JP2019143846A - Hot water storage type water heater - Google Patents

Abstract

To provide a hot water storage type water heater capable of suppressing variations in a hot water supply temperature even if a hot water supply operation is carried out during an operation to prevent fixing of a middle temperature taking-out selector valve or immediately after that operation.SOLUTION: A hot water storage type water heater includes a hot water storage tank 1, a middle temperature taking-out selector valve 28, mixing valves (a general hot water supply side electric mixing valve 7, and a bath hot water supply side electric mixing valve 11), and control means (a control device 24) for controlling the middle temperature taking-out selector valve 28 and the mixing valves. When a state in which the middle temperature taking-out selector valve 28 is not operated continues for a first reference time or longer, and a temperature of middle temperature water is lower than a first reference temperature, or when a state in which the middle temperature taking-out selector valve 28 is not operated continues for the first reference time or longer, and a difference between a temperature of the middle temperature water and a temperature of low temperature water is less than a first reference temperature difference, the control means carries out a fixing prevention operation in which the middle temperature taking-out selector valve 28 is caused to be operated with a first operation amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hot water storage type hot water supply apparatus.

  A hot water storage type hot water supply device having a function of supplying hot water stored in a hot water storage tank to a bathtub or the like is widely used. Medium-temperature water that accumulates in the middle of the hot water storage tank becomes a factor that lowers boiling efficiency. In order to suppress a decrease in boiling efficiency, there is a hot water storage type hot water supply apparatus provided with an intermediate temperature extraction switching valve for extracting intermediate temperature water from an intermediate part of a hot water storage tank and using it for hot water supply.

  In the following Patent Document 1, in the hot water storage type hot water supply apparatus, when the state where the electric mixing valve has not been operated for a long time continues, the electric mixing valve is compulsory at least once a day to prevent the electric mixing valve from sticking. Discloses a technique for operating an electric mixing valve.

JP 2000-18423 A

  If the intermediate temperature extraction switching valve continues to be inoperative for a long time, there is a possibility that the intermediate temperature extraction switching valve may be fixed due to adhesion of scales or the like. In the invention of Patent Document 1, the sticking prevention operation for forcibly operating the electric mixing valve is performed at midnight when it is considered that the user does not use hot water.

  However, with the diversification of lifestyles, the number of users who use hot water supply in the late night hours is increasing. If the user uses hot water during the late night sticking prevention operation, the hot water temperature may vary greatly with respect to the set temperature.

  The present invention has been made to solve the above-described problems, and suppresses fluctuations in the hot water temperature even if the hot water supply operation is performed during or immediately after the operation for preventing the intermediate temperature take-off switching valve from sticking. It is an object of the present invention to provide a hot water storage type hot water supply device that can be used.

  The hot water storage type hot water supply apparatus according to the present invention includes a hot water storage tank, a high temperature pipe communicating with the first position of the hot water storage tank, an intermediate temperature pipe communicating with the hot water storage tank at a second position lower than the first position, and a hot water storage tank. A medium temperature position that has a medium temperature inlet through which medium temperature water supplied through medium temperature piping flows, a low temperature inlet into which low temperature water having a lower temperature than the medium temperature water flows, and a water outlet, and connects the medium temperature inlet to the water outlet. And a medium temperature extraction switching valve that can switch the flow path to a low temperature position where the low temperature inlet communicates with the water outlet, a hot water side inlet through which high temperature hot water supplied from a hot water tank through high temperature piping flows, and medium temperature extraction switching A mixing valve having a water side inlet through which water from the water outlet of the valve flows in, a hot water outlet from which hot water flowing in from the hot water side inlet and water flowing from the water side inlet are mixed, and medium temperature extraction switching Detects the temperature of the medium temperature water, which is the temperature of the medium temperature water supplied to the valve's medium temperature inlet Medium temperature water temperature detecting means, low temperature water temperature detecting means for detecting the temperature of the low temperature water supplied to the low temperature inlet of the intermediate temperature extraction switching valve, and control means for controlling the intermediate temperature extraction switching valve and the mixing valve When the intermediate temperature extraction switching valve is not operating for more than the first reference time and the intermediate temperature water temperature is lower than the first reference temperature, or the intermediate temperature extraction switching valve is not operating When the state continues for the first reference time or more and the difference between the medium temperature water temperature and the low temperature water temperature is less than the first reference temperature difference, the control means sets the medium temperature extraction switching valve at the first operation amount. The sticking prevention operation is performed.

  ADVANTAGE OF THE INVENTION According to this invention, even if the hot water supply operation is performed during the operation | movement which prevents sticking of a middle temperature extraction switching valve, or immediately after that, the hot water storage type hot water supply apparatus which can suppress the fluctuation | variation of hot water supply temperature is provided. It becomes possible.

It is a figure which shows the hot water storage type hot-water supply apparatus by Embodiment 1. FIG. 4 is a flowchart illustrating processing performed by the control device in the first embodiment. It is a figure which shows the example of a display of the display part of the remote control with which the hot water storage type hot-water supply apparatus by Embodiment 2 is provided.

  Hereinafter, embodiments will be described with reference to the drawings. In the drawings, common or corresponding elements are denoted by the same reference numerals, and redundant description is simplified or omitted.

Embodiment 1 FIG.
1 is a diagram showing a hot water storage type hot water supply apparatus according to Embodiment 1. FIG. As shown in FIG. 1, the hot water storage type hot water supply apparatus of the present embodiment includes a heat pump unit 2 that is a heating means for heating water and a hot water storage unit 40 having a hot water tank 1. The heat pump unit 2 and the hot water storage unit 40 are connected via an HP outgoing pipe 48, an HP return pipe 49, and electrical wiring (not shown). The heat pump unit 2 includes a heat pump circuit in which a compressor, a hot water supply heat exchanger, an expansion valve, and an air heat exchanger are sequentially connected by a refrigerant pipe.

  The hot water tank 1 stores hot water. Inside the hot water tank 1, temperature stratification can be formed in which the upper side is hot and the lower side is cold due to the difference in water density depending on the temperature. Hot water storage tank 1 in the present embodiment includes only one hot water storage tank. As a modification, the hot water tank 1 may include a plurality of hot water storage tanks connected in series. In the plurality of hot water storage tanks connected in series, the lower part of the upper hot water storage tank and the upper part of the next hot water storage tank lower than the hot water storage tank are sequentially connected via a pipe. In the following description, reference is made to the vertical position of the hot water tank 1, but when the hot water tank 1 includes a plurality of hot water storage tanks connected in series, the entire hot water tank 1 including the plurality of hot water tanks is used. In the hierarchy, the vertical position is specified. In the following description, the hot water stored in the hot water tank 1 may be referred to as “tank water”.

