JP2013155999A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater having a high usability by displaying decision results whether to perform a heat recovery operation in a display means.SOLUTION: A water heater includes a hot water storage tank 1, a bathtub 3, a heat exchanger 4 for exchanging heat between a hot water in the hot water storage tank 1 and a hot water of the bathtub 3, a display means 20, and control means 18. The water heater has a detection mode for detecting a hot water amount and/or a hot water temperature in the bathtub 3 prior to start of a heat recovery operation. The water heater decides whether to perform a heat recovery operation for recovering heat of the hot water in the bathtub 3 by the heat exchanger 4 into the hot water in the hot water storage tank 1 based on the detection results in the detection mode, and displays the decision results in the display means 20.

Description

  The present invention relates to a hot water supply apparatus having a function of recovering heat from bathtub water.

  Conventionally, in this type of hot water supply device, after hot water is supplied to the bathtub, the temperature of the hot water is kept constant for a certain period of time, and when the time set by the timer has elapsed since the end of the heat insulation operation, Some have a function of starting a heat recovery operation for recovering heat from (see, for example, Patent Document 1).

  Moreover, after performing the boiling operation which heats the water in a hot water storage tank, there exists what was equipped with the function to start the heat recovery driving | operation which collect | recovers heat from the hot water of a bathtub (for example, refer patent document 2).

  FIG. 6 shows a hot water supply apparatus having a heat recovery operation as a function. 1 is a hot water storage tank, 2 is a heat pump unit, 3 is a bathtub, 4 is a heat exchanger, 5a is a hot water tank water transport pump, and 5b is a bath water transport pump. , 6 is a heat recovery branch pipe, 7 is a three-way valve, 8 is a high temperature water supply pipe, 9 is a low temperature water supply pipe, 10 is a hot water supply pipe, 11 is a mixing valve, 12 is a bath water circulation pipe, 13 is an on-off valve, 14 is A water supply pipe, 15 is a hot water supply branch pipe, and 16 is a heat exchange return pipe.

  The bathtub water circulation pipe 12 is configured by connecting the forward pipe and the return pipe of the bathtub 3 in an annular shape, and includes a heat exchanger 4 and a bathtub water conveyance pump 5b on the circuit.

  The mixing valve 11 is configured to connect the high temperature water supply pipe 8 and the low temperature water supply pipe 9 to the inlet side, and connect the hot water supply pipe 10 to the outlet side, and the bathtub water circulation pipe 12 via the on-off valve 13. Connected. Further, a bathtub water temperature detecting means 17 for detecting the water temperature in the bathtub is provided in the middle of the bathtub water circulation pipe 12.

  When this hot water supply apparatus performs bath automatic operation, first, the hot water stored in the hot water storage tank 1 and the water supplied from the water supply pipe 14 are mixed with hot water at a desired temperature by the mixing valve 11, and hot water is supplied to the bathtub 3. To do. After the hot water is supplied to the bathtub 3, a heat retaining operation is performed in order to keep the temperature of the hot water constant for a certain period of time.

  The heat insulation operation is performed when the bath water temperature falls below a certain temperature. The hot water storage tank water transport pump 5a and the bath water transport pump 5b are operated, and the heat exchanger 4 performs hot water (for example, The hot water (for example, about 35 ° C.) in the bathtub 3 is heated by about 80 ° C.).

  Moreover, in order to judge whether the water temperature of the bathtub 3 has fallen below the fixed temperature, the bathtub water temperature detection operation | movement which drives only the bathtub water conveyance pump 5b is performed intermittently.

  When the bath water temperature detecting means 17 detects that the water temperature of the bathtub 3 is lowered below a certain temperature, the heat retaining operation is performed, and when the bath water temperature detecting means 17 is not lowered, it waits as it is. After a certain period of time has elapsed, automatic bath operation is automatically terminated.

  When the reheating operation is performed, the hot water storage tank water transfer pump 5a and the bathtub water transfer pump 5b operate, and the hot water (for example, about 80 ° C.) in the hot water storage tank 1 is stored in the bathtub 3 in the heat exchanger 4. Warm hot water (eg, about 35 ° C.). As a result, the water temperature in the bathtub 3 rises, and the amount of heat (heat storage amount) stored as hot water in the hot water tank 1 decreases.

