JP6885818B2 - Hot water storage type hot water supply device - Google Patents

Description

The present invention relates to a hot water storage type hot water supply device provided with an overpressure relief valve.

Conventionally, in this type of hot water storage type hot water supply device, as disclosed in Patent Document 1, a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, and a hot water storage tank using the heating means. An overpressure relief valve that releases overpressure due to heating of hot water, a high temperature pipe that connects the upper part of the hot water storage tank and the inlet of the overpressure relief valve, and a low temperature pipe that connects the lower part of the hot water storage tank and the inlet of the overpressure relief valve. Some high-temperature pipes have a check valve that blocks the flow from the overpressure relief valve side to the high-temperature pipe, and the expanded water generated by heating by the heating means is discharged by the low-temperature water from the low-temperature pipe. It was.

Japanese Patent No. 4986911

In this conventional one, when draining the hot water in the hot water storage tank, even if the overpressure relief valve is manually opened and the drain plug connected to the lower part of the hot water storage tank is opened, the overpressure is caused by the action of the check valve. The air from the relief valve is blocked from flowing to the upper part of the hot water storage tank through the high temperature pipe, and the replacement air flows into the hot water storage tank from the bottom of the hot water storage tank through the low temperature pipe, so it takes time to drain the hot water storage tank. There was a problem that it took.

Therefore, an object of the present invention is to provide a hot water storage type hot water supply device that enables the expanded water to be discharged with low temperature water and does not require a long time for drainage.

Therefore, in order to solve the above problems, the present invention supplies water with a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, a high temperature tube connected to the upper part of the hot water storage tank, and water. To drain the water supply pipe, the mixing valve that mixes the hot water from the high temperature pipe and the water from the water supply pipe, the hot water supply pipe that is connected to the outlet of the mixing valve to supply hot water, and the hot water in the hot water storage tank. The drain pipe and the drain plug, the overpressure relief valve for releasing the expanded water due to the heating of the hot water in the hot water storage tank by the heating means, and the control unit for controlling the heating means and the mixing valve are provided. The inlet side path of the pressure relief valve has two routes, and the first path is passed to the high temperature pipe via a thermal valve that prevents hot water of high temperature from flowing from the high temperature pipe to the overpressure relief valve. The second path is connected to the hot water supply pipe, and the control unit controls the opening degree of the mixing valve so that the water supply pipe and the hot water supply pipe communicate with each other during the operation of the heating means. When draining the hot water storage tank, the opening degree of the mixing valve is controlled so that the high temperature pipe and the hot water supply pipe communicate with each other.

According to the present invention, the expanded water during heating by the heating means can be discharged with low temperature water, and the residual air accumulated in the hot water storage tank passes through the resistor from the high temperature pipe and reaches the overpressure relief valve. When the hot water storage tank is drained, the replacement air flows in from the upper part of the hot water storage tank through the second path, hot water supply pipe, and high temperature pipe from the overpressure relief valve. The time required for drainage can be shortened.

Schematic block diagram of the first embodiment of the present invention Schematic block diagram of the second embodiment of the present invention Schematic block diagram of the third embodiment of the present invention

<First Embodiment>
Next, the hot water storage type hot water supply device according to the first embodiment of the present invention will be described with reference to FIG.
1 is a closed hot water storage tank that stores hot water, 2 is an electric heater as a heating means for heating the hot water in the hot water storage tank 1, and 3 is a water supply that supplies city water or the like to the bottom of the hot water storage tank 1 and a mixing valve 6 described later. A pipe 4 is a pressure reducing valve that lowers the water supply pressure of the water supply pipe 3 to a predetermined pressure, and 5 is a high temperature pipe that connects the top of the hot water storage tank 1 and a mixing valve 6 described later and discharges hot water in the hot water storage tank 1. Is a mixing valve that mixes the water from the water supply pipe 3 and the hot water from the high temperature pipe 5 to the hot water supply set temperature set by the user in advance with the remote control 20, and 7 is the hot water supply of the hot water from the mixing valve 6 The hot water supply pipe 8 supplied to the tip (not shown) is an on-off valve provided in the middle of the hot water supply pipe 7 to control the start and stop of hot water supply.

Reference numeral 9 denotes an overpressure relief valve for releasing the expanded water generated by heating the hot water in the hot water storage tank by the heating means. The overpressure relief valve 9 forcibly opens the discharge path 10 for discharging the expanded water and the overpressure relief valve 9 to the atmosphere. The opening lever 11 is provided, the inlet side of the overpressure relief valve is branched into two paths, the first path 12 is connected to a high temperature pipe, and the second path 13 opens and closes with the mixing valve 6 of the hot water supply pipe 7. It is connected between the valves 8.

