JP2007278674A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately compute the circulating flow rate of a bath circulating circuit to which a rotary detecting type flow sensor cannot be mounted due to plenty of foreign matter such as hair. <P>SOLUTION: This water heater comprises a bath return temperature sensor 32, a bath bound temperature sensor 33, a circulating flow sensor 36, a heat exchanger outlet temperature sensor 34, and a bath circulating flow arithmetic unit 37 computing a bath circulating flow rate using a detection signal of the circulating return temperature sensor 36. The circulating flow rate is thereby computed accurately without being influenced by dispersion of the heating value of a heat source due to the kind of gas and gas components, dispersion of equipment and dispersion of thermal efficiency due to the circulating water temperature of a primary side circulating circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus provided with a hot water supply heat exchanger heated by combustion of a burner, and relates to a hot water supply apparatus provided with a bath heat exchanger in a hot water supply circulation circuit for circulating hot water heated by the hot water supply heat exchanger. In particular, the present invention relates to a hot water supply apparatus provided with a bath circulation flow rate calculation device for calculating a circulation flow rate of a bath circulation circuit in which foreign substances such as hair are large and a rotation detection type flow rate sensor cannot be attached.

Conventionally, as a hot water supply device of this type, in a canned two-water channel combustion device that has a common heat exchanger for the hot water supply path and the bath retreating path connected to the bathtub, the water in the bathtub is guided into the hot water retreating path, A circulation pump that circulates and a temperature detection means that measures the temperature of the water in the bathtub led into the bath retreating path, and when the combustion is not performed, the circulation pump is driven to reduce the temperature of the water in the bathtub. To detect. Also, the water in the bathtub is led into the bath retreat path, the circulation pump, the temperature detection means of the water in the bathtub led into the bath retreat path, and the circulation amount of the water in the bath retreat path by the circulation pump Control means, when a bath replenishment request is issued during hot water supply, the control means drives the circulation pump with a circulation amount that does not change the hot water supply temperature, and the temperature detection means There is something to detect. (For example, see Patent Document 1)
Also, the hot water heated by the heat source is circulated to heat the hot water in the bathtub through a liquid-liquid bath heat exchanger, or the hot water is used as a hot water mat for a floor heating or a hot water heating radiator. There is a heating circulation system that heats indoors by flowing through a simple heating terminal.

At this time, the circulation flow rate of the bathtub water is determined by obtaining the amount of heat transmitted to the hot water in the bathtub through the heat exchanger for bath from the heat generation amount of the heat source and the efficiency of the hot water heat exchanger, and passing through the bath heat exchanger. It has come to be obtained based on the temperature rise temperature. And based on this circulation flow rate, the calculation of the amount of remaining hot water in the bathtub was performed.
JP-A-11-37551

  However, the amount of heat transferred to the hot water in the bathtub through the bath heat exchanger is determined from the heat generation amount of the heat source and the efficiency of the hot water supply heat exchanger, but the heat generation amount of the heat source varies depending on the gas type and gas component, In addition, the heat efficiency of the hot water heat exchanger varies depending on equipment variations and the circulating water temperature of the primary circulation circuit, resulting in an error in the amount of heat transferred to the hot water in the bathtub through the bath heat exchanger, and the circulation flow rate Has a problem that it is not calculated accurately.

  The present invention solves the conventional problem, a bath return temperature sensor for detecting a return temperature from the bathtub, a bath temperature sensor for detecting the temperature to the bathtub heated by the bath heat exchanger, A circulation flow sensor for detecting the circulation flow rate on the hot water supply circulation circuit, a heat exchanger outlet temperature sensor for detecting the outlet temperature of the hot water heat exchanger, and a circulation return temperature sensor for detecting hot water returning to the hot water heat exchanger, The circulation flow sensor, the heat exchanger outlet temperature sensor, and accurately calculating the amount of heat transferred to the hot water in the bathtub using the detection signal of the circulation return temperature sensor, the bath return temperature sensor, A bath circulation flow rate calculation device that accurately calculates the bath circulation flow rate using the detection signal of the bath temperature sensor is provided.