  On the outer surface of the hot water tank 1, the volume from the upper part of the hot water tank 1 is, for example, at each position of 0L, 50L, 100L, 150L, 170L, 220L, the first temperature sensor 5a, the second temperature sensor 5b, The third temperature sensor 5c, the fourth temperature sensor 5d, the fifth temperature sensor 5e, and the sixth temperature sensor 5f are provided, and detect the water temperature at each position. The first to sixth temperature sensors 5a to 5f function as a remaining hot water calorie detecting means for detecting the remaining hot water calorie in the hot water tank 1. The HP outgoing pipe 48 is provided with a seventh temperature sensor 5 g for detecting the temperature of water entering the heat pump unit 2.

  In the hot water storage unit 40, the circulation pump 4, the general hot water supply side electric mixing valve 7, the high temperature pipe 8, the water supply pipe 9, the bath hot water supply side electric mixing valve 11, the bath opening / closing valve 13, the bath circulation pump 14, the incoming water switching valve 17, Hot water flow sensor 19, hot water temperature sensor 20, bath flow sensor 21, bath temperature sensor 22, hot water temperature sensor 23, hot water switching valve 26, medium temperature return switching valve 27, medium temperature extraction switching valve 28, medium temperature piping 30, etc. Is further provided.

  The upstream of the water supply pipe 9 is connected to a water source such as a water pipe. The downstream side of the water supply pipe 9 is branched into a water supply pipe 9a and a water supply pipe 9b. The water supply pipe 9 a is connected to the lower part of the hot water tank 1. The low temperature water supplied from the water source flows into the lower part of the hot water tank 1 from the water supply pipe 9a, whereby the hot water tank 1 is maintained in a full state.

  The intermediate temperature extraction switching valve 28 includes an intermediate temperature inlet 28a, a low temperature inlet 28b, and a water outlet 28c. A water supply pipe 9b is connected to the low temperature inlet 28b. One end of the intermediate temperature pipe 30 is connected to the intermediate temperature inlet 28a. The upstream portion of the high-temperature pipe 8 communicates with the hot water tank 1 at a first position 1 a at the upper part of the hot water tank 1. The other end of the intermediate temperature pipe 30 communicates with the hot water tank 1 at a second position 1b which is lower than the first position 1a. The second position 1b is higher than the lower part of the hot water tank 1 to which the water supply pipe 9a is connected. That is, the second position 1b is in an intermediate portion between the upper part and the lower part of the hot water tank 1.

  Medium temperature water supplied from the hot water tank 1 through the intermediate temperature pipe 30 flows into the medium temperature inlet 28a. Low temperature water having a temperature lower than that of the medium temperature water flows into the low temperature inlet 28b. In the present embodiment, the low temperature water supplied from the water source through the water supply pipe 9b flows into the low temperature inlet 28b. The intermediate temperature extraction switching valve 28 can switch the flow path between an “intermediate temperature position” and a “low temperature position”. In the “intermediate temperature position”, the intermediate temperature inlet 28a communicates with the water outlet 28c, and the low temperature inlet 28b is blocked. At the “medium temperature position”, the medium temperature water from the medium temperature pipe 30 flows to the water outlet 28c. In the “low temperature position”, the low temperature inlet 28b communicates with the water outlet 28c, and the intermediate temperature inlet 28a is blocked. When in the “low temperature position”, low temperature water from the water supply pipe 9b flows to the water outlet 28c.

  The general hot water supply side electric mixing valve 7 includes a hot water side inlet 7a, a water side inlet 7b, and a hot water outlet 7c. The bath hot water supply side electric mixing valve 11 includes a hot water side inlet 11a, a water side inlet 11b, and a hot water outlet 11c. The downstream portion of the high temperature pipe 8 communicates with each of the hot water side inlet 7a and the hot water side inlet 11a. The water outlet 28c of the intermediate temperature extraction switching valve 28 communicates with each of the water side inlet 7b and the water side inlet 11b.

  One end of the first hot water supply pipe 10 is connected to the hot water outlet 7c. The general hot water supply side electric mixing valve 7 mixes high temperature hot water supplied from the hot water tank 1 through the high temperature pipe 8 and water from the water outlet 28c of the intermediate temperature take-off switching valve 28 to adjust the temperature. The hot water whose temperature has been adjusted flows into the first hot water supply pipe 10. Hot water that passes through the first hot water supply pipe 10 is supplied to, for example, a faucet and a shower.

  One end of the second hot water supply pipe 18 is connected to the hot water outlet 11c. The hot water supply side electric mixing valve 11 mixes high temperature hot water supplied from the hot water tank 1 through the high temperature pipe 8 and water from the water outlet 28c of the intermediate temperature extraction switching valve 28 to adjust the temperature. The hot water whose temperature has been adjusted flows into the second hot water supply pipe 18.

  The water supply pipe 9 is provided with a water supply temperature sensor 23. The feed water temperature sensor 23 detects the feed water temperature, which is the temperature of the water flowing through the feed water pipe 9. The first hot water supply pipe 10 is provided with a hot water supply flow rate sensor 19 and a hot water supply temperature sensor 20. The hot water flow sensor 19 detects the flow rate of hot water flowing through the first hot water supply pipe 10. Hot water temperature sensor 20 detects a first hot water temperature that is the temperature of hot water flowing through first hot water pipe 10. The second hot water supply pipe 18 is provided with a bath on-off valve 13, a bath flow sensor 21, and a bath temperature sensor 22. The bath flow rate sensor 21 detects the flow rate of hot water flowing through the second hot water supply pipe 18. The bath temperature sensor 22 detects a second hot water temperature that is the temperature of hot water flowing through the second hot water pipe 18.

  The second hot water supply pipe 18 is connected to the bath side circulation circuit 12. A heat exchanger 15 is disposed in the hot water storage unit 40. The bath side circulation circuit 12 is connected to a bathtub (not shown) in a bathroom outside the hot water storage type hot water supply apparatus. In the following description, the hot water stored in the bathtub may be referred to as “bath water”. The bath-side circulation circuit 12 is a path through which bath water can be drawn from the bathtub and the bath water passed through the heat exchanger 15 can be returned to the bathtub. When the bath circulation pump 14 connected in the middle of the bath side circulation circuit 12 is operated, the bath water circulates from the bathtub so as to pass through the bath side circulation circuit 12 and return to the bathtub.

