JP2007278599A - Hot-water supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize an apparatus, reduce weight, and improve efficiency by combining a hot water supply heat exchanger and a latent heat recovery heat exchanger into a single heat source for hot water supply, heating, and a bath. <P>SOLUTION: In the one tank multiple passage hot-water supply apparatus, water supplied from a water supply passage 1 is heated by combustion of a burner 2 and supplied to a hot water supply passage via the latent heat recovery heat exchanger 16 and the hot water supply heat exchanger 15, the water is returned again to the hot water supply heat exchanger 15 via a circulating pump 17 to form a hot water circulation circuit 19, utilization side heat exchangers 18, 27 are arranged in the hot water circulation circuit 19 to form a circuit supplying a heating value to a load side, and the hot water circulation circuit 19 after passing the utilization side heat exchangers 18, 27 is branched off to form a hot water supply passage 3 for a hot water tap 6 or for bath hot water filling. Water filling operation to the hot water circulation circuit 19 can be easily and safely carried out by switch operation on a board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hot water supply device for a single can multi-channel that circulates hot water supplied through a hot water supply heat exchanger heated by combustion heat of a burner and supplies heat to a plurality of loads.

Conventionally, as this type of combustion apparatus, as disclosed in Patent Document 1, a hot water supply heat exchanger that heats water supplied through a water supply path by combustion of a burner to supply hot water to the hot water supply path, and heating supplied through an inlet path A hot water supply apparatus provided with a fluid heat exchanger that heats a target fluid by combustion of the burner and flows out to an outlet, and the hot water heat exchanger recovers sensible heat of combustion exhaust gas of the burner A sensible heat exchanger for hot water supply, and a sensible heat exchanger for hot water supply, which is arranged downstream of the sensible heat exchanger for hot water supply in the flow direction of the combustion exhaust gas of the burner and recovers the latent heat of the combustion exhaust gas of the burner The fluid heat exchanger recovers sensible heat of the combustion exhaust gas of the burner, and the combustion exhaust gas of the burner than the fluid sensible heat exchange unit. Arranged downstream of the flow direction of And a fluid latent heat exchange part for recovering the latent heat of the combustion exhaust gas of the burner, and the sensible heat exchange part for hot water supply and the sensible heat exchange part for fluid are integrated in a state of conducting heat to each other. And a hot water supply device in which the latent heat heat exchange part for hot water supply and the latent heat heat exchange part for fluid are integrally formed in a state of conducting heat to each other are disclosed (for example, see Patent Document 1). .
JP 2002-267262 A

  However, since the conventional hot water supply apparatus forms two paths for hot water supply and fluid as the paths heated by the burner, the piping configuration becomes complicated and the heat exchange on the shutdown side during single operation It had the subject that the boiling of the residual water in a container generate | occur | produced.

  In addition, a hot water supply heat exchanger and a fluid heat exchanger are respectively disposed in the burner combustion gas outflow path, and the hot water supply heat exchanger is provided with a sensible heat exchange unit for hot water supply and a latent heat exchange unit for hot water supply. The fluid heat exchanger is provided with a sensible heat exchange section for fluid and a latent heat exchange section for fluid, so that the sensible heat exchange section and the latent heat exchange section respectively have a hot water supply heat exchanger and a fluid It is necessary to integrally form the heat exchanger, and the heat exchanger for hot water supply and the heat exchanger for fluid are forced to have extremely complicated configurations.

  Furthermore, although not disclosed in the above conventional example, in a configuration in which hot water heated by a burner is circulated and heat is supplied to a plurality of utilization circuits using the circulated water, after installation or after draining When there is no circulating water, such as when reusing, even if there is an operation request from the utilization circuit, the burner burns when it starts burning, so it cannot be used until it is filled with water, and normal hot water supply operation However, there was a problem that water circulation of the circulation circuit could not be performed easily and safely.

The present invention solves the above-mentioned conventional problems, and forms one heating path with a hot water supply heat exchanger and a latent heat recovery heat exchanger, and uses circulating water in the heating path to form a heating circuit or a bath circuit. By adopting a structure for supplying heat, it is possible to configure a use-side heat exchanger that is not related to the heat exchanger for hot water supply and the latent heat recovery heat exchanger. The present invention provides an easy-to-use hot water supply apparatus that prioritizes the hot water supply performance by making the heating path mainly a hot water supply path. It is another object of the present invention to provide a hot water supply apparatus that can easily and safely fill water to a heating path in one heating path configuration mainly including a hot water supply path.

