JPH0579698A - Electric warm water supplying apparatus - Google Patents

Abstract

PURPOSE:To supply hot water of the volume or more of a hot water storage tank by heating a heating tank to a bathing temperature, supplying the heated hot water by a circulation pump to heat a hot water storage tank to the bathing temperature, opening a valve when the water level of the storage tank is an uppermost level or lower, and supplying water until supplying water quantity reaches the capacity of the heating tank. CONSTITUTION:A controller 3 drives an electric heater 23 in a heating mode when the temperature of a heating tank 22 to be detected by a temperature sensor TH2 is a set value or lower, and heats it to a bathing temperature. When the water level of a hot water storage tank 12 to be detected by a water level sensor LS1 is a predetermined value or more and the detected temperature of a temperature sensor TH1 is a set temperature or lower, a circulation pump 21 is driven to supply hot water of the tank 22. When the temperature of the tank 22 is the set temperature and the water level of the tank 12 is a set highest level or lower, hot water heated in the tank 22 is sequentially supplied into a hot water storage tank 11 by controlling to open or close a valve 24, and heating to a bathing temperature is completed when the highest level is detected by the sensor LS1. If the entire volume of the tank 11 is used, hot water is supplied from the tank 22 to the tank 11.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric water heater.

[0002]

2. Description of the Related Art An electric water heater is conventionally provided with a hot water storage tank having a water supply port at the bottom and a hot water outlet at the top, and a heater (electric heater) attached to the bottom of the tank. In general, the water stored in the tank is heated by a heater provided at the bottom, and the convection of the water caused by the heating raises the entire water temperature in the hot water storage tank to the boiling temperature. Then, the above-mentioned boiling operation is configured to be performed during the normal nighttime electricity charge time zone (11:00 pm to 7:00 am).

[0003]

By the way, according to the conventional electric water heater, the hot water storage tank and the heater have an integral structure, and the overall shape and size of the electric water heater is inevitably large. For this reason, there is a problem that the degree of freedom of installation conditions is narrow, a large amount of exclusive space is required, and in some cases outdoor specifications are required.

Further, when hot water is supplied in excess of the hot water storage capacity of the hot water storage tank, so-called hot water shortage may occur, in which only low temperature water is discharged from the hot water supply port. When such hot water runs out, conventionally, it is necessary to heat the entire water in the large-capacity hot water storage tank (500 liters) to the boiling temperature, and it takes a long time to heat it and hot water cannot be supplied for a long time. There was a problem that it became the state of. Furthermore, since the hot water is supplied by pushing up the water supply, there is a problem that a mixed water layer forms at the boundary between hot water and 100% of the hot water boiled in the hot water storage tank cannot be used.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to have a structure in which a hot water storage tank and a heater are separated, and more than the hot water storage capacity of the hot water storage tank. An object is to provide an electric water heater capable of supplying hot water.

[0006]

In order to achieve the above-mentioned object, in the first invention, as shown in FIG. 1 corresponding to the embodiment, a heating tank 22 and a heating element are arranged inside the tank 22. Electric heater 23, water supply means 5 for pressurizing and supplying water into heating tank 22, valve 24 and flow rate sensor FS connected to water supply pipe 13, atmosphere open type hot water storage tank 11, and this hot water storage A forward pipe 15 and a return pipe 16 having one end communicating with the bottom position in the tank 11 and the other end communicating with the inside of the heating tank 22, and the forward pipe 15
A circulation pump 21 connected to the heating tank 22 so as to serve as a discharge port, a hot water supply means 4 for guiding hot water stored in the hot water storage tank 11 to a predetermined portion, and a liquid level in the hot water storage tank 11 is detected. Liquid level sensor LS1 and hot water storage tank 1
1st temperature sensor TH1 which detects the water temperature of the bottom position in 1
A second temperature sensor TH2 for detecting the water temperature in the heating tank 22 and a control means 3 are provided. Then, the control means 3 drives the electric heater 23 to drive the heating tank 2 when the temperature detected by the second temperature sensor TH2 is equal to or lower than the set temperature.
When the water temperature in 2 reaches the set temperature, the electric heater 2
3 is stopped and the temperature detected by the second temperature sensor TH2 is at the set temperature, the liquid level sensor LS1
When the detection level by the first temperature sensor TH1 is equal to or higher than the specified level (for example, 50 liter level) and is lower than the set temperature, the operation of driving the circulation pump 21 and the temperature detected by the second temperature sensor TH2 are set. When the level detected by the liquid level sensor LS1 is below the set maximum level in the temperature state, the valve 24 is opened and the amount of water supplied is calculated from the value detected by the flow rate sensor FS. The valve 24 is configured to be closed when its capacity is reached.

