JP2015232425A - Hot water storage water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of suppressing insufficiently heated water from flowing into a hot water storage tank at an initial stage of a hot water storage operation, and capable of suppressing variation of required time from a start instruction of the hot water storage operation until the start of the hot water storage operation.SOLUTION: The hot water storage type water heater includes: heating means for heating water; a hot water storage tank for storing water heated by the heating means; a hot water storage path having a flow passage for guiding the water from the hot water storage tank to the heating means, and a flow passage for guiding the water which has passed through the heating means to the hot water storage tank; a heat utilization path having a flow passage for guiding the water from the heating means to heat utilization equipment, and a flow passage for guiding the water which has passed through the heat utilization equipment to the heating means; switching means for switching between the hot water storage path and the heat utilization path; and control means for allowing the water to circulate in the heat utilization path before starting the hot water storage operation for circulating the water in the hot water storage path, and after the elapsed time from the circulation start has reached a threshold value, for switching from the heat utilization path to the hot water storage path.

Description

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

  In the conventional hot water storage type water heater disclosed in Patent Document 1 below, when a request to shift from a reheating operation to a hot water storage operation occurs, the target temperature of the heated water heated by the heating means (water refrigerant heat exchanger) Is switched from the second target value to the first target value, the hot water transfer operation is performed to supply the heated water to the additional circuit and the hot water transfer operation is performed after the hot water storage operation is performed. When the hot water storage operation is performed immediately after the operation, the temperature of the hot water stored in the tank is prevented from deviating from the requirement and rising and falling.

JP 2013-32903 A

  In the above-described conventional technology, the hot water storage operation is controlled to start based on the temperature condition of the heated water heated by the heating means. Therefore, the hot water storage operation is performed depending on the temperature state of the system when the hot water storage operation is started. The time required to start varies greatly. Since the timing at which switching to hot water storage operation occurs after the user gives an instruction to switch operation, the user may have a suspicion that the product is malfunctioning (defective).

  The present invention has been made to solve the above-described problems, and can prevent inadequately heated water from flowing into the hot water storage tank in the initial stage of the hot water storage operation, and the hot water storage operation starts from the start instruction of the hot water storage operation. It is an object of the present invention to provide a hot water storage type hot water heater that can suppress variations in required time to start.

  The hot water storage type hot water heater according to the present invention includes a heating means for heating water, a hot water storage tank for storing water heated by the heating means, a flow path for guiding water from the hot water storage tank to the heating means, and water that has passed through the heating means. A hot water storage path having a flow path for guiding water to the hot water storage tank, a heat utilization path having a flow path for guiding water from the heating means to the heat utilization apparatus, and a flow path for guiding water that has passed through the heat utilization apparatus to the heating means, and hot water storage Switching means for switching between the path and the heat utilization path, and circulating water in the heat utilization path before starting the hot water storage operation for circulating water in the hot water storage path, and after the elapsed time from the start of the circulation reaches a threshold, And a control means for switching from the use route to the hot water storage route.

  According to the hot water storage type water heater of the present invention, inadequately heated water can be prevented from flowing into the hot water storage tank in the initial stage of the hot water storage operation, and variation in the time required from the start of the hot water storage operation to the start of the hot water storage operation can be reduced. It becomes possible to suppress.

It is a block diagram which shows the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the water flow path | route in the hot water storage operation of the hot water storage type water heater of Embodiment 1 of this invention. It is a figure which shows the water flow path | route in the heat | fever utilization driving | operation of the hot water storage type water heater of Embodiment 1 of this invention. It is a flowchart which shows the control operation which a control part implements when starting hot water storage operation in Embodiment 1 of this invention. It is a flowchart which shows the control action which a control part implements when starting a hot water storage driving | operation in a reference example. It is a flowchart which shows the control action which a control part implements when starting hot water storage operation in Embodiment 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a hot water storage type water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, a hot water storage type water heater 70 according to the first embodiment includes a tank unit 60 including a hot water storage tank 7, an HP unit 6 that uses a heat pump cycle, and a user's operation command and set value. Remote control device 52 that accepts the change operation. The HP unit 6 and the tank unit 60 are connected to each other via an HP outgoing pipe 11, an HP return pipe 12, and electrical wiring (not shown). The tank unit 60 includes a control unit 51 (control unit). Operations of various valves, pumps and the like included in the tank unit 60 and the HP unit 6 are controlled by a control unit 51 electrically connected thereto. The control unit 51 and the remote control device 52 are connected so that they can communicate with each other. Although not shown, the remote control device 52 is equipped with a display unit for displaying information such as the state of the hot water storage hot water heater 70, an operation unit such as a switch operated by a user, a speaker, a microphone, and the like.