  In order to solve the above-mentioned conventional problems, the hot water supply apparatus of the present invention heats the water supplied from the water supply passage by combustion of the burner and supplies the water to the hot water supply passage through the latent heat recovery heat exchanger and the hot water supply heat exchanger. In addition, a hot water supply circulation circuit is formed by returning to the hot water supply heat exchanger again via a circulation pump, and a circuit for supplying a heat amount to the load side by disposing a use side heat exchanger in the hot water supply circulation circuit. A hot water supply path that branches from the hot water supply circulation circuit via the use side heat exchanger and supplies hot water to the hot water tap, and a hot water that branches from the hot water supply path and passes through the hot water on / off valve A hot water supply device of a single can multi-channel with a hot water pouring circuit for performing after opening the pouring valve and pouring a predetermined amount into a bath by any operation such as pressing a switch on the substrate The hot water supply circulation by circulating the circulation pump for a predetermined time. It is obtained to perform the water filling circuit.

  Thereby, one heating path is formed by the heat exchanger for hot water supply and the heat exchanger for latent heat recovery, and the heat amount is supplied to the heating circuit and the bath circuit using the circulating water of the heating path. Enables the configuration of the use side heat exchanger that is not related to the hot water supply heat exchanger or the latent heat recovery heat exchanger. It is possible to provide an easy-to-use hot water supply system that prioritizes hot water supply performance by making the route the hot water supply path main body, and heat exchange at the time of single operation by having a single heating path structure mainly made of the hot water supply path Eliminates the problem of residual water boiling in the vessel. Further, it is possible to provide a hot water supply apparatus that can easily and safely fill water in a hot water supply circulation circuit by automatically performing water injection and circulation into a bath without performing combustion by operating a switch on the substrate.

  The hot water supply apparatus of the present invention forms one heating path with the hot water supply heat exchanger and the latent heat recovery heat exchanger, and uses the circulating water of the heating path only when a flow rate signal exists in the heating path. The configuration of supplying heat to the heating circuit and the bath circuit enables the configuration of the use side heat exchanger not related to the heat exchanger for hot water supply and the latent heat recovery heat exchanger, and the main body configuration including the piping configuration It is possible to provide an easy-to-use hot water supply apparatus that prioritizes hot water supply performance by using the heating path as a main hot water supply path, as well as in the initial use and water. It is possible to provide a hot water supply device that can easily and safely fill water to the heating path by automatically performing water injection and circulation to the bath without performing combustion by operating a switch on the substrate at the time of reuse after removal. it can.

  According to a first aspect of the present invention, water supplied from a water supply passage is heated by combustion of a burner and supplied to a hot water supply passage through a latent heat recovery heat exchanger and a hot water supply heat exchanger, and the hot water supply is supplied again through a circulation pump. A hot water supply circulation circuit is formed by returning to the heat exchanger for use, and a use side heat exchanger is provided in the hot water supply circulation circuit to form a circuit for supplying heat to the load side, and the use side heat exchanger is One can that forms a hot water supply path that branches from the hot water supply circulation circuit that passes through and supplies hot water to the hot water tap, and a hot water supply circuit that branches from the hot water supply path and performs pouring into the bath through the on-off valve for pouring A hot water supply device of a multi-channel, by opening the pouring on / off valve and pouring a predetermined amount into a bath by any operation such as pressing a switch on the substrate, and then circulating the circulating pump for a predetermined time The water supply circulation circuit is filled with water. It is an.

And since one heating path is formed by the heat exchanger for hot water supply and the heat exchanger for latent heat recovery, and the amount of heat is supplied to the heating circuit or bath circuit using the circulating water of the heating path, the hot water supply It is possible to configure a heat exchanger on the use side that is not related to a heat exchanger for heat recovery or a heat exchanger for latent heat recovery. It is possible to provide an easy-to-use hot water supply apparatus that prioritizes hot water supply performance by using a hot water supply channel as a main component, and by adopting a single heating path configuration mainly consisting of a hot water supply channel, a heat exchanger during single operation The remaining water boiling problem is solved. In addition, by automatically performing water injection and circulation into the bath without performing combustion by operating a switch on the substrate, it is possible to provide a hot water supply apparatus that can easily and safely fill the hot water supply circulation circuit.

