JP5304602B2 - Hot water supply apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater enabling water supply to a hot water storage tank and water discharge from the hot water storage tank by a simple configuration; and a method of controlling the water heater. <P>SOLUTION: The water heater 100 includes: a water supply pipe 11 connected to the lower part of the hot water storage tank 10 and supplying hot water supply water to inside of the hot water storage tank 10; a water discharge pipe 16 having one end connected to the lower part of the hot water storage tank 10 and the other end opened in the atmosphere and discharging hot water within the hot water storage tank 10; an air suction/exhaust pipe 17 branched from an intermediate portion of the water discharge pipe 16 and connected to the upper part of the hot water storage tank 10; a three-way valve 18 provided in a branch portion where the air suction/exhaust pipe 17 is branched from the water discharge pipe 16 and capable of opening/closing the hot water storage tank 10 side of the water discharge pipe 16, the atmosphere open side of the water discharge pipe 16 and the air suction/exhaust pipe 17 side; and a control device 30 controlling opening/closing of three ways of the three-way valve 18. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a hot water storage type hot water supply apparatus that boils hot water and stores hot water and uses the stored hot water for hot water supply, and a control method thereof.

  As a conventional hot water supply apparatus, for example, one described in Patent Document 1 is known. In this hot water supply apparatus, a water supply pipe and a drain pipe are connected to a water supply port provided at the lower part of the hot water storage tank via an electric three-way valve. An air vent pipe is branched from the middle of the hot water supply pipe connected to the hot water tap from the hot water storage tank, and the air vent pipe is led to an open water tray. An electric on-off valve is provided in the middle of the air vent pipe, and a water level detection sensor is provided inside the water tray.

  In this hot water supply apparatus, when an administrator turns on the switch of the collective control panel at the time of water supply, the electric three-way valve is controlled by the system controller, and the water supply pipe is connected to the water supply port. At the same time, the electric on-off valve is opened. Then, water enters from the water supply port of the hot water tank, the water surface gradually rises, and water flows out from the air vent pipe in a state where the water is full. When a certain amount of water accumulates in the water tray, the water level detection sensor detects this and closes the contact. This signal confirms that the water is full, and the system controller closes the electric on-off valve.

  On the other hand, at the time of drainage, when the manager turns off the switch of the collective control panel, the electric three-way valve is controlled by the system controller, and the water supply port is connected to the drainage pipe. At the same time, the electric on-off valve is opened. As a result, air is sucked from the air vent pipe and smooth drainage is performed.

Japanese Patent No. 2690560

  However, in Patent Document 1, an electric three-way valve, an electric on-off valve, a water level sensor, a water tray, and the like are required to supply and drain water, and the structure is complicated and expensive.

  In view of the above problems, an object of the present invention is to provide a hot water supply apparatus and a control method thereof that enable water supply to the hot water storage tank and drainage from the hot water storage tank with a simple configuration.

In order to achieve the above object, the present invention employs the following technical means. That is, in the invention according to claim 1, in the hot water supply device (100),
A hot water storage tank (10) for storing hot water boiled by the heating means (20) and for discharging the stored hot water to a hot water outlet;
A water supply pipe (11) connected to the lower part of the hot water storage tank (10) and supplying hot water into the hot water storage tank (10);
A drain pipe (16) having one end connected to the lower part of the hot water storage tank (10) and the other end opened to the atmosphere to drain hot water in the hot water storage tank (10);
An intake / exhaust pipe (17) branched from an intermediate portion of the drain pipe (16) and connected to the upper part of the hot water storage tank (10);
Provided at the branching site where the intake / exhaust pipe (17) branches from the drain pipe (16), the hot water tank (10) side of the drain pipe (16), the open side of the drain pipe (16), and the intake / exhaust pipe (17) A three-way valve (18) that allows each side to be opened and closed,
And a control device (30) for controlling opening and closing of the three-way valve (18).

  In the hot water supply device (100), hot water supplied from the water supply pipe (11) to the hot water storage tank (10) is boiled as hot water by the heating means (20), and the hot water storage tank is used when the user uses the hot water. (10) The hot water that has been boiled in is discharged into the hot water outlet. At this time, at least the hot water storage tank (10) side of the drain pipe (16) and the intake / exhaust pipe (17) side of the three-way valve (18) are closed by the control device (30).

  In the present invention, when the three-way valve (18) is controlled to open and close by the control device (30), the automatic drain operation for automatically draining hot water in the hot water storage tank (10) and the hot water storage tank (10 ) Enables automatic water supply operation to automatically supply hot water.

  That is, in performing the automatic drain operation, after the supply of hot water from the water supply pipe (11) to the hot water storage tank (10) is stopped, the control device (30) is drained (16) by the three-way valve (18). When the hot water storage tank (10) side and the open side of the drain pipe (16) are opened and the first connection state is established between the two, the internal pressure of the hot water storage tank (10) is initially set to the external pressure (atmospheric pressure). Since it is higher, the hot water in the hot water storage tank (10) is drained from the drain pipe (16). As hot water is drained, the space in the hot water storage tank (10) expands and the internal pressure decreases, so that hot water becomes difficult to drain. Here, when the open side of the drain pipe (16) and the supply / exhaust pipe (17) side are opened by the three-way valve (18) and the two are connected to each other, the drain pipe (16) Since air can be supplied to the upper part of the hot water storage tank (10) through the intake / exhaust pipe (17) from the open side of the atmosphere, the pressure in the hot water storage tank (10) is made equal to the atmospheric pressure and again The hot water in the hot water storage tank (10) can be drained. And the hot water in hot water storage tank (10) can be drained by repeating said 1st connection state and 2nd connection state by a three-way valve (18).

  Next, in performing the automatic drain operation, after the hot water is supplied from the water supply pipe (11) to the hot water storage tank (10), the control device (30) is drained by the three-way valve (18). When the connection state between (16) and the intake / exhaust pipe (17) is the above-described second connection state, the upper space in the hot water storage tank (10) is connected to the air release side of the intake / exhaust pipe (17) and the drain pipe (16). Therefore, hot water can be smoothly supplied into the hot water storage tank (10) while the air in the hot water storage tank (10) is drawn outside.

  Thus, in the invention described in claim 1, only the three-way valve (18) is used for the one provided with the electric three-way valve and the electric on-off valve described in the cited reference 1 described in the “Background Art” section. As a simple configuration, automatic drain operation and automatic water supply operation are enabled by controlling the three-way valve (18).