The first path 12 is provided with a first check valve 14 that blocks the flow from the overpressure relief valve 9 side to the high temperature pipe 5 as a resistor that acts as a water flow resistance. The second path 13 is provided with a second check valve 15 that blocks the flow from the overpressure relief valve 9 side to the hot water supply pipe 7. The closing pressure of the second check valve 15 is smaller than the closing pressure of the first check valve 14, and the water flow resistance of the second check valve 15 to the overpressure relief valve 9 side is the first check valve. It is set to be smaller than the flow resistance of water to the overpressure relief valve 9 side of the valve 14, and when pressure is applied to the overpressure relief valve 9 side, the water from the second path 13 is the first path. It is easier to flow than the water from 12.

Reference numeral 16 denotes a drain pipe connected to the bottom of the hot water storage tank 1, and 17 is a manual drain plug provided in the drain pipe 16 for opening and closing the drain pipe 16. The drain plug 17 may be an electric type.

Reference numeral 18 denotes a hot water supply temperature sensor that detects the temperature of the hot water mixed by the mixing valve 6, and reference numeral 19 denotes a hot water storage temperature sensor that is provided in a plurality of directions in the vertical direction on the outer periphery of the hot water storage tank 1 and detects the temperature of the hot water stored. Reference numeral 20 denotes a remote controller, which is a display unit 21 for displaying the hot water supply set temperature and the operating state of the hot water storage type hot water supply device, a change switch for changing the hot water supply set temperature, and operations for performing various other settings and operation instructions. It has a switch.

Reference numeral 24 denotes a control unit that controls the operation of the hot water storage type hot water supply device. The microprocessor is mainly configured, the detection values of the hot water supply temperature sensor 18 and the hot water storage temperature sensor 19 are input, and the electric heater 2, the mixing valve 6, and the on-off valve 8 are input. It controls the operation of the remote controller 20 and is connected to the remote controller 20 so as to be communicable.

<Boiling operation>
Next, the operation of this hot water storage type hot water supply device will be described. At midnight, the control unit 24 energizes the electric heater 2 to start the boiling operation, and the plurality of hot water storage temperature sensors 19 all have a predetermined boiling temperature. When the above is detected, the energization of the electric heater 2 is stopped and the boiling operation is terminated.

During this boiling operation, the control unit 24 sets the mixing valve 6 in a state in which the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Here, it is preferable that only the water supply pipe 3 communicates with the hot water supply pipe 7 and the high temperature pipe 5 is cut off from the hot water supply pipe 7. When the boiling operation progresses and the temperature of the hot water in the hot water storage tank 1 rises, the hot water in the hot water storage tank 1 thermally expands and the pressure in the system rises. This pressure is applied to the overpressure relief valve 9 via the first path 12 via the high temperature pipe 5 and the second path 13 via the water supply pipe 3 and the hot water supply pipe 7.

When the pressure in the system reaches the valve opening pressure of the overpressure relief valve 9, the overpressure relief valve 9 is opened and low-temperature water flows from the lower part of the hot water storage tank 1 via the second path 13 having a small flow resistance. When the pressure in the system is discharged and becomes equal to or lower than the closing pressure of the overpressure relief valve 9, the overpressure relief valve 9 is closed and the discharge of low-temperature water is stopped, and this is repeated to reduce the pressure in the hot water storage tank 1. Is held at the proper pressure. In this way, since the expanded water can be discharged with the low-temperature water, the discharge of the high-temperature hot water can be suppressed, the wasteful consumption of the heating energy can be eliminated, and energy saving can be promoted.

On the other hand, the air content remaining in the hot water in the hot water storage tank 1 is separated from the water as the boiling operation progresses and rises in the hot water storage tank 1, and then the hot water is stored via the high temperature pipe 5 and the first path 12. It rises toward the overpressure relief valve 9 at the top of the tank 1. At this time, the air content passing through the first path 12 passed through the first check valve 14 without blocking the flow, and the pressure in the system rose to more than the valve opening pressure of the overpressure relief valve 9. Occasionally, it is discharged together with the low-temperature water, and the air content in the system can be discharged smoothly.