Further, in order to achieve the same object, in the second invention, as shown in FIG. 3 corresponding to the embodiment, a heating tank 122, an electric heater 123 arranged inside the tank 122, and a heating The water supply means 5 for pressurizing and supplying water into the tank 122, the first valve 24 connected to the water supply pipe 13, the open-air hot water storage tank 11, and one end at the bottom position in the hot water storage tank 11. A forward pipe 15 and a return pipe 16 which communicate with each other and communicate with the inside of the heating tank 122, a circulation pump 21 connected to the forward pipe 15 so that the heating tank side serves as a discharge port, and the pump 2
The second valve 27 connected to the discharge side of 1, the hot water supply means 4 for guiding the hot water stored in the hot water storage tank 11 to a predetermined portion, and the flow rate sensor FS1 for detecting the amount of water flowing into the heating tank 122. , FS2, a liquid level sensor LS1 for detecting the liquid level in the hot water storage tank 11, a first temperature sensor TH1 for detecting the water temperature at the bottom position in the hot water storage tank 11, and the temperature of the water supplied by the water supply means 5. Second temperature sensor T for detecting
And a control means 103. The control means 103 drives the circulation pump 21 and the electric heater 123 when the level detected by the liquid level sensor LS1 is equal to or higher than the specified level and the temperature detected by the first temperature sensor TH1 is equal to or lower than the set temperature. , Its first temperature sensor
Based on the difference between the temperature detected by TH1 and the set boiling temperature and the amount of heat generated by the electric heater 123, the heating tank 122
The amount of water supplied to the hot water storage tank 11 is calculated and the operation of controlling the opening of the second valve 27 based on the calculated amount of water and the detected value of the flow rate sensor FS2 and the detection level by the liquid level sensor LS1 are set to the maximum level. Below, and when the temperature detected by the first temperature sensor TH1 is the set temperature, the first valve 24 is opened, the electric heater 123 is driven, and the temperature detected by the second temperature sensor T and the boiling temperature are The calculated water amount is calculated from the temperature difference between and, and the operation of controlling the opening of the first valve 24 is performed based on the calculated water amount and the detection value of the flow rate sensor FS1.

[0008]

According to the first invention, the second temperature sensor TH2
The water temperature in the heating tank 22 is maintained at the set temperature (boiling temperature) by the drive control of the electric heater 23 based on the output of the liquid level sensor LS in this boiling state.
When the value detected by 1 is equal to or higher than the specified level and the output of the first temperature sensor TH1 is a signal indicating that the temperature is equal to or lower than the set temperature, the circulation pump 21 is driven and the first temperature sensor TH1
The pump drive is stopped when the output of becomes a signal indicating the set temperature. By repeating such operations, the entire hot water remaining in the hot water storage tank 11 is boiled up.

