JP2013213594A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that in a control of determining completion of replacement of water in a hot water storage tank by temperature changes in the hot water storage tank, it becomes difficult to detect a difference between the temperature of hot water in the hot water storage tank and the temperature of water supplied from a water supply pipe, when the temperature of the hot water remaining in the hot water storage tank is low or the temperature of tap water is high in summer time, and therefore, a replacement operation is terminated before the replacement of water in the hot water storage tank is completed.SOLUTION: When starting a replacement operation of the hot water in a hot water storage tank 10 and when the temperature detected by a temperature detecting means 40 is equal to or lower than a first threshold, the replacement operation of the hot water in the hot water storage tank 10 is carried out based on a valve opening time of a drain valve 34, and also, when starting the replacement operation of the hot water in the hot water storage tank 10 and when the temperature detected by the temperature detecting means 40 is equal to or higher than the first threshold, the replacement operation of the hot water in the hot water storage tank 10 is carried out based on temperatures detected by a plurality of temperature detecting means 40, 42.

Description

The present invention relates to a hot water storage type water heater, and more particularly, to a function of replacing old hot water in a hot water storage tank.

Conventionally, in hot water storage water heaters that heat and boil after accumulating water in the hot water storage tank, Legionella bacteria can be generated from old hot water in the hot water storage tank. We are replacing. In such a hot water storage type water heater, the hot water replacement time is set according to the capacity of the hot water storage tank, and the drain valve is opened until the set time elapses to replace the old hot water in the hot water storage tank. In order to prevent wasteful drainage, there is one that appropriately controls the amount of hot water to be replaced in a hot water storage tank. For example, Japanese Patent Application Laid-Open No. 2007-155286 (hereinafter referred to as “Patent Document 1”) is known.

In patent document 1, the hot water storage temperature in a hot water storage tank is monitored using a thermistor. Here, if it is determined that the amount of hot water in the hot water storage tank is insufficient with respect to the required amount of hot water based on the detection result of the thermistor, the required amount of hot water supply is calculated. When it is determined that the required amount of hot water is satisfied, the hot water storage temperature is monitored again.

Thereafter, cold water is supplied into the hot water storage tank by the required hot water supply amount. At the same time, hot water equivalent to the amount of cold water supplied is discharged from the drain pipe. Here, control of the supply amount of cold water is performed using a thermistor. For example, it is possible to detect that the cold water supplied from the water supply pipe reaches the position of the thermistor from the lower part of the hot water storage tank by making the detected temperature of the thermistor equal to the temperature of cold water supplied from the water supply pipe. .

Then, heating by the heating unit is performed, and the required amount of hot water is supplied to the hot water storage tank. Here, the supply amount of the hot water is controlled using a thermistor. For example, when the detected temperature of the thermistor becomes equal to the set hot water storage temperature, it can be detected that the hot water supplied from the heater return pipe has reached the position of the thermistor from the upper part of the hot water storage tank.

JP 2007-155286 A

However, the following problems have arisen in the conventional hot water storage type water heater. That is, in Patent Document 1, the temperature detected by the thermistor is equal to the temperature of the cold water supplied from the water supply pipe, so that the cold water supplied from the water supply pipe reaches the position of the thermistor from the lower part of the hot water storage tank. The amount of water discharged from the hot water storage tank is controlled, but if the temperature of the hot water in the hot water storage tank is slightly different from the temperature of the water supplied from the water supply pipe, the replacement of the water in the hot water storage tank is complete. This causes a problem that the replacement operation is terminated before the operation is performed.

As a condition that such a situation may occur, the temperature of the hot water in the hot water storage tank is the water supply when the temperature of the hot water remaining in the hot water storage tank is low or when the temperature of the tap water in the summer is rising. This occurs because the temperature and difference between the water supplied from the pipe is difficult to detect.

The present invention has been made in view of the above problems, and even if the difference between the temperature of the hot water in the hot water storage tank and the temperature of the water supplied from the water supply pipe is very small, the water in the hot water storage tank is correctly replaced. The goal is to provide a hot water storage water heater.

