JP6243209B2 - Hot water heater - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a hot water heater is known that stores hot water heated by a heater in a hot water storage tank and discharges the hot water from the hot water storage tank. In this hot water storage type water heater, the expansion water generated by the heating by the heater is discharged to the drain pipe, thereby preventing the drain pipe from being cut off.

  For example, if the hot water tank heater is not turned on for a predetermined period of time and the hot water is not boiled, the heater is automatically turned on to boil the hot water, and the generated expansion water is discharged to the drain pipe to seal it. There has been proposed a hot water storage hot water heater that prevents running out of water (for example, see Patent Document 1).

  In addition, a hot water storage water heater is proposed that opens the solenoid valve and automatically discharges the air generated in the hot water storage tank along with the hot water to the drain pipe when the hot water tank heater is turned on and the water is boiled. (For example, refer to Patent Document 2).

JP 2011-220600 A Japanese Patent Laid-Open No. 9-42768

  However, in the hot water storage hot water heaters of Patent Documents 1 and 2, it is necessary to boil hot water even in summer where hot water is not needed to prevent drainage of the drain pipe, and wasteful power is consumed. It becomes.

  The present invention has been made in view of the above, and an object of the present invention is to provide a hot water storage type water heater that can reduce power consumption without having to boil hot water in order to prevent drainage of the drain pipe. is there.

  (1) To achieve the above object, the present invention relates to a hot water storage tank (for example, a hot water storage tank 61 described later) for storing hot water, and a heater (for example, a hot water tank provided in the hot water storage tank). A heater 71) to be described later, a drainage passage (for example, an expansion water discharge pipe 83 to be described later) for discharging expansion water generated by heating by the heater to a drain pipe (for example, a drainage pipe 41 to be described later), and the hot water storage tank A mixing unit (for example, a mixing unit 69 described later) that mixes the hot water in the water and discharges it to the drain pipe, and an open / close valve provided on the outflow side of the mixing unit (for example, an electromagnetic switch described later) Valve 70) and a control unit (for example, a control unit 10 to be described later) that performs heater control for controlling energization to the heater and also performs opening / closing control of the on-off valve, and the control unit includes: The predetermined time has elapsed When the heater control is not performed and the on-off valve is not opened, the on-off valve is opened for a predetermined time, thereby draining water in the hot water storage tank through the mixing unit. A hot water heater (for example, a hot water heater 11 described later) that discharges to a pipe is provided.

In the invention of (1), when the energization control to the heater, that is, the heater control for heating up or keeping warm by the heater is not executed and the on-off valve is not opened until a predetermined time elapses, By opening the on-off valve provided on the outflow side of the mixing unit for a predetermined time, the water in the hot water storage tank is discharged to the drain pipe through the mixing unit.
As a result, if the heater is not heated or kept warm and no expansion water is generated, and if the hot water in the hot water storage tank is not discharged while the on-off valve is closed, mixing is continued. When the on-off valve provided on the outflow side of the section is opened for a predetermined time, the water in the hot water storage tank is discharged to the drain pipe through the mixing section. Therefore, according to the present invention, it is not necessary to boil hot water in order to prevent the drainage of the drainage pipe from running out (for example, the sealage of the sealing part of the drainage device 35 provided in the drainage pipe 41 described later). Electric power can be reduced.

  (2) The control unit is configured such that the amount of hot water used in the hot water storage tank within a predetermined time (for example, the amount of use Σ (n = 1 to 23) Qn described later) is the capacity of the hot water storage tank (for example, described later). When it is less than the hot water storage tank capacity Tc), it is preferable that a predetermined amount of hot water in the hot water storage tank is discharged to the drain pipe via the mixing section by opening the on-off valve.

In the invention of (2), when the usage amount of hot water in the hot water storage tank is less than the capacity of the hot water storage tank within a predetermined time, a predetermined amount of hot water in the hot water storage tank is supplied via the mixing section by opening the on-off valve. Drain to drain.
Thereby, the hot water staying in the hot water storage tank can be discharged and the hot water storage tank can be kept hygienic. Moreover, since the discharge of hot water remaining in the hot water storage tank contributes to the drainage of the drain pipe, drainage can be used effectively and water can be saved.

