JP2011094848A - Storage type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage type water heater capable of easily determining no-water with a simple constitution and preventing breakage of a circulation pump device. <P>SOLUTION: This storage type water heater includes: a storage tank 1 connected to heat exchange sections (2a, 20); a circulation passage connecting the heat exchange sections (2a, 20) and the storage tank 1, and the heat exchange section (20) and a bathtub 3; the circulation pump devices (P1, P2, P3) disposed in the circulation passage and having pump bodies and motors for driving the pump bodies; and a control device 100 for controlling the circulation pump devices (P1, P2, P3). The motors of the circulation pump devices (P1, P2, P3) are motors having the characteristics that a rotating speed is controllable and an input is changed according to a load. The control device 100 has a determining section 100a for determining no-water in the circulation passage in a case when the input of the motor is less than a prescribed value in rotating the motor at a prescribed rotating speed, and a stop control section 100b for stopping the motors when the determining section 100a determines the no-water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hot water storage type water heater.

  Conventionally, there is a bath apparatus in which water is circulated by a circulation pump through a bath pipe connected to a bathtub (see, for example, JP-A-2003-130447 (Patent Document 1)). In this bath apparatus, a water flow switch detects that water flowing in the bath pipe has flowed more than a predetermined amount, and the output of the circulation pump is increased when the water flow switch does not turn on even when the circulation pump is operated.

  In such a bath apparatus, if the circulation pump is operated when there is no water in the bathtub and the bath piping, the circulation pump may be damaged.

  Similarly, in a hot water storage water heater that circulates a hot water storage tank and a bathtub through a circulation path, there is a problem that the circulation pump is damaged if the circulation pump is operated when there is no water in the bathtub and the circulation path. . In particular, when installing the hot water storage type water heater, the operator will determine whether there is water in the hot water storage tank, and the circulation pump may be operated without water in the bathtub and circulation path. Increases nature.

JP 2003-130447 A

  Therefore, an object of the present invention is to provide a hot water storage type hot water heater that can easily determine the absence of water with a simple configuration and can prevent the circulation pump device from being damaged.

In order to solve the above problems, the hot water storage type water heater of the present invention is:
A heat exchange section;
A hot water storage tank connected to the heat exchange unit;
A circulation path connecting at least one of the heat exchange part and the hot water storage tank or between the heat exchange part and the bathtub;
A circulation pump device disposed in the circulation path and having a pump body and a motor for driving the pump body;
A control device for controlling the circulation pump device,
The motor of the circulation pump device is a motor having a characteristic that the rotation speed can be controlled and the input changes according to the load,
The control device, when rotating the motor at a predetermined rotational speed, when the input of the motor is less than a predetermined value, a determination unit that determines that there is no water in the circulation path;
And a stop control unit that stops the motor when the determination unit determines that there is no water.

  According to the said structure, the pump main body of the circulation pump apparatus arrange | positioned by the determination part of the control apparatus at the circulation path which connects at least one between a heat exchange part and a hot water storage tank or between a heat exchange part and a bathtub If the motor input is less than a predetermined value when the motor that drives the motor is rotated at a predetermined rotation speed, if it is determined that there is no water in the circulation path, the motor is stopped by the stop control unit of the control device. At this time, by setting the predetermined rotational speed to a rotational speed at which the motor is not damaged even when there is no water, it is possible to easily determine the absence of water with a simple configuration and prevent the circulation pump device from being damaged.

Moreover, in the hot water storage type water heater of one embodiment,
The heat exchange part is at least one of a boiling heat exchange part or a reheating heat exchanger of the heat pump unit.

  According to the above-described embodiment, it is easy to eliminate water in the circulation path between the heating heat exchange unit of the heat pump unit and the hot water storage tank, or in the circulation path between the reheating heat exchanger and the hot water storage tank. Can be determined.

Moreover, in the hot water storage type water heater of one embodiment,
The predetermined rotational speed is a rotational speed at the time of motor input that does not damage the motor even when there is no water.

  According to the embodiment, it can be determined that there is no water without damaging the motor of the circulation pump device.

Moreover, in the hot water storage type water heater of one embodiment,
When the determination unit determines that there is water, the control device includes a circulation control unit that switches to a rotation speed higher than the predetermined rotation speed and circulates a necessary flow rate of water in the circulation path.