After the above boiling of the remaining hot water is completed, when the value detected by the liquid level sensor LS1 is below the maximum level, the opening / closing control of the valve 24 controls the hot water boiled in the heating tank 22 into the hot water storage tank 11. The liquids are supplied sequentially in a batch system and the boiling operation is completed when the maximum level is detected by the liquid level sensor LS1. Here, the control means 3
Holds the water temperature of the heating tank 22 at the boiling temperature after the midnight power supply start time (11:00 pm), and when the water temperature at the bottom of the hot water storage tank 11 decreases,
The circulation pump 21 is driven. As a result, the hot water tank 1
A certain amount of hot water is always ensured in 1. When almost all of the hot water storage amount of the hot water storage tank 11 is used, hot water is supplied from the heating tank 22 to the hot water storage tank 11, and hot water corresponding to the capacity of the heating tank 22 can be supplied.

On the other hand, according to the second invention, the circulation pump 2
Hot water storage tank 11 when the remaining hot water is boiled by the driving of No. 1
In any case of adding the hot water storage amount, the amount of water passing through the heater 102 is adjusted by controlling the opening degree of the valves 24 and 27 so that the temperature of the hot water passing through the heater 102 is always the boiling temperature. Then, a constant amount of hot water is stored in the hot water storage tank 11 by continuously supplying the hot water to the hot water storage tank 11.
In this way, by continuously supplying hot water having the boiling temperature to the hot water storage tank 11, the hot water does not run out even when the hot water is used during the midnight electricity rate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of the first invention, and is a diagram showing a piping system diagram and a block diagram of a control system together.
The hot water storage tank 1 includes a hot water storage tank 11 that is open to the atmosphere.
This hot water storage tank 11 has an overflow pipe 1 at the top.
2a is connected, and the drainage pipe 12b is connected to the bottom thereof. The capacity of the hot water storage tank 11 is 350-50.
It is about 0 liter.

The heater 2 is a closed type heating tank (capacity 50
Liter) 22, an electric heater 23 in which a heating element is arranged, a circulation pump 21 and the like. The discharge port of the circulation pump 21 communicates with a bottom position in the heating tank 22 via a check valve 25, and the suction pipe has a forward pipe 15 whose end communicates with a bottom position in the hot water storage tank 11. Are connected. The upper end of the heating tank 22 communicates with the bottom position in the hot water storage tank 11,
A return pipe 16 equipped with a flow switch 6 is connected on the way, and a circulation pump 21 is connected in these pipe systems.
Is driven, water in the hot water storage tank 11 can be circulated through the heating tank 22.

At the bottom of the heating tank 22,
The water supply pipe 13 to which the electric valve 24, the flow rate sensor FS, and the check valve 26 are sequentially connected is in communication, and the water supply device 5 is connected to the water supply pipe 13. The water supply device 5 has a general structure including a pump 51 that pressurizes and feeds water stored in a water supply tank 52, and the pump 51 is driven when the pressure switch 53 detects a pressure drop on the pump discharge side. Then
Further, the driving is stopped when the pressure rise is detected.

On the other hand, the hot water storage tank 11 is connected to a hot water supply pipe 14 which communicates with a bottom position inside the hot water storage tank 11, and the hot water supply device 4 is connected to the hot water supply pipe 14. Water heater 4
Is a structure in which a check valve 42, a pressure switch 43, and a flow switch 44 are sequentially connected to the discharge side of the pressurized water supply pump 41. When the hot water tap (not shown) is opened, the pressure on the pump discharge side is When the pressure switch 43 detects the decrease, the pump 41 is driven, and then the pressure switch 43 detects the increase in pressure caused by the closing of the hot water tap, or the flow switch 44 causes the flow rate to fall below the specified amount. When it is detected that the pump is not driven, the hot water stored in the hot water storage tank 11 can be supplied to a predetermined location.

The hot water storage tank 11 is provided with a temperature sensor TH1 for detecting the water temperature at the bottom thereof.
In addition, a float sensor LS1 is arranged to detect the minimum and maximum levels of the liquid level in the tank, and to detect the minimum level up to 150 liters in increments of 50 liters. Further, in the heating tank 22, a temperature sensor TH2 for detecting the water temperature inside the heating tank 22, a high limit sensor HL for detecting an excessive temperature rise of the water temperature, and a water level for detecting whether or not the inside of the tank is filled with water. Sensor LS2 is placed in the appropriate position. Further, the water supply device 5 is provided with a thermistor sensor T for detecting the water temperature in the water supply tank 52.

