JP6021713B2 - Bath water heater - Google Patents

Description

  The present invention relates to a bath water heater that automatically performs a hot water filling operation and a chasing operation.

  Conventionally, a heat source device equipped with a heat exchanger and a bathtub are connected so that hot water can be supplied directly to the bathtub for hot water filling, etc., and the bath water filled in the bathtub is chased in the bathtub. There is known a bath water heater that can raise the temperature of the hot water.

  The heat source device used in the bath water heater is provided with a heat exchanger for hot water supply and a heat exchanger for bath. The bath heat exchanger and the bathtub are recirculation circulation pipes for circulating bath water. In order to fill the bathtub with hot water, the recirculation circulation line is connected to a hot water supply line for supplying hot water generated by the heat exchanger for hot water supply to the recirculation circulation line. It is connected via a hot water tube.

  When performing a hot water filling operation with this type of bath water heater, hot water generated by operating the heat source device and heated in the hot water heat exchanger is replenished via a hot water pipe branched from the hot water supply pipe. Supplying to the circulation line, filling the set amount of hot water. Then, when a predetermined amount of hot water is poured into the bathtub, the bath water stored in the bathtub is sucked in by a circulation pump provided in the additional circulation pipe as needed and circulated through the additional circulation pipe. In addition, a reheating operation is performed in which the temperature of the bath water is raised to a set temperature with a bath heat exchanger.

JP 2000-130844 A

  By the way, when the circulation pump is driven, if water stays in the circulation pump, the bath water can be quickly sucked in from the bathtub, and the bath water can be circulated through the additional circulation pipe.

  However, in recent years, due to diversification of housing facilities, heat source machines are installed on the second floor or more, and bathtubs are often installed on the ground floor. Therefore, a considerable height difference (for example, 5 m or more) is generated between the bathtub and the heat source device installed on the upper floor. As a result, after using the bathtub and draining the bath water or performing a hot water operation, when a certain time has elapsed, the water in the recirculation circulation pipe falls into the bathtub and the air easily enters the circulation pump . When the circulation pump is driven in such a state, the bath water in the bathtub becomes difficult to be sucked into the return pipe due to air biting, and the bath water has to be sucked up to the upper floor, so that the recirculation circulation pipe is There is a problem that a certain time is required to circulate the bath water. In addition, in a hot water supply system in which circulation heating is started with a heat exchanger for a bath after water flow is confirmed with a water flow switch provided in the additional circulation pipe, water flow is detected with the water flow switch when the air is caught. Therefore, there is a problem that, for example, it is erroneously determined that there is no bath water in the bathtub, and the chasing operation is stopped. Furthermore, if water does not stay in the circulation pump, the circulation pump is idled, so that there is a problem that a large noise is generated or the durability of the circulation pump is lowered.

  The present invention has been made to solve the above problems, and an object of the present invention is to have a hot water supply line and a recirculation circulation line, and bath water is provided by a circulation pump provided in the recirculation circulation line. In the bath hot-water supply apparatus which circulates, the bath hot-water supply apparatus which can perform hot water filling operation and a chasing operation smoothly is provided at low cost.

The present invention
A heat source machine comprising a heat exchanger for hot water supply and a heat exchanger for bath,
A hot water supply line for supplying hot water generated by heating in the hot water supply heat exchanger to a hot water supply terminal;
A recirculation circulation line that circulates and heats bath water in the bathtub with the heat exchanger for bath,
A hot-water pipe that connects the hot water supply line and the recirculation circulation line, and supplies hot water generated by heating in the hot water supply heat exchanger to the recirculation circulation line;
A circulation pump provided in the additional circulation line;
A drain discharge pipe connected to the upstream side of a connection portion between the hot water filling pipe and the recirculation circulation pipe in the hot water filling pipe and discharging drain generated by operating the heat source device to the hot water filling pipe. Road,
A control device for operating the heat source machine to perform a hot water filling operation or a chasing operation.
The recirculation circulation pipe includes a return pipe for returning bath water from the bathtub to the bath heat exchanger side by driving the circulation pump, and an outgoing pipe for sending bath water from the bath heat exchanger to the bathtub. And
A bath water heater in which a drain discharge pipe is branched and connected to the forward pipe, and a drain drainage switching valve is provided at a connection portion between the forward pipe and the drain discharge pipe,
When the operation instruction of the hot water filling operation or the chasing operation is given, the control device, from the hot water supply pipe line through the hot water filling pipe, the chasing circulation pipe before the hot water filling or bath water circulation to the bathtub. A bath hot water supply device that supplies water to a passage and switches the drain drain switching valve to a discharge position to discharge water from the hot water supply pipe to the outside through the drain discharge pipe .

