return pipe 17 is formed by, for example, a metal pipe or a rubber pipe, and the pipe line extending from the instrument case 60 to the inside 14 of the external bathtub. Is formed of, for example, a crosslinked polyethylene tube. One end side of the pipe line 21 is connected to the reheating heat exchanger 13, and the other end side of the pipe line 21 is connected to the discharge port side of the circulation pump 23 that circulates the bath water. The pipe 21 includes a water level sensor 25 that detects a water level of the bathtub 14 by water pressure, a water flow switch 26 that is turned on when it is detected that water has flowed through the pipe 21, and the temperature of the bathtub hot water. A bath temperature sensor (not shown) for detection is provided.

  A pipe line 20 is connected to the suction port side of the circulation pump 23, and a four-way switching valve 22 formed by a four-way valve is connected to the other end side of the pipe line 20. The four-way switching valve 22 is also connected to one end side of the pipelines 18 and 19 of the recirculation circuit 15 and one end side of the pipeline 28. A return pipe 17 is connected to the other end side of the pipe lines 18 and 19, and one end side of a pouring path 27 as a connection path is connected to the other end side of the pipe line 28 via a drain circuit switching valve 30. Has been. A pouring electromagnetic valve 29 is provided in the pouring passage 27, and the other end side of the pouring passage 27 is connected to the hot water supply passage 9. With this configuration, the recirculation circuit 15 is connected to the outlet side of the hot water supply side circuit via the pouring channel 27.

  Below the latent heat recovery hot water supply heat exchanger 6, a drain recovery means 31 for recovering drain generated in the latent heat recovery hot water supply heat exchanger 6, and a drain for storing the drain recovered by the drain recovery means 31 A drain tank 32 as storage means is provided. The drain collecting means 31 and the drain tank 32 are connected via a drain pipe 33, and the drain tank 32 is provided with a drain water level detection electrode 34 for detecting the water level of the drain stored in the drain tank 32. Yes. The drain is acidic because it contains nitrogen oxides (NOx) and the like in the combustion gas. Therefore, the drain tank 31 has a drain tank (for example, calcium carbonate) in the drain for neutralizing drain drainage (drain). Summing means 35 is provided.

  A drain lead-out path 36 that guides drain stored in the drain tank 32 to the recirculation path 15 is connected to the lower side of the drain tank 32, and a check valve 37 is provided in the drain lead-out path 36. The drain lead-out path 36 is connected to the pipe line 28 and the pouring path 27 through the drain circuit switching valve 30. Further, one end side of a pipe line 59 is connected to the drain tank 32, and the other end side of the pipe line 59 is connected to a drain outlet. The pipe 59 is a pipe for guiding the drain to the drain port when the drain overflows.

  A drain drain switching unit 37 is interposed in the outgoing pipe 16 of the reheating circulation path 15, and the drain led to the recirculation circulation path 15 is supplied to the drain drain switching unit 37. A drain drainage channel 38 that branches from 15 and drains into the bathroom is connected. In the drain drainage switching unit 37, a drain drainage switching valve 39 is provided at a connection portion between the drain drainage channel 38 and the outgoing pipes 16a and 16b.

  In the bath hot water supply apparatus of this embodiment, operations such as a hot water supply function to the kitchen, hot water filling to the bathtub 14, additional hot water, additional water, reheating of the hot water in the bathtub, drain draining function, drain cleaning function, etc. are given in advance. It is performed according to the sequence program. FIG. 1 shows the control configuration, and a characteristic drain drain cleaning control means 41 and hot water and reheating control means 42 are provided in the control device 40.

  The control device 40 is provided with control means for hot water supply function operation (not shown). First, an example of hot water supply function operation based on the control of the control means for hot water function operation will be briefly described. The hot water supply operation is started, for example, by opening a hot water tap (not shown) such as a kitchen or a washroom. The hot water supply operation exceeds the minimum operating flow rate through which the water supply pipe 8 is passed by the flow sensor 10 shown in FIG. When the flow rate is detected, the hot water supply function operation control means burns the hot water supply side burner 1, and the water passing through the hot water supply heat exchangers 4 and 6 (the main hot water supply heat exchanger 4 and the latent heat recovery hot water supply heat exchanger 6). Hot water is prepared by heating, and the hot water is discharged through the hot water supply pipe 9 as shown by the arrow in FIG.

  In the operation of the hot water supply function, the control means for the hot water supply function operation includes the incoming water temperature detected by the incoming water temperature sensor, the amount of hot water detected by the flow sensor 10, and the hot water temperature detected by the hot water temperature sensor ( The amount of gas supplied from the gas pipe 55 is controlled by the valve opening amount of the proportional valve 54 so as to reach the hot water supply set temperature based on the detection information such as the temperature of the hot water. The hot water supply operation is terminated when the hot water tap at the hot water supply destination is closed. That is, when the flow sensor 10 detects the stop of water flow by closing the hot water tap, the control device shuts off the gas supply to the hot water supply side burner 1 and stops the combustion of the hot water supply side burner 1.