  According to the above-described embodiment, after determining that there is water, the circulating pump device can be continuously operated without stopping, and a necessary flow rate of water can be allowed to flow in the circulation path.

  As is clear from the above, according to the hot water storage type hot water heater of the present invention, it is possible to easily determine the absence of water with a simple configuration and to realize a hot water storage type hot water heater that can prevent the circulation pump device from being damaged.

FIG. 1 is a piping system diagram of a hot water storage type water heater according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the hot water storage type hot water supply apparatus. FIG. 3 is a configuration diagram of a circulating pump for boiling the hot water storage type hot water heater. FIG. 4 is a flow chart for explaining the operation of determining no water in the control device for the hot water storage type hot water heater. FIG. 5 is a diagram showing the relationship between the pump rotation speed and the pump input.

  Hereinafter, the hot water storage type water heater of the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 shows a piping system diagram of a hot water storage type water heater according to an embodiment of the present invention. As shown in FIG. 1, the hot water storage type hot water heater includes a hot water storage tank 1 and a heat pump unit 2 for boiling water in the hot water storage tank 1. One end of the pipe L <b> 1 is connected to the lower part of the hot water storage tank 1, and the other end of the pipe L <b> 1 is connected to one end of the heating heat exchange unit 2 a of the heat pump unit 2. Further, the other end of the heating heat exchanging part 2 a of the heat pump unit 2 is connected to one end of the pipe L 2, and the other end of the pipe L 2 is connected to the input side of the three-way valve 10. One end of the pipe L3 is connected to one output side of the three-way valve 10, and the other end of the pipe L3 is connected to the upper part of the hot water storage tank 1. On the other hand, one end of the pipe L4 is connected to the other output side of the three-way valve 10, and the other end of the pipe L4 is connected to the lower part of the hot water storage tank 1. The pipes L1, L2, L3, and L4 constitute a circulation path between the hot water storage tank 1 and the heat pump unit 2. Further, a boiling circulation pump P1 as an example of a circulation pump device is disposed in the pipe L1.

  The boiling circulation pump P1 circulates the hot water in the hot water storage tank 1 through the piping L1, the heating heat exchanger 2a of the heat pump unit 2, the piping L2, the three-way valve 10, and the piping L3 (or L4). .

  Next, an external water supply pipe is connected to the lower part of the hot water storage tank 1 via a pipe L11. In this pipe L11, only the strainer 11, the check valve 12 that allows only the flow from the water supply pipe side to the hot water storage tank 1 side, the pressure reducing valve 13, and the flow from the water supply pipe side to the hot water storage tank 1 side are allowed. The check valve 14 is disposed in order from the upstream side.

  One end of the pipe L21 is connected to the upper part of the hot water storage tank 1, and the other end of the pipe L21 is connected to one input side of the bath mixing valve 5. A check valve 4 that allows only the flow from the hot water storage tank 1 side to the opposite side is disposed in the pipe L21. One end of the branch pipe L12 is connected to the other input side of the bath mixing valve 5, and the other end of the branch pipe L12 is connected between the pressure reducing valve 13 and the check valve 14 of the pipe L11. . Further, one end of the pipe L22 is connected to the output side of the bath mixing valve 5 and the other end of the pipe L22 is connected to a hot water supply port 9a of the connection adapter 9 provided in the bathtub 3. In order from the bath mixing valve 5 side of the pipe L22, a flow rate adjusting electromagnetic valve 6, a water amount sensor 7, and a check valve 8 that allows only the flow from the bath mixing valve 5 side to the bathtub 3 are arranged. ing.

  A composite water valve 30 is constituted by the flow rate adjusting electromagnetic valve 6, the water amount sensor 7 and the check valve 8.

  The piping L21 and the piping L22 constitute a water supply path between the hot water storage tank 1 and the bathtub 3. The bath mixing valve 5, the flow rate adjusting electromagnetic valve 6 and the check valve 8 constitute a valve mechanism.

  One end of the pipe L24 is connected to the reheating water inlet 9b of the connection adapter 9, and the other end of the pipe L24 is connected to an input on the secondary side of the reheating heat exchanger 20. The pipe L24 is provided with a bath circulation pump P3 as an example of a circulation pump device. Further, one end of the branch pipe L23 is connected to the downstream side of the check valve 8 of the pipe L22, and the other end of the branch pipe L23 is connected to the output on the secondary side of the reheating heat exchanger 20.