  The HP unit 6 functions as a heating unit that heats water. The HP unit 6 has a refrigerant circuit in which the compressor 1, the water-refrigerant heat exchanger 2, the expansion valve 3, and the air heat exchanger 5 are annularly connected by the refrigerant pipe 4, and operates the heat pump cycle. The water refrigerant heat exchanger 2 heats water by exchanging heat between the high-temperature and high-pressure refrigerant compressed by the compressor 1 and water.

  In the hot water storage tank 7, hot water can be stored by forming a temperature stratification in which the upper side is hot and the lower side is low. In addition to the hot water storage tank 7 and the control unit 51, the tank unit 60 incorporates various components such as the water pump 10, the heater 13, the three-way valve 14, the water pump 43, the hot water supply heat exchanger 44, and piping. The three-way valve 14 is a flow path switching means having an a port through which hot water flows in, and a b port and c port through which hot water flows out. A hot water outlet 7b and a heat source water outlet 7c are provided in the upper part of the hot water storage tank 7. The hot water outlet 7 b is connected to the b port of the three-way valve 14 via the hot water supply pipe 15. Heated water heated by the HP unit 6 during the hot water storage operation flows into the hot water storage tank 7 from the hot water outlet 7b. The heat source water outlet 7 c is connected to the primary inlet of the hot water supply heat exchanger 44 via the heat source introduction pipe 41. A water outlet 7 a and a heat source water inlet 7 d are provided in the lower part of the hot water tank 7. The water lead-in inlet 7 a is connected to the suction side of the water pump 10 through a water lead-in / pipe 9. The heat source water inlet 7d is connected to the primary outlet of the hot water supply heat exchanger 44 via the heat source outlet pipe 42. A water pump 43 and a hot water supply heat source flow sensor 46 are provided in the middle of the heat source outlet pipe 42. Low temperature water flows into the hot water storage tank 7 from the water outlet 7a or the heat source water inlet 7d.

  On the surface of the hot water storage tank 7, a plurality of hot water storage temperature sensors 31 and 32 are attached at different height positions. These hot water temperature sensors 31 and 32 can detect the temperature distribution of hot water in the hot water storage tank 7. The control part 51 can grasp | ascertain the amount of remaining hot water and the amount of heat storage in the hot water storage tank 7 based on the temperature distribution. In the illustrated configuration, the number of hot water storage temperature sensors is two, but three or more hot water storage temperature sensors may be provided.

  The HP outgoing pipe 11 connects the discharge side of the water pump 10 and the inlet side of the HP unit 6. The HP return pipe 12 connects the outlet side of the HP unit 6 and the a port of the three-way valve 14. A heater 13 (heating means) is disposed in the middle of the HP return pipe 12. The heater 13 is used when the HP unit 6 does not operate normally. Below, the driving | operation operation | movement when the HP unit 6 operate | moves normally and the heater 13 is not used is demonstrated. In the middle of the HP return pipe 12 between the heater 13 and the a port of the three-way valve 14, temperature detecting means for detecting the temperature of the heated water heated by the HP unit 6 (hereinafter referred to as “heated water temperature”). 34 is arranged.

  Outside the hot water storage type water heater 70, a heating device 22 that is a heat utilization device that uses the heat of the heated water heated by the HP unit 6 is installed. The c port of the three-way valve 14 is connected to the water inlet of the heating device 22 via the heat utilization side pipe 21. The water outlet of the heating device 22 is connected to the suction side of the water pump 10 (in the middle of the water outlet / inlet piping 9) via the heat utilization side piping 23. A water supply pipe 24 that supplies water from a water source such as a water supply is connected in the middle of the heat utilization side pipe 23. A water supply valve 25 is disposed in the middle of the water supply pipe 24 extending to the outside of the hot water storage type hot water supply device 70. By closing the water supply valve 25, water supply from the water supply pipe 24 can be stopped.