  In the invention according to claim 2, the area of the cross section intersecting with the longitudinal direction of the drain pipe (16) is determined based on the following formula 1 so that the time required for drainage is a predetermined drainage time. It is characterized by that.

(Formula 1)
Cross-sectional area of drainage pipe = {1/2 g × capacity of hot water storage tank × horizontal cross-sectional area of hot water storage tank / (predetermined drainage time) ² } ^1/2
However, g is a gravitational acceleration.

  According to this invention, it becomes possible to set the cross-sectional area of the drain pipe (16) taking into account the predetermined drainage time according to the capacity of the hot water storage tank (10) and the horizontal cross-sectional area based on the mathematical formula 1, and appropriate drainage time. It becomes possible to complete drainage.

  In the third aspect of the present invention, the detection means (17a) for detecting the flow state and supplying a detection signal to the control device (30) when hot water flows through the intake pipe (17). It is characterized by being provided.

  According to the present invention, in the automatic water supply operation, when hot water is supplied from the water supply pipe (11) into the hot water storage tank (10) and the hot water storage tank (10) is full, the hot water is supplied to the intake / exhaust pipe (17). And overflow from the open side of the drain pipe (16). At this time, it is possible to determine that the hot water storage tank (10) is full by detecting the flow of hot water in the intake / exhaust pipe (17) by the detection means (17a), so the automatic water supply operation is stopped at that time. Thus, it is possible to reliably supply water with the overflow amount of hot water being minimized.

  The invention according to claim 4 is characterized in that the water supply pipe (11) is provided with an on-off valve (11e) controlled to be opened and closed by the control device (30).

  According to the present invention, the hot water supply from the water supply pipe (11) can be stopped by closing the on-off valve (11e) by the control device (30) before controlling the three-way valve (18) in the automatic drain operation. In addition, before performing control of the three-way valve (18) in the automatic water supply operation, the controller (30) opens the on-off valve (11e) to enable hot water supply from the water supply pipe (11). Therefore, fully automatic drainage operation and supply operation are possible.

  In the invention described in claim 5, the control device (30) is incorporated in the hot water supply control device (30) for controlling the boiling of hot water into the hot water storage tank (10) and the hot water discharged from the hot water storage tank (10). It is characterized by that.

  According to this invention, in addition to the operation for performing normal boiling of hot water and control of tapping hot water, the user performs the operation of automatic drain operation and automatic water supply operation to the same hot water supply control device (30). This makes it possible to improve user convenience.

  The invention described in claim 6 relates to an automatic discharge operation in the hot water supply device (30) and a control method for the automatic water supply operation, the technical significance of which is essentially the same as that of the hot water supply device described in claim 1 above. Is the same.

  The invention according to claim 7 is characterized in that, in the automatic drain operation, it is determined that drainage is completed with the passage of a predetermined first predetermined time.

  According to the present invention, since the time required for draining all the hot water in the hot water storage tank (10) is set in advance as the first predetermined time, it is possible to clearly determine the completion of drainage. It is possible to perform automatic drainage operation.

  The invention according to claim 8 is characterized in that, in the automatic water supply operation, it is determined that the water supply is completed with the passage of a predetermined second predetermined time.

  According to this invention, since the time required for filling the hot water storage tank (10) with hot water is fully set as the second predetermined time, it is possible to clearly determine the completion of water supply. A reliable automatic water supply operation can be executed.

In the invention according to claim 9, when hot water is circulated in the intake / exhaust pipe (17), detection means (17 a) for detecting the circulation state is provided,
In the automatic water supply operation, it is characterized in that it is determined that the water supply has been completed by detecting the flow of hot water supply by the detection means (17a).

  According to the present invention, as in the invention described in claim 3 above, in the automatic water supply operation, the hot water storage tank (10) is detected by detecting the flow of hot water in the intake / exhaust pipe (17) by the detection means (17a). Since it can be determined that the inside has become full, the automatic water supply operation is stopped at that time, thereby enabling reliable water supply with the overflow amount of hot water being minimized.

In the invention according to claim 10, the water supply pipe (11) is provided with an on-off valve (11e) for opening and closing the water supply pipe (11),
The on-off valve (11e) is closed before the execution of the automatic drain operation, and the on-off valve (11e) is opened before the execution of the automatic water supply operation.

  According to this invention, similarly to the invention according to the fourth aspect, before the control of the three-way valve (18) in the automatic drain operation, the control device (30) closes the on-off valve (11e) to supply water. The hot water supply from the pipe (11) can be stopped, and before the control of the three-way valve (18) in the automatic water supply operation, the control device (30) opens the on-off valve (11e) to open the water supply pipe ( Since it is possible to supply hot water from 11), fully automatic drainage operation and supply operation are possible.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

It is a schematic diagram which shows the whole structure of the hot water supply apparatus in 1st Embodiment. It is a flowchart which shows the process at the time of automatic drain operation execution in 1st Embodiment. It is a schematic diagram which shows the flow direction of the hot water at the time of automatic drain operation execution in 1st Embodiment, and air. It is a graph which shows the change of the waste_water | drain flow volume when air is suck | inhaled from the hot water storage tank upper part. It is a graph which shows the change of the drainage flow volume when not inhaling air from the hot water storage tank upper part. It is a graph which shows the change of the waste_water | drain flow volume in 1st Embodiment. It is a flowchart which shows the process at the time of automatic water supply operation execution in 1st Embodiment. It is a schematic diagram which shows the hot water supply at the time of automatic water supply operation execution in 1st Embodiment, and the flow direction of air. It is a schematic diagram which shows the whole structure of the hot water supply apparatus in 2nd Embodiment. It is a flowchart which shows the process at the time of automatic water supply operation execution in 2nd Embodiment. It is a schematic diagram which shows the whole structure of the hot water supply apparatus in 3rd Embodiment. It is a flowchart which shows the process at the time of automatic drain operation execution in 3rd Embodiment. It is a flowchart which shows the process at the time of automatic water supply operation execution in 3rd Embodiment. It is a flowchart which shows the process at the time of automatic drain operation execution in other embodiment.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not specified unless there is a problem with the combination. Is also possible.