  The pouring water / replenishing control means 42 controls the operation of the automatic hot water filling function, the operation of the additional water function, and the operation of the single hot water filling function. In addition to the hot water filling operation to fill the bathtub 14 with hot water up to a predetermined set water level (or hot water of the set water amount), a heat retaining operation and a water retaining operation are included. Note that the automatic hot water filling operation can be performed only by the hot water filling operation. The operation of the automatic hot water filling function is started when a user or the like turns on the automatic switch of the remote control device 50. As shown in FIG. Added to the sowing control means 42 and started. Upon receiving an automatic switch ON signal, the hot water / reheating control means 42 opens the hot water solenoid valve 29 and passes through the hot water supply heat exchangers 4 and 6 by the combustion heating of the burner 1 in the same manner as the operation of the hot water supply function. Water is used as hot water, and the hot water is passed from the hot water supply pipe 9 to the pouring channel 27 and dropped into the bathtub 14 through the recirculation circuit 15.

  In FIG. 5, the region through which hot water passes during the hot water filling operation is indicated by hatched portions, and the flow of hot water is indicated by arrows. As shown in FIG. 5, during the filling operation, the pouring line 27 and the pipe line 28 are connected via the drain circuit switching valve 30, and the pipe line 28 and the pipe line 18 are connected via the four-way switching valve 22. The pipe 19 and the pipe 20 are connected to each other, and the outgoing pipes 16a and 16b are connected to each other via the drain / drainage switching valve 39 (hereinafter, this water passage is followed by a circulation circuit). It is also called a water passage).

  When hot water filling is started, the water level of the bathtub 14 is detected by the water level sensor 25, and when the detected water level reaches the preset water level of the bathtub set in advance, the pouring water and reheating control means 42 is poured. The hot water solenoid valve 29 is closed to end the hot water filling operation. In this hot water filling operation, the pouring water and reheating control means 42 performs combustion control of the burner 1 so as to reach a preset hot water filling temperature, and hot water supply water for the hot water supply heat exchangers 4 and 6. Control the temperature.

  A flow rate sensor (flow sensor) for detecting the flow rate is provided in the pouring channel 27, and when the flow rate detected by the flow rate sensor reaches a set flow rate (a predetermined amount of pouring water into the bathtub 14), The reheating control means 42 may close the hot water solenoid valve 29 to end the hot water filling operation. In addition, in a type that calculates the amount of bathtub water from the amount of heat that is poured into the bath water in the middle of hot water filling and the amount of rise in the bathtub water temperature, the amount of bathtub water that is calculated from the calculation result and the set flow rate (setting The hot water filling operation may be terminated as described above when the difference between the hot water amount and the difference is further filled and the bathtub hot water amount reaches a set flow rate (set hot water amount).

  Normally, the operation of the heat retaining function is performed for a predetermined time (for example, 4 hours) following the hot water filling operation. During the operation of the heat retaining function, the pouring water / refreshing control means 42 activates the circulation pump 23 for a short time at predetermined time intervals, and the hot water in the bathtub 14 is reheated as shown by the arrows in FIG. 15 (see the shaded area in FIG. 6). At this time, the bath temperature sensor (not shown) detects the hot water temperature (bath temperature) of the bathtub 14, and when the detected temperature falls outside the allowable range below the set temperature of the bath, the circulation pump 23 is turned on. While being driven to circulate hot water in the bathtub 14 through the recirculation circuit 15, the reheating heat exchanger 13 is heated by the combustion of the reheating burner 7 to perform the reheating operation. Then, when the temperature detected by the bath temperature sensor reaches the set temperature of the bath, the circulation pump 23 is stopped, and the combustion of the burner 7 on the reheating side is stopped.

  In addition, in the operation of the water retention function performed together with the heat retention function, the pouring water and reheating control means 42 performs the following control. That is, the water level of the bathtub 14 is monitored by the water level sensor 25, and when the water level of the bathtub 14 falls below the allowable range from the set water level, the hot water solenoid valve 29 is opened and the hot water supply operation is performed in the same manner as in the hot water filling operation. The amount of hot water that reaches the set water level from the circuit side is replenished (additional hot water operation is performed), and the water retention function is maintained to maintain the bathtub water level at the set water level.

  When the operation of lowering the temperature of the bathtub hot water is performed by operating the remote control device 50 (for example, when the “Nuruyu” switch of the remote control device 50 is operated), the hot water / reheating control means 42 The hot water solenoid valve 29 is opened to control the operation of an additional water function for pouring water not heated from the hot water supply circuit side into the bathtub 14 by a predetermined set amount, for example.