  A water supply pipe 8 for supplying water from a water source such as a water supply is connected to the secondary side inlet of the hot water supply heat exchanger 44. A hot water supply flow sensor 45 is disposed in the middle of the water supply pipe 8. A mixing faucet 47 is installed outside the hot water storage type water heater 70. The water supply pipe 53 is branched from the middle of the water supply pipe 8 extending to the outside of the hot water storage type water heater 70. The water supply pipe 53 is connected to the mixed water tap 47. The secondary outlet of the hot water supply heat exchanger 44 is connected to the hot water tap 48 via the hot water supply pipe 16. The hot water tap 48 is connected to the mixed water tap 47 via the hot water supply pipe 54. The mixing faucet 47 is connected to a hot water supply end (not shown) such as a faucet through a hot water supply pipe 55. The mixing faucet 47 can adjust the temperature of the hot water flowing through the hot water supply pipe 55 by adjusting the mixing ratio between the water supplied from the water supply pipe 53 and the hot water supplied from the hot water supply pipe 54.

  When supplying hot water to the hot water supply pipe 55, the control unit 51 operates the water pump 43 to heat the water supply in the hot water supply heat exchanger 44. The hot water in the hot water storage tank 7 is supplied to the hot water supply heat exchanger 44 through the heat source water outlet 7c and the heat source introduction pipe 41. The water supplied from the water supply pipe 8 is heated by the heat of the high-temperature water to form hot water and flows to the hot water supply pipe 16. The high-temperature water becomes low-temperature water by removing heat from the water supply in the hot water supply heat exchanger 44. The low-temperature water returns to the hot water storage tank 7 through the heat source outlet pipe 42, the water pump 43, and the heat source water inlet 7d.

  Next, the hot water storage operation will be described with reference to FIG. FIG. 2 is a diagram illustrating a water flow path in the hot water storage operation of the hot water storage type water heater 70 according to the first embodiment of the present invention. In the hot water storage operation, the control unit 51 operates the HP unit 6 and the water pump 10. The three-way valve 14 is configured to communicate with the HP return pipe 12 and the hot water supply pipe 15 (ab path). The water in the lower part of the hot water storage tank 7 is guided to the water / refrigerant heat exchanger 2 in the HP unit 6 through the water outlet / inlet 7a, the water outlet / inlet pipe 9, the water pump 10, and the HP outgoing pipe 11. The heated water heated by the water-refrigerant heat exchanger 2 flows into the upper part of the hot water storage tank 7 through the HP return pipe 12, the three-way valve 14, the hot water supply pipe 15, and the hot water outlet 7b. By such hot water storage operation, high-temperature heated water is stored in the hot water storage tank 7 from the top to the bottom, so that heat is accumulated in the hot water storage tank 7. In the first embodiment, the water outlet / inlet 7a, the water outlet / inlet pipe 9, the water pump 10, the HP outgoing pipe 11, the water refrigerant heat exchanger 2, the HP return pipe 12, the three-way valve 14, the hot water supply pipe 15, and the hot water The outlet 7b corresponds to a hot water storage path. During the hot water storage operation, the control unit 51 controls the operation speed of the water pump 10 so that the heating water temperature detected by the temperature detection unit 34 matches the first target value.

  Next, the heat utilization operation will be described with reference to FIG. FIG. 3 is a diagram illustrating a water flow path in the heat utilization operation of the hot water storage type water heater 70 according to the first embodiment of the present invention. In the heat utilization operation, the control unit 51 operates the HP unit 6 and the water pump 10. The three-way valve 14 is configured to communicate with the HP return pipe 12 and the heat utilization side pipe 21 (ac path). Heated water heated by the water / refrigerant heat exchanger 2 in the HP unit 6 is guided to the heating device 22 through the HP return pipe 12, the three-way valve 14, and the heat utilization side pipe 21. The temperature of the heated water decreases while passing through the heating device 22. This reduced temperature water passes through the heat utilization side pipe 23, a part of the water lead-in / out pipe 9, the water pump 10, and the HP outgoing pipe 11, and is led to the water refrigerant heat exchanger 2 in the HP unit 6. Circulate. In the first embodiment, the water refrigerant heat exchanger 2, the HP return pipe 12, the three-way valve 14, the heat use side pipe 21, the heat use side pipe 23, a part of the water outlet / inlet pipe 9, the water pump 10, and the HP Outward piping 11 corresponds to a heat utilization path. During the heat utilization operation, the control unit 51 controls the operation speed of the water pump 10 so that the heating water temperature detected by the temperature detection means 34 matches the second target value. The second target value is a temperature lower than the first target value.