In order to solve the above problems, the present invention has the following configuration. That is, a hot water storage tank to which a water supply pipe and a drain pipe are respectively connected, a heating unit for heating water in the hot water storage tank, a drain valve connected to the drain pipe, and the water supply pipe through the hot water storage tank A plurality of temperature detecting means for detecting the temperature at a position spaced from the direction of the water flow flowing from the side to the drain pipe side, and opening and closing the drain valve, and a signal for the hot water replacement operation in the hot water storage tank. A hot water storage type hot water heater comprising: a control unit that supplies the hot water in the hot water storage tank based on a valve opening time of the drainage valve, or detection of a plurality of the temperature detection means. One of the hot water replacement operations in the hot water storage tank based on the temperature is made to function.

In the above configuration, the control unit opens the drain valve when the temperature detected by the temperature detection means at the start of the hot water replacement operation in the hot water storage tank is equal to or lower than a first threshold value. When the temperature detected by the temperature detecting means at the start of the hot water replacement operation in the hot water storage tank is equal to or higher than a first threshold value, a plurality of hot water replacement operations are performed. It is good also as a structure which performs the replacement | exchange operation of the hot water in the said hot water storage tank based on the detected temperature of the said temperature detection means.

In addition, the control unit determines whether the drainage valve is open when the temperature detected by the temperature detection unit from the start of the hot water replacement operation in the hot water storage tank is variable below a second threshold. A hot water replacement operation in the hot water storage tank is performed, and a plurality of cases are detected when the temperature detected by the temperature detection means from the start of the hot water replacement operation in the hot water storage tank is more than a second threshold. It is good also as a structure which performs the replacement | exchange operation of the hot water in the said hot water storage tank based on the detected temperature of the said temperature detection means. Further, the control unit closes the drainage valve when a desired time has elapsed from the opening of the drainage valve as a hot water replacement operation in the hot water storage tank based on the valve opening time of the drainage valve. It is good also as composition to do.

Further, the control unit closes the drain valve when the temperatures of the plurality of temperature detection means are approximated as a hot water replacement operation in the hot water storage tank based on the temperature detected by the plurality of temperature detection means. It is good also as a structure. Furthermore, the control unit closes the drainage valve when the temperature of the plurality of temperature detection means remains unchanged as the hot water replacement operation in the hot water storage tank based on the temperature detected by the plurality of temperature detection means. It is good also as a structure.

As described above, either the hot water replacement operation in the hot water storage tank based on the valve opening time of the drainage valve or the hot water replacement operation in the hot water storage tank based on the temperature detected by the plurality of temperature detection means This prevents wasteful drainage, and even if the temperature of the hot water in the hot water storage tank is slightly different from the temperature of the water supplied from the water supply pipe, the hot water in the hot water storage tank is correctly replaced. A hot water storage type hot water heater can be realized.

Further, when the temperature detected by the temperature detecting means at the start of the hot water replacement operation in the hot water storage tank is equal to or lower than the first threshold value, the hot water replacement operation in the hot water storage tank based on the valve opening time of the drainage valve is performed. And when the temperature detected by the temperature detection means at the start of the hot water replacement operation in the hot water storage tank is equal to or higher than the first threshold value, the hot water in the hot water storage tank is based on the detected temperatures of the plurality of temperature detection means. The water temperature in the hot water storage tank is low and the temperature of the hot water in the hot water storage tank is increased from the water supply pipe. Even if the difference between the temperature and the temperature is very small, the hot water in the hot water storage tank is not changed without being replaced.

Further, when the temperature detected by the temperature detection means from the start of the hot water replacement operation in the hot water storage tank is variable below the second threshold, the hot water in the hot water storage tank is based on the valve opening time of the drainage valve. Hot water storage based on the detected temperatures of the plurality of temperature detection means when performing the replacement operation and the temperature detected by the temperature detection means from the start of the hot water replacement operation in the hot water storage tank is variable beyond the second threshold. By replacing the hot water in the tank, even if the temperature of the hot water in the hot water storage tank is low in winter, if there is a difference from the temperature of the water supplied from the water supply pipe, It can be judged that the replacement of hot water has ended, and wasteful drainage can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the hot water storage type water heater as a 1st Example of this invention. It is a schematic block diagram which shows transition of the hot water in the hot water storage tank in the hot water storage type water heater as a 1st Example. It is a flowchart explaining the replacement | exchange control of the hot water in the hot water storage tank in the hot water storage type water heater as a 1st Example.