In order to solve the above-described conventional problems, a hot water supply apparatus of the present invention includes a hot water supply heat exchanger that heats water supplied from a water supply channel by combustion of a burner and supplies hot water to the hot water supply channel, and the hot water supply channel and the water supply channel. A hot water supply circuit in which a bath heat exchanger and a circulation pump are arranged in a circulation path formed by connecting the hot water supply circuit, a hot water supply circuit that branches from the hot water supply circuit after passing through the bath heat exchanger and reaches the curan, and Circulating flow rate sensor that is arranged in a hot water supply circulation circuit and detects a circulating flow rate, a heat exchanger outlet temperature sensor that detects an outlet temperature of the hot water heat exchanger, and hot water after passing through the bath heat exchanger are detected. A circulation return temperature sensor; a bath return temperature sensor for detecting a return temperature from the bathtub; and a bath return temperature sensor for detecting a return temperature to the bathtub heated by the bath heat exchanger. Bath forward temperature sensor, those with circulation flow sensor, heat exchanger outlet temperature sensor, a bath circulation flow rate calculation unit for calculating the bath circulation flow rate by using a detection signal of the circulation return temperature sensor.

  As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is directly and accurately calculated. Therefore, variations in the amount of heat generated by the heat source due to gas types and gas components, device variations, and primary-side circulation The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature of the circuit.

  Since the hot water supply apparatus of the present invention directly and accurately calculates the amount of heat transferred to the hot water in the bathtub through the heat exchanger for baths, variation in the amount of heat generated by the heat source due to gas types and gas components, equipment variation, The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature on the primary side.

  1st invention heats the water supplied from a water supply path by combustion of a burner, and supplies hot water to a hot water supply path, bath heat in a circulation path formed by connecting the hot water supply path and the water supply path A hot water supply circulation circuit provided with an exchanger and a circulation pump, a hot water supply circuit that branches from the hot water supply circulation circuit after passing through the bath heat exchanger and reaches a currant, and is arranged in the hot water supply circulation circuit to detect a circulation flow rate. A circulating flow rate sensor, a heat exchanger outlet temperature sensor for detecting the outlet temperature of the hot water heat exchanger, a circulating return temperature sensor for detecting hot water after passing through the bath heat exchanger, and a return temperature from the bathtub A bath return temperature sensor for detecting the temperature and a bath temperature sensor for detecting the temperature going to the bathtub heated by the bath heat exchanger, the bath return temperature sensor, the bath temperature sensor, and the circulation flow sensor. , Those having the heat exchanger outlet temperature sensor, a bath circulation flow rate calculation unit for calculating the bath circulation flow rate by using a detection signal of the circulation return temperature sensor.

  As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as device variations and the primary side circulation circuit. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature.

  The second invention is a bath circulation flow rate calculation device that circulates hot water in a bathtub by circulation of a bath circuit and adds heat via a bath heat exchanger together with circulation of a hot water circulation circuit, and a predetermined time from the start of circulation. Calculate the amount of heat added from the circulation flow rate of the circulation flow sensor and the temperature difference between the heat exchanger outlet temperature sensor and the circulation return temperature sensor between them, and the temperature difference between the bath return temperature sensor and the bath temperature sensor. The bath circulation flow rate is calculated from the time. As a result, the amount of heat transferred to the hot water in the bathtub directly through the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as variations in equipment and circulation on the primary side. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the water temperature.

The third invention is a bath circulation flow rate calculation device that circulates hot water in a bathtub by circulating a hot water circulation circuit and adds heat via a bath heat exchanger, and a bath return temperature sensor from the start of the circulation. The time until the temperature reaches a predetermined temperature, the circulation flow rate of the circulation flow sensor,
Calculates the amount of heat added from the temperature difference between the heat exchanger outlet temperature sensor and the circulation return temperature sensor during that time, and then calculates the bath circulation flow rate from the temperature difference between the bath return temperature sensor and the bath temperature sensor and the time between them. It is. As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as device variations and the primary side circulation circuit. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature.