  The second hot water supply pipe 18 forms a passage of hot water supplied from the hot water outlet 11c of the bath hot water supply side electric mixing valve 11 to the bathtub. The bath opening / closing valve 13 opens and closes the passage of the second hot water supply pipe 18. Except for supplying hot water to the bathtub, the bath opening / closing valve 13 is closed and hot water does not flow to the second hot water supply pipe 18. When performing the operation | movement which inject | pours hot water into the bathtub from the hot water storage unit 40, it becomes as follows. The bath opening / closing valve 13 is opened, and a hot water flow is generated in the second hot water supply pipe 18. The bath hot water supply side electric mixing valve 11 is controlled so that the temperature of hot water flowing through the second hot water supply pipe 18 becomes equal to the target temperature. Hot water that has passed through the second hot water supply pipe 18 passes through the bath-side circulation circuit 12 and flows into the bathtub. When the bath opening / closing valve 13 is closed, the injection of hot water into the bathtub stops. In the following description, the operation of accumulating hot water in the bathtub as described above is referred to as “tub hot water”.

  The incoming water switching valve 17 is a flow path switching means having an a port and a b port as inlets and a c port as an outlet. The incoming water switching valve 17 is configured to be able to switch the flow path between two paths a-c and bc.

  The hot water switching valve 26 is a flow path switching means having an a port and a b port as inlets and a c port and a d port as outlets. The hot water switching valve 26 is configured to be able to switch the flow path between four paths a-c, a-d, bc, and b-d.

  The intermediate temperature return switching valve 27 is a flow path switching means having an a port as an inlet and b, c, and d ports as outlets. The intermediate temperature return switching valve 27 is configured to be able to switch the flow path between three paths ab, ac, and ad.

  The hot water storage unit 40 includes a low temperature pipe 41, a first water supply pipe 42, a first hot water pipe 43, a second hot water pipe 44, a third hot water pipe 45, a fourth hot water pipe 46, and a fifth hot water pipe 47. The low temperature pipe 41 connects between the lower part of the hot water tank 1 and the a port of the incoming water switching valve 17. The first water supply pipe 42 connects between the c port of the incoming water switching valve 17 and the inlet of the circulation pump 4. The HP outgoing pipe 48 connects between the outlet of the circulation pump 4 and the inlet of the heat pump unit 2. The HP return pipe 49 connects between the outlet of the heat pump unit 2 and the b port of the hot water switching valve 26. The first hot water pipe 43 connects between the d port of the hot water switching valve 26 and the a port of the intermediate temperature return switching valve 27. The third hot water pipe 45 connects between the b port of the intermediate temperature return switching valve 27 and the hot water inlet / outlet 1 c at the top of the hot water tank 1. The fourth hot water pipe 46 connects between the d port of the medium temperature return switching valve 27 and a position in the middle of the high temperature pipe 8. The fifth hot water pipe 47 connects between the c port of the intermediate temperature return switching valve 27 and the hot water inlet 1d provided between the upper part and the intermediate part of the hot water tank 1.

  An upper temperature sensor 6 is provided near the hot water introduction outlet 1c. According to the upper temperature sensor 6, it is possible to detect the temperature of hot water heated by the heat pump unit 2 and returned to the upper portion of the hot water tank 1 and the temperature of hot water supplied from the hot water tank 1 to the high temperature pipe 8.

  The first tank circulation pipe 16 connects between a position in the middle of the third hot water pipe 45 and the tank water inlet of the heat exchanger 15. The second tank circulation pipe 50 connects between the tank water outlet of the heat exchanger 15 and the b port of the incoming water switching valve 17. The second water supply pipe 51 branches from between the circulation pump 4 and the inlet of the heat pump unit 2 in the HP outgoing pipe 48 and is connected to the a port of the hot water switching valve 26. The bath heat recovery pipe 31 branches from a position in the middle of the second tank circulation pipe 50 and is connected to a position in the middle of the medium temperature pipe 30.

  The hot water storage type hot water supply apparatus of the present embodiment includes a control device 24 as control means. The control device 24 is electrically connected to each actuator and each sensor described above. The operation of the hot water storage type hot water supply apparatus is controlled by the control device 24. The control device 24 includes, for example, a processor and a memory. The control device 24 can store a history of the date and time when each device operates in a memory.

  The control device 24 and the remote controller 25 can communicate bidirectionally by wired communication or wireless communication. The control device 24 and the remote controller 25 may be communicable via a network. The remote controller 25 is an example of a user interface. The remote controller 25 has an operation unit operated by a user and a display unit 25a for displaying information. The remote controller 25 may include a touch screen having both functions of the operation unit and the display unit 25a. The user can operate the remote controller 25 to remotely operate the hot water storage type hot water supply apparatus and perform various settings. The display unit 25a of the remote controller 25 has a function as a notification unit that notifies the user of information. The remote controller 25 in the present embodiment includes the display unit 25a as a notification unit, but may include other notification units such as a voice guidance device as a modification.

  In the present embodiment, the remote controller 25 may be installed on a wall such as a kitchen, a living room, or a bathroom. Or you may comprise so that a portable information terminal like a smart phone may have a function as a user interface like the remote control 25, for example. A plurality of remote controllers 25 may be able to communicate with the control device 24.

  The user can change the set temperature for the general hot water supply side electric mixing valve 7 and the set temperature for the hot water supply side electric mixing valve 11 by operating the remote controller 25. In the following description, the set temperature for the general hot water supply side electric mixing valve 7 is referred to as “hot water supply set temperature”, and the set temperature for the bath hot water supply side electric mixing valve 11 is referred to as “hot water set temperature”.

  The hot water storage type hot water supply apparatus of the present embodiment can execute a hot water storage operation in which hot water heated by the heat pump unit 2 flows into the hot water storage tank 1. In hot water storage operation: The heat pump unit 2 and the circulation pump 4 are operated. The water taken out from the lower part of the hot water tank 1 is guided into the heat pump unit 2 through the low temperature pipe 41, the incoming water switching valve 17, the first water supply pipe 42, the circulation pump 4, and the HP outgoing pipe 48. The hot water heated in the heat pump unit 2 passes through the HP return pipe 49, the hot water switching valve 26, the first hot water pipe 43, the intermediate temperature return switching valve 27, and the third hot water pipe 45 from the hot water introduction outlet 1c. It flows into the hot water tank 1. The hot water storage operation is typically performed mainly in the late-night power hours, and hot water for the next day is stored in the hot water tank 1.

  When the hot water flow rate sensor 19 detects the water flow, the control device 24 controls the general hot water supply side electric mixing valve 7 so that the temperature detected by the hot water temperature sensor 20 becomes equal to the hot water set temperature that is the target temperature. Perform feedback control to adjust the mixing ratio. When the bath flow sensor 21 detects the water flow, the control device 24 causes the bath hot water supply side electric mixing valve 11 so that the temperature detected by the bath temperature sensor 22 is equal to the hot water set temperature that is the target temperature. Perform feedback control to adjust the mixing ratio.