  (3) It is preferable that the control unit discharges an amount of hot water corresponding to the capacity of the hot water storage tank to the drain pipe.

In the invention of (3), when the amount of hot water used in the hot water storage tank within a predetermined time is less than the capacity of the hot water storage tank, the on-off valve is opened to supply an amount of hot water corresponding to the capacity of the hot water storage tank to the drain pipe. Discharge.
Thereby, by discharging the entire amount of hot water in the hot water storage tank, the hot water staying in the hot water storage tank can be reliably discharged, and the hot water storage tank can be reliably kept hygienic.

  (4) It is preferable that the control unit discharges an amount of hot water corresponding to a difference between a capacity of the hot water storage tank and the usage amount to the drain pipe.

In the invention of (4), when the amount of hot water used in the hot water storage tank within a predetermined time is less than the capacity of the hot water storage tank, the on-off valve is opened and the unused hot water in the hot water storage tank is discharged to the drain pipe. To do.
Thus, by discharging only the unused hot water in the hot water storage tank, the hot water staying in the hot water storage tank can be reliably discharged, and the hot water storage tank can be reliably kept hygienic. Furthermore, since only unused parts are discharged, water can be saved.

  ADVANTAGE OF THE INVENTION According to this invention, in order to prevent the drain pipe running out of seal water, it is not necessary to boil hot water, and the hot water storage type water heater which can reduce power consumption can be provided.

It is a perspective view which shows the external appearance of the hot water storage type water heater which concerns on one Embodiment of this invention. It is a figure which shows the internal structure of the hot water storage type water heater which concerns on the said embodiment. It is a flowchart of the run-out operation control in the hot water storage type water heater which concerns on the said embodiment. It is a flowchart of the whole quantity replacement control in the hot water storage type water heater which concerns on the said embodiment. It is a flowchart of the exchange amount adjustment control in the hot water storage type water heater which concerns on the said embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a hot water heater 11 according to the first embodiment of the present invention, and shows an example in which the hot water heater 11 is applied to a sink 12. In FIG. 1, the sink 12 is shown in a perspective view.
The hot water storage water heater 11 includes a hot water storage tank (not shown) with a heater, which will be described later, in the casing 31. As shown in FIG. 1, the hot water storage water heater 11 is disposed inside the sink 12, and a power cable 52 is connected to a power outlet 51 disposed on the inner wall of the sink 12, and is provided on the front surface of the casing 31. The power switch 53 is turned on to operate.

  As shown in FIG. 1, there are a single hot water tap 32, a mixing tap 33, a stop cock 34, a drainage device 35, a hot water pipe 36, and a hot water pipe 37 around the hot water heater 11. And the same pressure water supply pipe 38, the water supply pipe 39, and the drainage hose 40 are provided.

  The hot water single water tap 32 and the mixed water tap 33 are disposed in the vicinity of the sink body 13 of the sink 12. The water stop cock 34 is disposed on the inner wall of the sink 12. The drainage device 35 is connected in the middle of the drainage pipe 41 extending downward from the drainage port 41 a of the sink body 13.

  One end of the hot water pipe 36 is connected to the single water tap 32 for hot water, and the other end is connected to the upper surface of the casing 31 of the hot water storage water heater 11. One end of the hot water outlet pipe 37 is connected to the mixing faucet 33, and the other end is connected to the upper surface of the casing 31 of the hot water storage type hot water heater 11. One end of the same-pressure water supply pipe 38 is connected to the mixing faucet 33, and the other end is connected to the upper surface of the casing 31 of the hot water storage water heater 11. One end of the water supply pipe 39 is connected to the stop cock 34, and the other end is connected to the upper surface of the casing 31 of the hot water storage water heater 11. The drain hose 40 has one end connected to the drainage device 35 and the other end connected to the upper surface of the casing 31 of the hot water storage water heater 11.