According to the bath hot water supply apparatus, water is supplied to the recirculation circulation pipe provided with the circulation pump before the hot water filling operation or the reheating operation, so that the air that has entered the circulation pump can be exhausted, The circulation pump can be driven in a state where water remains in the circulation pump.
In addition, according to the bath water heater, the bath water heater that discharges the generated drain and discharges it to the outside through the circulation pipeline can be circulated before the filling operation without adopting a special water supply structure. Water can be supplied to the pump.
Furthermore, according to the above bath water heater, the water supply to the recirculation circulation pipe that is performed before the hot water filling operation etc. is discharged to the outside without being supplied to the bathtub, thus preventing fluctuations in the amount of hot water and the hot water temperature. can do.

In the above bath water heater,
The heat source machine may be installed above the bathtub.

  When the heat source machine is installed above the bathtub, the water in the follow-up circulation conduit easily falls into the bathtub, so that the present invention can be applied more effectively.

In the bath water heater, preferably,
The return pipe is connected to the hot water filling pipe via a switching valve,
The circulation pump is provided on the downstream side of the connection portion with the hot water filling pipe in the return pipe,
The control device switches the switching valve to a discharge position where water supply from the hot water supply pipe is sent only from the connection portion to the circulation pump side in the return pipe to supply water to the recirculation circulation pipe. Then, the switching valve is switched to a hot water supply position for supplying hot water from the connecting portion to the circulation pump side and the bathtub side in the return pipe or a circulation position for circulating bath water in the recirculation circulation pipe, Perform hot water operation or chasing operation.

  In a hot water supply apparatus having a recirculation circulation line, when performing hot water filling operation, hot water filling to the bathtub is possible from either the forward pipe side or the return pipe side, but not only the forward pipe but also the return pipe. If water is supplied from the hot water supply pipe to the recirculation pipe by only the water supply pressure in a state where water can be supplied to the bathtub, it is difficult to raise the return pipe and supply water to the forward pipe. It is easy to be supplied with water. As a result, when the circulation pump is provided on the downstream side of the return pipe connected to the hot water filling pipe, it is difficult to reliably supply water into the circulation pump. However, according to the bath hot water supply apparatus, the hot water filling pipe and the return pipe are connected via the switching valve, and the water supply from the hot water supply pipe is located downstream of the connection portion of the return pipe with the hot water filling pipe. Since the switching valve is switched to the discharge position to be sent only to the circulation pump side and water is supplied, it is possible to prevent water from being supplied to the return pipe upstream from the connecting portion, and to retain water in the circulation pump in a short time. Can do. Then, in a state where water is retained in the circulation pump provided in the return pipe, the switching valve is switched to the hot water supply position or the circulation position, and the hot water filling operation or the reheating operation is performed. Can do.

  As described above, according to the present invention, the idling of the circulation pump can be prevented before the filling operation or the reheating operation. As a result, the bath water can be smoothly circulated through the circulation pipeline. Therefore, without adopting a special water supply structure, it is possible to prevent the operation from being stopped due to poor circulation and to prevent the circulation pump from deteriorating noise and durability.

FIG. 1 is a schematic configuration diagram showing an example of a hot water supply apparatus according to an embodiment of the present invention. FIG. 2 is a control flowchart in the case where automatic operation is performed in the bath hot water supply apparatus according to the present embodiment.

  Hereinafter, the bath hot-water supply apparatus of this Embodiment is demonstrated concretely, referring drawings.

  As shown in FIG. 1, a bath water heater 1 generates hot water by heating water supplied from a water supply to a predetermined temperature, and supplies the hot water to a hot water supply terminal P1 such as a currant or a bathtub P2, and a bathtub P2. And a reheating function unit that circulates the bath water while heating it to a predetermined temperature.

