JP2009047377A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater capable of simplifying an operation relating to reheating of hot water in a hot water storage tank, and preventing running-out of hot water on the day following a day when no-reheating is set. <P>SOLUTION: A restriction on reheating for restricting reheating in a daytime zone of a hourly rate system is manually set by a reheating restriction setting means 84. The reheating is performed by a heat pump unit 75 in the daytime zone when the reheating restriction is not set, and the amount of remaining hot water detected by a remaining hot water detecting means 86 is less than a predetermined amount of remaining hot water. When the reheating restriction is set in the daytime zone, reheating is not performed even when the amount of remaining hot water detected by the remaining hot water detecting means 86 becomes less than the predetermined amount of remaining hot water. The setting of reheating restriction is automatically released from the termination of the daytime zone having the reheating restriction, to the daytime zone of the next day by a releasing means 89. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus that uses a charge system according to time.

  As a power rate system, there is an hourly rate system in which electricity is supplied all day long, but the electricity rate in the nighttime period is low and the electricity rate in the daytime period is high, and the water heater that uses this hourly rate system Then, mainly hot water is boiled and stored in a hot water storage tank using electric power in the night time zone where electricity charges are low, and hot water is supplied from this hot water storage tank.

  In addition, if the amount of remaining hot water in the hot water storage tank is less than the preset amount of remaining hot water due to the large amount of hot water used during the daytime hours, the hot water is heated up to the preset amount of remaining hot water, causing hot water to run out. There is a function to prevent boiling.

  You can switch between setting and canceling the boiling increase during the daytime by manually operating the boiling increase setting button on the remote control. In the same manner, when the setting for increasing the boiling is canceled, the setting for increasing the boiling is continued unless the manual setting is performed (see, for example, Patent Document 1).

The setting and release of reheating during this daytime period is canceled when the user thinks that he / she does not use much hot water, and when he / she wants to prevent the hot water from running out. The setting is increased.
JP-A-11-223386 (page 3, FIG. 5)

  However, if the user wants to avoid running out of hot water the day after releasing the hot water setting because he thinks he will not use much hot water, he needs to set up hot water. There is a problem that both the release and the release must be manually operated, and the operation becomes complicated.

  In addition, if forgetting to set the heating on the next day after canceling the heating setting, the heating is not performed in the daytime period, and hot water may run out.

  The present invention has been made in view of the above points, and can simplify the operation related to the boiling of hot water in the hot water storage tank, and ensure that the hot water runs out on the day after the day set so as not to be heated. An object is to provide a hot water supply device that can be prevented.

  The hot water supply apparatus according to claim 1, wherein a hot water storage tank for storing hot water, a boiling means for boiling the hot water stored in the hot water storage tank using the electric power of the hourly rate system, and the remaining hot water amount in the hot water storage tank Manually set the remaining hot water amount detecting means to detect, the time zone detecting means for detecting the time zone of the hourly fee system, and the boiling increase limit for restricting the increase in daytime hours of the hourly fee system If there is no boiling increase restriction setting and the remaining hot water amount detected by the remaining hot water amount detecting means is less than a preset remaining hot water amount in the daytime hours of the boiling rate limit setting means and the hourly rate system The boiling means increases the amount of hot water in the hot water storage tank, and if the boiling increase limit is set, it increases even if the remaining hot water amount detected by the remaining hot water amount detecting means is less than a preset remaining hot water amount. Boiling increase control means that does not In which daytime which Kiniezo limit is set is provided with a release means for automatically releasing the setting of boiling up limit from the end of the next day of the daytime.

  The hot water supply apparatus according to claim 2 is the hot water supply apparatus according to claim 1, wherein a minimum remaining hot water amount setting for setting a minimum remaining hot water amount to ensure a minimum remaining hot water amount in the hot water storage tank even when the increase in boiling point is set. If the boiling increase control means has a setting for limiting the increase in boiling and the amount of remaining hot water detected by the remaining hot water amount detecting means is less than the minimum remaining hot water amount, The hot water in the hot water storage tank is heated up to the minimum remaining hot water amount by the boiling means.

  According to the hot water supply device according to claim 1, the boiling increase limit for limiting the increase in the daytime time zone of the hourly rate system can be manually set, and further, the daytime time zone in which the boiling increase limit is set ends. Since the boiling limit setting is automatically canceled by the daytime period of the next day, manual operation to cancel the boiling limit setting is not required, simplifying the operation and forgetting to cancel the boiling limit setting. It is possible to reliably prevent hot water from running out.