These sensors T, TH1, TH2, LS1, LS2, HL
The output signals of the flow sensor FS of the water supply pipe and the flow switch 6 of the return pipe are input to the control device 3. The control device 3 is configured to perform drive control of the electric heater 23 and the circulation pump 21 and open / close control of the electric valve 24, which will be described later, based on these input signals. Further, the control device 3 calculates the peak shift at the start point of the boiling operation in the time zone of the midnight electricity charge based on the detection value of the thermistor sensor T of the water supply device 5, and further based on the output of the float sensor LS1. The operation of a general electric water heater such as displaying the amount of remaining hot water on a display (not shown) or the like is also performed.

Next, the operation of the controller 3 and the operation of this embodiment will be described. First, in the boiling mode, when the output of the temperature sensor TH2 of the heating tank 22 is a signal indicating that the temperature is below the set temperature (boiling temperature 85 ° C), the controller 3 outputs water from the water level sensor LS2 to the heating tank 22. After confirming that it is satisfied, first, only the electric heater 23 is driven. By this heating, the heating tank 22
Water temperature rises, and when the water temperature reaches the boiling temperature, the driving of the electric heater 23 is stopped.

At such a boiling point,
If the detection value by the float sensor LS1 is 50 liters or more,
When the output of the temperature sensor TH1 on the hot water storage tank side is a signal indicating the boiling temperature or lower, the circulation pump 21 is driven, and the pump drive is stopped when the sensor output becomes a signal indicating the set temperature. After this stop, the temperature sensor
At the time when the output of TH1 becomes a signal indicating the boiling temperature or less, and when the output of the temperature sensor TH2 of the heating tank is a signal indicating the boiling temperature, the circulation pump 21 is driven and stopped in the same manner as above. .. By repeating such operations, the entire hot water remaining in the hot water storage tank 11 can be boiled up.

At the time when the above boiling of remaining hot water is completed, the value detected by the float sensor LS1 is equal to or lower than the maximum level, and the output of the heating tank temperature sensor TH2 is a signal indicating the boiling temperature. Sometimes the electric valve 24 is opened. As a result, water is supplied from the water supply device 5 into the heating tank 22, and hot water is supplied from the heating tank 22 to the hot water storage tank 11. At this time, the control device 3
Calculates the amount of water supplied to the heating tank 22 based on the detection value of the flow rate sensor FS, and the calculated value is the heating tank 22.
The electric valve 24 is closed at the time when the value corresponding to the capacity of, that is, 50 liters is reached.

By this operation, the inside of the heating tank 22 is filled with the low temperature water from the water supply device 5, and the hot water tank 11 has 50 liters of hot water (85 ° C.) heated by the heating tank 22. ) Will be supplied. Then, such an operation is sequentially repeated until the float sensor LS1 detects the maximum level, and the boiling operation is completed when the sensor detection value reaches the maximum level.

Here, after the midnight power energization start time (11:00 pm), the control device 3 controls the drive of the electric heater 23 based on the output of the temperature sensor TH2 of the heating tank, and the inside of the heating tank 22 is controlled. When the water temperature is kept at the boiling temperature and the output of the temperature sensor TH1 on the hot water storage tank side is below the boiling temperature, the circulation pump 21 is driven, and the pump is driven when the sensor output indicates the boiling temperature. To stop. However, at the start of this pump drive,
Only when the output of the heating tank temperature sensor TH2 is a signal indicating the boiling temperature. Further, when the output of the temperature sensor TH2 is a signal indicating the boiling temperature and the float sensor LS1 detects the minimum level, the electric valve 24 is controlled in the same manner as above to bring 50 liters of hot water into the hot water storage tank 11. And supply. Therefore, according to this embodiment, a constant amount of boiling water having the boiling temperature can be secured in the hot water storage tank 11, and the hot water will not run out.