When performing a hot water storage operation in which the water in the hot water tank 1 is boiled and stored at a high temperature, the boiling transport pump 5c is operated, water is guided from the lower part of the hot water tank 1 to the heat pump unit 2, and the heat pump unit 2 is operated. Water is boiled into hot water and returned to the upper part of the hot water tank 1 again.

  Finally, in the case of performing the heat recovery operation, the hot water storage tank water transfer pump 5a and the bathtub water transfer pump 5b operate as in the reheating operation. In the heat exchanger 4, the water in the hot water storage tank 1 (for example, (About 10 ° C.) cools the hot water (for example, about 35 ° C.) in the bathtub 3 and recovers heat.

  Since the heat recovery operation recovers heat from the hot water in the bathtub 3, it is necessary to perform it after all bathers have finished bathing. Therefore, the operation is started when the time set by the timer elapses after the heat insulation operation for keeping the hot water supplied to the bathtub 3 is completed, or the water in the hot water tank 1 is boiled using nighttime power at midnight. The operation is started after the hot water storage operation to raise.

JP 2007-278578 A JP 2009-198115 A

  However, in the conventional configuration, if there is no hot water in the bathtub or if the temperature of the hot water in the bathtub is low, even if the heat recovery operation cannot be performed, the user does not know, so incorrect use Without knowing the method, I had the problem of thinking that the heat recovery operation was possible all the time.

  This invention solves the said conventional subject, and it aims at providing the hot water supply apparatus with high usability by displaying the judgment result of whether to perform heat recovery driving | operation on a display means.

  In order to solve the conventional problem, a hot water supply apparatus of the present invention includes a hot water storage tank, a bathtub, a heat exchanger that exchanges heat between the hot water in the hot water tank and the hot water in the bathtub, display means, Control means, and having a detection mode for detecting the amount and / or temperature of hot water in the bathtub, and based on the detection result in the detection mode, the heat stored in the hot water in the bathtub by the heat exchanger In addition to determining whether or not to perform a heat recovery operation for recovering in hot water in the tank, the determination result is displayed on the display means.

  Thereby, since it is possible to notify the user that the heat recovery operation cannot be performed, it is possible to provide a hot water supply device with high usability that can prompt the user to correct incorrect usage.

  ADVANTAGE OF THE INVENTION According to this invention, the hot water supply apparatus with high usability can be provided by displaying the determination result of whether to perform heat recovery operation on a display means.

Configuration diagram of hot water supply apparatus in Embodiment 1 of the present invention External view of the remote controller of the water heater Figure of message display example when heat recovery operation is stopped with the remote control Illustration of heat recovery amount display example on the remote control Illustration of another heat recovery amount display example on the remote control Configuration diagram of conventional hot water supply equipment

  1st invention is provided with the hot water storage tank, the bathtub, the heat exchanger which heat-exchanges the hot water in the said hot water tank, and the hot water in the said bathtub, a display means, and a control means, The amount of hot water in the said bathtub And / or a detection mode for detecting the hot water temperature, and based on the detection result in the detection mode, a heat recovery operation for recovering the heat of the hot water in the bathtub into the hot water in the hot water tank by the heat exchanger is performed. And the determination result is displayed on the display means.

  This can inform the user that there is no hot water in the bathtub, or that the heat recovery operation could not be performed because the temperature of the hot water is low, and correct the misuse by notifying the reason for the failure. There is an effect that it can be urged.

  The second invention is characterized in that the determination result can be redisplayed by the display means even after the display of the determination result on the display means is completed.

  As a result, even if the display of the judgment result is missed or when other users have erased it, it can be confirmed again later, so that heat recovery could not be performed. There is an effect that the notification can be made more thorough.

  In a third aspect, if it is determined that the heat recovery operation cannot be performed in the detection mode after the heat recovery operation is started, the determination result is not displayed on the display means. The heat recovery operation is stopped.