  According to the hot water supply apparatus of the second aspect, in addition to the effect of the hot water supply apparatus of the first aspect, the boiling increase limit is set in the daytime period of the hourly rate system and is detected by the remaining hot water amount detecting means. When the amount of remaining hot water is less than the preset minimum remaining hot water amount, the boiling water is used to increase the hot water in the hot water storage tank to the minimum remaining hot water amount. A limited amount of remaining hot water can be secured and hot water shortage can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 2, the hot water supply device 11 includes a main body unit 12 and an outdoor unit 13 for boiling hot water, and has a function of adding bath water stretched on the bathtub 14.

  The main unit 12 has a hot water storage tank 17 for storing hot water. The hot water storage tank 17 includes an upper position of the hot water storage tank 17 and a 1/5 position and a 2/5 position corresponding to the capacity from the upper portion of the hot water storage tank 17. The thermistors 18a to 18f as temperature detecting means for detecting the hot water temperature in the hot water storage tank 17 are disposed at the 3/5 position, the 4/5 position, and the lower position of the hot water storage tank 17, respectively.

  A water supply path 20 connected to a water supply source such as a water pipe is connected to the lower part of the hot water storage tank 17. The water supply path 20 is provided with a pressure reducing valve 21 for reducing the water supply pressure and a check valve 22 for restricting the backflow.

  An upper take-out path 25 is connected to the upper part of the hot water tank 17, and an intermediate part take-out path 26 is located between the thermistor 18b at the 1/5 position and the thermistor 18c at the 2/5 position, which is the intermediate position in the vertical direction of the hot water tank 17. It is connected. A check valve 27 that allows hot water to flow only in the direction of removing hot water from the intermediate portion of the hot water storage tank 17 is disposed in the intermediate portion extraction path 26. The upper take-out path 25 and the intermediate take-out path 26 are connected to a regulating valve 28 that is a motorized valve, and by this regulating valve 28, the hot water in the upper part of the hot water storage tank 17 taken out from the upper take-out path 25 and the intermediate part take-out path 26 are connected. The hot water storage tank 17 is taken out by adjusting the mixing ratio with the hot water in the intermediate part. The mixing ratio that can be adjusted by the adjusting valve 28 includes the case where either one is 100% and the other is 0%. The adjustment valve 28 is connected to a hot water supply path 29 for supplying the hot water taken out. The hot water supply path 29 is provided with a take-off temperature detection sensor 30 for detecting the temperature of the hot water. The upper extraction path 25, the intermediate section extraction path 26, the regulating valve 28, and the hot water supply path 29 form an extraction path 31 for extracting hot water from the hot water storage tank 17.

  Further, the hot water supply path 29 (extraction path 31) and the water supply path 20 are connected to a mixing valve 34 for hot water supply and a mixing valve 35 for a bathtub, respectively. These mixing valves 34 and 35 mix hot water from the hot water supply path 29 (extraction path 31) and water from the water supply path 20 to supply hot water at a predetermined temperature. The mixing ratio that can be adjusted by the mixing valves 34 and 35 includes the case where either one is 100% and the other is 0%. The hot water supply path 29 and the water supply path 20 connected to the mixing valves 34 and 35 are provided with check valves 36 and 37 for restricting the back flow to the hot water supply path 29 side and the water supply path 20 side, respectively.

  The hot water mixing valve 34 supplies hot water having a hot water supply set temperature set by, for example, a main remote controller installed in a kitchen or the like, a bathroom remote controller installed in a bathroom, or the like. A hot water supply passage 38 for supplying hot water to a predetermined hot water supply place is connected to the mixing valve 34 for hot water supply, and a flow rate sensor 39 for measuring the flow rate and a hot water supply temperature sensor 40 for detecting the temperature are provided in the hot water supply passage 38. Yes.

  The mixing valve 35 for the bathtub supplies hot water at a hot water set temperature set by the main remote controller installed in the kitchen or the bathroom or the bathroom remote controller installed in the bathroom, for example, or at the time of reheating operation by the bathroom remote controller Supply hot water at a temperature according to the water repulsion ability. The mixing valve 35 for the bathtub is connected to a hot water supply path 41 for supplying hot water to the bathtub 14, and the hot water supply path 41 for bathtub is provided with a hopper 42 having a water supply electromagnetic valve for opening and closing the flow path. Yes.