In addition to the above operation, when the float sensor LS1 detects the minimum level, the circulation pump 21 and the hot water supply pressure feed pump 41 are interlocked. Further, even though the circulation pump 21 is being driven, when the flow switch 6 is turned off, the drive of that pump is stopped instantaneously. Further, when the high limit sensor HL detects, for example, 95 ° C., driving of the electric heater is immediately stopped.

In the above embodiment, the water temperature in the heating tank 22 is kept at the boiling temperature even after the boiling operation is completed. It can be used for cooking. For example, as shown in FIG. 2, a coiled heat exchanger 201 is inserted and arranged in the upper part of the heating tank 22, and the inlet and outlet of this heat exchanger 201 are communicated with the inside of the bath 203 by a piping system, and If the circulation pump 202 is connected on the way to form a circulation system, the circulation pump 202 can be driven to reheat the hot water in the bathtub 203 or to keep it warm.

Next, an embodiment of the second invention will be described.
FIG. 3 is a configuration diagram of the embodiment, and is a diagram showing a piping system diagram and a block diagram of a control system together. Also in this example,
Basically, the configuration is similar to that of the previous embodiment, and includes a hot water storage tank 1, a heater 102, a control device 103, a hot water supply device 4, and a water supply device 5. Among these configurations, the hot water storage tank 1, the hot water supply device 4, and the water supply device 5 have the same configurations as those of the previous embodiment.

The heater 102 differs from the previous embodiment in that the heating tank 122 has a small capacity of about 5 to 10 liters and is not provided with a temperature sensor or water level sensor for detecting the water temperature in the tank 122. The electric valve 27 and the flow rate sensor FS2 are sequentially connected to the discharge side of the circulation pump 21. For convenience of description, the flow rate sensor on the side of the water supply pipe 13 is denoted by FS1.

The control device 103 also controls the sensors T and TH.
1, LS1, HL, FS1, FS2, based on signals from the thermistor sensor T of the water supply device 5 and the flow switch 6, drive control of the electric heater 123 and the circulation pump 21, and opening of the two valves 24 and 27, which will be described later. It is configured to control the degree. The control device 103 calculates the peak shift and displays the amount of remaining hot water as in the previous embodiment.

Next, the operation of the control device 103 and the operation of this embodiment will be described. First, when the detection value by the float sensor LS1 is 50 liters or more and the output of the temperature sensor TH1 on the hot water storage tank side is a signal indicating the boiling temperature or less, the control device 103 drives the circulation pump 21, The electric heater 123 is driven when the flow switch 6 is turned on. At the same time, the difference between the temperature detected by the temperature sensor TH1 and the boiling temperature is obtained, and the amount of water supplied from the heating tank 122 to the hot water storage tank 11 is calculated based on the temperature difference and the amount of heat generated by the heater 123, and the calculation is performed. The opening degree of the electric valve 27 is controlled based on the water amount and the detection value of the flow rate sensor FS2. That is, the opening degree of the electric valve 27 is controlled so that the temperature of the hot water returned to the hot water storage tank 11 is always the boiling temperature.
Adjust the amount of water passing through 23. By this operation, hot water having a boiling temperature is continuously supplied to the hot water storage tank 11.

When the output of the temperature sensor TH1 on the hot water storage tank side becomes a signal indicating the boiling temperature due to this circulation, the circulation pump 21 is stopped and the flow switch 6 is turned on.
When it is turned off, the driving of the electric heater 123 is stopped. By such an operation, the whole hot water remaining in the hot water storage tank 11 can be boiled up. When the value detected by the float sensor LS1 is less than or equal to the maximum level value at the time when the remaining hot water boiling is completed, the electric valve 24 is opened and the electric heater 123 is driven when the flow switch 6 is turned on. , The difference between the temperature detected by the thermistor sensor T of the water supply device and the boiling temperature is obtained, and the opening degree of the electric valve 24 is adjusted in the same manner as above based on the temperature difference and the detection value of the flow rate sensor FS1. .. By this operation, hot water having a boiling temperature is continuously supplied into the hot water storage tank 11, and the amount of hot water stored in the tank 11 increases. Then, the electric valve 24 is closed when the float sensor LS1 detects the highest level, and the driving of the electric heater 123 is stopped when the flow switch 6 is turned off, thereby completing the boiling operation.