  Thus, when the heat recovery operation is normally performed and stopped, such as when it is determined that the temperature of the hot water in the bathtub is lowered and the heat recovery operation cannot be performed because the heat recovery operation is performed, the determination result is displayed. Does not give the user the misunderstanding that the user has used it incorrectly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a hot water supply apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a hot water supply apparatus includes a hot water tank 1, a heat pump unit 2 as a heating means for heating the water in the hot water tank 1, a bathtub 3 to be subjected to heat recovery, water in the bathtub 3, and the hot water tank 1. A heat exchanger 4 configured to exchange heat with water, a water supply pipe 14 connected to the hot water tank 1, a first hot water pipe 22 connected to substantially the upper part of the hot water tank 1, and a first Between the position where the hot water pipe 22 and the water supply pipe 14 are connected, that is, in the height direction, the second hot water pipe 23 connected to the substantially central part of the trunk of the hot water storage tank 1, and the first hot water pipe 22 A second hot water discharge pipe 23 is composed of a high temperature water mixing valve 24 connected to the inlet side.

  And connected to the outlet side of this high temperature water mixing valve 24, a high temperature water supply pipe 8 for supplying high temperature water in the hot water tank 1, and a low temperature water supply pipe 9 branched from the water supply pipe 14 for supplying low temperature water, The high temperature water supply pipe 8 and the low temperature water supply pipe 9 are connected to the inlet side, the hot water supply pipe 10 connected to the outlet side of the mixed valve 11, and the hot water supply pipe 10. And an open / close valve 13. The hot water tank 1 is provided with a plurality of hot water tank hot water temperature detecting means 28 a to 28 e for detecting the water temperature in the hot water tank 1.

In addition, a boil-out pipe 35 connecting the substantially bottom of the hot water tank 1 and the inlet side of the heat pump unit 2, a boil-up conveyance pump 5 c connected in the middle of the boil-out pipe 35, and the outlet side of the heat pump unit 2 A first boiling return pipe 29 connecting the inlet side of the three-way valve 34, a second boiling return pipe 30 connecting one outlet side of the three-way valve 34 and one inlet side of the switching means 26, switching It is composed of one outlet side of the means 26 and a third boiling return pipe 31 connecting the upper part of the hot water tank 1.

  Then, a recirculation pipe 32 branched from the first outlet pipe 22 and connected to the other inlet side of the switching means 26, the other outlet side of the switching means 26, and the first of the heat exchanger 4. The heat transfer pipe 33 connecting the inlet side of the flow path, the first hot water discharge pipe 22 and the second hot water discharge pipe 23 in the height direction of the hot water storage tank 1 and the outlet side of the first flow path of the heat exchanger 4. The hot water return pipe 16 connected to a position between the hot water tank 1 and the hot water tank water connected in the middle of the hot water return pipe 16 for circulating the water in the first flow path of the hot water tank 1 and the heat exchanger 4. It is comprised from the conveyance pump 5a.

  Furthermore, the hot water supply apparatus has a bathtub water circulation pipe 12 connected so that the water of the bathtub 3 circulates into the second flow path of the heat exchanger 4, and the bathtub water circulation pipe 12 includes the bathtub 3 and the heat exchanger 4. A bathtub water conveyance pump 5b that circulates water in the second flow path, a water level sensor 27 that detects the water level of the bathtub 3 by measuring the water pressure as a bathtub water amount detection means, and a bathtub water conveyance pump 5b. The bathtub water temperature detecting means 17 that detects the water temperature of the bathtub 3 by operating and circulating the water of the bathtub 3 and the bathtub water detecting means that detects the presence or absence of water in the bathtub 3 by circulating the water of the bathtub 3 similarly. 25. Further, the hot water supply pipe 10 is connected in the middle of the bathtub water circulation pipe 12, and is configured to use the bathtub water circulation pipe 12 when hot water is supplied to the bathtub 3.

  Next, the control part of the hot water supply device will be described. A remote controller 19 is connected to the hot water supply device for performing various settings and operation operations, and for displaying the settings, the operating state of the hot water supply device, and other various information. The remote controller 19 is provided with a display unit 20 as display means and a heat recovery operation start switch 21 for the user to arbitrarily start the heat recovery operation. FIG. 2 shows an external view of the remote controller 19 in the first embodiment.

  Further, the hot water supply apparatus includes hot water supply to the bathtub 3 and automatic bath operation for keeping the temperature of the bathtub water and maintaining the amount of water for a preset time thereafter, reheating operation for heating the water in the bathtub 3, A hot water storage operation for boiling water with the heat pump unit 2, a heat recovery operation for recovering the heat of water in the bathtub 3 in the hot water storage tank 1, and a control means 18 for exchanging information with the remote controller 19 are provided.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  As a basic operation in the use of hot water in a general home, hot water for the day is stored in the hot water tank 1 in the morning, and is sequentially used for hot water supply during an active time. When the amount of hot water storage is insufficient during use of hot water, the heat pump unit 2 may be operated as necessary, and an additional hot water storage operation may be performed.