  The bath hot-water supply apparatus 1 of this Embodiment guides the water supplied from the heat source machine 11 provided with the hot water supply heat exchanger 21A and the bath heat exchanger 21B to the hot water supply heat exchanger 21A. , A hot water supply line 2 to be supplied from the hot water supply heat exchanger 21A to the hot water supply terminal P1 and the bathtub P2, a recirculation circulation line 4 for circulating bath water between the bathtub P2 and the bath heat exchanger 21B, and a bath And a control device C that controls the operation of the entire hot water supply device 1. Further, an operation terminal 100 for instructing the operation of the bath water heater 1 is connected to the control device C by electric wiring or wirelessly.

  The hot water supply pipe line 2 supplies water from the water supply source to the hot water supply heat exchanger 21A and the hot water generated by the hot water supply heat exchanger 21A from the hot water supply heat exchanger 21A to the hot water supply terminal P1. And a bypass pipe for mixing water from the water supply pipe 2a for adjusting the hot hot water generated by heating in the hot water supply heat exchanger 21A to a predetermined temperature between the water supply pipe 2a and the hot water supply pipe 2b. It has.

  The water supply pipe 2a has a water amount sensor 31 for detecting the amount of water supplied to the hot water supply heat exchanger 21A and a water amount adjustment valve 32 capable of adjusting the water amount to the hot water supply heat exchanger 21A on the upstream side. In order.

  The recirculation circulation line 4 includes a return pipe 4a that returns the bath water from the bathtub P2 to the bath heat exchanger 21B, and an outgoing pipe 4b that sends the bath water heated by the bath heat exchanger 21B to the bathtub P2. ing. The ends of the return pipe 4a and the forward pipe 4b on the bathtub P2 side are respectively connected to circulation fittings (not shown) provided near the bottom inside the bathtub P2. In the recirculation circulation line 4 of the present specification, the return pipe side of the circulation path when the circulation pump 37 is driven to circulate the bath water is referred to as the upstream side, and the forward pipe side is referred to as the downstream side.

  A hot water filling pipe 3 for performing hot water filling to the bathtub P <b> 2 is branchedly connected to the hot water supply pipe 2 b of the hot water supply pipe 2, and the downstream end of the hot water filling pipe 3 is a return pipe of the recirculation circulation pipe 4. 4a. The hot water filling pipe 3 includes a hot water solenoid valve 33 capable of shutting off the supply of hot water from the hot water supply heat exchanger 21 </ b> A, and a bath check for preventing a reverse flow of bath water from the recirculation circulation pipe 4. A valve 34 and a hot water amount sensor 35 for detecting the flow rate of the hot water flowing through the hot water pipe 3 are provided in order from the upstream side.

  Inside the housing 10 of the heat source unit 11, a hot water supply heat exchanger 21A that heats the water supplied from the water supply pipe 2a by heat exchange with the combustion exhaust gas, and heat exchange of the bath water returned from the return pipe 4a with the combustion exhaust gas. The heat exchanger 21B for the bath heated by the gas and the gas burners 22A and 22B for generating the combustion exhaust gas by mixing the fuel gas supplied from the gas pipe 15 through the gas pipe with the combustion air and burning it are incorporated. . A combustion fan 23 that feeds combustion air into the housing 10 is provided at the lower portion of the housing 10.

  The hot water supply heat exchanger 21A is provided on the downstream side of the flow of combustion exhaust gas with respect to the hot water supply main heat exchanger 211 and the hot water supply main heat exchanger 211 for recovering the sensible heat of the combustion exhaust gas. And a hot water supply auxiliary heat exchanger 212 for recovering latent heat. A hot water supply pipe 2 a is connected to the upstream end of the hot water supply auxiliary heat exchanger 212, and a hot water discharge pipe 2 b is connected to the downstream end of the hot water supply main heat exchanger 211.

  Similarly to the hot water supply heat exchanger 21A, the bath heat exchanger 21B has a bath main heat exchanger 213 that recovers sensible heat of the combustion exhaust gas, and a flow of combustion exhaust gas more than the bath main heat exchanger 213. A bath auxiliary heat exchanger 214 that is provided on the downstream side and collects the latent heat of the combustion exhaust gas is provided. The return pipe 4 a is connected to the upstream end of the bath auxiliary heat exchanger 214, and the forward pipe 4 b is connected to the downstream end of the bath main heat exchanger 213. In addition, you may comprise the heat exchanger 21B for baths only from the main heat exchanger 213 for baths.