(First embodiment)
The hot water supply apparatus in 1st Embodiment is demonstrated using FIGS. 1 is a schematic diagram showing the overall configuration of a hot water supply apparatus 100A using the heat pump unit 20, FIG. 2 is a flowchart showing processing during execution of an automatic drain operation, and FIG. 3 is a flow of hot water and air during execution of the automatic drain operation. FIG. 4 is a graph showing a change in drainage flow rate when air is sucked from the upper part of the hot water storage tank, FIG. 5 is a graph showing a change in drainage flow rate when air is not sucked from the upper part of the hot water storage tank, and FIG. 6 is a graph showing changes in the drainage flow rate in the present embodiment, FIG. 7 is a flowchart showing processing during execution of the automatic water supply operation, and FIG. 8 is a schematic diagram showing flow directions of hot water and air during execution of the automatic water supply operation. .

  The hot water supply device 100A is a hot water storage type used for general household use, and stores hot water generated by the heat pump unit 20 in the hot water storage tank 10 (boiling operation) and also uses the stored hot water for hot water supply. As hot water, it is supplied to kitchens, washrooms, baths, etc. (hot water supply operation, hot water operation).

  As shown in FIG. 1, the hot water supply device 100A includes a hot water storage tank 10, various pipes 11, 11c, 11d, 12, 12a, 14, 15, 16, 17, a heat pump unit 20, control devices 30, 31 and the like. .

  The hot water storage tank 10 is a container for storing hot water for hot water supply, and is made of a metal having excellent corrosion resistance (for example, made of stainless steel). It can be kept warm across. In this embodiment, the total capacity of the hot water storage tank 10 is 185L.

  The hot water storage tank 10 has a vertically long shape, and a water supply / drain port 10a is provided on the bottom surface thereof. A water supply pipe 11 for supplying hot water (tap water) into the hot water storage tank 10 is connected to the water supply / drain port 10a. The water supply pipe 11 is adjusted so that the main plug 11a that opens and closes the water supply pipe 11 by a user's manual operation and the water pressure of the hot water to be introduced becomes a predetermined pressure, and prevents back flow of hot water due to water interruption or the like. A pressure reducing valve 11b is provided. On the other hand, a lead-out port 10b is provided at the uppermost part of the hot water storage tank 10, and a high-temperature take-out pipe 12 for leading out high-temperature hot water stored in the hot water storage tank 10 is connected to the lead-out port 10b.

  At the lower part of the hot water storage tank 10, there is provided a discharge port 10 c for discharging the lowermost hot water in the hot water storage tank 10 to the heat pump unit 20 described later, and at the upper part of the hot water storage tank 10, the heat pump unit 20. A suction port 10d through which hot water discharged from the side flows into the interior is provided. The discharge port 10c and the suction port 10d are connected by a circulation circuit 21, and a part of the circulation circuit 21 is disposed in the heat pump unit 20 (water refrigerant heat exchanger).

  A plurality of (for example, five) thermistors (not shown) as temperature detecting means for detecting the amount of stored hot water and the temperature of stored hot water are arranged on the outer wall surface of the hot water storage tank 10 at substantially equal intervals in the vertical direction (top and bottom direction). The thermistor outputs a temperature signal at each level of hot water or hot water filled in the hot water storage tank 10 to the control device 30 described later. The thermistor is disposed at positions 20L, 50L, 90L, 130L, and 165L from the upper end side of the hot water storage tank 10 when the total volume of the hot water storage tank 10 is 185L as described above, for example.

  Therefore, the control device 30 detects the boundary position between the hot water heated in the upper part of the hot water tank 10 and the hot water before being heated in the lower part of the hot water tank 10 based on the temperature signal from the thermistor. Can do. For example, when the detected temperature of a certain thermistor exceeds a predetermined temperature (for example, 50 ° C.) that can be used as the amount of stored hot water, the controller 30 can supply hot water that can be used for hot water supply from the top of the hot water storage tank 10 to the position of the thermistor. Judge that it has accumulated.

  Of these thermistors, the thermistor provided on the upper outer wall surface of the hot water storage tank 10 detects the hot water temperature at the top of the hot water storage tank 10 which is the temperature of the hot water sucked into the high temperature take-out pipe 12. It also has the thermistor function. Further, the thermistor provided on the lower outer wall surface of the hot water storage tank 10 also has a thermistor function for confirming the boiling state during the heating operation described later.

  The heat pump unit 20 is a heating unit that heats low temperature hot water at the lower side of the hot water storage tank 10 and stores high temperature hot water from the upper part of the hot water storage tank 10, and uses a low critical temperature carbon dioxide (CO 2) as a refrigerant. A cycle and a water supply pump (not shown) installed in the circulation circuit 21 are provided. According to the supercritical heat pump, hot water having a temperature higher than that of a general heat pump cycle (for example, about 85 ° C. to 90 ° C.) can be stored in the hot water storage tank 10.

  The heat pump cycle is composed of an electric compressor (not shown), a water refrigerant heat exchanger, an electric expansion valve, an air heat exchanger, and an accumulator, which are sequentially connected by refrigerant piping, and its operation is for a heat pump (not shown). It is controlled by a control device.

  The water-refrigerant heat exchanger includes a refrigerant passage through which refrigerant flows and a water passage through which hot water circulating through the circulation circuit 21 flows, and is discharged from the discharge port of the compressor and flows through the refrigerant passage. The hot water is boiled by heating the hot water flowing through the water passage (circulation circuit 21) with a high-temperature and high-pressure refrigerant.

  The water supply pump is disposed between the discharge port 10c of the circulation circuit 21 and the heat pump unit 20 (water refrigerant heat exchanger). The water supply pump is rotationally driven by a built-in electric motor (not shown), and discharges low temperature hot water from the discharge port 10c during the boiling operation of high temperature hot water so that hot water heated in the water refrigerant heat exchanger is stored in a hot water storage tank. It operates so as to recirculate to 10 suction ports 10d. The rotation speed of the feed water pump is controlled by a heat pump controller (not shown) so that the outlet water temperature of the water-refrigerant heat exchanger becomes a predetermined target boiling temperature determined under various operating conditions.

  The water supply pipe 11 is provided with branch water supply pipes 11c and 11d branched from the front portion of the water supply / drain port 10a, and the downstream ends of the branch water supply pipes 11c and 11d are connected to mixing valves 13a and 13b, which will be described later, respectively. ing.