  The hot water storage path and the heat utilization path partially overlap. That is, a part of the water lead-in / out pipe 9, the water pump 10, the HP outgoing pipe 11, the water refrigerant heat exchanger 2, the HP return pipe 12, and the three-way valve 14 are shared by the hot water storage path and the heat utilization path. The hot water storage path and the heat utilization path are switched by the three-way valve 14.

  The hot water storage operation of FIG. 2 and the heat utilization operation of FIG. 3 cannot be performed simultaneously due to the path configuration. When carrying out hot water storage operation, it is necessary to stop the heat utilization operation. In the heat utilization operation, heated water having a second target value lower than the first target value flows through the HP return pipe 12. When switching from the heat utilization operation to the hot water storage operation, heated water having a temperature lower than the first target value may flow into the upper portion of the hot water storage tank 7. When heated water having a temperature lower than the first target value flows into the upper part of the hot water storage tank 7, the temperature of the upper part of the hot water storage tank 7 decreases. It is not desirable that the temperature of the upper part in the hot water storage tank 7 decreases.

  FIG. 4 is a flowchart showing a control operation performed by control unit 51 when the hot water storage operation is started in the first embodiment. When there is an instruction to start the hot water storage operation in step S1 of FIG. 4, the control unit 51 proceeds to step S2. In step S2, the control unit 51 determines whether or not the three-way valve 14 has been switched to the heat utilization path side (ac path). If the three-way valve 14 is not switched to the heat utilization path side, the control unit 51 proceeds to step S3. The controller 51 proceeds to step S4 after switching the three-way valve 14 to the heat use path side in step S3. When the three-way valve 14 is switched to the heat utilization path side in step S2, the control unit 51 proceeds to step S4 as it is.

  In step S4, the control unit 51 operates the HP unit 6 and the water pump 10, and controls the operation speed of the water pump 10 so that the heating water temperature detected by the temperature detection unit 34 matches the first target value. . The control unit 51 proceeds from step S4 to step S5. In step S5, the control unit 51 has reached a threshold value (for example, 30 seconds) after the start of operation of the HP unit 6 and the water pump 10 in step S4 (hereinafter also simply referred to as “elapsed time”). Determine whether or not. When the elapsed time has not reached the threshold value in step S5, the control unit 51 continues the operation on the heat utilization route as it is. When the elapsed time reaches the threshold value in step S5, the control unit 51 proceeds to step S6. After switching the three-way valve 14 to the hot water storage path side (ab path) in step S6, the control unit 51 proceeds to step S7. In step S <b> 7, the hot water storage operation starts when the heated water heated by the HP unit 6 starts to flow into the upper part of the hot water storage tank 7.

  As described above, in the first embodiment, before the hot water storage operation is started, water is circulated through the heat utilization path, and after the elapsed time from the start of the circulation reaches the threshold, the hot water storage operation is switched to the hot water storage path. Start. The heating water temperature rises toward the first target value while the water circulates in the heat utilization path before the start of the hot water storage operation. Therefore, according to the first embodiment, after the hot water storage operation is started, water having a temperature lower than the first target value, that is, insufficiently heated water, can be reliably suppressed from flowing into the upper portion of the hot water storage tank 7. . In addition, since the hot water storage operation starts when the elapsed time after starting the operation of the HP unit 6 and the water pump 10 reaches the threshold value, there is a variation in the required time from the start instruction of the hot water storage operation to the start of the hot water storage operation. Can be suppressed. Therefore, according to this Embodiment 1, after a user instruct | indicates the switching of a driving | operation, it can suppress reliably that the timing which the switching to a hot water storage driving | occur | producing occurs can be suppressed reliably, and a user is in trouble (failure) of a product. It is possible to surely suppress the suspicion that there is. Furthermore, the control software corresponding to the flowchart of FIG. 4 does not need to be configured to start the hot water storage operation based on the temperature condition of the heated water, and can be simplified. Therefore, according to the first embodiment, the development load of control software can be reduced.