  Further, when a reheating switch provided in the remote control device 50 is manually operated, the command is applied to the pouring water / refreshing control means 42, and the hot water / refreshing control means 42 Control is performed in the same manner as the chasing operation during the hot water filling operation. By this control, a chasing single operation is performed.

  The drain drain cleaning control means 41 performs the operation of the drain drain function and the operation of the drain cleaning function based on the detection signal of the drain tank water level detection electrode 34 (that is, the drain drain cleaning control means 41 serves as the drain cleaning control means. Also works). In the present embodiment, the drain tank water level detection electrode 34 is configured to have four electrodes as shown in FIG. 3, for example, and is arranged on the right side of the drawing among the four electrodes. The two electrodes with the longest length are the ground electrode a and the reference water level electrode (LL electrode) b that serves as a reference for stopping drainage, and the second longest electrode disposed on the left side is the low water level electrode (L electrode). C) The electrode disposed on the left side and having the shortest length is the high water level electrode (H electrode) d.

  The drain drain cleaning control means 41 receives the detection signal from the drain tank water level detection electrode 34, and when the drain in the drain tank 32 is equal to or higher than a predetermined drain drain set water level, that is, at least the low water level electrode c sets the drain water level. When detected, the drainage function of the drain stored in the drain tank 32 is operated. For example, when the drain water level is detected by the low water level electrode c and the water level is not detected by the high water level electrode d (when the water level is between the electrode c and the electrode d), in addition to that, for example, the automatic filling operation is performed. When started, the drain drain function is operated, and when the drain water level is detected by the low water level electrode c and the high water level electrode d (when the water level exceeds the electrode c and further exceeds the electrode d). , So that the drain drain function works immediately.

  The hatched portion in FIG. 3 shows a region through which the drain led out from the drain tank 32 passes during operation of the drain drain function, and the flow of drain is indicated by an arrow indicating the flow of the shaded portion. In FIG. 3, an arrow D indicates a flow until the drain generated in the latent heat recovery hot water supply heat exchanger 4 reaches the lower side of the drain tank 32 and is led out to the drain lead-out path 38. The drain drain cleaning control means 41 drains the drain in the drain tank 32 through a drain drain path as shown in FIG. When performing the operation of the drain drainage function, the drain drainage cleaning control means 41 sets the four-way switching valve 22, the drain drainage switching valve 39, and the drain circuit switching valve 30, all at the position during the filling operation shown in FIG. 3 is switched to the drain drainage position shown in FIG. 3 to drain the drain as a drain drainage path to the bathroom via the recirculation circuit 15.

  Specifically, first, the drain drain cleaning control means 41 switches the four-way switching valve 22 so that the pipe line 20 and the pipe line 28 are connected via the four-way switching valve 22. By this switching, the pipe lines 18 and 19 and the return pipe 17 are disconnected from the circulation pump 23. Next, the drain drain cleaning control means 41 switches the drain drain switching valve 39 so that the forward pipe 16 a and the drain drain channel 38 are connected via the drain drain switching valve 39. Next, the drain drain cleaning control means 41 switches the drain circuit switching valve 30 so that the drain lead-out path 36 and the pipe line 28 are connected via the drain circuit switching valve 30. In this state, the circulation pump 23 is driven, and the drain is passed through the drain lead-out path 36, the pipe 28, the pipe 21 of the reheating circulation path 15, the reheating heat exchanger 13, and the forward pipe 16a in this order, and the drain drain path 38. Through the bathroom. Then, when the drain water level is no longer detected by the reference water level electrode b of the drain tank water level detection electrode 34, the operation of the drain drain function is terminated (stopped).

  After the drain draining operation by the drain drain function, the drain drain cleaning control means 41 performs the drain cleaning function operation. The operation of this drain cleaning function is performed by the route shown by the shaded portion in FIG. In FIG. 4, the flow of hot water in the hot water supply side circuit is omitted. The drain drain cleaning control means 41 switches the drain circuit switching valve 30 so that the pouring passage 27 and the pipe 28 are connected via the drain circuit switching valve 30 to form a drain cleaning path. In this state, the hot water solenoid valve 29 is opened, and the water flow path of the drain in the recirculation circuit 15 is washed by the water passed from the hot water supply side circuit side to the recirculation circuit 15 through the pouring line 27. The water used for this drain cleaning is usually unheated water. However, if necessary, the water is heated in a hot water supply side circuit (for example, to a bath set temperature), and the heated water is drained. It may be heated water to be used for cleaning.