  A gas main valve 25 capable of shutting off the supply of fuel gas to the gas burners 22A and 22B and a gas proportional valve 26 capable of adjusting the amount of fuel gas supplied to the gas burners 22A and 22B are provided in the gas pipe 15 from the upstream side. It is provided in order. Further, on the downstream side of the gas proportional valve 26, gas cutoff valves 27A and 27B capable of shutting off the supply of fuel gas to the gas burners 22A and 22B are provided.

  In addition, a drain receiver 24 is provided in the housing 10 for receiving drainage generated from the hot water and bath auxiliary heat exchangers 212 and 214 when the latent heat is recovered. A drain discharge line 5 is connected to the bottom of the drain receiver 24 for discharging the generated drain to the outside through the circulation line 4.

  The drain discharge pipe 5 is provided with a drain tank 50 that collects the drain received by the drain receiver 24. The drain recovered in the drain tank 50 is neutralized by the drain neutralizer that is loaded, When it is detected by the water level electrode 53 provided in the tank 50 that a predetermined water level or more has been stored, the water is discharged from the drain discharge pipe 5 to the hot water filling pipe 3, and then the return pipe 4a on the circulation pump side and the forward pipe It is discharged to the outside through 4b.

  At the connecting portion between the hot water filling pipe 3 and the drain discharge pipe 5, there is a hot water supply position where the hot water generated by the hot water supply heat exchanger 21 </ b> A is chased and led to the circulation pipe 4, and in the drain in the drain tank 50. A drain discharge electromagnetic valve 36 that can switch to a discharge position for discharging Japanese water to the hot water filling pipe 3 and leading to the recirculation circulation pipe 4 is provided.

  The return pipe 4a of the recirculation circulation line 4 includes a return thermistor 41 for detecting the temperature of the bath water in the bathtub P2 sucked into the return pipe 4a from the bathtub P2, a circulation pump 37, and a bath in the bathtub P2. A water level sensor 38 that detects the water level and a water flow switch 39 that is turned on and off in response to the water flow of the return pipe 4a are provided in order from the upstream side. It is connected to the upstream side of the circulation pump 37 in 4a.

  In the connecting portion between the hot water filling pipe 3 and the return pipe 4a, when performing a reheating operation, a circulating position for leading the bath water in the bathtub P2 to the bath heat exchanger 21B, and a hot water filling operation when performing the hot water filling operation. A hot water supply position for supplying hot water from the connecting portion to both the circulation pump side and the bathtub side through the upholstery pipe 3 and water supply to the circulation pump 37 through the hot water uptake pipe 3 before performing the hot water filling operation and the chasing operation. When draining or draining neutralized water from the drain tank 50, the supplied water or drained neutralized water is sent only to the circulating pump side downstream of the connecting portion of the return pipe 4a with the hot water filling pipe 3. A switching valve 40 is provided that can be switched to a discharge position.

  A forward-side thermistor 42 for detecting the temperature of the circulating and heated bath water to be sent to the bathtub P2 is provided in the forward pipe 4b of the additional circulation pipe 4. Further, a drain discharge pipe 17 for discharging drain neutralized water to the outside is branched and connected to the forward pipe 4b. Further, at the connection portion between the forward pipe 4a and the drain discharge pipe 17, a circulation position for returning the bath water sent to the bath heat exchanger 21B to the bathtub P2 and a discharge for discharging the drain neutralized water from the drain discharge pipe 17 are provided. A drain / drainage switching valve 46 that can be switched between positions is provided. The drain drainage switching valve 46 is also used to supply water to the circulation pump 37 from the hot water filling pipe 3 to the circulation pipe 4 before the hot water filling operation or the like. It is set at the discharge position so that it does not fall.

  The combustion fan 23, the gas main valve 25, the gas proportional valve 26, the gas cutoff valves 27A and 27B, the water amount sensor 31, the water amount adjustment valve 32, the hot water solenoid valve 33, the hot water sensor 35, the drain discharge electromagnetic valve 36, and the circulation described above. The pump 37, the water level sensor 38, the water flow switch 39, the switching valve 40, the forward and return side thermistors 42 and 41, the drain / drain switching valve 46, and the water level electrode 53 are each connected to the control device C through electrical wiring.