Next, the internal configuration of the hot water storage type water heater 11 according to the present embodiment will be described. FIG. 2 is a diagram illustrating an internal configuration of the hot water storage type water heater 11 according to the present embodiment.
As shown in FIG. 2, the hot water heater 11 includes a hot water storage tank 61, a hot water mixing valve 62, check valves 63, 65, 67, 68, a strainer 64, and a pressure reducing valve 66 in a casing 31. A mixing unit 69, an electromagnetic valve 70, a relief valve 72, the thermistors 73, 75, 77, a drain valve 74, a flow sensor 76, and the control unit 10.

  The water supplied from the water supply pipe 39 is removed from the water by the strainer 64, circulates through the check valve 65, depressurized by the pressure reducing valve 66, circulates through the water supply pipe 39, and is supplied into the hot water storage tank 61. Is done. At this time, the thermistor 75 detects the temperature of the water supply, and the flow sensor 76 detects the flow rate of the water supply.

The hot water storage tank 61 includes a heater 71 inside. In the hot water storage tank 61 supplied with water, hot water of 60 to 90 ° C. is boiled by energizing the heater 71. The hot water storage tank 61 includes a thermistor 77 inside. The temperature of the hot water in the hot water storage tank 61 is detected by the thermistor 77, and the detection signal is transmitted to the control unit 10 described later.
The hot water boiled in the hot water storage tank 61 is supplied to the single hot water tap 32 (see FIG. 1) through the hot water pipe 36 and flows out of the single hot water tap 32 to be used as drinking hot water. Is done.

A hot water branch pipe 81 branched at the branch portion 36a of the hot water pipe 36 is provided with a check valve 63 and a hot water mixing valve 62. Therefore, a part of the hot water boiled in the hot water storage tank 61 is diverted from the hot water pipe 36 to the hot water branch pipe 81 and flows through the check valve 63 and then supplied to the hot water mixing valve 62.
On the other hand, a part of the water supply is diverted from the water supply pipe 39 to the water supply branch pipe 82 branched at the branch portion 39 a of the water supply pipe 39. The water supplied to the water supply branch pipe 82 is supplied to the hot water supply mixing valve 62. Thereby, in the hot water supply mixing valve 62, the hot water supplied through the hot water branch pipe 81 and the water supplied through the hot water branch pipe 82 are mixed, so that the hot water supply mixing valve 62 It becomes hot water of set temperature (for example, 40 degreeC).

  Hot water generated by mixing hot water and water in the hot water mixing valve 62 is supplied to the mixing faucet 33 (see FIG. 1) through the hot water outlet pipe 37 and flows out of the mixing faucet 33, so that tableware is obtained. It is used as a hot water supply for miscellaneous purposes for performing cleaning and the like.

  A part of the water supply is diverted from the water supply pipe 39 to the same pressure water supply pipe 38 branched at the branch portion 39b of the water supply pipe 39. The same-pressure feed water is supplied to the mixing faucet 33 (see FIG. 1) through the same-pressure feed water pipe 38 and flows out of the mixing faucet 33 for use.

  In addition, when boiling water in the hot water storage tank 61, expanded water is generated due to an increase in pressure in the hot water storage tank 61. When the internal pressure exceeds a predetermined pressure, the relief valve 72 is opened, and the generated expansion water is supplied to the sealed portion in the drainage device 35 via the expansion water discharge pipe 83 and the drainage hose 40 (see FIG. 1). It becomes sealed water in the sealed part.

  The drain valve 74 is provided in the vicinity of the connecting portion between the lower part of the hot water storage tank 61 and the water supply pipe 39. The drain valve 74 is opened after operating a supply tap (not shown) provided for maintenance and freeze prevention purposes. Thereby, the water in the water supply pipe 39 is discharged outside.

  Further, in the hot water storage type hot water heater 11 of the present embodiment, the hot water branch pipe 91 is branched at the branch portion 36 b of the hot water pipe 36, and a part of the hot water is diverted from the hot water pipe 36 to the hot water branch pipe 91. Further, a water supply branch pipe 92 is branched at the branch portion 39 c of the water supply pipe 39, and a part of the water supply is diverted from the water supply pipe 39 to the water supply branch pipe 92. The hot water branch pipe 91 and the feed water branch pipe 92 merge at the mixing section 69.