  Hereinafter, this point will be described in detail. Usually, the routine drain drain function and the subsequent drain cleaning function operation are automatically performed when the drain water level is detected by the low water level electrode c and there is no residual water (when there is no remaining hot water in the bathtub) as described above. Since it is performed when the hot water filling operation is started, waste of heat energy for heating water can be eliminated by using unheated water during the operation of the drain cleaning function at this time. Also, in this case, washing is performed using water that is not heated before the automatic hot water filling operation is started, but since the automatic hot water filling operation is started immediately thereafter, the hot water supply side circuit is heated with water heated at the set temperature of the bath. The inside of the pipe is filled.

  On the other hand, when the drain water level is detected by the low water level electrode c and the high water level electrode d (that is, when the amount of hot water used is abnormally large) or from the end of the drain discharge operation of the previous drain drain function. When a predetermined set time for drain drainage (for example, 72 hours) has elapsed, for example, in the absence of a long period of time, water heated to the set temperature of the bath during the operation of the drain cleaning function is used to make hot water in the piping of the hot water supply side circuit. In the unlikely event that you take a shower immediately afterwards, it is easy to get hot water.

  As described above, the water heated to the set temperature of the bath during the operation of the drain cleaning function is used to fill the piping of the hot water supply side circuit with hot water for the following reasons. That is, for example, when the user sets the hot water supply temperature (hot water supply set temperature) to 60 ° C. and discharges the hot water from the hot water tap, the user intends to use the hot water. The user can recognize that it is filled with hot water. However, the drain drain function and the drain cleaning function are not intended to be used by the user (for example, when the user wants to perform these operations by pressing an operation button of the remote controller 50 or the like). Therefore, the user cannot recognize the operation timing.

  Therefore, when the hot water supply set temperature is set to a high temperature such as 60 ° C., water heated to the hot water supply set temperature is used during the operation of the drain cleaning function. For example, when the remote controller 50 is turned off and a cold shower is to be used, hot water is discharged from the shower, which may be dangerous. Therefore, as described above, when the drain cleaning function is performed with heated water, the temperature is comfortable for bathing. The water is heated to the set temperature of the bath set as the expected temperature), the drain cleaning function is operated, and the hot water heated to the bath set temperature is filled in the piping of the hot water supply side circuit to immediately shower The hot water of the temperature that seems to be comfortable is easy to come out.

  Further, the drain waste water cleaning control means 41 sets the water amount at this time to 9 liters / minute by the control by the water amount control valve 56, and is smaller than the flow rate (for example, 24 liters / minute) at the time of pouring or pouring water into the bathtub 14. Then, add a total of 6 liters of water. By doing in this way, the sound (drainage sound) of the water which flows at the time of drain washing can be made small.

  Further, in this embodiment, when water is passed through the recirculation circuit 15 during the water injection operation, water is injected from both sides of the forward pipe 16 and the return pipe 17, but when drain cleaning is performed through the recirculation circuit 15. Is a one-sided water flow that uses only the outgoing pipe 16 side of the recirculation circuit 15 and does not pass water to the return pipe 17 side. Therefore, when drain cleaning is performed by passing the same flow rate of water into the bathtub 14 through both the outgoing pipe 16 and the return pipe 17 to the outgoing pipe 16 side, the water pressure when the water passes is It becomes higher than during water injection operation. When a high water pressure is applied to the circulation pump 23, there is a risk that the resin circulation pump 23 or the like cannot withstand the water pressure, but there is a possibility that the water flow rate during operation of the drain cleaning function as described above. By making the flow rate smaller than the flow rate during the water injection operation, the water pressure of the water passing through the recirculation circuit 15 can be reduced, and an excessive pressure can be prevented from being applied to the circulation pump 23. In addition, since the flow rate which drains drain at the time of operation | movement of the said drain drainage function is pressurized by the circulation pump 23, it is small like the flow rate of the water flowed at the time of operation | movement of a drain cleaning function.

  The drain drain cleaning control means 41 switches the drain drain switching valve 39 after the operation of the drain cleaning function is completed, and the outgoing pipes 16a and 16b are connected via the drain drain switching valve 39 as shown in FIG. Thus, the four-way switching valve 22 is switched, and the pipe line 28 and the pipe line 18 are connected via the four-way switching valve 22, and the pipe line 19 and the pipe line 20 are connected. Route).

  By the way, when the drain drainage cleaning control means 41 performs the drain drainage function or the drain cleaning function, a power failure (AC100V energization stop) or failure (AC100V energization continues) occurs, and the bath water heater stops working. The drain tank 32 may be in a state where the drain is still stored, or the drain cleaning is not performed thereafter. Also, if drainage or cleaning of the drain generated during the combustion test when installing the bath water heater is not performed accurately (AC100V energization is stopped after the test), the drain tank 32 is still in a state where the drain is stored. Further, the subsequent drain cleaning is not performed. In order to prevent this, this embodiment has the following characteristic configuration.