  In addition, on the downstream side of the connection point of the mixing valves 34 and 35 in the hot water supply path 29 (extraction path 31), a check valve 43 that restricts the backflow to the upstream side, and the bathtub water in the bathtub 14 on the heat load side A return path 45 is connected via the heat exchanger 44 for heat exchange to return the hot water that has passed through the heat exchanger 44 for heat return to the hot water storage tank 17. In this return path 45, for hot water, the hot water is taken out from the hot water storage tank 17 through the extraction path 31 and the hot water that has passed through the heat exchanger for hot water 44 is circulated so as to return to the hot water storage tank 17 through the return path 45. A circulation pump 46 is provided, and an intake temperature detection sensor 51 for detecting the temperature of the hot water that has passed through the heat exchanger for remedy 44 is provided.

  A switching valve 47 is connected to the return path 45. The switching valve 47 is connected to the upper part of the hot water storage tank 17 and is located at the intermediate position in the vertical direction of the hot water storage tank 17 at the 3/5 position. An intermediate intake path 49 connected between the thermistor 18d and the 4/5 position thermistor 18e, and a lower intake path 50 connected to the lower part of the hot water storage tank 17 through the water supply path 20 are connected. By this switching valve 47, the return path 45 is switched so that any one of the upper intake path 48, the intermediate part intake path 49, and the lower intake path 50 is connected. Then, the return path 45, the upper intake path 48, the intermediate intake path 49, and the lower intake path 50 pass through the heat exchanger 44 for remedy at a plurality of positions in the upper, intermediate and lower portions of the hot water tank 17. A plurality of intake paths 52 for returning the hot water is formed.

  The take-out path 31, the plurality of take-in paths 52, and the switching valve 47 form a tracking circuit 53.

  In addition, the memorial heat exchanger 44 and the bathtub 14 are connected by a circulation path 54 for the bathtub. The circulation path 54 for the bathtub includes a return pipe 55 that takes in the bathtub water of the bathtub 14 and guides it to the heat exchanger 44 for remedy, and a forward pipe 56 that guides the bathtub water that has passed through the heat exchanger 44 for remedy to the bathtub 14. Have. The return pipe 55 includes a thermistor 57 for detecting the temperature of the bathtub water taken from the bathtub 14, a pressure sensor 58 for detecting the water level of the bathtub 14, a switching valve 59 for switching the flow path when automatically filling the bathtub 14, A bath circulation pump 60 for circulating the bath water and a flow switch 61 for detecting the bath water circulation are provided. The forward pipe 56 is provided with a thermistor 62 that detects the temperature of bathtub water introduced into the bathtub 14.

  The switching valve 59 is connected to a hot water supply passage 41 for the bathtub, and hot water supplied from the hot water supply passage 41 for the bathtub can be supplied to the bathtub 14 through one pipe of the return pipe 55 or two pipes of the return pipe 55 and the forward pipe 56. It has become.

  In addition, a relief valve 65 that releases excessive pressure during boiling is connected to the upper extraction path 25 of the hot water storage tank 17, and the relief valve 65 is connected to a drainage path 66. The lower part of the hot water storage tank 17 and the drainage path 66 are connected via a drain valve 67 that drains the water in the hot water storage tank 17.

  Further, the hot water storage tank 17 side and the outdoor unit 13 are connected by a boiling circuit 70. The boiling circuit 70 includes a boiling take-out path 71 that connects the lower part of the hot water storage tank 17 and the inlet side of the outdoor unit 13, and a boiling intake path that connects the outlet side of the outdoor unit 13 and the hot water storage tank 17. Has 72. The boiling intake path 72 is connected to the return path 45 of the tracking circuit 53, and shares the switching valve 47, the upper intake path 48, the intermediate intake path 49, and the lower intake path 50. Then, the connection to the outlet side of the outdoor unit 13 is switched by the switching valve 47 to any one of the upper intake path 48, the intermediate part intake path 49, and the lower intake path 50.