  A mixing valve 13a is provided at a downstream side joining portion between the high temperature take-out pipe 12 and the branch water supply pipe 11c. The mixing valve 13a is a temperature control valve, and adjusts the opening area ratio (valve opening degree) on each of the high temperature side and the low temperature side, and the hot water extracted from the high temperature extraction pipe 12 and the branch water supply pipe 11c. By adjusting the mixing ratio with the hot water supplied from, the temperature of hot water flowing through the hot water supply pipe 14 connected to the downstream side of the mixing valve 13a is adjusted to a set temperature set by the user. The valve opening degree of the mixing valve 13a is controlled by a control device 30 described later. The hot water supply pipe 14 is a pipe that guides hot water whose temperature is adjusted to a set temperature to a hot water faucet (curan, shower, etc. as a hot water supply section) as a terminal at the downstream end.

  The high temperature extraction pipe 12 is provided with a high temperature branch pipe 12a that branches from between the outlet 10b and the mixing valve 13a, and a mixing valve is provided at the downstream junction of the high temperature branch pipe 12a and the branch water supply pipe 11d. 13b is provided. Similar to the mixing valve 13a, the mixing valve 13b is a temperature control valve, and adjusts the opening area ratio (valve opening degree) on each of the high temperature side and the low temperature side so that the high temperature taken out from the high temperature branch pipe 12a. By adjusting the mixing ratio between the hot water and hot water supplied from the branch water supply pipe 11b, the user sets the temperature of the hot water to be circulated through the bath pipe 15 connected to the downstream side of the mixing valve 13b. Adjust to the set temperature. The opening degree of the mixing valve 13b is controlled by a control device 30 described later. The bath piping 15 is connected to a bath (hot water supply unit) (not shown), and hot water (hereinafter referred to as bath water) whose temperature is adjusted to a set temperature when hot water is filled in the bath, hot water, hot water, etc. It is provided as a pipe that guides. A hot water solenoid valve (not shown) for opening and closing the bath pipe 15 is provided in the middle of the bath pipe 15, and the valve opening degree of the hot water solenoid valve is controlled by a control device 30 described later. It has become so.

  A drain pipe 16 is provided below the hot water storage tank 10. One end of the drainage pipe 16 is connected to the water supply / drainage port 10a on the bottom surface of the hot water storage tank 10, and the other end is opened to the atmosphere and led to a side groove for drainage. Here, one end of the drainage pipe 16 joins in the vicinity of the lower part of the hot water storage tank 10 of the water supply pipe 11 and is connected to the water supply / drainage port 10a.

  Here, since the area of the cross section intersecting with the longitudinal direction of the drain pipe 16 (hereinafter referred to as the drain pipe cross-sectional area) greatly affects the drainability (drainage time) during drainage, in the present embodiment, the following formula 1 is used. Thus, the drain pipe cross-sectional area is calculated.

(Formula 1)
Drainage pipe cross-sectional area = {1/2 g × hot water storage tank capacity × hot water storage tank horizontal cross-sectional area / (predetermined drainage time) ² } ^1/2
However, g is a gravitational acceleration.

  The basis for setting the formula 1 is based on the following formulas 2 to 4. That is, the drainage time is calculated by the following formula 2.

(Formula 2)
Drainage time = Hot water storage tank capacity / (Drainage speed x Drainage pipe cross-sectional area)
Further, the drainage speed in Equation 2 is calculated by Equation 3 below.

(Formula 3)
Drainage speed = (2g x hot water tank water level) ^1/2
Further, the water level in the hot water storage tank in Equation 3 is calculated by Equation 4 below.

(Formula 4)
Water level in hot water tank = hot water tank capacity / hot water tank horizontal cross-sectional area)
Therefore, Formula 1 is obtained by substituting Formula 3 and Formula 4 into Formula 2 and arranging them by the drain pipe cross-sectional area. Formula 1 shows that the drain pipe cross-sectional area is proportional to the specifications (volume, horizontal cross-sectional area) of the hot water storage tank 10 and inversely proportional to the drainage time. In particular, when it is desired to keep the time required for drainage within a predetermined time, the time is determined as the predetermined drainage time, and the drain pipe cross-sectional area of the drain pipe 16 is determined along with the specifications of the hot water storage tank 10. Effective drainage can be made possible.

  An intake / exhaust pipe 17 is provided between the middle portion of the drain pipe 16 and the upper part of the hot water storage tank 10. That is, the intake / exhaust pipe 17 is branched from a part in the middle of the drain pipe 16, here the part on the other end side (atmosphere release side) of the junction with the water supply pipe 11 of the drain pipe 16, It is provided as a pipe connected to the suction port 10d.

  A three-way valve 18 is provided at a branch portion where the intake / exhaust pipe 17 branches from the drain pipe 16. The three-way valve 18 has openings in three directions, each opening is provided with an opening / closing valve, and each opening / closing valve is controlled by a control device 30 to be described later, so that the drain pipe 16 and the intake / exhaust pipe 17 are connected. It functions as a flow path switching valve for switching between. Since the three-way valve 18 is disposed at a branch portion of the intake / exhaust pipe 17 with respect to the drain pipe 16, one opening of the three-way valve 18 has a tank side that is closer to the hot water storage tank 10 than the three-way valve 18 in the drain pipe 16. The drain pipe 16a is connected, and the second opening of the three-way valve 18 is connected to an atmosphere-side drain pipe 16b that is closer to the atmosphere than the three-way valve 18 in the drain pipe 16. An intake / exhaust pipe 17 is connected to the third opening.

  In the upper part of the hot water storage tank 10, an escape pipe 19 that is branched from the intake / exhaust pipe 17 and opened to the atmosphere is provided, and in the escape pipe 19, an escape valve 19 a is provided. The relief valve 19a is opened when the pressure in the hot water storage tank 10 exceeds a predetermined pressure, and opens the internal pressure to the outside of the tank.

  The control device 30 is a control device for a hot water supply device that controls basic boiling operation, hot water supply operation, and hot water filling operation in the hot water supply device 100 </ b> A, and includes a control panel (remote control) 31. In addition to the basic operation control of the hot water supply device 100A, the control device 30 also performs control of automatic drain operation and automatic water supply operation. The control device 30 is mainly composed of a microcomputer, and a built-in ROM (not shown) is provided with a preset control program, and temperature signals from each thermistor and operations input by the user. Based on an operation signal from the panel 31, the mixing valves 13a, 13b, the hot water solenoid valve, and the three-way valve 18 are controlled. Moreover, the control apparatus 30 has a timer for timekeeping used at the time of automatic drain operation and automatic water supply operation.