  That is, in this embodiment, when the power cord of the bath water heater is plugged into the outlet or when the power supply recovers from a power failure (return from AC 100 V energization stop), the ON signal of the power source 43 is sent to the drain drain cleaning control means 41. In addition, when the remote control device 50 cancels the error signal that is output when a failure occurs during the operation of the drain drainage function or the drain cleaning function (in the case of recovery with continued AC100V energization) For example, when an error signal release signal is output from the remote control device 50), the error signal release signal is applied to the drain waste water cleaning control means 41. Then, the drain drain cleaning control means 41 is supplied with the bath hot water through the recirculation circulation path 15 by the pouring water / refreshing control means 42 after the ON signal of the power source 43 and the error signal cancel signal from the remote control device 50 are added. When at least one of the hot water circulation operation of circulating hot water and the water injection operation of pouring hot water into the bathtub 14 through the recirculation circuit 15, the operation start signal is received and the operation is received. The drain cleaning function is always performed immediately before the start.

  In this embodiment, the drain cleaning function is always performed as described above, so that a power failure or failure may occur during the drain drain function or the drain cleaning function. Even if drainage or cleaning of the drain generated at the time of the combustion test performed in the mounting is not performed, the drain can be cleaned by the operation of the present application, and then hot water is passed through the recirculation circuit 15 such as hot water filling. When the operation of passing water is performed, the drain remaining in the recirculation circuit 15 can be prevented from being mixed into the hot water in the bathtub 14.

  In detail, when the power cord of the bath water heater is inserted into an outlet or when an ON signal of the power source 43 at the time of recovery from a power failure is applied to the drain drain cleaning control means 41, that is, once the AC 100V is turned off. When the energization is resumed later, the drain drain cleaning control means 41 causes the hot water / refreshing control means 42 to circulate the hot / cold hot water through the recirculation circulation path 15 and the hot water through the recirculation circulation path 15. When at least one recirculation circuit passage water operation of the water injection operation for injecting water into the bathtub 14 is performed, immediately after the operation start signal is received, a drain cleaning operation that also serves as a priming water is performed. Always do it. This is because, for example, the power supply can be stopped in the middle of drainage of the drain generated during the combustion test performed when installing the bath water heater (there is a drain in the piping), and the expiratory water of the circulation pump 23 is drained to prevent freezing. This is because there is a case where there is no water in the circulation pump 23, and it is necessary to put water into the circulation pump 23.

  Further, after drain cleaning also serving as the exhalation water, for example, when the drain water level is detected by the low water level electrode c and the water level is not detected by the high water level electrode d (when the drain water level is between the electrode c and the electrode d). In addition, for example, when there is residual water in the bathtub 14 when the automatic hot water filling operation (water injection operation for pouring hot water into the bathtub 14 through the recirculation circuit 15) is started, for example, The drain drain function is operated immediately before the start, followed by the drain cleaning function using unheated water.

  On the other hand, after the drain cleaning also serving as the exhalation water, the drain water level is between the electrode c and the electrode d. In addition, there is no residual water in the bathtub 14 at the start of the automatic hot water filling operation. When at least one of the hot water circulation operation for circulating hot water in the bathtub through the water circulation circuit 15 and the water injection operation for pouring hot water into the bathtub through the recirculation circuit is started, Drain cleaning function operation is not performed, and each operation (automatic hot water filling operation, hot water circulation operation, water injection operation) should be performed promptly.

  Further, when the drain water level is detected by the low water level electrode c and the high water level electrode d (when the water level exceeds the electrode c and further exceeds the electrode d), the drain drain function is immediately operated. Subsequently, the operation of the drain cleaning function using water heated at the bath set temperature is performed. When the water level is not detected by either the low water level electrode c or the high water level electrode d (when the water level is equal to or lower than the electrode c), only the drain cleaning operation also serving as the priming water is performed, and nothing is performed thereafter.

  On the other hand, when the remote controller 50 cancels the error signal that is output when a failure occurs during the operation of the drain drain function or the drain cleaning function, that is, when the AC 100 V energization is continued, In the case of returning due to release or the like, the hot water circulation operation for circulating hot water in the bathtub through the recirculation circuit 15 and the water injection operation for injecting hot water into the bathtub 14 through the recirculation circuit 15 by the pouring water / reheating control means 42. When at least one recirculation water passage operation is performed, the operation start signal is received and immediately before the operation starts, the following operation is performed according to the situation.

  For example, when at least the drain water level is detected by the reference water level electrode b (only the electrode b is on, the electrodes c and d are off, the electrodes b and c are on, only the electrode d is off, the electrodes b, c, and electrodes In the case where all d are on), the drain drain function is operated, and then the drain cleaning function using water heated at the bath set temperature is performed. In addition, when the drain water level is not detected by the reference water level electrode b, the operation of the drain cleaning function using the water heated at the bath set temperature is performed. That is, in any of these patterns, the drain cleaning is always performed, but the drain cleaning in this case does not also serve as a priming water unlike the drain cleaning operation performed at the time of return from the AC 100 V energization stop. .