  The hot water in the bathtub 3 is circulated through the pipe L24, the secondary side of the reheating heat exchanger 20, the branch pipe L23, and the pipe L22 by the bath circulation pump P3.

  Further, one end of the branch pipe L25 is connected to the downstream side of the check valve 4 of the pipe L21, and the other end of the branch pipe L25 is connected to an input on the primary side of the reheating heat exchanger 20. One end of the pipe L26 is connected to the output on the primary side of the reheating heat exchanger 20, and the other end of the pipe L26 is connected to the lower part of the hot water storage tank 1. A recirculation circulation pump P2 as an example of a circulation pump device is disposed in the pipe L26.

  With the recirculation pump P2, the hot water in the hot water storage tank 1 is circulated through the pipe L21, the branch pipe L25, the primary side of the reheating heat exchanger 20, and the pipe L26.

  Further, one end of the pipe L31 is connected to the upper part of the hot water storage tank 1, and the other end of the pipe L31 is connected to one input side of the hot water mixing valve 22. A check valve 21 that allows only the flow from the hot water storage tank 1 side to the hot water supply mixing valve 22 is disposed in the pipe L31. In addition, one end of the branch pipe L13 is connected to the other input side of the bath mixing valve 5, and the other end of the branch pipe L13 is connected to the other input side of the hot water mixing valve 22 of the branch pipe L12. . A check valve 23 that allows only a flow from the branch pipe L12 side to the hot water supply mixing valve 22 is disposed in the branch pipe L13. One end of the pipe L32 is connected to the output side of the hot water mixing valve 22, and the other end of the pipe L32 is connected to the hot water supply section 25 (a faucet in this embodiment). A water amount sensor 24 is connected to the pipe L32.

  The hot water storage tank 1 is provided with six temperature sensors T1 to T6 at substantially equal intervals from the lower side to the upper side. In addition, a temperature sensor T <b> 11 that detects a hot water supply temperature is provided downstream of the water amount sensor 24 in the pipe L <b> 32 connected to the hot water supply unit 25. Further, in the pipe L24 connected to the bathtub 3, a water level sensor LS, a water flow switch SW, and a temperature sensor T12 are arranged in this order from the connection adapter 9 side between the connection adapter 9 on the bathtub 3 side and the circulation pump P3 for bath. Provided. Further, a temperature sensor T13 for detecting the feed water temperature is provided between the pressure reducing valve 13 and the check valve 14 of the pipe L11 and downstream of the connection point where the branch pipe L21 is connected to the pipe L11. Furthermore, the temperature of the hot water supplied to the bathtub 3 is set downstream of the check valve 8 of the pipe L22 connected to the bathtub 3 and upstream of the connection point where the branch pipe L23 is connected to the pipe L22. A temperature sensor T14 for detection is provided.

  The hot water storage type water heater includes a control device 100 including a microcomputer and an input / output circuit, and a remote controller 200 that transmits and receives signals to and from the control device 100. The control device 100 has a determination unit 100a that determines whether or not there is water in the circulation path, and a stop control unit 100b that stops the motors of the circulation pumps (P1, P2, and P3) when the determination unit 100a determines that there is no water. And a circulation control unit 100c that circulates a required flow rate of water in the circulation path. The control device 100 receives signals from the temperature sensors T1 to T14, the water level sensor LS, the water flow switch SW, and the water amount sensors 7 and 24, and receives the heat pump unit 2, the boiling circulation pump P1, and the recirculation circulation pump P2. The bath circulation pump P3, the bath mixing valve 5, the hot water supply mixing valve 22 and the three-way valve 10 are controlled.

  In the hot water storage type water heater having the above-described configuration, in the test operation after the installation is completed, water is supplied from the lower side of the hot water storage tank 1 through the strainer 11, the check valve 12 and the pressure reducing valve 13 to fill the hot water storage tank 1 with water. After that, the three-way valve 10 is switched to the pipe L4 side, the boiling circulation pump P1 is operated for a predetermined time, and the water in the hot water storage tank 1 is circulated through the circulation path to perform the air venting operation.