  The mixing unit 69 is a flow path junction between the hot water branch pipe 91 and the feed water branch pipe 92. Therefore, in the mixing unit 69, the hot water that has circulated through the hot water branch pipe 91 and the water that has circulated through the feed water branch pipe 92 are mixed. This mixed water is discharged to the drainage hose 40 through an electromagnetic valve 70 provided on the outflow side of the mixing unit 69. That is, the hot water storage type water heater 11 of the present embodiment includes a mixing unit 69 that mixes the hot water in the hot water storage tank 61 and water and discharges them to the drain hose 40 without using the hot water mixing valve 62.

  The mixing ratio of hot water and water in the mixing section 69 is a constant ratio determined in advance by adjusting the diameter of the flow path of hot water and water in the mixing section 69 so that the temperature of the mixed water is 50 ° C., for example. Yes, for example, the ratio of hot water to water is 4: 6. In order to prevent the backflow of the mixed water, check valves 67 and 68 are provided on the water inflow side (water supply branch pipe 92 side) and the hot water inflow side (hot water branch pipe 91 side) of the mixing unit 69, respectively. Yes.

  The thermistor 73 is provided on the downstream side of the electromagnetic valve 70. The thermistor 73 is used for detecting an abnormal temperature, and detects an abnormally high temperature of the drainage generated when the check valves 67 and 68 are fixed. When an abnormally high temperature is detected by the thermistor 73, the solenoid valve 70 is closed to ensure safety.

The control unit 10 is electrically connected to the heater 71, the electromagnetic valve 70, the flow sensor 76, the thermistors 73, 75, 77, and the like.
The control unit 10 is a module for executing the seal run-off operation control, the total amount replacement control, and the replacement amount adjustment control, which will be described in detail later, and a heater control unit that controls energization to the heater 71, and an open / close control of the electromagnetic valve 70. An electromagnetic valve control unit to be executed, a measurement unit that counts down the time when the heater control is not performed and the electromagnetic valve 70 is closed, a replacement amount integration unit that integrates the replacement amount of hot water in the hot water storage tank 61, and the like .
Various settings of the operating conditions are performed by the operator operating the operation unit 54 and stored in the control unit 10.

A basic operation of the hot water storage type water heater 11 of the present embodiment having the above configuration will be described with reference to FIG.
First, when water is supplied from the water supply pipe 39 to the hot water storage tank 61 through the strainer 64, the pressure reducing valve 66, etc., the supplied water is boiled up by the heater 71 provided in the hot water storage tank 61. This boiled hot water (for example, 60 to 90 ° C.) is supplied as hot drinking water through the hot water pipe 36.
Further, a part of the hot water is divided by the hot water branch pipe 81 and mixed with the water divided by the water supply branch pipe 82 by the hot water mixing valve 62, thereby being supplied as hot water for miscellaneous use at 40 ° C., for example. This miscellaneous hot water is supplied to the mixing faucet 33 (see FIG. 1) together with the same-pressure feed water and flows out of the mixing faucet 33.

Further, the expansion water generated by boiling the hot water in the hot water storage tank 61 is discharged through the expansion water discharge pipe 83 or the like when the relief valve 72 is opened, so that the drainage device 35 (see FIG. 1). It becomes the sealed water in the sealed water part.
A part of the boiled hot water is stored in the hot water storage tank 61. When discharging the hot water staying in the hot water storage tank 61 for replacement, the hot water diverted by the hot water branch pipe 91 and the water diverted by the hot water branch pipe 92 are not passed through the hot water mixing valve 62. Mixing is performed in the mixing unit 69 to, for example, 50 ° C. mixed water, and the electromagnetic valve 70 is opened and discharged.

  Next, the seal run out operation control executed by the control unit 10 of the hot water storage water heater 11 of the present embodiment will be described. FIG. 3 is a flowchart of the run-off control of the hot water storage water heater 11 according to this embodiment. The process of running out of the sealed water operation is repeatedly executed at a predetermined cycle.

  First, in step S11, it is determined whether or not the heater control is in an OFF state. Specifically, it is determined whether or not the energization control for the heater 71 is performed, and whether or not the heater 71 is boiling or keeping warm. Here, the heat retention by the heater 71 is ON / OFF feedback control of the heater 71 based on the detection signal of the thermistor 77 so that the temperature of the hot water in the hot water storage tank 61 becomes a predetermined target temperature set in advance. Means that.