An example showing the embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram of a hot water storage water heater according to a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a transition of hot water in a hot water storage tank in the hot water storage water heater, and FIG. The flowchart explaining the replacement control of the hot water in a hot water storage tank is shown in FIG.

In FIG. 1, a hot water storage type water heater 100 is a water heater that uses electricity to boil hot water and store hot water during a time period when the charge from midnight to morning when electricity consumption is low is cheap. The hot water storage type water heater 100 includes a hot water storage tank 10 for storing hot water, and the hot water storage tank 10 is always maintained in a state filled with hot water.

In addition, a heater 12 for heating water stored in the hot water storage tank 10 is installed in the lower part of the hot water storage tank 10. The heater 12 is configured so that a nichrome wire as a main body is covered with an insulator and covered with a protective tube. The water in the hot water storage tank 10 is directly heated by the heater 12, and the temperature rises almost uniformly due to the convection of the water.

A water supply pipe 20 for supplying water into the hot water storage tank 10 is connected to the lower part of the hot water storage tank 10. The hot water storage tank 10 is supplied with water from a water pipe as it flows through an arrow A20 in the water supply pipe 20. Further, the water supply pipe 20 is provided with a water supply valve 22 for adjusting the amount of water supplied to the hot water storage tank 10.

A hot water supply pipe 30 for discharging hot water from the hot water storage tank 10 is connected to the upper part of the hot water storage tank 10. Hot water from the hot water storage tank 10 is supplied to the user of the hot water storage type hot water heater 100 through the hot water supply pipe 30.

In addition, a drain pipe 32 for discharging old hot water in the hot water storage tank 10 is connected to the hot water supply pipe 30 so as to branch. Old hot water from the hot water storage tank 10 flows through an arrow B32 in the water distribution pipe 32 and is discharged to a drain outlet. Further, the drain pipe 32 is provided with a drain valve 34 for adjusting the amount of drainage from the hot water storage tank 10.

Further, when the hot water storage type hot water heater 100 uses the hot water in the hot water storage tank 10, the used amount of water is supplied from the water supply pipe 20, so that the hot water storage tank 10 is always full. Further, in the hot water storage tank 10, when the temperature difference between the hot water heated by the heater 12 and the water supplied from the water supply pipe 20 is 25 ° C. or more, a mixed layer is generated due to the specific gravity, Since the hot water in the hot water storage tank 10 is not mixed with the water supplied from the water supply pipe 20, the temperature of the hot water in the hot water storage tank 10 does not decrease.

A first temperature detecting means 40 for detecting the temperature of the hot water in the hot water storage tank 10 is installed below the hot water storage tank 10. Further, a second temperature detecting means 42 for detecting the temperature of the hot water in the drain pipe 32 is installed between the drain valve 34 of the drain pipe 32 and the drain port. The first temperature detecting means and the second temperature detecting means 42 are thermistors.

The hot water storage type water heater 100 includes a control unit 50 that controls the heater 12, the water supply valve 22, and the drainage valve. Further, the hot water in the hot water storage tank 10 is boiled to a constant hot water temperature of 85 to 90 ° C. by the controller 50.

Further, the control unit 50 receives the hot water tank side temperature signal T1 from the first temperature detecting means 40 and the drain pipe side temperature signal T2 from the second temperature detecting means 42, and receives the hot water tank side temperature. The hot water in the hot water storage tank 10 and the temperature of the hot water flowing in the drain pipe 32 are calculated according to the increase / decrease of the current amount of the signal T1 and the drain pipe side temperature signal T2. Further, the control unit 50 sends a water supply valve opening / closing signal C1 to the water supply valve 22 and a drainage valve opening / closing signal C2 to the drainage valve 34, and the water supply side valve 22 and the drainage side valve 34 is opening and closing.

Next, in FIG. 2, (a) shows a state in which the hot water in the hot water storage tank 10 is outdated. When the hot water in the hot water storage tank 10 becomes old, Legionella bacteria may be generated. Further, (b) to (d) show replacement of hot water in the hot water storage tank 10 by operating the water supply valve 22 and the drain valve 34.