  FIG. 2 is a schematic diagram showing the configuration of the hot water storage type hot water heater. As shown in FIG. 2, hot water in the hot water storage tank 1 is circulated through a circulation path (pipe L1 shown in FIG. 1, heat exchange part 2a for heating of the heat pump unit 2, pipe L2, three-way valve) by a circulating pump P1 for boiling. 10, circulate through pipe L3 (or L4)). Further, the recirculation circulation pump P2 causes hot water in the hot water storage tank 1 to pass through the circulation path (the piping L21, the branch piping L25, the primary side of the reheating heat exchanger 20, the piping L26 shown in FIG. 1). Circulate. Further, the hot water in the bathtub 3 is circulated through the circulation path (the pipe L24, the secondary side of the reheating heat exchanger 20, the branch pipe L23, the pipe L22) by the bath circulation pump P3. .

  FIG. 3 shows a configuration diagram of the boiling circulation pump P1 of the hot water storage type hot water heater, and the recirculation circulation pump P2 and the bath circulation pump P3 have the same configuration.

  As shown in FIG. 3, the boiling circulation pump P <b> 1 includes a pump main body 41 and a motor 42 that drives the pump main body 41. The motor 42 is a motor that can control the rotation speed and has an input that changes according to the load. In this embodiment, a DC motor that controls the rotation speed based on the speed command voltage is used.

  FIG. 4 shows a flowchart of the operation for determining the absence of water of the control device 100 of the hot water storage type hot water heater, and the operation of the control device 100 will be described below with reference to FIG. Here, the operation of the boiling circulation pump P1 at the start of the boiling operation for circulating the hot water in the hot water storage tank 1 through the circulation path will be described.

  First, when the process starts, the pump is operated at the first target rotational speed (predetermined rotational speed) in step S1. That is, in order to circulate hot water in the hot water storage tank 1 through the circulation path, the boiling circulation pump P1 is operated at the first target rotational speed.

  Next, it progresses to step S2 and the determination part 100a determines whether a pump input value is larger than a determination value (predetermined value). Here, the speed command voltage of the motor that drives the pump body of the circulating pump P1 for boiling corresponds to the pump input value.

  And if it determines with a pump input value being larger than a 1st determination value by step S2, it will progress to step S3 and the determination part 100a will determine with "water exists."

  And it progresses to step S4, a pump is drive | operated by the 2nd target rotational speed by the circulation control part 100c, this process is complete | finished, and a boiling operation is performed. That is, the boiling circulation pump P1 is operated at the second target rotation speed that is the normal rotation speed during the boiling operation.

  On the other hand, if it determines with a pump input value being below a determination value by step S2, it will progress to step S5 and the determination part 100a will determine with "no water".

  Next, the process proceeds to step S6. If it is determined that “no water” continues for a certain time or more, the process proceeds to step S7. On the other hand, if it is determined that “no water” continues for a certain time or more, the process returns to step S2. .

  Then, in step S7, the abnormality is confirmed, and the process proceeds to step S8, where the stop control unit 100b stops the pump. That is, the motor of the circulating pump P1 for boiling is stopped by the stop control unit 100b.

  Next, it progresses to step S9, an alarm is displayed on the remote controller 200 grade | etc., And this process is complete | finished.

  FIG. 5 shows the relationship between the pump rotation speed and the pump input. In FIG. 5, the horizontal axis represents the pump rotation speed (arbitrary scale), and the vertical axis represents the input to the pump (arbitrary scale). A shows the characteristics when there is water, and the curve B shows the characteristics when there is no water.

  As shown in FIG. 5, the curve A when the motor load with water is large has a larger change amount of input to the motor and the slope is larger than the curve B when the motor load without water is small. For this reason, in the curve A indicating the characteristics when there is water, the input to the pump is equal to or higher than the determination value at the first target rotation speed, whereas in the curve B indicating the characteristics when there is no water, the first target rotation is performed. The input to the pump at the speed is below the judgment value.