  The fourth aspect of the invention is a bath circulation flow rate calculation device that circulates hot water in a bathtub by circulation of a bath circuit and adds heat via a bath heat exchanger as a circulation of a hot water supply circulation circuit, and a predetermined time has elapsed from the start of circulation. The calculation of the bath circulation flow rate is started later. As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as device variations and the primary side circulation circuit. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature.

  In addition, by delaying the start of the bath circulation flow rate calculation for a predetermined time, it is possible to eliminate a significant portion of the temperature change at the beginning of the circulation start, so that the bath circulation flow rate can be calculated with higher accuracy.

  The fifth invention is a bath circulation flow rate calculation device, as well as circulation of the hot water supply circulation circuit, circulating hot water in the bathtub by circulation of the bath circuit, adding heat through the bath heat exchanger, and a predetermined time has elapsed from the start of circulation. The calculation of the bath circulation flow rate is started later. As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as device variations and the primary side circulation circuit. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature.

  In addition, by delaying the start of the bath circulation flow rate calculation until the bath return temperature sensor detects a predetermined temperature rise, the significant part of the temperature change at the beginning of the circulation can be eliminated, so the accuracy of the bath circulation flow rate can be further improved. can do.

  The sixth invention is a bath circulation flow rate calculation device, which circulates hot water in a bathtub by circulating a hot water circulation circuit and adds heat via a bath heat exchanger, and a predetermined time has elapsed from the start of circulation. The calculation of the bath circulation flow rate is started later. As a result, the amount of heat transferred to the hot and cold water in the bathtub via the bath heat exchanger is calculated directly and accurately, so there is a variation in the amount of heat generated by the heat source due to gas species and gas components, as well as device variations and the primary side circulation circuit. The circulation flow rate is accurately calculated without being affected by the variation in thermal efficiency due to the circulating water temperature.

  In addition, by delaying the start of the bath circulation flow rate calculation until the bath return temperature sensor detects the predetermined temperature, it is possible to eliminate a significant part of the temperature change at the beginning of the circulation, so the bath circulation flow rate is calculated with higher accuracy. be able to.

  In the seventh aspect of the invention, the calculation of the bath circulation flow rate is performed at the time of trial operation after installation of the equipment.

  This ensures that the calculation of the bath circulation flow rate is completed when the user uses the device.

  According to the eighth aspect of the invention, the bath operation cannot be performed unless the bath circulation flow rate is calculated during the test operation after the device is installed.

The ninth aspect of the invention prevents the bath operation from being performed unless the calculation of the bath circulation flow rate is performed at the time of the trial operation after the installation of the device, and the external input device is displayed so as to perform the bath test operation. is there.

  As a result, it is possible to prevent a contractor from forgetting to make a trial run, and when the user uses the device, the calculation of the bath circulation flow rate is surely completed.

(Embodiment 1)
FIG. 1 shows a structural diagram of a hot water supply apparatus according to a first embodiment of the present invention.

  In FIG. 1, first, water supplied from the water supply channel 1 is heated by combustion of the burner 2 and rises to a predetermined temperature, then supplied to the bath heat exchanger 27 via the hot water supply channel 3, and via the circulation pump 17. Thus, the hot water supply heat exchanger 15 is returned to the upstream water supply path 1 to constitute a hot water supply circulation circuit 19 in which the inlet and outlet of the hot water supply heat exchanger 15 are connected via a bath heat exchanger 27 and a circulation pump 17. The hot water supply circulation circuit 19 is provided with a circulation flow sensor 36 for detecting the circulation flow rate, and the circulation flow rate when the bath reheating operation is performed can be obtained.

  Then, a hot water supply circuit 26 branched from the middle of the hot water supply circulation circuit 17 reaching the circulation pump 17 via the bath heat exchanger 27 and connected to the hot water tap 6 is constituted, and the hot water supply circuit 26 and the water supply path 1 are communicated with each other. A part of the water supplied from the water supply channel 1 from the formed bypass passage 4 is supplied through the bypass control valve 5 to adjust to a desired hot water, and the hot water is discharged from the hot water tap 6.