When time has elapsed since the start of the replacement of hot water in the hot water storage tank 10, new water from the water pipe passes through the water supply pipe 20 from below the hot water storage tank 10 as shown in FIG. The first temperature detecting means 40 supplied with water detects the temperature of new water accumulated in the hot water storage tank 10. Further, old water from the hot water storage tank 10 is discharged to the drain outlet through the drain pipe 32, and the second temperature detecting means 42 detects the temperature of the old water passing through the drain pipe 32.

When the time elapses from the state shown in FIG. 2B, new water supplied from the water pipe through the water supply pipe 20 reaches the upper part of the hot water storage tank 10 as shown in FIG. 2C. ing. Further, old water discharged from the hot water storage tank 10 passes through the drain pipe 32.

The first temperature detecting means 40 detects the temperature of new water supplied into the hot water storage tank 10, and the second temperature detecting means 42 detects the temperature of old water passing through the drain pipe 32. Detected.

When the time elapses from the state of FIG. 2 (c), as shown in FIG. 2 (d), new water supplied from the water pipe through the water supply pipe 20 fills the hot water storage tank 10, and the drainage The tube has reached 32. Further, the first temperature detecting means 40 detects the temperature of new water supplied into the hot water storage tank 10, and the second temperature detecting means 42 detects the temperature of new water passing through the drain pipe 32. Detected.

Next, replacement control of hot water in the hot water storage tank 10 in the hot water storage type hot water heater 100 will be described with reference to FIG.

In FIG. 3, when the replacement of the old hot water in the hot water storage tank 10 is started periodically, the control unit 50 opens the drainage valve 34 (S1), and the control unit 50 (S1) At the same time, counting is started (S2). The first temperature detection means 40 and the second temperature detection means 42 detect the temperature of hot water passing through the hot water storage tank 10 or the drain pipe 32 (S3), and the control unit 50 (S3), it is determined whether the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detection means 40 is 30 ° C. or less (S4), and the first temperature detection means 40 is determined in (S4). When the temperature of the hot water in the hot water storage tank 10 detected is 30 ° C. or less, the control unit 50 detects that the temperature detected by the first temperature detection means 40 per relative time from (S3) is 10 ° C. It is determined whether the change is less than (S11).

Further, when the temperature detected by the first temperature detecting means 40 per relative time from (S3) in (S11) is a change of less than 10 ° C., the control unit 50 starts the storage of hot water from (S2). It is determined whether or not the time required for hot water replacement corresponding to the capacity of the tank 10 has elapsed (S12), and the time required for hot water replacement corresponding to the capacity of the hot water storage tank 10 has elapsed in (S12). If not, the control unit 50 returns to the process of (S11). Furthermore, when the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detection means 40 in (S4) is 30 ° C. or higher, or in (S11) the above per relative time from (S3) When the temperature detected by the first temperature detecting means 40 is changed by 10 ° C. or more, the controller 50 determines the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 = The determination is made until the temperature of the hot water passing through the drain pipe 32 detected by the second temperature detecting means 42 is reached (S21).

Further, the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 in (S21) = the temperature of the hot water passing through the drain pipe 32 detected by the second temperature detecting means 42. In this case, the controller 50 detects the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detection means 40 and the hot water passing through the drain pipe 32 detected by the second temperature detection means 42. The determination is made until there is no change in temperature (S22). Furthermore, when the time required for hot water replacement according to the capacity of the hot water storage tank 10 has elapsed in (S12), or in the hot water storage tank 10 detected by the first temperature detecting means 40 in (S22). When there is no change in the temperature of the hot water and the temperature of the hot water passing through the drain pipe 32 detected by the second temperature detecting means 42, the controller 50 closes the drain valve 34 (S5), The replacement of the old hot water in the hot water storage tank 10 is completed.