Then, when the boiling operation is completed, the control unit 24 maintains a state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6 until the hot water supply operation described below is started. In this way, by maintaining the state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6, the density of the hot water and the low temperature water depends on the state of the temperature distribution of the hot water in the hot water storage tank 1. It prevents natural convection due to the difference.

<Hot water supply operation>
When the user gives an instruction to supply hot water by operating the remote control 20, the control unit 24 puts the mixing valve 6 in a state where the water supply pipe 3, the high temperature pipe 5, and the hot water supply pipe 7 communicate with each other, and opens the on-off valve 8. , Water from the water supply pipe 3 and hot water from the high temperature pipe 5 flow into the mixing valve 6, and the control unit 24 opens the mixing valve 6 so that the temperature detected by the hot water supply temperature sensor 18 matches the hot water supply set temperature. Is adjusted, and hot water of the hot water supply set temperature is supplied from the hot water supply pipe 7 to the hot water supply destination.

At this time, since the second check valve 15 shuts off the second path 13 of the hot water from the hot water storage tank 1, it is prevented that the mixing valve 6 is bypassed and the hot water is short-cut to the hot water supply pipe 7. There is.

Then, when the user gives an instruction to stop the hot water supply by operating the remote controller 20, the control unit 24 closes the on-off valve 8 and sets the mixing valve 6 so that only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Stop hot water supply.

<Drainage operation>
Next, a drainage operation for draining the hot water in the hot water storage tank 1 will be described.
When the user gives an instruction to the remote controller 20 to perform the drainage operation, the control unit 24 sets the mixing valve 6 in a state where the high temperature pipe 5 and the hot water supply pipe 7 communicate with each other.

Then, when the user operates the release lever 11 to open the overpressure relief valve 9 to the atmosphere and open the drain plug 17, the hot water in the hot water storage tank 1 is drained through the drain pipe 16.

At this time, the replacement air that has flowed in from the discharge path 10 of the overpressure relief valve 9 flows into the hot water storage tank 1 from the upper part of the hot water storage tank 1 via the second path 13, the hot water supply pipe 7, and the high temperature pipe 5. The time required for draining the hot water storage tank can be shortened.

Then, when the release lever 11 is operated to close the overpressure relief valve 9, the drain plug 17 is closed, and the remote controller 20 is instructed to end the drainage operation, the control unit 24 receives an instruction. The drainage operation is terminated with the mixing valve 6 in a state where only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other.

In this way, the expanded water during heating by the electric heater 2 as the heating means can be discharged with the low temperature water, and the residual air accumulated in the hot water storage tank 1 is the first check valve as the resistor from the high temperature tube 5. It passes through the valve 14 and reaches the overpressure relief valve 9, and is discharged together with the low temperature water discharged at the time of heating, and at the time of draining the hot water storage tank 1, the replacement air is discharged from the overpressure relief valve 9 to the second path 13 and the hot water supply. Since the water flows in from the upper part of the hot water storage tank 1 through the pipe 7 and the high temperature pipe 5, the time required for draining the hot water storage tank 1 can be shortened.

<Second Embodiment>
Next, the hot water storage type hot water supply device according to the second embodiment of the present invention will be described with reference to FIG. The same configurations as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 25 denotes a thermal shutoff valve as a thermal valve provided in the first path 12. The thermal shutoff valve 25 has a temperature expansion element such as a wax element or a shape memory alloy inside the casing, and the temperature expansion element expands and contracts according to the temperature of hot water from the hot water storage tank 1 or the like that is about to pass through the casing. When the temperature exceeds a predetermined design temperature, the temperature expansion element extends to the maximum length and closes the outlet valve on the overpressure relief valve 9 side.

<Boiling operation>
During the boiling operation, the control unit 24 sets the mixing valve 6 in a state in which the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Here, it is preferable that only the water supply pipe 3 communicates with the hot water supply pipe 7 and the high temperature pipe 5 is cut off from the hot water supply pipe 7. When the boiling operation progresses and the temperature of the hot water in the hot water storage tank 1 rises, the hot water in the hot water storage tank 1 thermally expands and the pressure in the system rises. This pressure is applied to the overpressure relief valve 9 via the first path 12 via the high temperature pipe 5 and the second path 13 via the water supply pipe 3 and the hot water supply pipe 7.