  The operation panel 31 includes a hot water supply set temperature switch, a hot water filling switch, a hot water filling set temperature switch, a drainage switch, a water supply switch, and the like as operation switches. Moreover, the control apparatus 30 is installed in the hot water storage tank 10, and the operation panel 31 is installed in the vicinity of the place using hot water, such as a bathroom or a kitchen.

  Next, the operation of the hot water supply apparatus 100 configured as described above will be described.

1. The heating operation control device 30 uses a cheap midnight power in the midnight time zone (for example, from 23:00 to 7:00 on the next day) with respect to the heat pump control device (not shown), and the heat pump unit 20 (heat pump cycle and water pump). Instruct the operation and boil hot water for the next day. That is, the control device 30 circulates the hot water on the lower side in the hot water storage tank 10 through the circulation circuit 21 and heats it with the heat pump unit 20 so that the generated hot water is supplied to the upper side of the hot water storage tank 10 from the inlet 10d. I will save it.

  Specifically, the control device 30 sets the following boiling conditions at the start time of the midnight time zone, and performs the boiling operation based on the boiling conditions. Here, the boiling conditions are a target heat storage amount, a boiling temperature, a boiling heat amount (target heat storage amount-tank hot water storage amount), a boiling time, a boiling start time, and a boiling end time.

  The target heat storage amount is calculated by adding a standard deviation σ to the average usage amount obtained by averaging the usage amount of hot water in a stored predetermined period (for example, the past seven days) to the usage amount of hot water per day. . The target heat storage amount can be viewed as the product of the total volume of the hot water storage tank 10 and the temperature rise width (temperature difference) when boiling the hot water from the hot water.

  The boiling temperature is calculated by adding the temperature of the hot water supply to a value obtained by dividing the target heat storage amount by the total volume of the hot water storage tank 10 (for example, 85 ° C.). The amount of stored hot water in the tank is the amount of heat of hot water remaining in the hot water storage tank 10 at 23:00, and is calculated from the temperature of hot water obtained by each thermistor, the temperature of hot water supply, and the volume between the thermistors. The boiling start time is determined by back-calculating the boiling time required for boiling from the boiling end time. Here, the boiling end time is the end time of the midnight time zone (7 o'clock). The boiling time is calculated as the amount of boiling heat / heat pump heating capacity when the amount of heat obtained by subtracting the amount of heat stored in the tank from the target amount of stored heat is used as the amount of boiling heat. The boiling start time is determined by subtracting the calculated boiling time from the end time of the midnight time zone.

  At the boiling start time, the control device 30 operates the heat pump unit 20 to start boiling hot water. When the boiling is finished or when the boiling finish time is reached, the heat pump unit 20 is stopped and the boiling of the hot water is finished. Note that the determination of the completion of boiling is made when the temperature obtained by the thermistor at the bottom of the hot water storage tank 10 is equal to or higher than (boiling temperature−predetermined temperature).

2. Hot water supply operation, hot water filling operation When using hot water in a kitchen or a washroom in the daytime, the control device 30 causes the mixing valve 13a to match the set temperature input by the user from the hot water set temperature switch of the operation panel 31. By adjusting the valve opening degree of the hot water, the hot water of the high temperature take-out pipe 12 taken out from the outlet 10b of the hot water storage tank 10 and the hot water supplied from the branch water supply pipe 11c are mixed to obtain hot water whose temperature is adjusted. The hot water supply pipe 14 supplies the hot water tap.

  At the time of filling the bath, the control device 30 opens the filling solenoid valve, and the valve of the mixing valve 13b is set so as to coincide with the set temperature input and set by the user from the set temperature switch on the operation panel 31. The hot water of the high temperature branch pipe 12a taken out from the outlet 10b of the hot water storage tank 10 and the hot water supplied from the branch water supply pipe 11d are mixed to adjust the opening, and the temperature adjusted hot water is used for the bath. Supply from the pipe 15 to the bathtub.

3. Automatic drain operation When the user does not use the hot water supply device 100A for a long period of time, for example, in the winter season, the hot water in the hot water storage tank 10 is used to prevent the tank from freezing or to prevent the tank from decaying. It is necessary to discharge. In such a case, the user first closes the main plug 11a by a manual operation, and inputs the drainage treatment with the drainage switch of the operation panel 31.

  When receiving a signal from the drain switch, the control device 30 executes an automatic drain operation based on the flowchart shown in FIG. During the automatic drain operation, the control device 30 repeatedly turns the flowchart of FIG. 2 to constantly monitor the state at each step and perform necessary processing.

  First, in step S100 in FIG. 2, the control device 30 receives an ON signal from the drain switch, starts an automatic drain operation, and starts timing by a timer from this point.

  In step S110, the three-way valve 18 is switched to the drain side. That is, among the open / close valves in the openings of the three-way valve 18, the open / close valves on the tank side of the drain pipe 16 and the open side of the water distribution pipe 16 are opened, and the open / close valve on the intake / exhaust pipe 17 side is closed. By switching the on-off valve, the tank-side drain pipe 16a and the atmosphere-side drain pipe 16b communicate with each other (corresponding to the first connection state of the present invention), the original drain pipe 16 functions, and a solid line arrow in FIG. As shown, the hot water in the hot water storage tank 10 passes through the drain pipe 16 (tank side drain pipe 16a, atmosphere side drain pipe 16b) and is drained into a side groove or the like. In addition, the control apparatus 30 will start time measurement by a timer from the time, if step S110 is performed.

  Here, when the hot water in the hot water storage tank 10 is drained, if an intake valve or the like is provided in the upper part of the hot water storage tank 10 and the intake valve is opened and the air is sucked in while sucking air, as shown in FIG. The drainage can be performed with a sufficient drainage flow rate.

  However, in the case where there is no intake valve or the like and there is no intake of air from the upper part of the hot water storage tank 10, the internal pressure of the hot water storage tank 10 is initially higher than the external pressure (atmospheric pressure) as shown in FIG. Hot water in the hot water storage tank 10 is drained from the drain pipe 16. However, as hot water is drained, the space in the hot water storage tank 10 expands and the internal pressure decreases (the internal pressure decreases from the atmospheric pressure), making it difficult for the hot water to be drained (see FIG. “Exhaust” part at the lower right in 5). Then, when a behavior such as forcibly sucking air from the drain pipe 16 on the lower side of the hot water storage tank 10 occurs, the internal pressure of the hot water storage tank 10 approaches atmospheric pressure, and the drainage is restored (the “suction” on the upper right in FIG. 5). ”Part). As described above, when there is no air suction from the upper part of the hot water storage tank 10, the drainage proceeds by repeating the drainage and the forced intake. In such a drainage form, depending on the tank capacity (the amount of hot water), the drain pipe specification, etc., the hot water in the hot water storage tank 10 may not be completely drained.