  According to a second aspect of the present invention, there is provided a flow rate sensor in a hot water supply circulation circuit until branching to a hot water supply path after passing through the use side heat exchanger, and the opening and closing for pouring is performed by an arbitrary operation such as pressing a switch on the board. After opening the valve and injecting a predetermined amount into the bath, circulating the circulating pump for a predetermined time, detecting the flow rate with the flow sensor, if not detecting a flow rate above a predetermined amount, a predetermined number of times, It is characterized by repeating water injection and circulation to the bath. It automatically determines whether water filling has been performed sufficiently by the circulation flow rate, and if it is insufficient, it automatically performs water filling operation again. Water can be reliably applied to the circuit.

  3rd invention supplies a heat quantity to the heat circuit for heating which supplies a heat quantity to the heating circuit which has a heating apparatus which performs heating, bathroom drying, etc. as a use side heat exchanger, and the bath circuit which retreats a bath A bath heat exchanger is provided, and when heating or a trial run operation of the bath is performed, water is poured into the bath and circulated to automatically fill the hot water supply circuit. Therefore, it is possible to reliably fill the hot water supply circulation circuit during the trial operation after the installation of the equipment without separately performing the water filling operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 shows a structural diagram of a hot water supply apparatus according to a first embodiment of the present invention.

  In FIG. 1, first, water supplied from a water supply channel 1 is heated by combustion of a burner 2 to rise to a predetermined temperature, and then supplied to a hot water supply channel, and a heating heat exchanger 18 that is a use side heat exchanger and a bath. The hot water supply circulation circuit 19 is formed by opening the on-off valve 35 and passing through the primary path of the bath heat exchanger 27 and then rejoining the water supply path 1 via the circulation pump 17. Then, a hot water supply path 3 is formed by branching from the hot water supply circulation circuit 19 after passing through the heat exchanger 18 for heating and the heat exchanger 27 for bath, and the bypass formed by communicating the hot water supply path 3 and the water supply path 1. A part of the water supplied from the water supply path 1 from the passage 4 is supplied via the bypass control valve 5 to adjust to a desired hot water, and a hot water supply path for discharging hot water from the hot water tap 6 is configured.

  Here, the burner 2 is supplied with fuel from a gas supply passage 10 provided with a gas source solenoid valve 7, a gas proportional valve 8, and a gas switching valve 9, and supplied with combustion air from a combustion fan 11, in advance. A combustion operation is performed according to a predetermined sequence. Then, the combustion gas generated by the combustion of the burner 2 passes through the combustion chamber 12, passes through the exhaust passage 13, and is discharged out of the instrument from the exhaust port 14.

  A hot water supply heat exchanger 15 that recovers sensible heat of the combustion gas and a latent heat recovery heat exchanger 16 that recovers the latent heat of the combustion exhaust gas are disposed in the exhaust path of the combustion gas. Specifically, a hot water supply heat exchanger 15 is provided in the downstream combustion chamber 12 of the burner 2, a latent heat recovery heat exchanger 16 is provided in the downstream exhaust passage 13, and water supplied from the water supply passage 1 is supplied. First, after supplying the latent heat recovery heat exchanger 16 to recover the latent heat in the combustion exhaust gas, the latent heat is supplied to the hot water supply heat exchanger 15, heated to a predetermined high temperature water by combustion of the burner 2, and supplied to the hot water supply passage 3. . Thus, in addition to heat recovery by the conventional hot water supply heat exchanger 15, by providing the latent heat recovery heat exchanger 16 for recovering the latent heat of the combustion exhaust gas, the overall thermal efficiency is improved and energy saving is achieved.

The heating circuit 20 is connected to a load such as a radiator 21 on the secondary side of the heating heat exchanger 18 to form a closed circuit, and is circulated by the heating circulation pump 22, whereby the heating heat exchanger 18. Thus, heat is exchanged with the high-temperature water supplied from the hot water supply circuit 19 so as to secure the amount of heating heat.