  Here, the burner 2 is supplied with fuel from a gas supply passage 10 provided with a gas source solenoid valve 7, a gas proportional valve 8, and a gas switching valve 9, and supplied with combustion air from a combustion fan 11, in advance. A combustion operation is performed according to a predetermined sequence. Then, the combustion gas generated by the combustion of the burner 2 passes through the combustion chamber 12, passes through the exhaust passage 13, and is discharged out of the instrument from the exhaust port 14.

  Next, the bath heat exchanger 27 is connected to the hot water supply circulation circuit 19, exchanges heat while circulating the high-temperature water heated by the hot water supply heat exchanger 15 with the circulation pump 17, and supplies heat to the bath reheating circuit 28. To do. The bath reheating circuit 28 replenishes the bath water by supplying the hot water in the bath 31 to the bath heat exchanger 27 through the bath pump 29 and the water amount detection unit 30 and circulating it for a predetermined time. In addition, as the pouring circuit 32 for filling the bathtub 31 with water, a path is formed which communicates from the hot water outlet 3 on the downstream side of the bypass passage 4 to the bath reheating circuit 28.

  First, at the time of hot water supply operation, when the hot water tap 6 is opened, the water supply side flow rate sensor 23 disposed in the water supply passage 1 detects water flow, and the combustion fan 11 is operated by this water flow signal and simultaneously the gas source solenoid valve 7, The gas proportional valve 8 is opened, fuel and combustion air are supplied to the burner 2, and combustion is started by an ignition operation. Combustion gas generated by the start of combustion of the burner 2 is discharged from the exhaust port 14 via the exhaust passage 13 from the combustion chamber 12. In the process of exhausting the combustion gas, the water supplied from the water supply channel 1 is heated by the hot water supply heat exchanger 15 disposed in the combustion chamber 12.

  Hot water heated by the hot water supply heat exchanger 15 is supplied to the water supply side by a bypass control valve 5 provided in a bypass passage 4 provided to connect the water supply passage 1 and the hot water supply circuit 26 so as to bypass the hot water supply heat exchanger 15. Mixed with water. The mixed hot water is heated from the hot water tap 6 by adjusting the opening degree of the bypass control valve 5 by a signal from the hot water thermistor 25 so that the hot water supply set temperature set by the remote control remote control 24 is reached.

  Thus, when selecting the hot water supply independent operation, the hot water set automatically can be secured by setting a desired temperature with the remote control remote controller 24 and opening the hot water tap 6.

Next, at the time of bath operation, when a bath operation instruction is given by the remote control remote controller 24, the bath pump 29 provided in the bath reheating circuit 28 is driven, and when the water flow detector 30 detects the circulation of the bath water, The circulation pump 17 that circulates hot water in the hot water supply circulation circuit 19 by the detection signal is driven, and at the same time, combustion is started by the ignition operation of the burner 2.

  Combustion gas generated by the start of combustion of the burner 2 is discharged from the exhaust port 14 via the exhaust passage 13 from the combustion chamber 12. In the process of exhausting the combustion gas, the water supplied from the water supply channel 1 is heated by the hot water supply heat exchanger 15 disposed in the combustion chamber 12.

  The hot water heated by the hot water supply heat exchanger 15 is supplied to the bath heat exchanger 27 by the circulation pump 17, and is heat-exchanged by the water-water heat exchange configuration and transferred to the bath reheating circuit 28. The heat of the bath reheating circuit 28 received by the bath heat exchanger 27 raises the hot water temperature of the bathtub 31 to ensure a predetermined reheating water temperature. Then, the high-temperature water heat-exchanged by the bath heat exchanger 27 is returned to the upstream water supply channel 1 of the hot water supply heat exchanger 15 to form a hot water supply circulation circuit 19, and a predetermined follow-up set by the remote control remote control 24 is formed. Maintain circulation at a predetermined hot water temperature until the sowing conditions are satisfied.