  When the intermediate temperature extraction switching valve 28 is in the low temperature position, the low temperature water from the water source and the high temperature hot water from the upper part of the hot water tank 1 are mixed by the general hot water supply side electric mixing valve 7 and the bath hot water supply side electric mixing valve 11. The hot water supply operation can be executed. When the intermediate temperature take-off switching valve 28 is in the intermediate temperature position, the intermediate hot water flowing out from the hot water tank 1 to the intermediate temperature pipe 30 and the hot water from the upper part of the hot water tank 1 are connected to the general hot water supply side electric mixing valve 7 and the bath hot water supply side electric. The hot water supply operation mixed by the mixing valve 11 can be executed. According to the present embodiment, the medium-temperature water flowing out from the hot water tank 1 to the medium-temperature pipe 30 can be used for hot water supply, so that the amount of medium-temperature water in the hot water tank 1 can be reduced. For this reason, the temperature of water entering the heat pump unit 2 can be lowered, and the operating efficiency of the heat pump unit 2 can be improved. In the following description, using the intermediate temperature water for hot water supply by setting the intermediate temperature extraction switching valve 28 to the intermediate temperature position may be referred to as “use of intermediate temperature water”.

  The hot water storage type hot water supply apparatus of the present embodiment can perform a chasing operation. The reheating operation is an operation in which the bath water circulating from the bathtub is heated by the tank water circulating from the hot water tank 1 in the heat exchanger 15. At the time of chasing driving, it becomes as follows. The bath circulation pump 14 is operated, and bath water circulates in the bath side circulation circuit 12. The circulation pump 4 is operated, and the tank water taken out from the hot water tank 1 is circulated as follows. The high-temperature tank water that has flowed out of the hot water introduction outlet 1 c at the top of the hot water tank 1 flows into the heat exchanger 15 through the first tank circulation pipe 16. In the heat exchanger 15, the temperature of the tank water is lowered by taking heat away from the bath water from the bathtub, and becomes a temperature of about 50 ° C., for example. Hereinafter, the tank water whose temperature has been lowered is referred to as “reflecting hot water”. The recuperated hot water is supplied from the heat exchanger 15 to the second tank circulation pipe 50, the incoming water switching valve 17, the first water supply pipe 42, the circulation pump 4, the second water supply pipe 51, the hot water switching valve 26, and the first hot water pipe 43. Then, it flows into the hot water tank 1 from the hot water inlet 1d through the intermediate temperature return switching valve 27 and the fifth hot water pipe 47. When the temperature of the bath water in the bathtub rises to an appropriate temperature, the control device 24 stops the operation of the bath circulation pump 14 and the circulation pump 4 and ends the reheating operation.

  The hot water storage type hot water supply apparatus of the present embodiment can execute a bath heat recovery operation. In the bath heat recovery operation, after the bathing is completed, the heat in the bathtub is recovered in the hot water tank 1 by heating the tank water circulating from the hot water tank 1 with the bath water circulating from the bathtub in the heat exchanger 15. Driving. During bath heat recovery operation: The bath circulation pump 14 is operated, and bath water circulates in the bath side circulation circuit 12. The circulation pump 4 is operated, and the tank water taken out from the hot water tank 1 is circulated as follows. The low-temperature tank water flowing out from the lower part of the hot water tank 1 to the low-temperature pipe 41 is the water input switching valve 17, the first water supply pipe 42, the circulation pump 4, the second water supply pipe 51, the hot water switch valve 26, the first hot water pipe 43, It flows into the heat exchanger 15 through the intermediate temperature return switching valve 27, the third hot water pipe 45, and the first tank circulation pipe 16. In the heat exchanger 15, the tank water is heated by the heat of the bath water from the bathtub, and becomes a temperature close to the temperature of the bath water in the bathtub. This heated tank water is hereinafter referred to as “heat recovery hot water”. The heat recovery hot water flows from the heat exchanger 15 through the bath heat recovery pipe 31 and the medium temperature pipe 30 into the hot water tank 1 from the second position 1b. When the bath heat recovery operation is performed in this manner, the heat recovery hot water is stored in a region of the hot water tank 1 that is close to the second position 1b. When the recovery of the residual heat of the bath water in the bathtub ends, the control device 24 stops the operation of the bath circulation pump 14 and the circulation pump 4 and ends the bath heat recovery operation.

  The hot water storage type hot water supply apparatus of the present embodiment can execute an air bleeding operation. The air bleeding operation is an operation for bleeding air in the pipe. When the operation of starting the air bleeding operation is performed with the remote controller 25, the control device 24 performs the air bleeding operation. At the time of air bleeding operation, it is as follows. The circulation pump 4 is operated. The hot water taken out from the upper part of the hot water tank 1 passes through the heat exchanger 15, the incoming water switching valve 17, the circulation pump 4, the heat pump unit 2, the hot water switching valve 26, the intermediate temperature return switching valve 27, and the hot water inlet 1d. It flows into the hot water tank 1. At the same time, the hot water in the hot water storage tank 1 flows from the second position 1b through the intermediate temperature pipe 30 and the bath heat recovery pipe 31 into the second tank circulation pipe 50 and merges. During the air bleeding operation, the bath circulation pump 14 is not operated, and the bath water does not circulate to the heat exchanger 15. For this reason, the hot water passing through the heat exchanger 15 does not exchange heat and flows into the hot water tank 1 from the hot water inlet 1d while maintaining a high temperature. When the operation time of the air bleed operation exceeds a predetermined time or when the operation of ending the air bleed operation is performed with the remote controller 25, the control device 24 stops the operation of the circulation pump 4, and the air bleed operation is performed. Exit.

  The control device 24 includes a medium warm water use control unit 24a, a medium warm water use prohibition unit 24b, and a medium warm water use stop unit 24c. The medium temperature water use control means 24a determines whether medium temperature water can be used, and sends an operation instruction to the medium temperature extraction switching valve 28. The medium temperature water use control means 24a determines whether medium temperature water can be used based on the temperature of the medium temperature water supplied from the hot water tank 1 to the medium temperature pipe 30. The fourth temperature sensor 5d is at the same height as or substantially the same height as the second position 1b. It can be considered that the temperature detected by the fourth temperature sensor 5d is equal to the temperature of the medium-temperature water supplied from the hot water tank 1 to the medium-temperature pipe 30. Therefore, the temperature of the intermediate temperature water supplied from the hot water storage tank 1 to the intermediate temperature pipe 30 can be detected by the fourth temperature sensor 5d. In the following description, the temperature detected by the fourth temperature sensor 5d is referred to as “medium temperature water temperature”. The fourth temperature sensor 5d corresponds to a medium hot water temperature detecting means.