It should be noted that the control device 103, when the output of the temperature sensor TH1 of the hot water storage tank is a signal indicating the boiling temperature or less after the midnight power energization start time (11:00 pm), the above-described residual hot water boiling is performed. The hot water in the hot water storage tank 11 is reheated by the same operation as when raising. Here, according to the embodiment of FIG. 1 described above, when hot water is used during the midnight electricity rate, hot water may run out, and in the worst case, until the water in the heating tank 22 is boiled up. However, in this embodiment, hot water is continuously supplied to the hot water storage tank 11, so that the hot water is not supplied during such a late night electricity charge time period. No hot water runs out upon use.

Further, in the above embodiment, since the hot water of the capacity of the heating tank 22 is supplied in a batch system at the time of boiling the residual hot water, the hot water temperature in the hot water storage tank 11 becomes uniform to some extent. Although it takes time, the time for boiling the remaining hot water becomes long. However, according to this embodiment, as the hot water temperature in the hot water storage tank 11 approaches the boiling temperature, the flow rate of hot water supplied to that tank is increased. Increases proportionally,
The temperature of the hot water in the hot water storage tank 11 quickly becomes uniform, so that the remaining hot water boiling operation is completed in a short time. Further, there are advantages over the previous embodiment that the circulating pump 21 is driven and stopped, the number of times the electric valve 24 is opened and closed is extremely small, and the life of these devices is long.

In the above embodiments, one hot water storage tank is provided, but the present invention is not limited to this, and the number of hot water storage tanks may be plural.

[0032]

As described above, the first and second
According to any of the inventions, either, the hot water boiled by the heater is supplied to the hot water storage tank, or the water in the hot water storage tank is circulated through the heater, so that a fixed amount of hot water is stored in the hot water storage tank. Since it is configured to store hot water, the hot water storage tank and the heater can be placed separately, and the degree of freedom of installation conditions is improved. As a result, for example, the hot water storage tank can be placed in a dead space such as under the floor, and the occupied space indoors can be greatly reduced as compared with the conventional one. Also, since there is no mixing of hot water with water in the hot water storage tank, 100% of the boiling water can be used.

Further, according to the first aspect of the invention, the water temperature of the heating tank is kept at the boiling temperature state after the start time of the power supply at midnight, so that almost the entire amount of hot water stored in the hot water storage tank is used. Even in such a case, hot water corresponding to the capacity of the heating tank 22 can be supplied and hot water having a capacity larger than the hot water storage capacity of the hot water storage tank can be supplied.

Further, according to the second aspect of the invention, since the hot water of the boiling temperature is continuously supplied to the hot water storage tank, almost all of the hot water storage amount of the hot water storage tank is used during the nighttime electricity charge period. Even in such a case, there is an advantage that the hot water can be supplied instantly and the hot water does not run out.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the first invention, showing a piping system diagram and a block diagram of a control system together.

FIG. 2 is a diagram for explaining an application example of the heating tank 22 of the first invention embodiment.

FIG. 3 is a configuration diagram of an embodiment of the second invention, showing a piping system diagram and a control system block diagram together.