  The bath circuit 28 supplies the hot water in the bathtub 31 to the bath heat exchanger 27 through the bath circulation pump 29 and the water amount detection unit 30 and circulates it for a predetermined time, thereby opening the bath opening / closing valve 35 and the hot water supply circulation circuit. 19 heats up the hot water supplied to the bath heat exchanger 27 to reheat the bath water.

  Further, as the pouring circuit 32 for filling the bathtub 31 with hot water, a path is formed that branches from the hot water supply path 3 on the downstream side of the bypass passage 4 and communicates with the bath circuit 28 via the pouring open / close valve 34.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, at the time of hot water supply operation, when the hot water tap 6 is opened, the water supply side flow rate sensor 23 disposed in the water supply passage 1 detects water flow, and the combustion fan 11 is operated by this water flow signal and simultaneously the gas source solenoid valve 7, The gas proportional valve 8 is opened, fuel and combustion air are supplied to the burner 2, and combustion is started by an ignition operation. Combustion gas generated by the start of combustion of the burner 2 is discharged from the exhaust port 14 via the exhaust passage 13 from the combustion chamber 12. In the process of exhausting the combustion gas, the water supplied from the water supply passage 1 is heated by the hot water supply heat exchanger 15 disposed in the combustion chamber 12 and the latent heat recovery heat exchanger 16 disposed in the exhaust passage 13. .

  Hot water heated by the hot water supply heat exchanger 15 passes through a bypass passage 4 provided in communication between the water supply passage 1 and the hot water supply passage 3 so as to bypass the hot water supply heat exchanger 15 and the latent heat recovery heat exchanger 16. The bypass control valve 5 is mixed with the water on the incoming side. The opening of the bypass control valve 5 is adjusted by a signal from the hot water thermistor 25 so that the mixed hot water reaches a hot water supply set temperature set by the remote control remote controller 24, and hot water is supplied from the hot water tap 6 through the hot water connection port 26. .

  Thus, when selecting the hot water supply independent operation, the hot water set automatically can be secured by setting a desired temperature with the remote control remote controller 24 and opening the hot water tap 6.

  During the heating operation, the heating circulation pump 22 provided in the heating circuit 20 is driven by the operation command of the radiator 21, and the pump 17 that circulates the hot water in the hot water supply circulation circuit 19 is driven in conjunction with it to ignite the burner 2. Then, the hot water heated by the hot water supply heat exchanger 15 that recovers the burned heat is heat-exchanged by the heating heat exchanger 18 and transferred to the heating circuit 20. Heat of the heating circuit 20 received by the heating heat exchanger 18 is radiated as warm air by the radiator 21.

  Further, during bath operation, when the bath circulation pump 29 provided in the bath circuit 28 is driven by the operation command of the remote control remote controller 24 and the circulation is detected by the water flow detection unit 30, the hot water supply circulation circuit 19 is interlocked. When the pump 17 for circulating the hot water is driven, the burner 2 is ignited, the bath opening / closing valve 35 is opened, and the hot water heated by the hot water supply heat exchanger 15 that collects the burned heat is exchanged for bath heat. Heat is exchanged in the vessel 27 and transferred to the bath circuit 28. The heat of the bath circuit 28 received by the bath heat exchanger 27 is circulated to the bathtub 31 and reheated.

  Further, during heating and bath simultaneous operation, the heating circuits 20 and the pumps 22 and 29 of the bath circuit 28 are driven by the operation commands from the radiator 21 and the remote control remote controller 24, and combustion is started by the ignition operation of the burner 2. By this combustion, the circulating water in the hot water supply circuit 19 is heated by the latent heat recovery heat exchanger 16 and the hot water heat exchanger 15 and circulates while maintaining a predetermined high-temperature water state. This high-temperature circulating water is supplied to the heating heat exchanger 18 and the bath heat exchanger 27 at substantially the same temperature, and is transferred to the heating circuit 20 and the bath circuit 28.

  In this way, by using a configuration in which the hot water supply path 3 is branched from the hot water supply circulation circuit 19 after passing through the heating heat exchanger 18 and the bath heat exchanger 27 that are the use side heat exchangers, Hot water supply priority operation that can adjust and supply hot water in a wide range from high temperature water to low temperature water to the hot water supply path can be ensured while securing high temperature water necessary for operation.