  Therefore, in the present embodiment that does not include an intake valve or the like, the time (internal pressure reduction time) until the internal pressure of the hot water storage tank 10 decreases and the drainage becomes difficult due to the drainage in the first connection state by the three-way valve 18. It is determined in advance, and in step S120, it is determined whether or not the time measured by the timer from the execution time of step S110 has passed the internal pressure reduction time. If the determination is affirmative, the process proceeds to step S130. The internal pressure reduction time can be experimentally grasped in advance, and is set to, for example, 5 minutes in this embodiment.

  In step S130, the three-way valve 18 is switched to the intake side. That is, among the open / close valves at the openings of the three-way valve 18, the open / close valve on the atmosphere opening side of the water distribution pipe 16 and the open / close valve on the intake / exhaust pipe 17 side are opened, and the open / close valve on the tank side of the water distribution pipe 16 is closed. By switching the opening / closing valve, the atmosphere side exhaust pipe 16b and the intake / exhaust pipe 17 communicate with each other (corresponding to the second connection state of the present invention), and the air (atmosphere) is on the atmosphere side as shown by the broken line arrow in FIG. The water is supplied into the hot water storage tank 10 through the drain pipe 16b and the intake / exhaust pipe 17. In addition, the control apparatus 30 will start the time measurement by a timer from the time, if step S130 is performed.

  Then, in step S140, it is determined whether or not the time measured by the timer from the execution time of step S130 has passed for a time during which the pressure in the hot water storage tank 10 is balanced with the outside. If the determination is affirmative, the process proceeds to step S150. Yes. The above-described pressure equilibration time is the time required for air to be supplied into the hot water storage tank 10 and the pressure in the hot water storage tank to be equal to the external atmospheric pressure (the time corresponding to the “suction” portion described with reference to FIG. 5). In this embodiment, for example, it is set to 30 seconds.

  In step S150, it is determined whether or not the time measured by the timer from the execution time of step S100 has passed a predetermined drainage completion expected time. The expected completion time of drainage corresponds to the first predetermined time of the present invention. As shown in FIG. 6, the drainage from the drainage pipe 16 (downward to the right in FIG. And the supply of air into the hot water storage tank 10 using the intake / exhaust pipe 17 (the upwardly rising part in FIG. 6) is necessary until the hot water storage tank 10 becomes completely empty. And is set based on the time. For example, the estimated drainage completion time = (measurement required time + margin time) is set.

  If it is determined NO in step S150, steps S110 to S150 are repeated. Then, if an affirmative determination is made in step S150, it is considered that drainage has been completed, and in step S160, the automatic drainage operation is terminated. At the end of this automatic drain operation, in order to prevent foreign matter from entering the hot water storage tank 10, at least the opening / closing valve on the tank side of the drain pipe 16 and the opening / closing on the intake / exhaust pipe 17 side among the openings of the three-way valve 18. It is better to close the valve.

4). Automatic Water Supply Operation When the user uses the hot water supply device 100A again after performing the automatic drain operation, first, the hot water storage tank 10 needs to be filled with hot water. In such a case, the user first opens the main plug 11a by manual operation, and inputs the water supply process with the water supply switch of the operation panel 31. As described above, when the user opens the main plug 11 a, hot water flows into the hot water storage tank 10 from the water supply / drain port 10 a through the water supply pipe 11.

  When receiving a signal from the water supply switch, the control device 30 executes an automatic water supply operation based on the flowchart shown in FIG. During the automatic water supply operation, the control device 30 repeatedly turns the flowchart of FIG. 7 (step S220) to constantly monitor the state at each step and perform necessary processing.

  First, in step S200 in FIG. 7, the control device 30 receives an ON signal from the water supply switch, starts an automatic water supply operation, and starts timing by a timer from this point.

  In step S210, the three-way valve 18 is switched to the exhaust side. That is, among the open / close valves at the openings of the three-way valve 18, the open / close valve on the atmosphere opening side of the water distribution pipe 16 and the open / close valve on the intake / exhaust pipe 17 side are opened, and the open / close valve on the tank side of the water distribution pipe 16 is closed. By switching the opening / closing valve, the atmosphere side exhaust pipe 16b and the intake / exhaust pipe 17 communicate with each other (corresponding to the second connection state of the present invention). Then, as hot water flows into the hot water storage tank 10, the air in the hot water storage tank 10 passes through the intake / exhaust pipe 17 and the atmospheric drain pipe 16 b from the inlet 10 d as shown by the broken line arrows in FIG. 8. , It will be discharged to the outside (atmosphere).

  Then, in step S220, it is determined whether or not the time measurement result by the timer from the execution time of step S200 has passed the predetermined expected full water time. If the determination is affirmative, it is considered that the water supply has been completed, and the process proceeds to step S230. I try to go forward. The expected full water time corresponds to the second predetermined time of the present invention, and is necessary until the hot water storage tank 10 becomes full when the hot water storage tank 10 in the empty state is supplied from the water supply pipe 11. And is set based on the time. For example, the estimated full water time = (actually required time + margin time) is set.

  In step S230, the three-way valve 18 is switched to the closing side. That is, among the open / close valves in the openings of the three-way valve 18, the open / close valve on the atmosphere opening side of the water distribution pipe 16 and the open / close valve on the intake / exhaust pipe 17 side are closed. In step S240, the automatic water supply operation is terminated.

  As described above, in the hot water supply apparatus 100A of the first embodiment, the boiling operation, the hot water supply operation, and the hot water filling operation can be performed, and the automatic drain operation and the automatic water supply operation can be performed as necessary. Yes.