With the above configuration, the replacement of the old hot water in the hot water storage tank 10 is detected by the operation of the passage of time necessary for the replacement of hot water according to the capacity of the hot water storage tank 10 or by the first temperature detection means 40. The temperature of the hot water in the hot water storage tank 10 = the temperature of the hot water passing through the drain pipe 32 detected by the second temperature detection means 42 and the hot water storage tank detected by the first temperature detection means 40 10 by closing the drainage valve 34 from one of the operations in which the temperature of the hot water in 10 and the temperature of the hot water passing through the drain pipe 32 detected by the second temperature detecting means 42 are unchanged. In addition to preventing wasteful drainage, even if the temperature of the hot water in the hot water storage tank 10 is slightly different from the temperature of the water supplied from the water supply pipe 20, the hot water in the hot water storage tank 10 is correctly replaced. be able to.

Further, the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 is 30 ° C. or less, and the first temperature detection per relative time from the opening of the drain valve 34. When the temperature detected by the means 40 is a change of less than 10 ° C., the hot water storage valve 34 is closed from the operation over time necessary for replacement of the hot water according to the capacity of the hot water storage tank 10. The temperature of the hot water in the tank 10 is low, and the temperature of the hot water in the hot water storage tank 10 is increased to about 28 ° C. as in the case of tap water in summer. Even if the difference between the temperature and the temperature is very small, the hot water in the hot water storage tank 10 is not changed without being replaced.

In the above, the hot water storage hot water heater 100 is installed outdoors, so that the temperature of the hot water in the hot water storage tank 10 is lowered in winter, and the temperature of the hot water in the hot water storage tank 10 is reduced to the water supply pipe. Even if the difference in temperature and temperature of the water supplied from 20 is very small, the hot water in the hot water storage tank 10 can be replaced correctly.

Further, the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 is 30 ° C. or less, and the first temperature detection per relative time from the opening of the drain valve 34. When the temperature detected by the means 40 is changed by 10 ° C. or more, the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 = detected by the second temperature detecting means 42. The temperature of the hot water passing through the drain pipe 32 and the temperature of the hot water in the hot water storage tank 10 detected by the first temperature detecting means 40 and the drain pipe 32 detected by the second temperature detecting means 42 are detected. Even if the temperature of the hot water in the hot water storage tank 10 in the winter is lowered by closing the drain valve 34 from the operation in which the temperature of the hot water passing through the inside remains unchanged, the water supply pipe 20 supplies the hot water. Hot water in the hot water storage tank 10 if there is a difference from the temperature of the hot water It determines that the replacement has been completed, it is possible to prevent wasteful drainage.

As a modified example of the first embodiment, the hot water heater 100 is configured to heat water by the heater 12 provided in the hot water storage tank 10, but includes the heater 12 outside the hot water storage tank 10. It is also possible to heat the water by circulating water through the heating channel. The hot water storage type hot water heater 100 may be configured to heat water in the hot water storage tank 10 using a heat pump that uses heat in the gas, oil, or the atmosphere. Furthermore, the configuration of the water supply means including the water supply pipe 20 connected to the hot water storage tank 10, the hot water supply pipe 30, and the drainage means including the drain pipe 32 may be changed to any configuration depending on design circumstances.

Further, the first temperature detecting means 40 and the second temperature detecting means 42 are spaced apart from the direction of the water flow flowing from the water supply pipe 20 side to the drain pipe 32 side through the hot water storage tank 10. As long as the position is the same, it may be installed at an arbitrary position depending on design circumstances. Furthermore, the first temperature detection means 40 and the second temperature detection means 42 may be configured by, for example, a thermocouple or a resistance temperature detector other than a semiconductor such as a thermistor.

Moreover, although the threshold temperature compared with the temperature which the said 1st temperature detection means 40 detected at the time of replacement | exchange of the water in the said hot water storage tank 10 performed in (S4) was 30 degreeC, this threshold temperature is in Japan. It is determined by the temperature of the tap water in summer being 25-30 ° C., and the threshold temperature may be changed according to the environment in which the hot water storage hot water heater 100 is used.

Further, the threshold temperature for comparing the change in temperature detected by the first temperature detection means 40 per relative time from the opening of the drain valve 34 performed in (S6) is 10 ° C. The temperature is determined in order to accurately determine from the performance of the first temperature detection means 40 and the second temperature detection means 42 that the replacement of hot water in the hot water storage tank 10 has been completed. The threshold value may be changed according to the performance of the first temperature detecting means 40 and the second temperature detecting means 42.