When the pressure in the system reaches the valve opening pressure of the overpressure relief valve 9, the overpressure relief valve 9 is opened and low temperature water flows from the lower part of the hot water storage tank 1 via the second path 13 having a small flow resistance. At the same time as being discharged, the residual hot water in the pipe is discharged via the first path 12, and when the hot water from the hot water storage tank 1 flows into the thermal shutoff valve 25, the thermal shutoff valve 25 is acted on by the action of the temperature expansion element. It will be closed and only cold water will be discharged via the second path 13.

When the pressure in the system becomes equal to or lower than the closing pressure of the overpressure relief valve 9, the overpressure relief valve 9 is closed and the discharge of low-temperature water is stopped, and this is repeated to make the pressure in the hot water storage tank 1 appropriate. Hold on to pressure. In this way, since the expanded water can be discharged with the low-temperature water, the discharge of the high-temperature hot water can be suppressed, the wasteful consumption of the heating energy can be eliminated, and energy saving can be promoted.

On the other hand, the air content remaining in the hot water in the hot water storage tank 1 is separated from the water as the boiling operation progresses and rises in the hot water storage tank 1, and then the hot water is stored via the high temperature pipe 5 and the first path 12. It rises toward the overpressure relief valve 9 at the top of the tank 1. At this time, the air content passing through the first path 12 passes through the thermal shutoff valve 25, but since the amount of heat retained by the air is smaller than that of water, the thermal shutoff valve 25 is not closed and the air can flow. When the air passes through and the pressure in the system rises above the valve opening pressure of the overpressure relief valve 9, it is discharged together with the low-temperature water, and the air content in the system can be smoothly discharged.

Then, when the boiling operation is completed, the control unit 24 maintains a state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6 until the hot water supply operation described below is started. In this way, by maintaining the state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6, the density of the hot water and the low temperature water depends on the state of the temperature distribution of the hot water in the hot water storage tank 1. It prevents natural convection due to the difference.

<Hot water supply operation>
When the user gives an instruction to supply hot water by operating the remote control 20, the control unit 24 puts the mixing valve 6 in a state where the water supply pipe 3, the high temperature pipe 5, and the hot water supply pipe 7 communicate with each other, and opens the on-off valve 8. , Water from the water supply pipe 3 and hot water from the high temperature pipe 5 flow into the mixing valve 6, and the control unit 24 opens the mixing valve 6 so that the temperature detected by the hot water supply temperature sensor 18 matches the hot water supply set temperature. Is adjusted, and hot water of the hot water supply set temperature is supplied from the hot water supply pipe 7 to the hot water supply destination.

At this time, since the first path 12 of the hot water from the hot water storage tank 1 is blocked by the thermal shutoff valve 25, it is prevented that the mixing valve 6 is bypassed and the hot water is short-cut to the hot water supply pipe 7. ..

Then, when the user gives an instruction to stop the hot water supply by operating the remote controller 20, the control unit 24 closes the on-off valve 8 and sets the mixing valve 6 so that only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Stop hot water supply.

<Drainage operation>
Next, a drainage operation for draining the hot water in the hot water storage tank 1 will be described.
When the user gives an instruction to the remote controller 20 to perform the drainage operation, the control unit 24 sets the mixing valve 6 in a state where the high temperature pipe 5 and the hot water supply pipe 7 communicate with each other.

Then, when the user operates the release lever 11 to open the overpressure relief valve 9 to the atmosphere and open the drain plug 17, the hot water in the hot water storage tank 1 is drained through the drain pipe 16.

At this time, the replacement air that has flowed in from the discharge path 10 of the overpressure relief valve 9 flows into the hot water storage tank 1 from the upper part of the hot water storage tank 1 via the second path 13, the hot water supply pipe 7, and the high temperature pipe 5. Since the amount of heat of the air is small, the heat shutoff valve 25 allows the air to pass through without being closed, so that the time required for draining the hot water storage tank can be shortened.

Then, when the release lever 11 is operated to close the overpressure relief valve 9, the drain plug 17 is closed, and the remote controller 20 is instructed to end the drainage operation, the control unit 24 receives an instruction. The drainage operation is terminated with the mixing valve 6 in a state where only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other.

In this way, the expanded water at the time of heating by the electric heater 2 as the heating means can be discharged with the low temperature water, and the residual air accumulated in the hot water storage tank 1 is provided from the high temperature tube 5 in place of the resistor. It passes through the thermal shutoff valve 9 as a thermal valve, reaches the overpressure relief valve 9, and is discharged together with the low temperature water discharged during heating, and when the hot water storage tank 1 is drained, the replacement air is an overpressure relief valve. Since the water flows from the upper part of the hot water storage tank 1 through the paths from 9 to the second path 13, the hot water supply pipe 7, the high temperature pipe 5, and the overpressure relief valve 9 through the first path 12 and the high temperature pipe 5, the hot water storage tank 1 The time required for drainage can be shortened.