  Further, the outdoor unit 13 is provided with a heat pump unit 75 as a boiling means for boiling hot water. The heat pump unit 75 has a refrigerant circuit including a boiling heat exchanger 76 functioning as a compressor and a condenser, an expansion valve, an evaporator, and the like. A heating circuit 70 is connected to the heating heat exchanger 76 of the heat pump unit 75. On the upstream side of the heating heat exchanger 76 of the heat pump unit 75, the heating circulation pump 77 for circulating the water below the hot water storage tank 17 from the boiling extraction path 71 side to the boiling intake path 72 side. Is arranged.

  The hot water supply device 11 includes a control unit 81 that controls the hot water supply device 11. FIG. 1 shows a configuration related to the heating of the control unit 81. The control unit 81 includes a main unit operation unit 82 as an operation unit provided in the main unit 12, and an operation unit installed in a kitchen or a bathroom. The remote controller 83, the thermistors 18a to 18f of the hot water storage tank 17, the heat pump unit 75, and the like are connected.

  The remote control 83 (which may be the main body operation unit 82) has a boiling increase limit setting means 84 for manually setting a boiling increase limit for limiting the increase in the daytime time period (for example, 7:00 to 23:00) of the hourly fee system. Even when the boiling increase limit is set, the hot water storage tank 17 is provided with a minimum remaining hot water amount setting means 85 for setting a minimum remaining hot water amount that secures a minimum remaining hot water amount. These boiling increase restriction setting means 84 and minimum remaining hot water amount setting means 85 can be set and operated by buttons provided on the main body operation unit 82 or the remote controller 83.

  Then, the control unit 81 detects the remaining hot water amount detecting means 86 for detecting the remaining hot water amount in the hot water storage tank 17 from the detected temperatures of the thermistors 18a to 18f, and the time zone detecting means 87 which is a timer for detecting the time zone of the hourly rate system. In the daytime hours of the hourly rate system, if there is no boiling increase restriction and the remaining hot water amount detected by the remaining hot water detection means 86 is less than a preset boiling increase reference remaining hot water amount, hot water is stored in the heat pump unit 75. The hot water in the tank 17 is boiled up to the boiling increase reference remaining hot water amount, and if the boiling increase limit is set, even if the remaining hot water amount detected by the remaining hot water amount detecting means 86 is smaller than the preset boiling increase reference remaining hot water amount Boiling increase control means 88 that does not increase boiling, function of cancellation means 89 that automatically cancels the setting of boiling increase limit from the end of the daytime time zone where the boiling increase limit is set to the daytime time zone of the next day ing.

  Further, the boiling increase control means 88 has a boiling increase limit setting in the daytime hours of the hourly rate system, and the remaining hot water amount detected by the remaining hot water amount detection means 86 is smaller than the preset minimum remaining hot water amount. If so, the heat pump unit 75 has a function of boiling the hot water in the hot water storage tank 17 to the minimum remaining hot water amount. The minimum remaining hot water amount is smaller than the boiling increase reference remaining hot water amount, and is the minimum necessary remaining hot water amount that can be arbitrarily set by the user.

  In addition, the control unit 81 includes storage means 90 that stores data handled by the control unit 81 such as setting and releasing of the boiling increase limit.

  Next, the operation of the present embodiment will be described.

  First, the hot water storage operation of the hot water storage tank 17 will be described.

  The heat pump unit 75 and the boiling circulation pump 77 of the outdoor unit 13 are operated in the night time zone (for example, from 23:00 to 7:00) of the hourly lighting system. With the operation of the boiling circulation pump 77, the water in the lower part of the hot water storage tank 17 is taken out from the boiling take-out path 71 and sent to the heat pump unit 75, and the hot water boiled in this heat pump unit 75 is boiled in the intake path 72. To the hot water storage tank 17.

  When the temperature of the hot water discharged from the heat pump unit 75 of the outdoor unit 13 is low, the switching valve 47 switches to the lower intake path 50 or the intermediate intake path 49, and the hot water having a low temperature is returned to the lower or intermediate area of the hot water storage tank 17. Prevents the temperature drop of hot water at the top of the hot water storage tank 17. In addition, when the temperature of the hot water boiled by the heat pump unit 75 of the outdoor unit 13 is equal to or higher than the target boiling temperature, the switching valve 47 switches to the upper intake path 48 and the upper temperature of the hot water storage tank 17 is higher than the target boiling temperature. Send hot water and store hot water. Thereby, low temperature hot water is not stored in the upper part of the hot water storage tank 17, and the hot water storage temperature can be increased.