  In recent years, there have been an increasing number of hot water supply apparatuses having a function of automatic bath operation that automatically performs from hot water supply to the bathtub 3 to heat insulation. When performing hot water supply and heat insulation operation to the bathtub 3 by automatic bath operation, hot water stored in the hot water storage tank 1 is used to supply hot water to the bathtub 3, and when the bathtub water temperature decreases, the hot water stored in the hot water storage tank 1 The heat insulation operation is performed using the heat of the stored hot water, and the bath water temperature is kept at a preset temperature. Further, when the hot water in the bathtub 3 is heated by performing a reheating operation, the heat of the hot water stored in the hot water tank 1 is used.

When the use of heat such as one day of hot water supply ends, most of the hot water in the hot water storage tank 1 is replaced with water supply, and the hot water storage operation for the next use is performed again at midnight thereafter. At this time, the hot water supplied to the bathtub 3 for bathing is often left at a relatively high temperature with respect to the water temperature in the hot water tank 1 at the end of use of the hot water supply. Heat is recovered in 1.

  First, an operation when performing bath automatic operation will be described. When hot water is supplied to the bathtub 3, hot water from the first hot water discharge pipe 22 and the second hot water discharge pipe 23 is mixed from the hot water storage tank 1 by the high temperature water mixing valve 24 and supplied to the high temperature water supply pipe 8. The hot water supplied to the high-temperature water supply pipe 8 and the water supplied from the water supply pipe 14 to the low-temperature water supply pipe 9 are mixed with hot water having a desired hot water supply temperature by the mixing valve 11 and supplied to the hot water supply pipe 10. The

  Here, the temperature of the hot water supplied from the high-temperature water mixing valve 24 to the high-temperature water supply pipe 8 is a temperature higher than the above-mentioned desired hot water supply temperature by a predetermined temperature or more (for example, 45 ° C. or more when the desired hot water supply temperature is 40 ° C.). It is adjusted to. The on-off valve 13 is opened, and hot water having a desired temperature supplied to the hot water supply pipe 10 is supplied to the bathtub 3 from the bathtub water circulation pipe 12.

  The opening degree of the high temperature water mixing valve 24 and the mixing valve 11 is generally feedback controlled based on the temperature of hot water supplied to the high temperature water supply pipe 8 and the hot water supply pipe 10 respectively connected to the outlet side. For the high temperature water mixing valve 24, hot water from the first hot water supply pipe 22 and the second hot water discharge pipe 23, and for the mixing valve 11, hot water from the high temperature water supply pipe 8 and water supply from the low temperature water supply pipe 9 Varies with temperature.

  When the hot water in the bathtub 3 is kept warm, the hot water storage tank water transfer pump 5a and the bathtub water transfer pump 5b start operation, and the switching means 26 is a reflow pipe 32 and the first flow path of the heat exchanger 4. The flow path is switched so that the inlet side of the gas flows. Then, by the operation of the hot water tank water transfer pump 5a, hot water is supplied from the substantially upper part of the hot water tank 1 to the first flow path of the heat exchanger 4 through the recirculation pipe 32 from the first hot water discharge pipe 22, and bath water circulation The hot water of the bathtub 3 circulating through the pipe 12 is heated to increase the bath water temperature. Hot water that has left the heat exchanger 4 and has become relatively cold returns to the hot water tank 1 through the heat exchange return pipe 16.

  Next, although the operation in the case of the reheating operation is performed, the operation of the reheating operation is the same as the heat retaining operation, and the description is omitted.

  Finally, the case where the heat recovery operation of the hot water left in the bathtub 3 is performed will be described. In order to perform the heat recovery operation, there is hot water in the bathtub 3 and the temperature of the hot water needs to be equal to or higher than a predetermined temperature. Therefore, when the heat recovery operation start switch 21 of the remote controller 19 is pressed and the start of the heat recovery operation is received, detection mode for detecting the presence or absence of hot water in the bathtub 3 and detecting the hot water temperature when hot water is present are set. Make it work.