  The drain drain cleaning control means 41, after the operation of the drain cleaning function or after the drain drain function and the drain cleaning function, as described above, the four-way switching valve 22, the drain drain switching valve 39, the drain circuit. The switching valve 30 is switched to switch to the recirculation circulation passage water passage, and in this state, the reheating circulation passage water flow operation by the pouring water / refreshing control means 42 is performed.

  Also, for example, during the period from construction to delivery of the apartment or when there is a possibility of freezing in a cold region, the circulation pump 23 may be drained and the power supply 43 may be turned off. Thereafter, when only the hot water supply side circuit is used and the operation of passing water through the recirculation circuit 15 is not performed at all, the circulation pump 23 is driven when the drain drain function is operated. However, there is a case where air is accumulated in the circulation pump 23 and the drain cannot be retaken and guided to the circulation path 15 side. Therefore, in the present embodiment, the drain drain cleaning control means 41 is configured so that the operation of the drain function may enter after the ON signal of the power source 43 is applied (in preparation for the drain operation). The drain drainage function is performed after water is put into the circulation pump 23 by a washing operation that also serves as an exhalation operation for passing water from the hot water supply side circuit side through the pouring channel 27 to the recirculation circuit 15 through the water path. I am trying to do the operation. In addition, the operation example in a present Example is shown with the flowchart of FIGS.

  In addition, this invention is not limited to the said Example, It sets suitably. For example, in the above-described embodiment, the drain drain cleaning control means 41 releases the error signal that is output after the power source 43 of the bath water heater is turned on and when the drain drain function or the drain cleaning function is stopped due to a failure. The drain cleaning function is operated at the time of starting the recirculation circuit passage water operation by the pouring water / refreshing control means 42, and immediately after turning on the power supply 43 of the bath water heater, The drain cleaning function may be operated immediately after the error signal output at the time of a stop due to a failure of the function or the drain cleaning function is released (when the error signal release signal is output from the remote control device 50). Good.

  In addition, when the drain drainage control means 41 operates the drain drainage function or when the drain cleaning function operates, a storage unit for storing the operation is provided in the control device 40 (the control device board), and the power is shut off. However, the immediately preceding situation may be stored.

  Then, based on the information stored in the storage unit, when a failure occurs during the operation of the drain drainage function and the operation stops, and there is memory (memory during the operation of the drain drainage function) When the recirculation circulation passage water flow operation is started, the operation of the drain drainage function after the water is put in the circulation pump 23 by the expiratory operation immediately before the start of the operation and the operation of the drain cleaning function subsequent thereto May be performed. In addition, when a failure occurs during the operation of the drain cleaning function and the operation stops, and there is a memory (memory during the operation of the drain cleaning function), a recirculation circuit water flow operation is started. The drain cleaning function may also be operated as a priming operation immediately before the start of the operation.

  In this configuration, when the substrate of the control device 40 is replaced at the time of failure repair, the operation of the drain cleaning function cannot be performed based on the information of the storage unit. The drain cleaning function can always be performed after the power supply 43 is turned on.

  Further, the drain drain cleaning control means 41 detects the position information of the valve switching of the four-way switching valve 22, the drain drain switching valve 39, and the drain circuit switching valve 30, and based on this position information, becomes the drain drain path. When an error signal release signal is output from the remote control device 50 in a state of being in the drained state, the drain cleaning function is operated. When an error signal release signal is output from the remote control device 50 in the state of the drain cleaning path, The operation of the cleaning function may be performed.

  Further, in the above-described embodiment, the drain drain cleaning control means 41 is turned on after the power source 43 of the bath water heater is turned on and the error signal output at the time of stoppage due to the failure of the drain drain function or the drain cleaning function is canceled ( Immediately thereafter, or when the recirculation circuit passage water operation is started by the pouring water and reheating control means 42), the drain cleaning function is operated. At this time, the drain cleaning is performed due to a failure of the pouring electromagnetic valve 29 or the like. If the operation of the function cannot be performed, only the operation of the drain drain function may be performed, and for example, a drain cleaning error signal may be output to the remote control device 50.

  In other words, when the drain is full, it is not drained and the hot water supply heat exchanger for latent heat recovery cannot be heated to supply hot water. However, if the drain is drained, the drain can be washed. Since the hot water supply side circuit can be used even without it, in this case, only the operation of the drain drainage function is performed, for example, until a part for recovering the drain cleaning function (for example, a pouring solenoid valve) is procured. (For example, until the next day), even if the user cannot bathe in the bath water, the shower can be used, and on the basis of the drain cleaning error signal output to the remote controller 50. Drain cleaning may be performed after repair is performed.