  For example, the following may be used. The medium temperature water use control means 24a calculates the medium temperature extraction permission temperature based on at least one of the hot water supply set temperature and the hot water beam set temperature. The medium temperature extraction permission temperature is a temperature lower than the hot water supply set temperature or the hot water beam set temperature. If the intermediate temperature water temperature is equal to or lower than the intermediate temperature extraction permission temperature, the intermediate temperature water use control means 24a determines that the intermediate temperature water can be used, and issues a request to set the intermediate temperature extraction switching valve 28 to the intermediate temperature position. If the intermediate temperature water temperature is higher than the intermediate temperature extraction permission temperature, the intermediate temperature water use control means 24a determines that the intermediate temperature water use is not possible and issues a request to set the intermediate temperature extraction switching valve 28 to a low temperature position.

  For example, the medium-temperature water use prohibiting unit 24b may prohibit the use of medium-temperature water when the temperature of the medium-temperature water may be higher than the current temperature. The medium-temperature water use prohibiting means 24b performs, for example, an operation in which the temperature of the intermediate part in the hot water tank 1 may increase or an operation in which the temperature of the intermediate part in the hot water tank 1 may fluctuate sharply. The use of medium-temperature water may be prohibited if Accordingly, it is possible to reliably prevent hot water having a temperature higher than the set temperature from being supplied to the first hot water supply pipe 10 or the second hot water supply pipe 18 or the fluctuation of the hot water supply temperature. The medium temperature water use prohibiting means 24b issues a request to set the medium temperature extraction switching valve 28 to a low temperature position when the use of medium temperature water is prohibited. In the following description, hot water having a temperature higher than the set temperature is supplied to the first hot water supply pipe 10 or the second hot water supply pipe 18 as “high temperature hot water supply”. The fluctuation of the temperature of the flowing hot water is referred to as “hot water supply temperature fluctuation”. When high temperature hot water supply or hot water supply temperature fluctuations occur, the user may feel uncomfortable. Therefore, it is necessary to suppress the occurrence of high temperature hot water supply or hot water supply temperature fluctuations as much as possible.

  The medium-temperature water use stopping means 24c is capable of driving the temperature of the intermediate portion in the hot water tank 1 during the use of the medium-temperature water or the temperature of the intermediate portion in the hot water tank 1 may fluctuate rapidly. When a request to start a certain operation is generated, a request to switch the intermediate temperature extraction switching valve 28 from the intermediate temperature position to the low temperature position is issued.

  The control device 24 performs a switching operation for switching the intermediate temperature extraction switching valve 28 from the low temperature position to the intermediate temperature position in response to requests from the above-described intermediate temperature water use control means 24a, intermediate temperature water use prohibition means 24b, and intermediate temperature water use stop means 24c. And the switching operation which switches the intermediate temperature extraction switching valve 28 from the intermediate temperature position to the low temperature position can be performed.

  In the present embodiment, the feed water temperature sensor 23 can detect the temperature of the low temperature water supplied to the low temperature inlet 28 b of the intermediate temperature extraction switching valve 28. In the following description, the temperature detected by the feed water temperature sensor 23 is referred to as “low temperature water temperature”. The feed water temperature sensor 23 corresponds to a low temperature water temperature detecting means. The upper temperature sensor 6 can detect the temperature of the hot water supplied from the hot water tank 1 to the hot water inlet 7a of the general hot water supply side electric mixing valve 7 and the hot water inlet 11a of the hot water supply side electric mixing valve 11. .

  The bath hot water supply side electric mixing valve 11 includes, for example, a valve body rotated by a stepping motor, and by changing the ratio of the opening degree of the hot water side inlet 11a and the opening degree of the water side inlet 11b by the rotation of the valve body, Adjust the mixing ratio of hot water and water. In this case, since the mixing ratio changes according to the rotation amount of the stepping motor, the control device 24 can hold information on the mixing ratio corresponding to the information on the rotation amount of the stepping motor. In the following description, a state in which the mixing ratio of water from the water side inlet 11b is maximized is referred to as “water side full open”, and a state in which the mixing ratio of hot water from the hot water side inlet 11a is maximized is “hot water side fully open”. Sometimes called. The water side full open may be an opening degree where the mixing ratio of water from the water side inlet 11b is 100% and the mixing ratio of hot water from the hot water side inlet 11a is 0%. The hot water side full open may be an opening degree where the mixing ratio of hot water from the hot water side inlet 11a is 100% and the mixing ratio of water from the water side inlet 11b is 0%. In addition, the structure of the general hot water supply side electric mixing valve 7 is the same as that of the bath hot water supply side electric mixing valve 11 described above.

  The intermediate temperature extraction switching valve 28 includes, for example, a valve body that is rotated by a stepping motor, and switches the flow path between an intermediate temperature position and a low temperature position by the rotation of the valve body. In this case, the control device 24 can hold the position information of the valve body of the intermediate temperature extraction switching valve 28 corresponding to the information on the rotation amount of the stepping motor.

  When the state in which the intermediate temperature extraction switching valve 28 is not operating continues for the first reference time or longer and the intermediate temperature water temperature is lower than the first reference temperature, the control device 24 switches the intermediate temperature extraction switching valve 28 to the first intermediate temperature extraction switching valve 28. An anti-sticking operation that operates with one operation amount is performed. The “first reference time” may be 24 hours, for example. The “first reference temperature” may be 40 ° C., for example. The “first operation amount” may be, for example, an operation amount for rotating the valve body of the intermediate temperature extraction switching valve 28 by 180 °. According to the present embodiment, it is possible to prevent the state where the intermediate temperature extraction switching valve 28 is not operating from becoming too long, so that it is possible to reliably prevent the intermediate temperature extraction switching valve 28 from adhering due to adhesion of scale or the like. . If the medium hot water temperature is lower than the first reference temperature, even if the hot water supply operation using the general hot water supply side electric mixing valve 7 or the bath hot water supply side electric mixing valve 11 is performed during or immediately after the sticking prevention operation. High temperature hot water supply or hot water supply temperature fluctuation is unlikely to occur. In this embodiment, since the sticking prevention operation is performed on the condition that the intermediate warm water temperature is lower than the first reference temperature, even if the hot water supply operation is performed during or immediately after the sticking prevention operation, It is possible to reliably suppress high temperature hot water supply or hot water temperature fluctuation.