  As a detection mode, first, the operation of the bathtub water conveyance pump 5b is started, and hot water in the bathtub 3 is circulated in the bathtub water circulation pipe 12 for a predetermined time (for example, 1 minute). And the presence or absence of bathtub water is detected by the bathtub water detection means. When there is bathtub water, the bathtub water temperature detecting means 17 detects the bathtub water temperature.

  During the detection mode, the hot water tank water transfer pump 5a is not operated yet. Based on the detection result in the detection mode, the control means 18 determines whether or not to perform the heat recovery operation. Since there is hot water in the bathtub 3 and the hot water temperature is equal to or higher than the predetermined temperature, when it is determined that the heat recovery operation is performed, the heat recovery operation is started.

  Since the heat recovery operation cannot be performed if there is no hot water in the bathtub 3, detection of the presence or absence of the bath water is indispensable. However, since the appropriate amount of heat can be recovered by setting the hot water temperature as the detection condition, It is more desirable to use the temperature as a detection condition.

  At the start of the heat recovery operation, the operation of the already-operated bathtub water conveyance pump 5b is continued, and the hot water in the bathtub 3 is circulated through the bathtub water circulation pipe 12. Next, in order to circulate the water at the substantially bottom of the hot water tank 1 from the boil-out pipe 35 to the heat exchanger 4 via the heat pump unit 2, the three-way valve 34 has the first boil-back return pipe 29 and the second boil-off pipe 29. The flow path is switched so that the boiling return pipe 30 flows.

  Moreover, the switching means 26 switches a flow path so that the 2nd boiling return pipe 30 and the entrance side of the 1st flow path of the heat exchanger 4 may distribute | circulate. Here, the operation of the hot water tank water transfer pump 5a is started, the water at the substantially bottom portion of the hot water tank 1 is supplied to the first flow path of the heat exchanger 4, and the bathtub 3 is transferred to the second flow path of the heat exchanger 4. Exchange heat with the hot water being supplied.

  Hot water that has left the heat exchanger 4 and has reached a relatively high temperature (approximately the same temperature as the hot water in the bathtub 3) returns to the hot water tank 1 through the heat exchange return pipe 16. Thereby, the heat of the hot water in the bathtub 3 is collected in the hot water storage tank 1.

  In addition, the required flow volume by the bathtub water conveyance pump 5b is ensured by making the conveyance amount of the hot water by the bathtub water conveyance pump 5b larger than the conveyance amount of the hot water by the hot water tank water conveyance pump 5a, and the temperature distribution in the bathtub 3 Can be stably recovered from the bathtub 3, and the transport flow rate by the hot water tank water transport pump 5a becomes excessive, so that the hot water in the hot water tank 1 is not stirred and temperature stratification is achieved. Therefore, it is possible to efficiently perform the subsequent boiling operation of the hot water in the hot water tank 1.

  By performing the heat recovery operation, the hot water temperature in the bathtub 3 decreases. When the hot water temperature in the bathtub 3 becomes lower than a predetermined temperature, when the control means 18 determines that the heat recovery operation should be stopped from the detected temperature of the hot water tank hot water temperature detecting means 28a to 28e, or when the user uses the remote control When the heat recovery operation start switch 21 is turned off, the heat recovery operation is terminated.

  Moreover, although it cannot occur in a normal use state, the amount of hot water in the bathtub 3 decreases during the heat recovery operation, and the heat recovery operation is also ended when the bathtub water detection means 25 determines that there is no hot water in the bathtub 3. To do.

  Next, in the detection mode when the start of the heat recovery operation is accepted, it is detected that there is no hot water in the bathtub 3 or the hot water temperature is lower than a predetermined temperature, and the control means 18 determines that the heat recovery operation is not performed. A case where the heat recovery operation is stopped will be described.

  In this case, if no notification is given, the user does not know whether the heat recovery operation has not been performed or has ended early. Therefore, a message is displayed on the display unit 20 of the remote controller 19.

  An example of the message to be displayed is shown in FIG. In the first embodiment, the reason for discontinuing the heat recovery operation as a message example is “because the temperature of the bath water is low or there is no hot water”, but whether the reason for the discontinuation is because the temperature is low or there is no hot water. Since it is known in the detection mode, another message may be displayed for each reason.