  Although not shown in the figure, the control device C includes a combustion operation control unit that controls the combustion of the gas burners 22A and 22B and the rotation speed of the combustion fan 23 when performing a filling operation and a reheating operation, a filling operation and a reheating operation. Before performing, the water supply operation unit for supplying water to the recirculation circulation line 4 from the hot water supply line 2 through the hot water filling pipe 3, the circulation control part for controlling the drive of the circulation pump 37, and the water level electrode 53 are detected. When the drain in the drain tank 50 exceeds a predetermined amount, a drain discharge execution unit that discharges drain, a pipe cleaning operation unit that performs pipe cleaning after draining, and a program for performing each operation It has a circuit configuration such as a stored memory and timer.

Next, the control flow in the case of performing the hot water filling operation or the chasing operation in the bath hot water supply apparatus 1 of the present embodiment will be described.
When the power switch is turned on at the operation terminal 100 and the automatic operation switch for the hot water filling operation or the chasing operation is turned on (steps ST1 to ST2), a water supply operation for supplying water into the circulation pump 37 is executed (step ST1). ST3).

  In this water supply operation, first, the hot water solenoid valve 33 is opened, the drain discharge electromagnetic valve 36 is set to the hot water supply position, and the switching valve 40 and the drain drainage switching valve 46 are set to the discharge position. Thereby, the hot water supply line 2 and the recirculation circulation line 4 are in communication with each other. Further, water is not supplied to the upstream side of the switching valve 40 of the return pipe 4a.

  Next, when the water amount sensor 31 detects a minimum working water amount or more, the combustion fan 23 is operated, the gas burner 22A for heating the hot water supply heat exchanger 21A is ignited, and hot water is heated by the hot water supply heat exchanger 21A. Generated. Then, a predetermined amount of hot and cold water is supplied to the return pipe 4a of the recirculation circulation line 4 through the hot water filling pipe 3, and further sent out only toward the circulation pump side. Therefore, even if the bathtub P2 is located below the heat source unit 11, the water supply operation can supply water into the circulation pump 37 by the supply water pressure without driving the circulation pump 37. Even if air enters, it can be exhausted. Moreover, since the switching valve 40 is set at a discharge position where water is not supplied upstream of the switching valve 40 in the return pipe 4a, water can be reliably supplied into the circulation pump 37 provided in the return pipe 4a. it can.

  Since the circulation pump 37 is not driven during the water supply operation, no noise is generated by driving the circulation pump 37. In addition, the water supplied to the recirculation circulation line 4 in the water supply operation is further sent to the forward pipe 4b via the bath heat exchanger 21B, but the drain drain switching valve 46 on the upstream side of the bathtub P2. Is set at the discharge position, it is possible to prevent the bath water exceeding the amount of hot water set by the operation terminal 100 or the like from being stored even if the hot water filling operation is performed after the water supply operation. Furthermore, the temperature drop of the bath water can be prevented in the chasing operation.

  When the amount of hot water detected by the hot water sensor 35 reaches a predetermined amount, an automatic operation of a hot water filling operation or a chasing operation is started (step ST4). For example, in the case of hot water filling operation, the supply amount of the fuel gas is changed so that the hot water temperature set by the operation terminal 100 is reached, the switching valve 40 is set to the hot water supply position, and the drain / drainage switching valve 46 is set to the circulation position. . Thereby, the hot water supplied from the hot water filling pipe 3 is dropped into the bathtub P2 not only from the forward pipe 4b but also from the return pipe 4a. When a predetermined amount of hot water is counted by the hot water sensor 35, the hot water solenoid valve 33 is closed so that the temperature of the bath water detected by the forward-side thermistor 42 becomes the hot water temperature set by the operation terminal 100. In addition, the bath water is circulated and heated by the bath heat exchanger 21B while the circulation pump 37 is driven to circulate the bath water. Further, in the case of a chasing operation, similarly, with the switching valve 40 and the drain / drainage switching valve 46 set to the circulation position, the bath heat exchanger 21B drives the circulation pump 37 to circulate the bath water. The bath water is circulated and heated until the hot water temperature set on the operation terminal 100 is reached. Therefore, even in the bath water heater 1 in which the circulation heating in the bath heat exchanger 21B is started after the water flow is confirmed by the water flow switch 39, the water flow detection by the water flow switch 39 due to the entrapment of air is detected. Since the delay can be prevented, the chasing operation can be executed smoothly. If the user pauses each operation with the operation terminal 100 before the automatic operation is completed, the automatic operation is temporarily stopped (step ST5), and the above steps are repeated.