  Instead of the above control or in addition to the above control, as a modified example, the following control may be performed. When the state in which the intermediate temperature take-off switching valve 28 is not operating continues for the first reference time and the difference between the intermediate hot water temperature and the low temperature water temperature is less than the first reference temperature difference, The same sticking prevention operation as described above may be performed. The “first reference temperature difference” may be 20 ° C., for example. If the difference between the medium temperature water temperature and the low temperature water temperature is less than the first reference temperature difference, even if the hot water supply operation is performed during or immediately after the sticking prevention operation, high temperature hot water supply or hot water supply temperature fluctuations are unlikely to occur. Also by this modification, the effect similar to the effect mentioned above is acquired.

  FIG. 2 is a flowchart showing processing performed by the control device 24 in the first embodiment. In step S100 of FIG. 2, the control device 24 determines whether or not the current time is within a sticking prevention operation time zone that is a specific time zone set in advance. It is desirable that the sticking prevention operation time zone is set to a time zone in which the user is less likely to use hot water. For example, the time period from 2 am to 3 am may be set as the sticking prevention operation time zone. The control device 24 proceeds to step S200 when the current time is within the sticking prevention operation time zone, and waits when the current time is not within the sticking prevention operation time zone. In the present embodiment, the hot water supply operation can be performed during or immediately after the sticking prevention operation by performing the sticking prevention operation of the intermediate temperature extraction switching valve 28 only during the sticking prevention operation time period. Low. For this reason, it can suppress more reliably that high temperature hot water supply or hot water supply temperature fluctuation | variation generate | occur | produces.

  In step S200, the control device 24 controls the general hot water supply side electric mixing valve 7, the bath hot water supply side electric mixing valve 11, the intermediate temperature extraction switching valve 28, the fourth temperature sensor 5d, the hot water supply temperature sensor 20, and the bath temperature sensor 22. For at least one of the devices, it is determined whether there is any abnormality such as a failure error. If there is an abnormality with respect to at least one of these devices, the control device 24 proceeds to step S701, prohibits the sticking prevention operation, and performs the sticking prevention operation of the intermediate temperature extraction switching valve 28. The process of this flowchart is complete | finished. If the operation for preventing the intermediate temperature take-off switching valve 28 from sticking is performed when there is an abnormality in the above-mentioned device that is important in hot water supply temperature control, there is a high possibility that high temperature hot water supply or hot water supply temperature fluctuations occur when the hot water supply operation is performed. . In the present embodiment, the occurrence of high temperature hot water supply or hot water supply temperature fluctuations can be more reliably prevented by prohibiting the sticking prevention operation of the intermediate temperature extraction switching valve 28 when there is an abnormality.

  If there is no abnormality in the device in step S200, the control device 24 proceeds to step S300 and determines whether or not there is a history of operation of the intermediate temperature extraction switching valve 28 within the past first reference time (for example, within the past 24 hours). Check. If there is a history of operation of the intermediate temperature extraction switching valve 28 within the past 24 hours, the possibility of the intermediate temperature extraction switching valve 28 sticking is low, and the necessity of performing the sticking prevention operation is low. In this case, the control device 24 proceeds to step S701, and ends the processing of this flowchart without performing the sticking prevention operation.

  On the other hand, when there is no history of operation of the intermediate temperature extraction switching valve 28 within the past 24 hours, that is, when the state where the intermediate temperature extraction switching valve 28 is not operating continues for the first reference time or longer, the control device 24. Advances to step S400 to determine whether the medium hot water temperature is lower than the second reference temperature. This second reference temperature is higher than the first reference temperature described above. The second reference temperature may be 80 ° C., for example. When the intermediate temperature water temperature is lower than the second reference temperature, the process proceeds to step S501. When the intermediate temperature water temperature is equal to or higher than the second reference temperature, the process proceeds to step S502.

  In step S501, the control device 24 records the history of the hot water supply operation in the sticking prevention operation time zone during the past predetermined number of days (for example, the past seven days) (hereinafter referred to as “hot water supply history of the sticking prevention operation time zone”). Check if there is. If there is no hot water supply history during the sticking prevention operation time zone, the process proceeds to step S600, and if there is a hot water supply history during the sticking prevention operation time period, the process proceeds to step S502.

  In step S502, the control device 24 checks whether or not there is an operation history of the intermediate temperature extraction switching valve 28 during the past predetermined number of days (for example, the past seven days). This “predetermined number of days” corresponds to a second reference time that is longer than the first reference time described above. When there is no operation history of the intermediate temperature extraction switching valve 28 during the past predetermined number of days, that is, when the state where the intermediate temperature extraction switching valve 28 is not operating continues for the second reference time or longer, the control device 24 performs step S702. Proceed to In step S702, the control device 24 performs a sticking prevention operation for operating the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount described above, and thereafter ends the processing of this flowchart. The “operation amount smaller than the first operation amount” may be, for example, an operation amount for rotating the valve body of the intermediate temperature extraction switching valve 28 by 90 °.

  If the hot water supply operation is performed during or immediately after the sticking prevention operation performed when the medium hot water temperature is equal to or higher than the second reference temperature, the possibility of high temperature hot water supply or hot water temperature fluctuations is relatively high. When the hot water temperature is equal to or higher than the second reference temperature, it is desirable to prevent the sticking prevention operation as much as possible. However, when the state in which the intermediate temperature extraction switching valve 28 is not operating continues for the second reference time or longer, the intermediate temperature extraction switching valve 28 is relatively likely to be fixed, and therefore, the sticking prevention operation is performed. The necessity is high. In the present embodiment, in consideration of the above matters, when the temperature of the intermediate temperature water is equal to or higher than the second reference temperature and the state where the intermediate temperature extraction switching valve 28 is not operating continues for the second reference time or longer. In Step S702 described above, the control device 24 performs the sticking prevention operation for operating the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount. As a result, the intermediate temperature take-off switching valve 28 can be more reliably prevented from sticking. Further, if the intermediate temperature extraction switching valve 28 is operated with an operation amount smaller than the first operation amount during the sticking prevention operation, even if the medium hot water temperature is equal to or higher than the second reference temperature, It is possible to reduce the possibility of high temperature hot water supply or hot water supply temperature fluctuations occurring immediately after the hot water supply operation.

  On the other hand, if there is an operation history of the intermediate temperature extraction switching valve 28 during the past predetermined number of days in step S502, the possibility of the intermediate temperature extraction switching valve 28 sticking is not so high yet, and the sticking prevention operation is performed. The need is not so high yet. For this reason, in this case, the process proceeds to step S701, and the process of this flowchart is terminated without performing the sticking prevention operation. Thus, in the present embodiment, the temperature during which the intermediate temperature water temperature is equal to or higher than the second reference temperature and the state in which the intermediate temperature extraction switching valve 28 is not operating is longer than the first reference time is the second reference temperature. When it is less than the time, the control device 24 prohibits the operation of preventing the intermediate temperature take-off switching valve 28 from sticking. Thereby, generation | occurrence | production of hot water supply or hot water supply temperature fluctuation can be prevented reliably.