  Further, during the drain discharge operation of the drain drain function, the drain passed through the recirculation circuit 15 is reheated and heated to, for example, 60 ° C. or more by the heat exchanger 13 to drain the drain while performing heat sterilization. Good. In addition, a drain trap is usually provided on the outlet side of the drain drainage channel 38 (the drain port side of the bathroom). If the water flowing in during the operation of the drain cleaning function remains in the drain trap, Bacteria can grow. Therefore, after the drain cleaning control means 41 performs the drain cleaning function operation, the drain water cleaning control means 41 further performs additional water passing through the drain water passage of the circulation path 15 by replenishing a predetermined amount of water. Thus, the water that has flowed into the drain trap during the operation of the drain cleaning function may be replaced with the additional water flow.

  For example, the pipe for drain cleaning (only the outward pipe 16 side) is formed using, for example, a cross-linked polyethylene pipe 10A (inner diameter 9.8 mm), and the length is, for example, 25 m at the longest, so the capacity is 1.88 + α. (0.49 × 0.49 × π × 2500/21000 = 1.88, α is the capacity of the water pipe in the appliance, etc.) liters. Therefore, considering only the drain water passage in the recirculation circulation path 15, it is sufficient to inject water of 1.88 + α liters. Water injection of 6 liters, which is about 4 liters greater than (1.88 + α liter), is performed.

That is, since there is a possibility that various germs may propagate in the drain tank 32, the drain drainage channel 38 (for example, a cross-linked polyethylene pipe 7A (inner diameter 7 mm) is a longest 2.5 m pipe with a capacity of 0.1 liter, for example). The capacity of the drain trap in the bathroom as a drain destination is, for example, 0.5 liter (for example, the reverse one drain trap main body draft surface inner diameter 113 mm, lower end inner diameter 107 mm, average inner diameter 110 mm, water pipe in the drain trap When the outer diameter is 55 mm, the sealing depth is 50 mm (from the upper end of the water distribution pipe to the lower end of the one), and the distance between the lower end of the one and the lower end of the drain trap is 20 mm, the internal capacity is {π (110/2) ² −π (110/2) ² } × (50 + 20) = about 0.5 liters), so almost all of the water exchanged by passing through the drain trap (for example, 4 liters of water that is 8 times the trap capacity) As can be up example, if the renewal rate of about 99.9% or more), and water injection a total of 6 liters of water. In addition to the reverse one drain trap, a confluence trap is known as the drain trap, but there is not much difference in the internal capacity itself. Therefore, even if the trap type changes, it is considered that water can be exchanged in the trap in the bathroom at the above flow rate.

  In addition, the 4 liters of water has the following functions. That is, the replacement is sufficient only by pouring water of 1.88 + α liter, but for example, from completion inspection to confirm that normal operation is performed by performing hot water supply operation etc. for installation, from drain cleaning after moving in It may take time. In such a case, sticking that cannot be cleaned only by replacement may occur. In particular, since the hot water supply heat exchanger 6 for recovering latent heat of the present application is close to the exhaust outlet, surrounding dust, dirt, dust and the like may enter from the exhaust outlet. Become. The role of passing 4 liters of water is set as an amount sufficient to eliminate sticking containing formaldehyde.

  Further, when the power supply 43 is turned on when the power cord of the bath water heater is plugged into the outlet or when the power supply 43 is restored from a power failure, the drain drain cleaning control means 41 promptly switches the switching valve. Etc. may be controlled to form a drain cleaning path, and may wait in the drain cleaning path forming state until the start of the recirculation circulation path water supply operation by the pouring water and reheating control means 42. If it does in this way, possibility that drain will come out to bathtub 14 can be lost, and a priming operation can be performed prior to a follow-up circulation way water passage operation.

  Further, in order to prevent freezing of the recirculation circuit 15, a sensor for detecting the outside air temperature or a water temperature detection sensor provided at any position in the apparatus of the recirculation circuit 15 reaches a temperature at which the pipe freezing may occur. When lowered, there is a case where a function of intermittently circulating hot water in the bathtub 14 by driving the circulation pump 23 may be provided. This function activates the circulation pump 23 to check the hot water in the bathtub 14, and when the flowing water switch 26 detects that the water has flowed through the recirculation circuit 15 and turns it on, the hot water in the bathtub is subsequently turned on. When the circulating water switch 26 is not turned on when intermittent circulation is performed, it is assumed that there is no hot water in the recirculation circulation path 15 and the circulation pump 23 is not driven thereafter. Such a freeze prevention function may operate after the power supply cord of the bath water heater is plugged into an outlet or after recovery from a power failure. That is, the recirculation circulation path water passing operation is an operation performed by the user of the bath water heater or a trouble repair operator consciously operating the remote controller 50, whereas the freeze prevention function is It is not the operation performed by conscious operation while the same recirculation circuit water flow operation.