<Third Embodiment>
Next, the hot water storage type hot water supply device according to the third embodiment of the present invention will be described with reference to FIG. The same configurations as those of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 26 denotes a thermal three-way valve as a thermal valve provided in the first path 12. In the thermal three-way valve 26, the first path 12 is connected to one inlet, the second path 13 is connected to the other inlet, and the inlet of the overpressure relief valve 9 is connected to the outlet. A temperature expansion element such as a wax element or a shape memory alloy is provided in the casing on one inlet side, and the opening degree on one inlet side and the opening degree on the other inlet side are inversely proportional to the tip of the temperature expansion element. A valve body is provided. The temperature expansion element expands and contracts according to the temperature of hot water from the hot water storage tank 1 and the like that is about to pass through one inlet, and when the atmospheric temperature of the temperature expansion element rises, the temperature expansion element expands and one inlet side closes. The valve body is driven, and the valve body is driven in the direction in which the other inlet side opens. When the temperature exceeds a predetermined design temperature, the temperature expansion element extends to the maximum length, the opening degree on the one inlet side becomes 0, and the first path 12 is blocked.

<Boiling operation>
During the boiling operation, the control unit 24 sets the mixing valve 6 in a state in which the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Here, it is preferable that only the water supply pipe 3 communicates with the hot water supply pipe 7 and the high temperature pipe 5 is cut off from the hot water supply pipe 7. When the boiling operation progresses and the temperature of the hot water in the hot water storage tank 1 rises, the hot water in the hot water storage tank 1 thermally expands and the pressure in the system rises. This pressure is applied to the overpressure relief valve 9 via the first path 12 via the high temperature pipe 5 and the second path 13 via the water supply pipe 3 and the hot water supply pipe 7.

When the pressure in the system reaches the valve opening pressure of the overpressure relief valve 9, the overpressure relief valve 9 is opened and low temperature water flows from the lower part of the hot water storage tank 1 via the second path 13 having a small flow resistance. At the same time as being discharged, the residual hot water in the pipe is discharged via the first path 12, and when the hot water from the hot water storage tank 1 flows into the thermal three-way valve 26, the thermal three-way valve 26 acts due to the action of the temperature expansion element. The side of the first path 12 is closed, the second path 13 is opened, and only the low-temperature water via the second path 13 is discharged.

When the pressure in the system becomes equal to or lower than the closing pressure of the overpressure relief valve 9, the overpressure relief valve 9 is closed and the discharge of low-temperature water is stopped, and this is repeated to make the pressure in the hot water storage tank 1 appropriate. Hold on to pressure. In this way, since the expanded water can be discharged with the low-temperature water, the discharge of the high-temperature hot water can be suppressed, the wasteful consumption of the heating energy can be eliminated, and energy saving can be promoted.

On the other hand, the air content remaining in the hot water in the hot water storage tank 1 is separated from the water as the boiling operation progresses and rises in the hot water storage tank 1, and then the hot water is stored via the high temperature pipe 5 and the first path 12. It rises toward the overpressure relief valve 9 at the top of the tank 1. At this time, the air content passing through the first path 12 passes through the thermal three-way valve 26, but since the amount of heat retained by the air is smaller than that of water, the first path 12 side of the thermal three-way valve 26 is closed. When the air passes through without being exhausted and the pressure in the system rises above the valve opening pressure of the overpressure relief valve 9, it is discharged together with the low-temperature water mentioned above, and the air content in the system is smoothed. Can be discharged.

Then, when the boiling operation is completed, the control unit 24 maintains a state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6 until the hot water supply operation described below is started. In this way, by maintaining the state in which only the water supply pipe 3 communicates with the hot water supply pipe 7 through the mixing valve 6, the density of the hot water and the low temperature water depends on the state of the temperature distribution of the hot water in the hot water storage tank 1. It prevents natural convection due to the difference.

<Hot water supply operation>
When the user gives an instruction to supply hot water by operating the remote control 20, the control unit 24 puts the mixing valve 6 in a state where the water supply pipe 3, the high temperature pipe 5, and the hot water supply pipe 7 communicate with each other, and opens the on-off valve 8. , Water from the water supply pipe 3 and hot water from the high temperature pipe 5 flow into the mixing valve 6, and the control unit 24 opens the mixing valve 6 so that the temperature detected by the hot water supply temperature sensor 18 matches the hot water supply set temperature. Is adjusted, and hot water of the hot water supply set temperature is supplied from the hot water supply pipe 7 to the hot water supply destination.