  In step S600, the control device 24 determines whether or not the medium hot water temperature is lower than the first reference temperature. When the intermediate temperature water temperature is lower than the first reference temperature, the control device 24 proceeds to step S703, performs the sticking prevention operation for operating the intermediate temperature extraction switching valve 28 with the first operation amount, and then ends the processing of this flowchart. To do. If the hot water temperature is lower than the first reference temperature, even if the hot water supply operation is performed during or immediately after the sticking prevention operation of operating the intermediate temperature take-off switching valve 28 with a relatively large first operation amount, the hot water temperature is high. It is possible to reliably suppress hot water supply or hot water temperature fluctuation. Therefore, in this case, a more excellent anti-adhesion effect can be obtained by performing an anti-adhesion operation that operates the intermediate temperature extraction switching valve 28 with a relatively large first operation amount.

  On the other hand, when the intermediate warm water temperature is equal to or higher than the first reference temperature in step S600, the control device 24 proceeds to step S702 and operates to prevent the sticking prevention valve 28 from operating with the operation amount smaller than the first operation amount. Then, the process of this flowchart is terminated. Thus, in the present embodiment, the state where the intermediate temperature extraction switching valve 28 is not operating continues for the first reference time or more, and the intermediate temperature water temperature is equal to or higher than the first reference temperature and lower than the second reference temperature. In this case, the control device 24 performs a sticking prevention operation that operates the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount. If the intermediate temperature water temperature is equal to or higher than the first reference temperature and lower than the second reference temperature, the amount of operation of the intermediate temperature take-off switching valve 28 in the sticking prevention operation can be made relatively small during or immediately after the sticking prevention operation. Even if the hot water supply operation is performed, it is possible to reliably suppress the occurrence of high temperature hot water supply or hot water supply temperature fluctuation. For this reason, by doing as above, it is possible to reliably prevent the hot water supply or the hot water supply temperature fluctuation from occurring while reliably preventing the intermediate temperature extraction switching valve 28 from sticking.

  In the present embodiment, when there is a hot water supply history in the sticking prevention operation time zone during the past predetermined number of days in step S501, the control device 24 controls the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount. The sticking prevention operation to be operated is performed (step S702), or the sticking prevention operation of the intermediate temperature extraction switching valve 28 is prohibited (step S703). If there is a hot water supply history during the sticking prevention operation time period in the past predetermined number of days, it can be predicted that the possibility of the hot water supply operation being performed during or immediately after the sticking prevention operation is relatively high. Therefore, in such a case, it is possible to more reliably suppress the occurrence of high-temperature hot water supply or hot-water supply temperature fluctuations as described above.

  In the sticking prevention operation after the intermediate temperature extraction switching valve 28 has been stopped for a long time at the low temperature position, the control device 24 operates the intermediate temperature extraction switching valve 28 from the low temperature position toward the intermediate temperature position, and then the low temperature position. It is desirable to return to Thereby, even if the hot water supply operation is performed after the sticking prevention operation, it is possible to reliably suppress the occurrence of high temperature hot water supply or hot water supply temperature fluctuation.

  Further, in the sticking prevention operation after the intermediate temperature extraction switching valve 28 has been stopped at the intermediate temperature position for a long time, the control device 24 operates the intermediate temperature extraction switching valve 28 from the intermediate temperature position toward the low temperature position and then moves the intermediate temperature position. It is desirable to return to Thereby, even if the hot water supply operation is performed after the sticking prevention operation, it is possible to reliably suppress the occurrence of high temperature hot water supply or hot water supply temperature fluctuation.

  Hereinafter, modified examples will be described. In the present embodiment, instead of the above control or in addition to the above control, the following control may be performed. A temperature difference larger than the first reference temperature difference is referred to as a “second reference temperature difference”. This second reference temperature difference may be 40 ° C., for example. The state where the intermediate temperature extraction switching valve 28 is not operating continues for the first reference time or more, and the difference between the intermediate warm water temperature and the low temperature water temperature is the first reference temperature difference or more and less than the second reference temperature difference. Alternatively, the control device 24 may perform a sticking prevention operation that operates the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount. Thereby, the effect similar to the effect mentioned above is acquired.

  Further, the control device 24 is a case where the state where the intermediate temperature extraction switching valve 28 is not operating continues for the first reference time or more when the difference between the intermediate temperature water temperature and the low temperature water temperature is equal to or greater than the second reference temperature difference. However, the operation for preventing the sticking of the intermediate temperature extraction switching valve 28 may be prohibited. Thereby, the effect similar to the effect mentioned above is acquired.

  In addition, when the difference between the medium temperature water temperature and the low temperature water temperature is equal to or greater than the second reference temperature difference and the state where the medium temperature extraction switching valve 28 is not operating continues for the second reference time or longer, the control device 24 may perform the sticking prevention operation of operating the intermediate temperature extraction switching valve 28 with an operation amount smaller than the first operation amount. Thereby, the effect similar to the effect mentioned above is acquired.

Embodiment 2. FIG.
Next, the second embodiment will be described with reference to FIG. 3. The description will focus on the differences from the first embodiment described above, and the description of the same or corresponding parts will be simplified or omitted. FIG. 3 is a diagram illustrating a display example of the display unit 25a of the remote controller 25 provided in the hot water storage type hot water supply apparatus according to the second embodiment.

  In the first embodiment, in order to minimize the possibility that the hot water supply operation is performed during or immediately after the sticking prevention operation of the intermediate temperature extraction switching valve 28, the sticking prevention operation time zone is set in the midnight time zone. . However, depending on the lifestyle of the user, there is a possibility that the hot water supply operation is frequently performed even at midnight.

  Therefore, in this embodiment, the user can set the sticking prevention operation time zone to an arbitrary time zone by operating the remote controller 25. FIG. 3 shows a display example of the display unit 25a when an operation for setting the sticking prevention operation time zone is performed on the remote controller 25. In this example, the sticking prevention operation time zone is displayed with the name “maintenance time zone”. For example, by using such a name, the user can easily understand.

  As shown in FIG. 3, when an operation for setting the sticking prevention operation time zone is performed, a setting screen a “maintenance time zone XX hour to XX hour” is first displayed on the display unit 25a. The user can confirm the sticking prevention operation time zone set by the user by looking at the setting screen a. The display on the display unit 25a is switched from the setting screen a to the guidance screen b “Maintenance time zone has been set”, and then to the guidance screen c “In maintenance time zone”. Switch to the guidance screen d "Please refrain". By displaying such guidance screens b to d, the user is notified that hot water should not be used during the sticking prevention operation time period. Thereby, since possibility that a user will utilize hot water supply in an adhesion prevention operation time zone can be reduced reliably, generation | occurrence | production of high temperature hot water supply or hot water supply temperature fluctuation can be suppressed reliably.