In addition, the control unit 50 uses the plurality of first temperature detection means 40 provided with a plurality of (S21) and (S22) at positions spaced from the direction of the water flow flowing through the hot water storage tank 10. The position at which the water supply from the pipe 20 has reached may be determined, and the drain valve 34 may be closed to end the replacement of the hot water in the hot water storage tank 10, or the water supply in the hot water storage tank 10 by other methods. It may be configured such that the position where the water reaches has been determined, the drainage valve 34 is closed, and the replacement of hot water in the hot water storage tank 10 is completed.

10: Hot water storage tank
12: Heater
20: Water supply pipe
22: Water supply valve
30: Hot water supply pipe
32: Drain pipe
34: Valve for drainage
40: First temperature detection device (first thermistor)
42: Second temperature detection device (second thermistor)
50: Control unit
100: Hot water storage water heater
C1: Water supply valve open / close signal
C2: drain valve open / close signal
T1: Hot water tank side temperature signal
T2: Drain pipe side temperature signal

Claims (6)

A hot water storage tank 10 to which the water supply pipe 20 and the drain pipe 32 are respectively connected, a heating unit 12 for heating water in the hot water storage tank 10, a drain valve 34 connected to the drain pipe 32, and the hot water storage tank 10 A plurality of temperature detecting means 40, 42 for detecting the temperature at positions spaced from the direction of the water flow flowing from the water supply pipe 20 side to the drain pipe 32 side, and opening and closing the drain valve 34, In the hot water storage type hot water heater 100 provided with a control unit 50 that supplies a signal for the hot water replacement operation in the hot water storage tank 10,
The control unit 50 replaces the hot water in the hot water storage tank 10 based on the valve opening time of the drain valve 34 or the hot water storage tank 10 based on the detected temperatures of the plurality of temperature detecting means 40, 42. A hot water storage type hot water heater 100 that allows one of the hot water and hot water replacement operations to function. When the temperature detected by the temperature detecting means at the start of the hot water replacement operation in the hot water storage tank 10 is equal to or lower than a first threshold value, the control unit 50 is based on the opening time of the drain valve 34. In addition, a hot water replacement operation in the hot water storage tank 10 is performed, and a plurality of cases are detected when the temperature detected by the temperature detecting means at the start of the hot water replacement operation in the hot water storage tank 10 is equal to or higher than a first threshold value. The hot water storage type hot water heater 100 according to claim 1, wherein a hot water replacement operation in the hot water storage tank 10 is performed based on the temperature detected by the temperature detecting means 40, 42. The controller 50 opens the drainage valve 34 when the temperature detected by the temperature detecting means from the start of the hot water replacement operation in the hot water storage tank 10 is variable below a second threshold. The hot water replacement operation in the hot water storage tank 10 based on the above is performed, and the temperature detected by the temperature detection means from the start of the hot water replacement operation in the hot water storage tank 10 is more than a second threshold. 3. The hot water storage type hot water heater 100 according to claim 1, wherein a hot water replacement operation in the hot water storage tank 10 is performed based on detected temperatures of the plurality of temperature detecting means 40, 42. The controller 50 replaces the drainage valve 34 when a desired time has elapsed from the opening of the drainage valve 34 as a hot water replacement operation in the hot water storage tank 10 based on the valve opening time of the drainage valve 34. The hot water storage type water heater 100 according to any one of claims 1 to 3, wherein the water heater is closed. When the temperature of the plurality of temperature detection means 40, 42 is approximated as the hot water replacement operation in the hot water storage tank 10 based on the temperature detected by the plurality of temperature detection means 40, 42, the control unit 50 The hot water storage type water heater 100 according to claim 1, wherein the valve 34 is closed. When the temperature of the plurality of temperature detecting means 40, 42 remains unchanged, the controller 50 performs the hot water replacement operation in the hot water storage tank 10 based on the detected temperatures of the plurality of temperature detecting means 40, 42. The hot water storage type water heater 100 according to claim 5, wherein the valve 34 is closed.

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