  In this way, the hot water supplied to the bath heat exchanger 27 is branched from the hot water supply path 3 constituting the hot water supply circuit, and the hot water supply circulation circuit 19 is formed, thereby securing high temperature water necessary for the bath reheating operation. On the other hand, hot water supply priority operation that can adjust and supply hot water in a wide range from high temperature water to low temperature water to the hot water supply circuit can be ensured.

  In addition, the hot water that is efficiently heated by the hot water supply heat exchanger 15 is supplied from the bypass passage 4 by supplying the hot water mixed in the pouring circuit 32 from the hot water outlet 3 on the downstream side of the bypass passage 4. After the desired hot water is ensured by mixing with water, the bath is supplied from the pouring circuit 32 to the bath circuit 28, thereby enabling efficient bath operation.

  In addition, during the bath trial operation, the interior of the bathtub 31 is first emptied and then securely plugged, and by pressing the bath trial operation switch on the control board 37, a constant temperature and a certain amount of hot water are poured into the bathtub 31 automatically. The hot water circuit 32 pours hot water.

  Thereafter, the bath operation is performed, and the heat of the bath reheating circuit 28 received by the bath heat exchanger 27 raises the hot water temperature of the bathtub 31, and the temperature detected by the airway return thermistor 32 reaches a predetermined temperature. When detected, the bath operation is terminated, and at the same time, the bath trial operation is terminated.

Here, in order to obtain the bath circulation flow rate q (l / min), the temperature T1 (° C.) detected by the heat exchange outlet thermistor 34 during bath operation and the temperature T2 (detected by the hot water supply circulation return temperature thermistor 35). The temperature difference ΔT (deg) of [° C.] is measured and stored at regular intervals, and the tracking time t (min) is also measured and stored. At the same time, the temperature difference Δt (deg) between the temperature t3 (° C.) detected by the air path return thermistor 32 and the temperature t4 (° C.) detected by the air path return thermistor 33 is measured and stored at regular intervals. Keep it. Further, the circulating flow rate Q (l / min) detected by the circulating flow rate sensor 36 is measured and stored at regular intervals. Using these values, the bath circulation flow rate q (l / min) is obtained by (Equation 1).
q = QAvr × (ΔTAvr) / (ΔtAvr) (1)
(However, ΔTAvr (deg): average value of ΔT (deg)
ΔtAvr (deg): Average value of Δt (deg)
ΔQAvr (l / min): the average value of Q (l / min))
Further, at this time, by starting taking in the values of the respective temperatures and the circulation flow rate after a predetermined time has elapsed, a significant portion of the temperature change at the beginning of the circulation can be eliminated, so that the bath circulation flow rate can be calculated with higher accuracy.

In addition, by calculating the bath circulation flow rate during the trial operation of the bath, it is possible to provide a hot water supply device that is easy to use immediately after the installation of the device.

  As described above, the hot water supply apparatus according to the present invention includes a bath return temperature sensor that detects a return temperature from the bathtub, a bath temperature sensor that detects the temperature to the bathtub heated by the bath heat exchanger, A circulation flow sensor for detecting the circulation flow rate on the hot water supply circulation circuit, a heat exchanger outlet temperature sensor for detecting the outlet temperature of the hot water heat exchanger, and a circulation return temperature sensor for detecting hot water returning to the hot water heat exchanger, The circulation flow sensor, the heat exchanger outlet temperature sensor, and accurately calculating the amount of heat transferred to the hot water in the bathtub using the detection signal of the circulation return temperature sensor, the bath return temperature sensor, Since it is possible to accurately calculate the bath circulation flow rate using the detection signal of the bath temperature sensor, it can also be used for gas, oil, electric hot water bath equipment, hot water heaters, etc. You can use.