  Therefore, the anti-freezing operation may be prohibited until the recirculation circuit passage water operation performed by conscious operation is performed or until a timer time of, for example, 60 minutes elapses after the start of energization. By doing this, even if the outside air temperature is low and the start condition of the freeze prevention function is satisfied, a worker who repairs the failure has a timer that measures the time after the start of energization to prohibit the freeze prevention operation. Can take the time to complete the repair.

  Furthermore, the details of the system configuration of the bath water heater are not particularly limited. For example, it may be a device that does not have a heat retaining function, a water retaining function, a warm water function, a reheating function, a heating function, or a solar heat function. Other functions such as a heat collecting function may be provided.

  Furthermore, the bath hot-water supply apparatus of this invention may provide the burner for oil combustion instead of the burner which performs the gas combustion provided in the said Example, for example.

  The bath hot water supply apparatus of the present invention can be used as a household hot water supply apparatus for home use, for example, since it can be prevented from being washed after draining drainage through the recirculation circuit.

DESCRIPTION OF SYMBOLS 1 Burner 6 Hot water supply heat exchanger for latent heat recovery 15 Reheating circulation path 16, 16a, 16b Outward pipe 17 Return pipe 18, 19, 20, 21 Pipe line 22 Four-way switching valve 23 Circulation pump 27 Hot water supply path 28 Pipe line 29 Note Hot water solenoid valve 30 Drain circuit switching valve 34 Drain tank water level detection electrode 39 Drain drainage switching valve 40 Control device 41 Drain drainage cleaning control means 42 Pouring water and reheating control means 43 Power supply 44 Four-way switching valve 50 Remote control device

Claims (3)

A burner, a main hot water supply heat exchanger that absorbs sensible heat in the combustion gas of the burner, and a latent heat that is disposed downstream of the main hot water supply heat exchanger in the flow of the combustion gas and recovers exhaust latent heat A hot water supply side circuit provided with a recovery hot water supply heat exchanger, and a recirculation circuit connected to the bathtub, and the recirculation circuit is connected to the hot water side of the hot water supply circuit via the connection path The drain collecting means for collecting the drain generated by the hot water heat exchanger for collecting latent heat, the drain storing means for storing the drain recovered by the drain collecting means, and the drain stored by the drain storing means. It has a drain lead-out path that leads to the recirculation circulation path, and a drain drain path that drains the drain led to the recirculation circulation path from the recirculation circulation path and drains it into the bathroom. Has been The serial drain and the reheating circulation path and the drain outlet passage and said drain drainage channel and drain water discharge function of discharging the bathroom via the prior SL hot water supply side circuit and the reheating circulation path via the connecting passage from the side A bath water heater having a drain cleaning function for cleaning a water passage through which the drain of the recirculation circuit passes by the water passed, and the drain cleaning function is always performed after the power of the bath water heater is turned on. A bath water heater having a drain cleaning control means for performing the above operation. A burner, a main hot water supply heat exchanger that absorbs sensible heat in the combustion gas of the burner, and a latent heat that is disposed downstream of the main hot water supply heat exchanger in the flow of the combustion gas and recovers exhaust latent heat A hot water supply side circuit provided with a recovery hot water supply heat exchanger, and a recirculation circuit connected to the bathtub, and the recirculation circuit is connected to the hot water side of the hot water supply circuit via the connection path The drain collecting means for collecting the drain generated by the hot water heat exchanger for collecting latent heat, the drain storing means for storing the drain recovered by the drain collecting means, and the drain stored by the drain storing means. It has a drain lead-out path that leads to the recirculation circulation path, and a drain drain path that drains the drain led to the recirculation circulation path from the recirculation circulation path and drains it into the bathroom. Has been A drain drain function for discharging the drain to the bathroom via the drain lead-out path, the reheating circulation path, and the drain drain path, and passing the drain from the hot water supply side circuit side to the reheating circulation path via the connection path. A bath water heater having a drain cleaning function for cleaning the water passage through which the drain passes in the recirculation circuit, and an error that is output when the drain drain function or the drain cleaning function is stopped A bath hot water supply apparatus comprising drain cleaning control means for performing the operation of the drain cleaning function regardless of whether or not the operation of the drain draining function is performed after the signal is released. The drain cleaning control means cancels the error signal output after turning on the power supply of the bath water heater according to claim 1 or when stopping due to a failure of the drain drainage function or the drain cleaning function according to claim 2 Later, the drain cleaning function is not performed immediately, and at least one of the hot water circulation operation for circulating hot water in the bathtub through the recirculation circuit and the water recirculation operation for injecting hot water into the bathtub through the recirculation circuit The bath hot-water supply apparatus according to claim 1 or 2 , wherein the drain cleaning function is operated when a water flow operation is performed.

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