  Here, the latent heat recovery heat exchanger 16 that recovers the latent heat of the combustion exhaust gas is located downstream of the hot water supply heat exchanger 15 with respect to the exhaust gas path, and is upstream of the hot water supply heat exchanger 15 with respect to the water supply path. The hot water preheated by the latent heat recovery heat exchanger 16 is heated by the hot water supply heat exchanger 15. As a result, the amount of heat generated by the combustion of the burner 2 can be efficiently exchanged, leading to energy saving.

  During the pouring operation, the pouring on / off valve 34 is opened by an operation command from the remote operation remote control 24, and the bath temperature hot water set by the remote operation remote control 24 is adjusted in the same way as during the hot water supply operation. By supplying the hot water from the pouring circuit 32 to the bathtub 31 through the bath circuit 28 by an amount set by the remote control remote control 24, hot water having a desired temperature and amount can be automatically applied to the bathtub.

  Further, a hot water supply flow rate sensor 33 for detecting a circulation amount is provided in the middle of the hot water supply circulation circuit 19 until it branches off from the hot water supply passage 3 after passing through the heat exchanger 18 for heating and the heat exchanger 27 for bath. Only when a predetermined flow rate signal is output from the hot water supply flow rate sensor 33, the combustion operation of the burner 2 is performed. In other words, the hot water supply flow rate sensor 33 prevents the so-called air-burning combustion, which prevents the burner 2 from performing a combustion operation when hot water is not present in the hot water supply circulation circuit 19 or is not circulated. Is provided.

  As described above, the hot water supply apparatus cannot perform the heating operation or the reheating operation unless water filling in the hot water supply circulation circuit 19 is completely performed. Therefore, it is necessary to fill the hot water supply circulation circuit 19 immediately after installation, after draining water, or after replacing parts for maintenance. If only a normal hot water supply operation is performed, air remains around the circulation pump 17 and inside the bath heat exchanger 17 and water filling is insufficient.

  Therefore, in the present invention, a water filling switch is provided on an electrical board (not shown), and an operation dedicated to water filling is performed by pressing the switch.

  During the water filling operation, the bath opening / closing valve 35 is opened to fill the bath heat exchanger 27 with water. Further, the bypass control valve 5 is closed. This is to prevent a large amount of water from flowing into the bypass passage 4 and reducing the amount of water flowing into the hot water supply circulation circuit 19. Thereafter, the pouring on / off valve 34 is opened and combustion is not performed, but a fixed amount (about 3 L) of water is allowed to flow through the hot water supply circulation circuit 19 to the bathtub 31. After the water injection is completed, the circulating pump 17 is rotated for a predetermined time (about 30 seconds) to push out air around the pump. At this time, if the water filling is sufficient, a normal circulating flow rate is detected by the hot water supply flow rate sensor 33, so that the water filling operation is terminated. However, if the circulating flow rate is low, it is determined that the water filling is insufficient, and the bathtub is again inserted. After injecting water into the water, circulate. Normally, the water filling operation is normally completed in about two times, but there are cases where the water pressure is low and the flow rate of water injection is small. If water filling is not performed normally even after a predetermined number of times, there is a high possibility that a component has failed, so an error code is displayed on the electrical board and the remote control remote controller 24, and the water filling operation is terminated.

In addition, it is necessary to perform a trial run after the installation of the appliance in order to perform heating and bathing normally. However, since the hot water supply circuit 19 is not normally filled with water before the trial run, The water filling operation is performed at the beginning of a dedicated operation (by pressing a switch on the substrate or by operating a switch on the remote control remote controller 24). Since the water filling operation does not need to be performed many times, the information is memorized when the water filling operation is completed in one of the test operation operations, and it is considered not to be performed during the other test operation operation. .