  If the determination result is NO, it is determined that the heater 71 is energized to generate expanded water, and the sealed water is supplied to the sealed portion of the drainage device 35 of the drain pipe 41. Accordingly, in this case, the process proceeds to step S16 to reset the count for 7 days, and then returns to step S11. On the other hand, if this determination is YES, the process proceeds to step S12.

In step S12, it is determined whether or not the solenoid valve 70 is being opened. Whether or not the solenoid valve 70 is open is determined based on the energized state of the solenoid valve 70. At this time, the electromagnetic valve 70 may be opened and closed manually.
If this determination result is YES, the hot water staying in the hot water storage tank 61 for a long time from the viewpoint of hygiene is discharged to the drain pipe 41 through the mixing portion 69, and sealed water in the drainage device 35 of the drain pipe 41. It is determined that sealed water has been supplied to the section. Accordingly, in this case, the process proceeds to step S16 to reset the count for 7 days, and then returns to step S11. On the other hand, if this determination result is NO, the process proceeds to step S13.

In step S13, since it is determined that no sealing water is supplied to the sealing portion in the drainage device 35 of the drain pipe 41, the 7-day count is decremented by 1, and the process proceeds to step S14.
Here, the 7-day count means that when no sealed water is supplied to the sealed water portion in the drainage device 35 of the drain pipe 41, the sealed water will run out in 7 days. These seven days are changed according to the capacity of the sealed portion and the season. Further, the value of the 7-day count is set according to this control cycle.

  In step S14, it is determined whether or not the 7-day count is zero. If this determination result is NO, it is determined that the sealing water in the sealing part in the drainage device 35 of the drain pipe 41 is still sufficient, and the process returns to step S11. On the other hand, if this determination result is YES, the process proceeds to step S15 to energize the solenoid valve 70, and the solenoid valve 70 is opened for 3 seconds. As a result, a part (about 100 mL) of the water in the hot water storage tank 61 is discharged to the drain pipe 41 through the mixing section 69, which is sufficient to fill the sealing section in the drainage device 35 of the drain pipe 41. An amount of sealed water is supplied. Then, it progresses to step S16 and resets a 7-day count.

  Next, the total amount replacement control for exchanging the total amount of hot water in the hot water storage tank 61, which is executed by the control unit 10 of the hot water storage water heater 11 of the present embodiment, will be described. FIG. 4 is a flowchart showing the procedure of the total amount replacement control in the hot water storage type hot water heater 11 according to the present embodiment. This total amount replacement control process is repeatedly executed at a predetermined cycle, and is executed independently of the above-described seal water out operation control.

  In step S21, it is determined whether it is a replacement start time. Here, the replacement start time is set in advance to, for example, a predetermined time before the normal use start time of the hot water storage water heater 11. If this determination result is NO, the process returns to step S21 again. On the other hand, if this determination is YES, the process proceeds to step S22.

  In step S22, it is determined whether or not the hot water use amount Σ (n = 1 to 23) Qn in the hot water storage tank 61 from 23 hours before to 1 hour ago is smaller than the hot water storage tank capacity Tc. If this determination result is NO, it is determined that there is no hot water remaining in the hot water storage tank 61, and the process returns to step S21. On the other hand, if the determination result is YES, it is determined that there is hot water remaining in the hot water storage tank 61, and thus the process proceeds to step S23.

In step S23, integration of the hot water replacement amount in the hot water storage tank 61 is started, and the process proceeds to step S24 to open the solenoid valve 70. Thereby, discharge of hot water in the hot water storage tank 61 is started, and replacement of hot water in the hot water storage tank 61 is started.
The integration of the hot water replacement amount in the hot water storage tank 61 is executed by the control unit 10 based on the detection signal of the flow sensor 76.

  In step S25, it is determined whether or not the integrated replacement amount obtained by integrating the replacement amount exceeds the hot water storage tank capacity Tc. If this determination result is NO, the process returns to step S25 again. That is, the process of step 25 is repeated until the integrated replacement amount exceeds the hot water storage tank capacity Tc. And if the determination result of step S25 is YES, since the integrated replacement | exchange amount exceeded the hot water storage tank capacity | capacitance Tc, it progresses to step S26.