  The HP unit 6 may have a variable heating capacity for heating water. For example, by making the capacity of the compressor 1 variable, the heating capacity of the HP unit 6 can be made variable. In the case of the inverter-controlled compressor 1, by changing the rotational speed of the compressor 1, the capacity of the compressor 1 can be changed and the heating capacity of the HP unit 6 can be made variable. The control unit 51 may shorten the threshold value of step S5 in FIG. 4 as the heating capacity of the HP unit 6 is higher. For example, the threshold is set to 30 seconds for a heating capacity of 4.5 kW, the threshold is set to 20 seconds for a heating capacity of 6.0 kW, and the threshold is set to 10 seconds for a heating capacity of 7.2 kW. Also good. The higher the heating capacity, the faster the temperature of the heated water rises. When the heating capacity is high, even if the threshold is set to a short time, it is possible to sufficiently suppress the insufficiently heated water from flowing into the upper part of the hot water storage tank 7 after the hot water storage operation is started. When the heating capacity is high, the hot water storage operation can be started early by shortening the threshold value, and energy efficiency is improved.

  In the case of the hot start in which the hot water storage operation is started from the state where the HP unit 6 is warm, the control unit 51 performs the steps of FIG. 4 compared to the case of the cold start in which the hot water storage operation is started from the state where the HP unit 6 is cooled. The threshold value of S5 may be a short time. When the HP unit 6 performs another operation before the start of the hot water storage operation, such as when switching from the heat utilization operation to the hot water storage operation, this corresponds to a hot start. When the HP unit 6 has been stopped for a long time before the start of the hot water storage operation, it corresponds to a cold start. In the case of hot start, the temperature of the heated water rises faster than in the case of cold start. In the case of hot start, even if the threshold value is set to a short time, it is possible to sufficiently suppress the insufficiently heated water from flowing into the upper part of the hot water storage tank 7 after the hot water storage operation is started. In the case of hot start, the hot water storage operation can be started early by shortening the threshold value, and energy efficiency is improved. In the case of cold start, by setting the threshold value longer than in the case of hot start, it is possible to lengthen the time for water to circulate in the heat utilization path before the start of hot water storage operation, and to raise the temperature of the heated water sufficiently. it can. For this reason, even in the case of a cold start, it is possible to reliably suppress the insufficiently heated water from flowing into the upper part of the hot water storage tank 7 after the hot water storage operation is started.

  Next, a reference example will be described. FIG. 5 is a flowchart illustrating a control operation performed by the control unit 51 when the hot water storage operation is started in the reference example. In the flowchart of FIG. 5, the same or corresponding parts as those in the flowchart of FIG. As illustrated in FIG. 5, in the reference example, the control unit 51 proceeds from step S4 to step S8. In step S8, the control unit 51 determines whether or not the heating water temperature detected by the temperature detection unit 34 has reached the first target value. When the heating water temperature does not reach the first target value in step S8, the control unit 51 continues the operation on the heat utilization path as it is. When the heating water temperature reaches the first target value in step S8, the control unit 51 proceeds to step S6 and switches the three-way valve 14 to the hot water storage path side.

  In the reference example, since the hot water storage operation is started when the temperature of the heated water detected by the temperature detection means 34 reaches the first target value, switching to the hot water storage operation occurs depending on the temperature state of the system at that time. Timing varies greatly. In particular, when the heating capacity of the HP unit 6 is low, in the case of a cold start, etc., since it takes a long time for the heated water temperature to reach the first target value, the timing for switching to hot water storage operation is greatly delayed. There is a fear. Therefore, in the reference example, the time required for the hot water storage operation to start after the user gives an instruction to switch the operation greatly varies, and in particular, the timing of switching to the hot water storage operation may be greatly delayed. The user may have a suspicion that the product is malfunctioning. Further, the control software corresponding to the flowchart of the reference example of FIG. 5 needs to be configured to start the hot water storage operation based on the temperature condition of the heated water, and thus becomes complicated. Therefore, in the reference example, the development load of the control software is large.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 6. The description will focus on the differences from the first embodiment described above, and the same or corresponding parts will be denoted by the same reference numerals. Is omitted.