  In performing the automatic drain operation, after the main plug 11a is closed by the user and the supply of hot water from the water supply pipe 11 to the hot water storage tank 10 is stopped, the control device 30 is connected to the tank side ( By opening the tank side water distribution pipe 16a) and the atmosphere open side (atmosphere side water distribution pipe 16b) of the drain pipe 16, and setting the first connection state between the two, the hot water in the hot water storage tank 10 is drained. 16 can be drained. Since the internal pressure in the hot water storage tank 10 decreases as the hot water is drained, the hot water becomes difficult to drain. Here, when the atmosphere open side (atmosphere side water distribution pipe 16b) and the air supply / exhaust pipe 17 side of the drain pipe 16 are opened by the three-way valve 18, and the two are connected to each other, the air side water pipe 16b is connected. Since the air can be supplied to the upper part of the hot water storage tank 10 through the intake / exhaust pipe 17, the hot water in the hot water storage tank 10 is drained again by setting the pressure in the hot water storage tank 10 to be equal to the atmospheric pressure. It becomes possible to do. Then, the hot water in the hot water storage tank 10 can be drained by repeating the first connection state and the second connection state by the three-way valve 18. In the first embodiment, since air is actively supplied into the hot water storage tank 10 by forming the second connection state as described above, when air is forcibly sucked as described in FIG. Compared with, the time to complete drainage is shortened.

  Next, when the automatic drain operation is executed, after the main plug 11a is opened by the user and hot water is supplied from the water supply pipe 11 to the hot water storage tank 10, the control device 30 uses the three-way valve 18 to discharge the water pipe. When the connection state between the exhaust pipe 16 and the intake / exhaust pipe 17 is the above-described second connection state, the upper space in the hot water storage tank 10 communicates with the outside through the intake / exhaust pipe 17 and the atmosphere-side drain pipe 16b. Hot water can be smoothly supplied into the hot water storage tank 10 while the air is extracted to the outside.

  Thus, in this 1st Embodiment, the simple structure which used only the three-way valve 18 with respect to what is equipped with the electric three-way valve of the cited reference 1 demonstrated in the section of "background art", and an electric on-off valve. As described above, the automatic drain operation and the automatic water supply operation are enabled by controlling the three-way valve 18.

  Further, in setting the cross-sectional area of the drain pipe 16, it is possible to set the cross-sectional area of the drain pipe 16 taking into account the predetermined drainage time according to the capacity of the hot water storage tank 10 and the horizontal cross-sectional area based on Equation 1. The drainage can be completed in the drainage time.

  In addition to the basic heating operation, hot water supply operation, and hot water filling operation of the hot water supply device 100A, the control device 30 as the hot water supply device control device can also control the automatic drain operation and the automatic water supply operation. Therefore, in addition to operations for performing normal hot water boiling and tapping control, the user can also perform automatic drainage operation and automatic water supply operation in the same control device (hot water supply control device) 30. This makes it possible to improve user convenience.

  Further, in the automatic drain operation, since it is determined that drainage is completed after a predetermined drainage completion expected time (first predetermined time) has elapsed, it is possible to clearly determine whether drainage is complete, and to ensure Automatic drain operation can be executed.

  In addition, in automatic water supply operation, it is determined that the water supply has been completed after the elapse of a predetermined expected full water time (second predetermined time), so that it is possible to clearly determine the completion of water supply, and a reliable automatic The water supply operation can be executed.

(Second Embodiment)
A second embodiment of the present invention is shown in FIGS. The hot water supply apparatus 100B according to the second embodiment is different from the first embodiment in that a flow sensor 17a as a detection unit is provided in the intake / exhaust pipe 17. When the flow of hot water in the intake / exhaust pipe 17 is generated, the flow sensor 17a detects that the flow is generated and outputs a detection signal to the control device 30 as shown in FIG.

  In the second embodiment, the automatic water supply operation using the flow sensor 17a is executed based on the flowchart shown in FIG. The flowchart of FIG. 10 is obtained by changing step S220 to step S221 with respect to the flowchart of FIG. 7 in the first embodiment.

  That is, in the automatic water supply operation, when the control device 30 executes step S200 and step S210 as in the first embodiment, hot water is supplied from the water supply pipe 11 into the hot water storage tank 10. When the hot water storage tank 10 is filled with hot water, the hot water flows through the intake / exhaust pipe 17 and overflows from the atmosphere side exhaust pipe 16b. At this time, since the flow sensor 17a detects the flow of hot water in the intake / exhaust pipe 17, the controller 30 determines in step S221 that the hot water storage tank 10 is filled with hot water by detecting this flow. After the process in step S230, the automatic water supply operation is terminated in step S240.

  As described above, in the second embodiment, in the automatic water supply operation, it is possible to determine that the hot water storage tank 10 is full by detecting the flow of hot water in the intake and exhaust pipe 17 by the flow sensor 17a. By stopping the automatic water supply operation, it is possible to reliably supply water with the overflow amount of hot water being minimized.

(Third embodiment)
A third embodiment of the present invention is shown in FIGS. The hot water supply apparatus 100C of the third embodiment is obtained by providing an opening / closing valve 11e as an opening / closing means in the water supply pipe 11 with respect to the first embodiment. The on-off valve 11e is a valve that is controlled to open and close by the control device 30 as shown in FIG. 11, and opens and closes the water supply pipe 11. The water supply pipe 11 is provided on the hot water storage tank 10 side of the pressure reducing valve 11b.

  In the third embodiment, the automatic drain operation is executed based on the flowchart shown in FIG. 12, and the automatic water supply operation is executed based on the flowchart shown in FIG. The flowchart in FIG. 12 is obtained by adding step S50 before step S100 to the flowchart in FIG. 2 in the first embodiment, and the flowchart in FIG. 13 is the flowchart in FIG. 7 in the first embodiment. On the other hand, step S60 is added before step S200.

  In the automatic drain operation, the user inputs the drainage treatment with the drain switch of the operation panel 31 while keeping the main plug 11a open without manual operation. Upon receiving a signal from the drain switch, the control device 30 first closes the on-off valve 11e in step S50, and then executes steps S100 to S160.

  Further, in the automatic drain operation, the user inputs the water supply process with the water supply switch of the operation panel 31 while keeping the main plug 11a open without being manually operated. When receiving a signal from the water supply switch, the control device 30 first opens the on-off valve 11e in step S60, and then executes steps S200 to S240.

  As described above, in the third embodiment, the water supply pipe 11 is provided with the on-off valve 11e that is controlled to be opened and closed by the control device 30, and the control device 30 closes the on-off valve 11e at the beginning of the automatic drain operation. It is possible to stop the hot water supply from the water supply, and it is possible to supply hot water from the water supply pipe 11 by opening the on-off valve 11e by the control device 30 at the beginning of the automatic water supply operation. Drainage operation and supply operation are possible.