  As described above, in the present embodiment, one heating path is formed by the hot water supply heat exchanger 15 and the latent heat recovery heat exchanger 16, and the use side load circuit utilizes the circulating water of the heating path. Since the amount of heat is supplied to the heating circuit 20 and the bath circuit 28, the heating heat exchanger 18 and the bath, which are the use-side heat exchangers not related to the hot water heat exchanger 15 and the latent heat recovery heat exchanger 16, are used. The heat exchanger 27 can be configured, and the main body configuration including the piping configuration can be simplified to reduce the size and weight of the appliance, and the heating path is mainly used for the hot water supply path, giving priority to hot water supply performance. The hot water supply apparatus can be provided, and the problem of residual water boiling in the heat exchanger during single operation is eliminated by adopting a single heating path configuration mainly including the hot water supply path. In addition, water can be easily and safely filled in the hot water supply circulation circuit 19 by automatically performing water injection and circulation into the bath without performing combustion by operating a switch on the electrical board. In addition, when performing a trial operation of a heating or bath, the water filling operation is automatically performed at the beginning of the trial operation, so that it is possible to ensure that the test operation after installation of the equipment is performed without performing the water filling operation separately. The hot water supply circuit 19 can be filled with water.

  As described above, the hot water supply apparatus according to the present invention has a hot water supply circulation circuit as a main circuit, hot water supply and heating, or hot water supply and bath, or hot water supply and heating and bath, with a single circulation path as a heat source, and the presence or absence of hot water in the circulation path. After confirming the above, by controlling the combustion operation of the burner, it is possible to reliably prevent the idling operation, and to easily, safely and reliably fill the hot water supply circulation circuit. In addition, it is possible to reduce the size and weight of the equipment, ensure sufficient installation space, improve workability, and provide a latent heat recovery heat exchanger to achieve high efficiency and save energy by reducing running costs. Therefore, the present invention can also be applied to uses such as gas and oil hot water bath devices and hot water heaters.

Structure diagram of hot water supply apparatus in Embodiment 1 of the present invention

Explanation of symbols

1 Water supply path 2 Burner (heating means)
3 Hot water supply path 5 Bypass control valve 13 Exhaust passage (exhaust heat path)
15 Heat Exchanger for Hot Water Supply 16 Heat Exchanger for Latent Heat Recovery 17 Circulation Pump 18 Heat Exchanger for Heating (Use-side Heat Exchanger)
DESCRIPTION OF SYMBOLS 19 Hot water supply circulation circuit 20 Heating circuit 21 Radiator 22 Heating circulation pump 23 Water supply side flow rate sensor 24 Remote control remote control (remote control device)
27 Heat exchanger for bath (use side heat exchanger)
28 Bath Circuit 29 Bath Circulation Pump 31 Bathtub 32 Pouring Circuit 33 Hot Water Flow Rate Sensor 34 Pouring Switch Valve 35 Bath Opening Valve

Claims (3)

Water supplied from the water supply passage is heated by combustion of the burner and supplied to the hot water supply passage through the latent heat recovery heat exchanger and the hot water supply heat exchanger, and is returned to the hot water supply heat exchanger again through the circulation pump. A hot water supply circulation circuit is formed, a use side heat exchanger is provided in the hot water supply circulation circuit to form a circuit for supplying heat to the load side, and from the hot water supply circulation circuit via the use side heat exchanger A hot water supply passage that branches and supplies hot water to the hot water tap, and a hot water supply device of one can multi-water passage that forms a hot water pouring circuit for pouring hot water into the bath through the hot water on / off valve. There,
The hot water supply circuit is filled by circulating the circulation pump for a predetermined time after opening the water pouring valve and pouring a predetermined amount into the bath by any operation such as pressing a switch on the substrate. A hot water supply device. A flow sensor is provided in the hot water supply circulation circuit until it branches to the hot water supply path after passing through the use side heat exchanger,
After opening the pouring on-off valve and pouring a predetermined amount into the bath by any operation such as pressing a switch on the board, the circulating pump is circulated for a predetermined time and the flow rate sensor detects the flow rate. The hot water supply apparatus according to claim 1, wherein the water injection and circulation are repeated a predetermined number of times if the flow rate is not detected and a flow rate of a predetermined amount or more is detected.   Heating heat exchanger for supplying heat to a heating circuit having a heating device that performs heating, bathroom drying, etc. as a use side heat exchanger, and a heat exchanger for bath that supplies heat to a bath circuit that retreats the bath The hot water supply apparatus according to claim 1, wherein when a heating operation or a trial operation of the bath is performed, water is poured and circulated into the bath to automatically fill the hot water supply circulation path.