  FIG. 6 is a flowchart illustrating a control operation performed by the control unit 51 when the hot water storage operation is started in the second embodiment. In the flowchart of FIG. 6, the same or corresponding parts as those in the flowchart of FIG. As shown in FIG. 6, in the second embodiment, the control unit 51 proceeds from step S4 to step S9. In step S9, the control unit 51 determines whether or not the heating water temperature detected by the temperature detection unit 34 has reached the first target value. When the heating water temperature reaches the first target value in step S9, the control unit 51 proceeds to step S6 and switches the three-way valve 14 to the hot water storage path side. If the heating water temperature has not reached the first target value in step S9, the control unit 51 proceeds to step S10. In step S10, the control unit 51 determines whether or not the elapsed time after starting the operation of the HP unit 6 and the water pump 10 in step S4 has reached a threshold (for example, 30 seconds). If the elapsed time has not reached the threshold value in step S10, the control unit 51 returns to step S9. When the elapsed time reaches the threshold value in step S10, the control unit 51 proceeds to step S6 and switches the three-way valve 14 to the hot water storage path side.

  As described above, in the second embodiment, when the heating water temperature reaches the first target value, the heat utilization path is switched to the hot water storage path even if the elapsed time has not reached the threshold value. According to the second embodiment, when the heating capacity of the HP unit 6 is high, in the case of hot start, etc., when the heated water temperature reaches the first target value in a time shorter than the threshold value, the hot water storage operation is performed early. To improve energy efficiency. On the other hand, when the heating capacity of the HP unit 6 is low or when the heating water temperature rises slowly, such as in a cold start, the hot water storage operation starts by switching to the hot water storage path when the elapsed time reaches the threshold value. It is possible to prevent the time required until the time is increased. According to the second embodiment, after the user gives an instruction to switch the operation, it is possible to reliably suppress the timing at which the switching to the hot water storage operation is greatly delayed. It is possible to surely suppress the suspicion that there is.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above. In the above-described embodiment, the heat utilization device is described as the heating device 22, but the heat utilization device in the present invention can be applied to a device that supplies heat to a heat load other than heating.

DESCRIPTION OF SYMBOLS 1 Compressor, 2 Water refrigerant | coolant heat exchanger, 3 Expansion valve, 4 Refrigerant piping, 5 Air heat exchanger, 6 HP unit, 7 Hot water storage tank, 7a Water outlet inlet, 7b Hot water outlet inlet, 7c Heat source water outlet, 7d Heat source water inlet, 8 water supply piping, 9 water lead-in / out piping, 10 water pump, 11 HP outgoing piping, 12 HP return piping, 13 heater, 14 three-way valve, 15 hot water supply piping, 16 hot water supply piping, 21 heat utilization side piping , 22 Heating equipment, 23 Heat utilization side piping, 24 Water supply piping, 25 Water supply valve, 31, 32 Hot water storage temperature sensor, 34 Temperature detection means, 41 Heat source introduction piping, 42 Heat source extraction piping, 43 Water pump, 44 Hot water supply heat Exchanger, 45 Hot-water supply flow sensor, 46 Hot-water supply heat source flow sensor, 47 Mixer tap, 48 Hot-water tap, 51 Control unit, 52 Remote control device, 53 Water supply pipe, 54, 55 Hot water supply piping, 60 tank units, 70 hot water storage type water heater

Claims (5)

Heating means for heating water;
A hot water storage tank for storing water heated by the heating means;
A hot water storage path having a flow path for guiding water from the hot water storage tank to the heating means and a flow path for guiding water that has passed through the heating means to the hot water storage tank;
A heat utilization path having a flow path for guiding water from the heating means to the heat utilization apparatus and a flow path for guiding water that has passed through the heat utilization apparatus to the heating means;
Switching means for switching between the hot water storage path and the heat utilization path;
Control for switching water from the heat utilization path to the hot water storage path after the water has been circulated through the heat utilization path before starting the hot water storage operation for circulating water through the hot water storage path, and the elapsed time from the start of the circulation reaches a threshold value Means,
Hot water storage type water heater equipped with.   The hot water storage type hot water supply device according to claim 1, wherein the threshold value is set to be shorter as the heating capability of the heating means is higher.   In the case of hot start in which the hot water storage operation is started from a state in which the heating means is warm, the threshold value is made shorter than in the case of cold start in which the hot water storage operation is started from a state in which the heating means is cold. The hot water storage type water heater according to claim 1 or 2.   The hot water storage type water heater according to any one of claims 1 to 3, wherein the heat utilization device is a heating device. Temperature detecting means for detecting the temperature of the water heated by the heating means,
The said control means switches from the said heat utilization path | route to the said hot water storage path | route, even if the said elapsed time has not reached the said threshold value, when the detected temperature of the said temperature detection means reaches | attains a target value. The hot water storage type water heater according to any one of 4.

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