  Although not shown, in the hot water supply apparatus 1 of the present embodiment, the drain discharge pipe 5 is connected to the hot water filling pipe 3, so that a drain of a predetermined amount or more is detected by the water level electrode 53 in the drain tank 50. If this is the case, the automatic operation is interrupted and the drain discharge operation is performed. In this drain discharge operation, the drain discharge electromagnetic valve 36, the switching valve 40, and the drain drain switching valve 46 are set to the discharge position. When the drain in the drain tank 50 is reduced, the drain discharge electromagnetic valve 36 is set at the hot water supply position, and a pipe cleaning operation for supplying a predetermined amount of water from the hot water supply pipe 2 to the circulation pipe 4 is performed. Is called. Therefore, water may be further supplied into the circulation pump 37 by this pipe cleaning operation.

  In the above embodiment, the bath water heater in which the bath heat exchanger 21B and the bathtub P2 are directly connected by the recirculation circulation line 4 has been described. However, the floor heating apparatus and the floor heating circulation line are further described. A sub-heat exchanger for bath and a circulation line for floor heating are connected, and the bath water is circulated and heated by liquid heat exchange between the circulation line for floor heating and the circulation circulation line. You may apply this invention to the bath water heater to perform.

DESCRIPTION OF SYMBOLS 1 Bath hot-water supply apparatus 2 Hot-water supply pipe 2a Hot-water supply pipe 2b Hot-water supply pipe 3 Hot water filling pipe 4 Reheating circulation pipe 4a Return pipe 4b Outward pipe 5 Drain discharge pipe 11 Heat source machine 21A Hot water supply heat exchanger 21B Bath heat exchanger 37 Circulation pump 40 Switching valve P2 Bathtub

Claims (3)

A heat source machine comprising a heat exchanger for hot water supply and a heat exchanger for bath,
A hot water supply line for supplying hot water generated by heating in the hot water supply heat exchanger to a hot water supply terminal;
A recirculation circulation line that circulates and heats bath water in the bathtub with the heat exchanger for bath,
A hot-water pipe that connects the hot water supply line and the recirculation circulation line, and supplies hot water generated by heating in the hot water supply heat exchanger to the recirculation circulation line;
A circulation pump provided in the additional circulation line;
A drain discharge pipe connected to the upstream side of a connection portion between the hot water filling pipe and the recirculation circulation pipe in the hot water filling pipe and discharging drain generated by operating the heat source device to the hot water filling pipe. Road,
A control device for operating the heat source unit to perform a hot water operation or a chasing operation, and
The recirculation circulation pipe includes a return pipe for returning bath water from the bathtub to the bath heat exchanger side by driving the circulation pump, and an outgoing pipe for sending bath water from the bath heat exchanger to the bathtub. And
A bath water heater in which a drain discharge pipe is branched and connected to the forward pipe, and a drain drainage switching valve is provided at a connection portion between the forward pipe and the drain discharge pipe,
When the operation instruction of the hot water filling operation or the chasing operation is given, the control device, from the hot water supply pipe line through the hot water filling pipe, the chasing circulation pipe before the hot water filling or bath water circulation to the bathtub. A bath hot water supply apparatus that supplies water to a passage and switches the drain drain switching valve to a discharge position to discharge water from the hot water supply pipe to the outside through the drain discharge pipe . In the bath hot water supply device according to claim 1,
The said heat source machine is a bath hot-water supply apparatus installed above the said bathtub. In the bath hot water supply apparatus according to claim 1 or 2,
The return pipe is connected to the hot water filling pipe via a switching valve,
The circulation pump is provided on the downstream side of the connection portion with the hot water filling pipe in the return pipe,
The control device switches the switching valve to a discharge position where water supply from the hot water supply pipe is sent only from the connection portion to the circulation pump side in the return pipe to supply water to the recirculation circulation pipe. Then, the switching valve is switched to a hot water supply position for supplying hot water from the connecting portion to the circulation pump side and the bathtub side in the return pipe or a circulation position for circulating bath water in the recirculation circulation pipe, A bath hot water supply device that performs hot water filling operation or chasing operation.

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