At this time, since the first path 12 of the hot water from the hot water storage tank 1 is blocked by the thermal three-way valve 26, it is prevented that the mixing valve 6 is bypassed and the hot water is short-cut to the hot water supply pipe 7. ..

Then, when the user gives an instruction to stop the hot water supply by operating the remote controller 20, the control unit 24 closes the on-off valve 8 and sets the mixing valve 6 so that only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other. Stop hot water supply.

<Drainage operation>
Next, a drainage operation for draining the hot water in the hot water storage tank 1 will be described.
When the user gives an instruction to the remote controller 20 to perform the drainage operation, the control unit 24 sets the mixing valve 6 in a state where the high temperature pipe 5 and the hot water supply pipe 7 communicate with each other.

Then, when the user operates the release lever 11 to open the overpressure relief valve 9 to the atmosphere and open the drain plug 17, the hot water in the hot water storage tank 1 is drained through the drain pipe 16.

At this time, the replacement air that has flowed in from the discharge path 10 of the overpressure relief valve 9 flows into the hot water storage tank 1 from the upper part of the hot water storage tank 1 via the second path 13, the hot water supply pipe 7, and the high temperature pipe 5. Since the amount of heat of the air is small, the air passes through the first path 12 side of the thermal three-way valve 26 without being blocked, so that the time required for draining the hot water storage tank can be shortened.

Then, when the release lever 11 is operated to close the overpressure relief valve 9, the drain plug 17 is closed, and the remote controller 20 is instructed to end the drainage operation, the control unit 24 receives an instruction. The drainage operation is terminated with the mixing valve 6 in a state where only the water supply pipe 3 and the hot water supply pipe 7 communicate with each other.

In this way, the expanded water at the time of heating by the electric heater 2 as the heating means can be discharged with the low temperature water, and the residual air accumulated in the hot water storage tank 1 is provided from the high temperature tube 5 in place of the resistor. It passes through the thermal three-way valve 26 as a thermal valve, reaches the overpressure relief valve 9, and is discharged together with the low-temperature water discharged during heating, and when the hot water storage tank 1 is drained, the replacement air is an overpressure relief valve. Since the water flows from the upper part of the hot water storage tank 1 through the paths from 9 to the second path 13, the hot water supply pipe 7, the high temperature pipe 5, and the overpressure relief valve 9 through the first path 12 and the high temperature pipe 5, the hot water storage tank 1 The time required for drainage can be shortened.

The present invention is not limited to the above embodiment, and can be modified without changing the gist of the invention. For example, a heat pump heat source machine may be used instead of the electric heater 2.

1 Hot water storage tank 2 Electric heater (heating means)
3 Water supply pipe 5 High temperature pipe 6 Mixing valve 7 Hot water supply pipe 9 Overpressure relief valve 12 1st path 13 2nd path 14 1st check valve (resistor)
15 Second check valve 16 Drain pipe 17 Drain plug 24 Control unit 25 Thermal shutoff valve (thermal valve)
26 Thermal three-way valve (thermal valve)

Claims (1)

A hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, a high temperature pipe connected to the upper part of the hot water storage tank, a water supply pipe for supplying water, hot water from the high temperature pipe, and the above. A mixing valve that mixes water from a water supply pipe, a hot water supply pipe that is connected to the outlet of the mixing valve to supply hot water, a drain pipe and a drain plug for draining hot water from the hot water storage tank, and the heating means. An overpressure relief valve for releasing expanded water due to heating of hot water in the hot water storage tank and a control unit for controlling the heating means and the mixing valve are provided, and the inlet side path of the overpressure relief valve has two routes. The first path is connected to the high temperature tube via a thermal valve that prevents hot water at a high temperature from flowing from the high temperature tube to the overpressure relief valve, and the second path is connected to the hot water supply pipe. Then, the control unit controls the opening degree of the mixing valve so that the water supply pipe and the hot water supply pipe communicate with each other during the operation of the heating means, and when the hot water storage tank is drained, the high temperature pipe and the high temperature pipe are used. A hot water storage type hot water supply device characterized in that the opening degree of the mixing valve is controlled so as to communicate with the hot water supply pipe.

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