  In the first embodiment, if the message continues to appear, items normally displayed on the display unit 20 of the remote controller 19 such as the hot water supply temperature setting cannot be seen, so the message is displayed after a predetermined time (for example, 1 minute). The message is automatically deleted, but if priority is given to more thorough alerting to the user, the message may be deleted by the user confirming the message and pressing any switch.

In this manner, the heat recovery operation is stopped because the state of the hot water in the bathtub 3 is not suitable, and the hot water is left before the heat recovery by displaying on the display unit 20 of the remote controller 19 and informing the user. In addition, it is possible to prompt the user to recognize that it is necessary to carry out the operation before the hot water temperature falls, and to urge the user to correct the wrong usage.

  Information display by the remote controller 19 will be described. The remote controller 19 can display various information (for example, the amount of hot water used) of the hot water supply device on the display unit 20 by a switch operation. The amount of heat recovered from the bathtub 3 during the heat recovery operation can be displayed as the amount of heat recovered. A display example of the heat recovery amount is shown in FIG. In the first embodiment, the result of the previous heat recovery operation, the total for one week, and the total from the start of use can be displayed.

  If the previous heat recovery operation was canceled because the condition of the hot water in the bathtub 3 was not suitable, the heat recovery amount would be 0, but the heat recovery operation was abundant in the result of the previous heat recovery amount. A message is displayed notifying that the hot water temperature is low or the hot water is not available. A display example of the message is shown in FIG.

  As a result, even if the user activates the heat recovery operation and misses the message when the heat recovery operation is canceled, the previous heat recovery Since it is possible to know that the recovery operation has been canceled because the state of the hot water in the bathtub 3 was not suitable, correction can be urged so as not to use it incorrectly during the next heat recovery operation.

  In addition, when it is judged that the heat recovery operation is possible in the detection mode before the start and is once stopped and then stopped because the temperature of the bathtub 3 has decreased, the user's method of use is normal and there is no error. Since the message is not displayed, the above message is not displayed, and the normal heat recovery amount is also displayed in the previous portion of the heat recovery amount. As a result, it is possible to classify whether the cause of the heat recovery operation being stopped is due to the initial state of hot water in the bathtub 3 or the factor after the start of the heat recovery operation.

  As described above, the hot water supply apparatus according to the present invention displays the determination result on whether or not to perform the heat recovery operation on the display means, and can prompt the user to correct the usage method. Applicable to equipment.

1 Hot water tank 2 Heating means (heat pump unit)
DESCRIPTION OF SYMBOLS 3 Bathtub 4 Heat exchanger 5a Hot water storage tank water conveyance pump 5b Bath water conveyance pump 5c Boiling conveyance pump 8 High temperature water supply pipe 9 Low temperature water supply pipe 10 Low temperature water supply pipe 11 Mixing valve 12 Bath water circulation pipe 13 On-off valve 14 Water supply pipe 16 Heat Return pipe 17 Bath water temperature detection means 18 Control means 19 Remote control 20 Display means (display section)
DESCRIPTION OF SYMBOLS 21 Heat recovery operation start switch 22 1st tapping pipe 23 2nd tapping pipe 24 High temperature water mixing valve 25 Bath water detection means 26 Switching means 27 Bath water quantity detection means (water level sensor)
28a to e Hot water storage tank hot water detection means 29 First boiling return pipe 30 Second boiling return pipe 31 Third boiling return pipe 32 Reheating pipe 33 Heat exchange pipe 34 Three-way valve 35 Boiling forward tube

Claims (3)

A hot water storage tank, a bathtub, a heat exchanger for exchanging heat between the hot water in the hot water tank and the hot water in the bathtub, a display means, and a control means; It has a detection mode to detect, and based on the detection result in the detection mode, it is determined whether or not to perform a heat recovery operation for recovering the heat of the hot water of the bathtub into the hot water of the hot water storage tank by the heat exchanger. In addition, the hot water supply apparatus is configured to display the determination result on the display means. 2. The hot water supply apparatus according to claim 1, wherein the determination result can be displayed again on the display unit even after the display of the determination result on the display unit is completed. If it is determined that the heat recovery operation cannot be performed in the detection mode after the heat recovery operation is started, the determination result is not displayed on the display means, and the heat recovery operation is performed. The hot water supply apparatus according to claim 1, wherein the hot water supply apparatus is configured to stop.