[Explanation of symbols]

 1 ... ・ Hot water storage tank 11 ・ ・ ・ ・ Hot water storage tank 13 ・ ・ ・ ・ Water supply piping 14 ・ ・ ・ ・ Hot water supply piping 15 ・ ・ ・ ・ ・ ・ Outgoing piping 16 ・ ・ ・ ・ ・ ・ Return piping 2,102 ・ ・ ・ ・ Heating Equipment 21 ... Circulation pump 22, 122 ... Heating tank 23, 123 ... Electric heater 24, 27 ... Electric valve 3, 103 ... Control device 4 ... Hot water supply Device 5 ・ ・ ・ ・ Water supply device TH1 ・ ・ ・ ・ Temperature sensor (first sensor) TH2 ・ ・ ・ ・ Temperature sensor (second sensor) T ・ ・ ・ ・ Thermistor sensor (second sensor) FS, FS1 , FS2 ・ ・ ・ ・ Flow sensor LS1 ・ ・ ・ ・ ・ ・ Float sensor (liquid level sensor)

Claims (2)

[Claims] 1. A heating tank, an electric heater in which a heating element is arranged inside the tank, a water supply means for pressurizing water into the heating tank, a valve and a flow rate sensor connected to the water supply pipe. An atmosphere open type hot water storage tank, and a forward pipe and a return pipe, one end of which communicates with a bottom position in the hot water storage tank and the other end of which communicates with the inside of the heating tank,
A circulation pump connected to the upstream piping so that the heating tank side serves as a discharge port, a hot water supply means for guiding the hot water stored in the hot water storage tank to a predetermined portion, and a liquid level in the hot water storage tank A liquid level sensor for detecting, a first temperature sensor for detecting a water temperature at a bottom position in the hot water storage tank, a second temperature sensor for detecting a water temperature in the heating tank, and a control means are provided. Is an operation of driving the electric heater when the temperature detected by the second temperature sensor is equal to or lower than a set temperature, and stopping the drive of the electric heater when the water temperature in the heating tank reaches the set temperature. When the temperature detected by the second temperature sensor is at the set temperature, the level detected by the liquid level sensor is equal to or higher than a specified level, and the temperature detected by the first temperature sensor is the set temperature. When the temperature is below, the operation of driving the circulation pump is performed. When the temperature detected by the second temperature sensor is at the set temperature and the level detected by the liquid level sensor is below the set maximum level, the valve is opened and An electric water heater configured to obtain the amount of supplied water from the detection value of the flow rate sensor and to close the valve when the calculated amount of water reaches the capacity of the heating tank. 2. A heating tank, an electric heater having a heating element arranged inside the tank, a water supply means for pressurizing and supplying water into the heating tank, and a first water supply pipe connected to the water supply means.
Valve, an open-air hot water storage tank, a forward pipe and a return pipe, one end of which communicates with the bottom position in the hot water storage tank and the other end of which communicates with the inside of the heating tank, and the heating tank side is connected to the forward pipe. A circulation pump connected to serve as a discharge port, a second valve connected to the discharge side of the pump, hot water supply means for guiding the hot water stored in the hot water storage tank to a predetermined portion, and the heating A flow rate sensor that detects the amount of water flowing into the tank, a liquid level sensor that detects the liquid level in the hot water storage tank, a first temperature sensor that detects the water temperature at the bottom position in the hot water storage tank, and the water supply means. A second temperature sensor for detecting the temperature of the supply water by
Control means is provided, and the control means drives the circulation pump and the electric heater when the level detected by the liquid level sensor is equal to or higher than a specified level and the temperature detected by the first temperature sensor is equal to or lower than a set temperature. In addition, the amount of water supplied from the heating tank to the hot water storage tank is calculated based on the difference between the temperature detected by the first temperature sensor and the set boiling temperature and the amount of heat generated by the electric heater.
An operation of controlling the opening of the second valve based on the calculated water amount and the detected value of the flow rate sensor, and the detection level by the liquid level sensor is equal to or lower than a set maximum level, and detected by the first temperature sensor. When the temperature is the set temperature, the first valve is opened, the electric heater is driven, and the calculated water amount is calculated from the temperature difference between the temperature detected by the second temperature sensor and the boiling temperature. And an electric water heater configured to perform an operation of controlling the opening of the first valve based on the calculated water amount and the detected value of the flow rate sensor.