Structure diagram of hot water supply apparatus in Embodiment 1 of the present invention

Explanation of symbols

1 Water supply path 2 Burner (heating means)
3 Hot water outlet 13 Exhaust passage 15 Hot water supply heat exchanger 17 Hot water supply circulation pump
19 Hot water circulation circuit
23 Flow sensor 27 Bath heat exchanger 28 Bath circuit 29 Bath circulation pump 31 Bath 32 Bath return thermistor 33 Bath return thermistor 34 Heat transfer outlet thermistor 35 Circulation return thermistor 36 Circulation flow sensor 37 Control base

Claims (9)

A hot water supply heat exchanger that heats the water supplied from the water supply passage by combustion of the burner and supplies hot water to the hot water supply passage, and a bath heat exchanger and a circulation pump in the circulation passage formed by connecting the hot water supply passage and the water supply passage. A hot water supply circulation circuit, a hot water supply circuit that branches from the hot water supply circulation circuit after passing through the bath heat exchanger and reaches the currant, a circulation flow sensor that is arranged in the hot water supply circulation circuit and detects a circulation flow rate, Heat exchanger outlet temperature sensor for detecting outlet temperature of the hot water heat exchanger, circulating return temperature sensor for detecting hot water after passing through the bath heat exchanger, and bath return temperature for detecting return temperature from the bathtub A sensor and a bath temperature sensor for detecting the temperature going to the bathtub heated by the bath heat exchanger, the bath return temperature sensor, the bath temperature sensor, the circulation flow sensor, the heat exchanger output Temperature sensor, circulating back water heater provided with a bath circulation flow rate calculation unit for calculating the bath circulation flow rate by using a detection signal of the temperature sensor. The bath circulation flow rate calculation device circulates the hot water in the bathtub by circulating operation of the hot water circulation circuit and adds heat through the bath heat exchanger, and circulates for a predetermined time from the start of the circulation operation. Calculate the amount of heat added from the circulation flow rate of the flow rate sensor and the temperature difference between the heat exchanger outlet temperature sensor and the circulation return temperature sensor between them, and the temperature difference between the bath return temperature sensor and the bath temperature sensor, and the time between them. The hot water supply apparatus of Claim 1 which calculates | requires a bath circulation flow rate. The bath circulation flow rate calculation device circulates the hot water in the bathtub by the circulation operation of the hot water supply circulation circuit and adds heat through the bath heat exchanger, and the bath return temperature sensor is set to the specified value from the start of the circulation operation. Calculate the amount of heat added from the time until the temperature reaches, the circulation flow rate of the circulation flow sensor, and the temperature difference between the heat exchanger outlet temperature sensor and the circulation return temperature sensor, and then return to the bath return temperature sensor and the bath. The hot water supply apparatus of Claim 1 which calculates | requires a bath circulation flow volume from the temperature difference of a temperature sensor, and the time in the meantime. The bath circulation flow calculation device circulates the hot water in the bathtub by the circulation operation of the hot water supply circulation circuit and adds heat through the bath heat exchanger, and the bath circulation flow rate after a predetermined time has elapsed from the start of circulation. The hot-water supply apparatus of Claim 2, 3 which starts the calculation of. The bath circulation flow rate calculation device circulates the hot water in the bathtub by the circulation operation of the hot water circulation circuit and adds heat through the bath heat exchanger, and the bath return temperature sensor starts at the predetermined temperature from the start of the circulation operation. The hot water supply apparatus according to claim 3 or 4, wherein calculation of the bath circulation flow rate is started after rising. The bath circulation flow rate calculation device circulates the hot water in the bathtub by the circulation operation of the hot water circulation circuit and adds heat through the bath heat exchanger, and the bath return temperature sensor starts at the predetermined temperature from the start of the circulation operation. The hot water supply apparatus according to claim 3 or 4, wherein the calculation of the bath circulation flow rate is started after reaching the value. The hot water supply apparatus according to any one of claims 4 to 6, wherein the calculation of the bath circulation flow rate is performed during a trial operation after installation of the equipment. The hot water supply apparatus according to any one of claims 4 to 6, wherein bath operation cannot be performed unless calculation of a bath circulation flow rate is performed during a test operation after installation of the device. The hot water supply apparatus according to any one of claims 4 to 6, wherein if the calculation of the bath circulation flow rate is not performed at the time of trial operation after installation of the equipment, the bath operation cannot be performed and the external input device is displayed to perform the bath test operation.