  According to the present embodiment, the user can arbitrarily set the sticking prevention operation time zone according to the lifestyle of each user, so that the middle temperature take-off switching valve 28 is prevented from sticking while improving convenience. The possibility that the hot water supply operation is performed during or immediately after the operation can be further reduced.

DESCRIPTION OF SYMBOLS 1 Hot water tank, 1a 1st position, 1b 2nd position, 1c Hot water introduction outlet, 1d Hot water introduction port, 2 Heat pump unit, 4 Circulation pump, 7 General hot water supply side electric mixing valve, 7a Hot water side inlet, 7b Water side inlet, 7c hot water outlet, 8 high temperature piping, 9, 9a, 9b water supply pipe, 10 first hot water supply pipe, 11 bath hot water supply side electric mixing valve, 11a hot water side inlet, 11b water side inlet, 11c hot water outlet, 12 bath side circulation circuit, 13 Bath open / close valve, 14 Bath circulation pump, 15 Heat exchanger, 17 Inlet switch valve, 18 Second hot water supply pipe, 19 Flow rate sensor for hot water supply, 20 Temperature sensor for hot water supply, 21 Flow rate sensor for bath, 22 Temperature sensor for bath, 23 Water supply temperature sensor, 24 control device, 24a medium warm water use control means, 24b medium warm water use prohibition means, 24c medium Hot water use stop means, 25 remote control, 25a display, 26 hot water switching valve, 27 medium temperature return switching valve, 28 medium temperature extraction switching valve, 28a medium temperature inlet, 28b low temperature inlet, 28c water outlet, 30 medium temperature piping, 31 bath heat recovery piping 40 Hot water storage unit, 48 HP forward piping, 49 HP return piping

Claims (8)

A hot water tank,
High-temperature piping communicating with the first position of the hot water tank;
An intermediate temperature pipe communicating with the hot water storage tank at a second position lower than the first position;
An intermediate temperature inlet into which intermediate temperature water supplied from the hot water tank through the intermediate temperature pipe flows, a low temperature inlet into which low temperature water having a temperature lower than the intermediate temperature water flows, and a water outlet; An intermediate temperature extraction switching valve capable of switching the flow path between an intermediate temperature position communicating with the water outlet and a low temperature position communicating the low temperature inlet with the water outlet;
The hot water supplied from the hot water tank through the high temperature pipe flows in the hot water side inlet, the water side inlet from the water outlet of the intermediate temperature extraction switching valve, and the hot water side inlet. A mixing valve having a hot water outlet from which hot water mixed with high temperature hot water and water flowing in from the water side inlet is discharged;
Medium temperature water temperature detecting means for detecting a medium temperature water temperature which is a temperature of medium temperature water supplied to the medium temperature inlet of the medium temperature extraction switching valve;
Low temperature water temperature detecting means for detecting a low temperature water temperature that is a temperature of the low temperature water supplied to the low temperature inlet of the intermediate temperature extraction switching valve;
Control means for controlling the intermediate temperature extraction switching valve and the mixing valve,
The state where the intermediate temperature extraction switching valve is not operating continues for a first reference time and the intermediate temperature water temperature is lower than the first reference temperature, or the intermediate temperature extraction switching valve is not operating. Is continued for the first reference time and the difference between the intermediate temperature water temperature and the low temperature water temperature is less than the first reference temperature difference, the control means sets the intermediate temperature extraction switching valve to A hot water storage type hot water supply device that performs an anti-sticking operation that operates with a single operation amount.   In the sticking prevention operation after the intermediate temperature extraction switching valve is stopped at the low temperature position, the control means operates the intermediate temperature extraction switching valve from the low temperature position toward the intermediate temperature position and then performs the low temperature operation. The hot water storage type hot water supply device according to claim 1, which is returned to the position.   In the sticking prevention operation after the intermediate temperature extraction switching valve is stopped at the intermediate temperature position, the control means operates the intermediate temperature extraction switching valve from the intermediate temperature position toward the low temperature position after the intermediate temperature extraction switch valve is operated. The hot water storage type hot water supply device according to claim 1 or 2, wherein the hot water storage device is returned to the position. The second reference temperature is a temperature higher than the first reference temperature,
The second reference temperature difference is a temperature difference larger than the first reference temperature difference,
The state where the intermediate temperature extraction switching valve is not operating continues for the first reference time and the intermediate temperature water temperature is equal to or higher than the first reference temperature and lower than the second reference temperature, or the intermediate temperature The state in which the take-out switching valve is not operating continues for the first reference time or more, and the difference between the medium hot water temperature and the low temperature water temperature is the first reference temperature difference or more and less than the second reference temperature difference. The control means implements a sticking prevention operation for operating the intermediate temperature extraction switching valve with an operation amount smaller than the first operation amount. Hot water storage system.   The control means operates when the intermediate temperature extraction switching valve operates when the intermediate temperature water temperature is equal to or higher than the second reference temperature, or when the difference between the intermediate temperature water temperature and the low temperature water temperature is equal to or higher than the second reference temperature difference. 5. The hot water storage type hot water supply apparatus according to claim 4, wherein the operation of preventing the sticking of the intermediate temperature take-off switching valve is prohibited even when the state of not being continued for the first reference time or longer. The second reference time is longer than the first reference time,
The intermediate temperature water temperature is not less than the second reference temperature, or the difference between the intermediate temperature water temperature and the low temperature water temperature is not less than the second reference temperature difference, and the intermediate temperature extraction switching valve is not operating. The said control means implements the sticking prevention operation | movement which operates the said intermediate temperature extraction switching valve by the operation amount smaller than the said 1st operation amount when it continues more than said 2nd reference time. The hot water storage type hot water supply apparatus described in 1. The control means performs the sticking prevention operation of the intermediate temperature extraction switching valve in a specific time zone of the day,
The hot water storage type hot water supply apparatus according to any one of claims 1 to 6, further comprising a user interface that allows a user to set the specific time zone. The control means performs the sticking prevention operation of the intermediate temperature extraction switching valve in a specific time zone of the day,
If there is a history of hot water supply from the mixing valve in the specific time period during the past predetermined number of days, the control means operates the intermediate temperature extraction switching valve with an operation amount smaller than the first operation amount. The hot water storage type hot water supply apparatus according to any one of claims 1 to 7, wherein the sticking prevention operation is performed or the sticking prevention operation of the intermediate temperature extraction switching valve is prohibited.

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