  Next, the hot water supply operation will be described.

  By opening a hot water tap or the like disposed on the downstream side of the hot water supply path 38, the hot water in the hot water storage tank 17 is pushed out by the supply water pressure, and through the upper outlet path 25, the intermediate part outlet path 26, the regulating valve 28 and the hot water path 29. The hot water taken out from the hot water storage tank 17 and the water supplied from the water supply path 20 are mixed by the hot water mixing valve 34 to obtain hot water having a predetermined hot water supply temperature, and this hot water is supplied from the hot water supply passage 38. The hot water taken out to the hot water supply passage 29 is adjusted by adjusting the mixing ratio between the hot water in the upper portion of the hot water storage tank 17 taken out from the upper take-out passage 25 and the hot water in the intermediate portion of the hot water storage tank 17 taken out from the intermediate take-out passage 26 by the adjusting valve 28. Take out.

  Next, use of the bathtub 14 will be described.

  When filling the bathtub 14 with hot water, the hot water in the hot water storage tank 17 is pushed out by the water supply pressure by opening the water supply solenoid valve of the hopper 42, and the upper outlet path 25, the intermediate outlet path 26, the regulating valve 28 and the hot water path The hot water taken out from the hot water storage tank 17 through the water 29 and the water supplied from the water supply path 20 are mixed by the mixing valve 35 for the bathtub to obtain hot water at a preset temperature, and this hot water is supplied. Hot water is supplied to the bathtub 14 through the bathtub circulation path 54 constituting a part of the bathtub hot water supply path 41. When filling the bathtub 14 with hot water, by switching the hot water to flow through the return pipe 55 and the forward pipe 56 with the switching valve 59, a predetermined amount of hot water can be quickly supplied and filled. When filling the bathtub 14 with hot water, the switching valve 59 is switched so that hot water flows only to one pipe of the outgoing pipe 56, and hot water is supplied while monitoring the water level with the pressure sensor 58 of the return pipe 55. The hot water can be filled so that the water level exactly matches the set water level. In addition, the hot water taken out to the hot water supply passage 29 is adjusted by the adjustment valve 28 to adjust the mixing ratio of the hot water in the upper portion of the hot water storage tank 17 taken out from the upper take-out passage 25 and the hot water in the intermediate portion of the hot water storage tank 17 taken out from the intermediate portion take-out passage 26. And take it out.

  Then, after filling the bathtub 14, the bathtub circulation pump 60 is operated every predetermined time to circulate the bathtub water in the bathtub 14 in the circulation path 54 for the bathtub, and the temperature of the bathtub water is detected by the thermistor 57. Then, it is monitored whether there is a need for heat insulation, that is, a chasing action.

  Further, when the temperature of the bathtub water falls below the set temperature, the reheating operation is automatically performed, and the reheating operation is also performed by manual operation of the remote controller 83 or the like.

  In the reheating operation, first, the bathtub circulation pump 60 is operated, and the bathtub water is taken into the bathtub circulation path 54 and circulated to the reheating heat exchanger 44. In that state, the hot water in the hot water storage tank 17 is taken out through the upper take-out path 25, the intermediate part take-out path 26, the regulating valve 28, and the hot water supply path 29 (take-out path 31) by operating the circulation pump 46 for memory. It is sent to the heat exchanger for remedy 44, and heat is exchanged between the hot water from the hot water storage tank 17 and the bathtub water from the bathtub 14 by the heat exchanger for remedy 44. The hot water temperature in the bathtub 14 is raised. Note that the hot water taken out to the hot water supply path 29 (take-out path 31) is adjusted with the hot water in the upper part of the hot water storage tank 17 taken out from the upper take-out path 25 and the hot water in the middle part of the hot water storage tank 17 taken out from the intermediate part take-out path 26. Adjust and adjust the mixing ratio.

  Further, the hot water from the hot water storage tank 17 whose temperature has dropped after passing through the heat exchanger for remnant 44 is a return path 45, a switching valve 47, an upper intake path 48, an intermediate intake path 49, and a lower intake path 50. It returns to the hot water storage tank 17 through any one of these.

  Next, hot water boiling increase control in the daytime hours of the hourly lighting system will be described.

  In the daytime hours of the hourly electric light system, it is monitored whether the remaining hot water amount detected by the remaining hot water amount detecting means 86 is less than a preset boiling increase reference remaining hot water amount.