  According to the hot water storage type water heater having the above-described configuration, the determination unit 100a of the control device 100 connects the heat exchange unit (2a, 20) and the hot water storage tank 1 with the circulation path, the heat exchange unit (20), and the bathtub 3. The motor that drives the pump body of the circulation pump device (P1, P2, P3) disposed in the circulation path connecting between the motor and the motor is rotated at the first target rotation speed (predetermined rotation speed), and the motor input is If it is determined that there is no water in the circulation path when it is less than the determination value (predetermined value), the motor is stopped by the stop control unit 100b of the control device 100. Accordingly, it is possible to easily determine the absence of water with a simple configuration, and it is possible to prevent the circulation pump devices (P1, P2, P3) from being damaged.

  In this embodiment, a circulation path for circulating hot water in the hot water storage tank 1 by the boiling circulation pump P1, a circulation path for circulating hot water in the hot water storage tank 1 by the recirculation circulation pump P2, and a circulation for the bath Although the absence of water is determined for the circulation path for circulating hot water in the bathtub 3 by the pump P3, the absence of water in any one or two circulation paths may be determined.

  Further, in the hot water storage type hot water heater, circulation in the circulation path between the heating heat exchanging portion 2 a of the heat pump unit 2 and the hot water storage tank 1 and between the reheating heat exchanger 20 and the hot water storage tank 1 is performed. The absence of water in the path can be easily determined.

  Further, the motor of the circulation pump device (P1, P2, P3) is damaged by setting the first target rotation speed (predetermined rotation speed) to a rotation speed at the time of motor input that is not damaged even when the motor is in the absence of water. Without water can be determined.

  In addition, when the determination unit 100a determines that there is water, the control device 100 switches to a rotation speed higher than the first target rotation speed (predetermined rotation speed) and circulates a necessary flow of water in the circulation path. Since it has the portion 100c, after determining that there is water, the circulating pump device (P1, P2, P3) can be continuously operated without stopping, and water of a necessary flow rate can be caused to flow in the circulation path.

  In the hot water storage type water heater, the control device 100 first switches the three-way valve 10 to the pipe L3 side, operates the boiling circulation pump P1 and the heat pump unit 2, and supplies the water in the hot water storage tank 1 through the circulation path. The water is circulated to perform a boiling operation for boiling water in the hot water storage tank 1. This boiling operation is performed by controlling the circulating pump P1 for heating and the heat pump unit 2 by the control device 100 based on the temperature of hot water detected by the temperature sensors T11 to T16.

  In the hot water filling operation to the bathtub 3, the bath mixing valve 5 and the flow rate adjusting electromagnetic valve 6 are controlled to fill the hot water at a desired water level. At this time, water is supplied into the hot water storage tank 1 from the lower part of the hot water storage tank 1 by the water supply pressure via the pipe L11, and hot water discharged from the upper part of the hot water storage tank 1 is mixed with water by the bath mixing valve 5. Then, it is supplied to the bathtub 3 through the pipe L22. At this time, the control device 100 controls the mixing ratio of hot water and water in the bath mixing valve 5 so that the temperature of the hot water detected by the temperature sensor T14 becomes the set temperature.

  In the reheating operation, the recirculation circulation pump P2 is operated to circulate the hot water in the hot water storage tank 1 through the primary side of the reheating heat exchanger 20, and the bath circulation pump P3 is operated. Then, the hot water in the bathtub 3 is circulated through the secondary side of the reheating heat exchanger 20. Thereby, the hot water on the bathtub 3 side is heated by the reheating heat exchanger 20 for reheating.

  When the faucet of the hot water supply section 25 is opened, water is supplied into the hot water storage tank 1 from the lower part of the hot water storage tank 1 by the hot water supply pressure, and hot water discharged from the upper part of the hot water storage tank 1 is supplied to the hot water mixing valve 22. And then supplied to the hot water supply section 25 through the pipe L32. At this time, the control device 100 controls the mixing ratio of hot water and water in the hot water mixing valve 22 so that the hot water temperature detected by the temperature sensor T11 becomes the set hot water temperature.

  In addition, the heat pump unit 2 of the hot water storage type hot water heater includes a compressor, a condenser having one end (primary side) connected to the discharge side of the compressor (a heat exchanging part 2a for heating), An expansion valve having one end connected to the other end (primary side), an evaporator having one end connected to the other end of the expansion valve and the other end connected to the suction side of the compressor, and external air to the evaporator It has a blower fan to be supplied, and a compressor, a condenser, an expansion valve, and an evaporator constitute a refrigerant circuit. In the casing in which the condenser and the evaporator are disposed and the chamber in which the compressor is disposed are partitioned by a partition plate, the condenser (boiling heat exchange unit 2a) is disposed in the chamber in which the evaporator is disposed. And a fan is arranged.