  In addition, the installation position of the on-off valve 11e is not limited to the hot water storage tank 10 side of the pressure reducing valve 11b in the water supply pipe 11, and may be between the main plug 11a and the pressure reducing valve 11b.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  Another embodiment is shown in FIG. In this embodiment, the safety at the time of the automatic drain operation is enhanced with respect to the first embodiment, and the automatic drain operation is executed based on the flowchart shown in FIG. The flowchart in FIG. 14 is obtained by adding step S105 between step S100 and step S110 to the flowchart in FIG. 2 in the first embodiment.

  That is, in the automatic drain operation, when the control device 30 starts the automatic drain operation in step S100, in step S105, the controller 30 is left for a predetermined time until the temperature of the hot water in the hot water storage tank 10 cools to some extent, and then starts draining in step S110. Like to do.

  In order to prevent the user from being burned by the hot hot water that is discharged during the automatic drain operation, this is a predetermined time until the hot water temperature is such that there is no fear of burns. Draining starts after being left. The predetermined time can be set, for example, by confirming in advance the time required for the hot water at the highest temperature that can be assumed to cool to a temperature that does not affect the burns.

  Moreover, in the said embodiment, although the control apparatus which performs an automatic drain operation and an automatic water supply operation was provided integrally as the control apparatus 30 for hot water supply apparatuses, you may make it provide as a single control apparatus. Alternatively, a command for executing automatic drainage operation and automatic water supply operation is transmitted to each hot water supply device by a centralized control panel that enables centralized control of the operation of a plurality of water heaters installed in an apartment house, etc. There may be.

  Further, the working refrigerant flowing through the heat pump cycle of the heat pump unit 20 is not limited to carbon dioxide, but may be other refrigerants such as Freon. Furthermore, the heating means for boiling the hot water is not limited to the heat pump 20 and may be other means such as an electric heater.

100A, B, C Hot water supply apparatus 10 Hot water storage tank 11 Water supply pipe 11e On-off valve 16 Drain pipe 17 Intake / exhaust pipe 17a Flow sensor (detection means)
18 Three-way valve 20 Heat pump unit (heating means)
30 Control device

Claims (10)

A hot water storage tank (10) for storing hot water boiled by the heating means (20) and for discharging the stored hot water to a hot water outlet;
A water supply pipe (11) connected to the lower part of the hot water storage tank (10) and supplying hot water into the hot water storage tank (10);
A drain pipe (16) having one end connected to the lower part of the hot water storage tank (10) and the other end opened to the atmosphere to drain hot water in the hot water storage tank (10);
An intake / exhaust pipe (17) branched from an intermediate portion of the drain pipe (16) and connected to an upper portion of the hot water storage tank (10);
Provided at a branching site where the intake / exhaust pipe (17) branches from the drain pipe (16), the hot water storage tank (10) side of the drain pipe (16), the air release side of the drain pipe (16), And a three-way valve (18) capable of opening and closing each of the intake and exhaust pipe (17) side,
A hot water supply device comprising a control device (30) for controlling opening and closing of the three-way valve (18) in three directions. The area of the cross section that intersects the longitudinal direction of the drain pipe (16) is determined based on the following Equation 1 so that the time required for drainage is a predetermined drainage time. 1. A hot water supply apparatus according to 1.
(Formula 1)
Cross-sectional area of the drain pipe = {1/2 g × capacity of the hot water storage tank × horizontal cross-sectional area of the hot water storage tank / (predetermined drainage time) ² } ^1/2
However, g is a gravitational acceleration.   The intake / exhaust pipe (17) is provided with detection means (17a) for detecting the flow state of the hot-water supply and for outputting a detection signal to the control device (30). The hot water supply apparatus according to claim 1 or 2.   The hot water supply according to any one of claims 1 to 3, wherein the water supply pipe (11) is provided with an on-off valve (11e) controlled to be opened and closed by the control device (30). apparatus.   The control device (30) is incorporated in a hot water supply control device (30) that controls boiling of hot water into the hot water storage tank (10) and hot water from the hot water storage tank (10). The hot water supply device according to any one of claims 1 to 4. A hot water storage tank (10) for storing hot water boiled by the heating means (20) and for discharging the stored hot water to a hot water outlet;
A water supply pipe (11) connected to the lower part of the hot water storage tank (10) and supplying hot water into the hot water storage tank (10);
A drain pipe (16) having one end connected to the lower part of the hot water storage tank (10) and the other end opened to the atmosphere to drain hot water in the hot water storage tank (10);
An intake / exhaust pipe (17) branched from an intermediate portion of the drain pipe (16) and connected to an upper portion of the hot water storage tank (10);
A control method for a hot water supply device comprising a three-way valve (18) provided at a branching site where the intake and exhaust pipe (17) branches from the drain pipe (16),
In the automatic drain operation in which the hot water in the hot water storage tank (10) is drained after the supply of the hot water from the water supply pipe (11) is stopped, the drain pipe (16 ) In the first connection state in which the hot water storage tank (10) side and the drainage pipe (10) are connected to the atmosphere open side, the atmosphere side of the drainage pipe (16), and the intake / exhaust pipe (17). And a second connection state in which are connected,
In the automatic water supply operation for supplying the hot water into the hot water storage tank (10) after the hot water is supplied from the water supply pipe (16), the three-way valve (18) causes the first A control method for a hot water supply apparatus, characterized in that two connection states are formed.   The method for controlling a hot water supply apparatus according to claim 6, wherein in the automatic drain operation, it is determined that the drain has been completed after a predetermined first predetermined time has elapsed.   The method for controlling a hot water supply apparatus according to claim 6 or 7, wherein, in the automatic water supply operation, it is determined that the water supply has been completed when a predetermined second predetermined time has elapsed. The intake / exhaust pipe (17) is provided with detection means (17a) for detecting the flow state when the hot water is circulated therein,
The method for controlling a hot water supply apparatus according to claim 6 or 7, wherein in the automatic water supply operation, it is determined that the water supply has been completed by detecting the flow of the hot water supply by the detection means (17a). . The water supply pipe (11) is provided with an on-off valve (11e) for opening and closing the water supply pipe (11).
The open / close valve (11e) is closed before the execution of the automatic drain operation, and the open / close valve (11e) is opened before the execution of the automatic water supply operation. A method for controlling the hot water supply apparatus according to claim 1.

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