  When the remaining hot water amount detected by the remaining hot water detection means 86 is less than the preset boiling increase reference remaining hot water amount, the heat pump unit 75 boils the hot water in the hot water storage tank 17 if the boiling increase limit is not set. Boil up to the amount of remaining reference hot water.

  Also, when the user determines that hot water is no longer used or low, the boiling increase limit setting means 84 of the remote controller 83 is manually operated to set the boiling increase limit in the daytime period.

  In this case, since the boiling increase limit is set, even if the remaining hot water amount detected by the remaining hot water amount detecting means 86 is smaller than a preset boiling increase reference remaining hot water amount, boiling is not increased.

  However, even if the boiling increase limit is set, if the remaining hot water amount detected by the remaining hot water amount detection means 86 is smaller than the preset minimum remaining hot water amount, the heat pump unit 75 will use the minimum remaining hot water in the hot water storage tank 17. Boiling up to the amount of hot water, ensuring the minimum amount of remaining hot water, can prevent hot water shortage.

  In addition, when the daytime period when the boiling increase limit is set ends and the nighttime period starts, or when the daytime starts from the nighttime period to the next day, that is, the daytime period when the boiling increase limit is set. The setting of the boiling increase limit is automatically canceled by the daytime time of the next day after ending.

  Therefore, on the next day, if the amount of remaining hot water detected by the remaining hot water amount detecting means 86 is smaller than the preset boiling increase reference remaining hot water amount during the daytime, the heat pump unit 75 increases the amount of hot water in the hot water storage tank 17. Boil up to the standard remaining hot water volume. At this time, if the boiling increase limit is set by the user's manual operation on the next day, the boiling is not increased even if the remaining hot water amount is smaller than the preset boiling increase reference remaining hot water amount.

  In this way, it is possible to manually set the boiling increase limit that restricts the increase in daytime hours of the hourly rate system, and the daytime of the next day after the daytime period where the boiling increase limit is set ends. Since the boiling limit setting is automatically canceled by the time period, manual operation to cancel the boiling limit setting is not necessary, simplifying the operation and forgetting to cancel the boiling limit setting the next day. In addition, it is possible to reliably prevent the hot water from running out on the next day.

  The boiling means is not limited to the heat pump unit 75, and a heater may be used, or both the heat pump unit 75 and the heater may be used.

It is a block diagram about the boiling increase of the hot-water supply apparatus which shows one embodiment of this invention. It is a block diagram of a hot-water supply apparatus same as the above.

Explanation of symbols

11 Water heater
17 Hot water storage tank
75 Heat pump unit as a boiling means
84 Boiling increase limit setting means
85 Minimum remaining hot water setting method
86 Remaining hot water detection method
87 Time zone detection method
88 Boiling control means
89 Release means

Claims (2)

A hot water storage tank for storing hot water,
A boiling means for boiling hot water to be stored in the hot water storage tank using the electric power of the hourly rate system;
A remaining hot water amount detecting means for detecting a remaining hot water amount in the hot water storage tank;
A time zone detecting means for detecting a time zone of the rate system according to the time zone;
A boiling increase limit setting means for manually setting a boiling increase limit for limiting the increase in boiling in the daytime time zone of the hourly rate system
If there is no setting for the increase in boiling and the amount of remaining hot water detected by the remaining hot water amount detecting means is less than a preset amount of remaining hot water during the daytime hours of the hourly rate system, the hot water storage means will store the hot water. Boiling control means for boiling up hot water in the tank, and if there is a setting for limiting the increase in boiling, the remaining hot water amount detected by the remaining hot water amount detecting means does not increase even if the remaining hot water amount is less than a preset remaining hot water amount; ,
A hot water supply apparatus comprising: release means for automatically canceling the setting of the boiling increase restriction between the daytime time period when the boiling increase restriction is set and the daytime time period of the next day. Comprising a minimum remaining hot water amount setting means for setting a minimum remaining hot water amount to secure a minimum remaining hot water amount in the hot water storage tank even when the boiling increase limit is set;
The boiling increase control means has a boiling increase limit set in the daytime period of the hourly rate system, and if the remaining hot water amount detected by the remaining hot water amount detecting means is less than the minimum remaining hot water amount, The hot water supply apparatus according to claim 1, wherein the hot water in the tank is boiled up to the minimum remaining hot water amount.

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