  In the heat pump unit 2, the ratio R / H of the fan diameter R to the casing height H is 0.68 or more. The heat pump unit 2 includes a blower outlet on the front side of the casing, and a ratio Su / S of the area Su of the blower outlet to the area S of the casing front is set to 0.30 or more. Thereby, noise can be reduced while ensuring the air volume required for performance. Here, the bell mouth provided in the blower outlet on the front side of the casing has a notch in a portion close to the control device arranged on the upper side. It is desirable that this notch is notched linearly. The condenser (boiling heat exchanging section 2a) is disposed below the blower fan and at the bottom of the casing. Furthermore, it is desirable that the control device is not disposed above the blower fan.

  Although the hot water storage type hot water heater using the reheating heat exchanger 20 has been described in the above-described embodiment, the hot water storage type water heater is not limited to this, and the hot water storage type having another configuration that does not use the reheating heat exchanger. You may apply this invention to a water heater. Moreover, although the hot water storage type hot water heater provided with one hot water storage tank 1 has been described, the present invention is not limited thereto, and the present invention may be applied to a hot water storage type hot water heater in which two hot water storage tanks are configured in two stages.

  Moreover, in the said embodiment, although the hot water storage type water heater provided with the valve mechanism which has the mixing valve 5 for baths, and the electromagnetic valve 6 for flow control was demonstrated, the valve mechanism is not restricted to this, The valve mechanism of another structure The present invention may be applied to a hot water storage type water heater provided with

  Moreover, in the said embodiment, after performing air venting control by the air vent control part 100a, the water level finalization operation | movement of the bathtub 3 was performed by the water level confirmation operation | movement control part 100b, However, The water level finalization operation does not need to be.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Hot water storage tank 2 ... Heat pump unit 2a ... Heat-exchange part for boiling 3 ... Bathtub 5 ... Bath mixing valve 6 ... Solenoid valve for flow control 7,24 ... Water quantity sensor 9 ... Connection adapter 13 ... Pressure reducing valve 20 ... Reheating Heat exchanger 22 ... Hot water mixing valve 30 ... Composite water valve 41 ... Pump body 42 ... Motor 100 ... Control device 100a ... Air vent control unit 100b ... Water level determination operation control unit 200 ... Remote controller LS ... Water level sensor P1 ... Boiling Circulation pump P2 ... Recirculation circulation pump P3 ... Bath circulation pump SW ... Water flow switch

Claims (4)

Heat exchanger (2a, 20);
A hot water storage tank (1) connected to the heat exchange section (2a, 20);
A circulation path connecting at least one of the heat exchange part (2a, 20) and the hot water storage tank (1) or the heat exchange part (20) and the bathtub (3);
A circulation pump device (P1, P2, P3) disposed in the circulation path and having a pump body and a motor for driving the pump body;
A control device (100) for controlling the circulation pump device (P1, P2, P3),
The motor of the circulation pump device (P1, P2, P3) is a motor having a characteristic that the rotation speed can be controlled and the input changes according to the load,
The control device (100) determines that there is no water in the circulation path when the motor input is less than a predetermined value when the motor is rotated at a predetermined rotation speed. When,
A hot water storage type hot water heater comprising a stop control unit (100b) for stopping the motor when the determination unit (100a) determines that there is no water. In the hot water storage type water heater according to claim 1,
The hot water storage type hot water supply apparatus, wherein the heat exchanging section is at least one of a heating heat exchanging section (2a) and a reheating heat exchanger (20) of the heat pump unit (2). In the hot water storage type water heater according to claim 1 or 2,
The hot water storage type hot water heater is characterized in that the predetermined rotational speed is a rotational speed at the time of motor input that is not damaged even when the motor is in a waterless state. In the hot water storage type water heater according to any one of claims 1 to 3,
When the determination unit (100a) determines that there is water, the control device (100) switches to a rotation speed higher than the predetermined rotation speed and circulates a required flow rate of water in the circulation path ( 100c). A hot water storage type water heater characterized by having 100c).

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