  In step S26, the integration of the replacement amount is terminated, the process proceeds to step S27, and the electromagnetic valve 70 is closed. As a result, the replacement of all the hot water in the hot water storage tank 61 is completed.

Next, the hot water replacement amount adjustment control in the hot water storage tank 61, which is executed by the control unit 10 of the hot water storage water heater 11 of the present embodiment, will be described. FIG. 5 is a flowchart showing a procedure for replacement amount adjustment control in the hot water storage type hot water heater 11 according to the present embodiment. This replacement amount adjustment control process is repeatedly executed at a predetermined cycle, and is executed independently of the above-described sealed-out operation control. Moreover, it is selectively executed with the above-described total amount replacement control.
The replacement amount adjustment control is a control for replacing only the hot water in the hot water storage tank 61 that is not used as hot drinking water or hot water for miscellaneous use.

  Since the process of step S31-34 is the same process as step S21-24 in the above-mentioned total amount replacement control, description is abbreviate | omitted.

  In step S35, the integrated replacement amount obtained by integrating the replacement amount is the hot water storage tank capacity Tc and the hot water usage amount Σ (n = 1 to 23) in the hot water storage tank 61 from 23 hours to 1 hour ago. It is determined whether or not the difference from Qn (Tc−Σ (n = 1 to 23) Qn) is exceeded. If this determination result is NO, the process returns to step S35 again. That is, the process of step 35 is repeated until the integrated replacement amount exceeds the difference, that is, the unused amount of hot water in the hot water storage tank 61. And if the determination result of step S35 is YES, since the integrated replacement | exchange amount exceeded the said difference, ie, the unused part of the hot water in the hot water storage tank 61, it progresses to step S36.

  In step S36, the integration of the replacement amount is terminated, the process proceeds to step S37, and the electromagnetic valve 70 is closed. Thereby, the replacement of unused hot water in the hot water storage tank 61 is completed.

According to this embodiment, the following effects are produced.
In the present embodiment, the solenoid valve 70 provided on the outflow side of the mixing unit 69 without performing the energization control to the heater 71, that is, the heater control for heating or keeping warm by the heater 71, until a predetermined time elapses. When the valve is not opened, the electromagnetic valve 70 is opened for a predetermined time, so that the water in the hot water storage tank 61 is discharged to the drain pipe 41 via the mixing unit 69.
As a result, when the heater 71 is not heated or kept warm and no expanded water is generated and when the solenoid valve 70 is closed and the hot water in the hot water storage tank 61 is not discharged for a predetermined time. When the solenoid valve 70 provided on the outflow side of the mixing unit 69 is opened for a predetermined time, the water in the hot water storage tank 61 is discharged to the drain pipe 41 through the mixing unit 69. Therefore, according to the present embodiment, it is not necessary to boil hot water in order to prevent the sealed portion of the drainage device 35 provided in the drain pipe 41 from being cut off, and power consumption can be reduced.
Further, according to the present embodiment, when the heater control is not performed and the electromagnetic valve 70 is closed for a predetermined time, the hot water in the hot water storage tank 61 is discharged to the drain pipe 41 via the mixing unit 69. Therefore, the hot water in the hot water storage tank 61 can be prevented from staying for a long time, and the hot water storage tank 61 can be kept hygienic. Moreover, since the discharge of the hot water staying in the hot water storage tank 61 contributes to the drainage of the drain pipe 41, drainage can be used effectively and water can be saved.

In the present embodiment, when the amount of hot water used in the hot water storage tank 61 within a predetermined time is less than the capacity of the hot water storage tank 61, the solenoid valve 70 is opened to place the hot water in the hot water storage tank 61 via the mixing unit 69. A fixed amount of hot water was discharged to the drain pipe.
Thereby, the hot water stayed in the hot water storage tank 61 can be discharged, and the hot water storage tank 61 can be kept hygienic. Moreover, since the discharge of the hot water staying in the hot water storage tank 61 contributes to the drainage of the drain pipe 41, drainage can be used effectively and water can be saved.

Further, in the present embodiment, when the amount of hot water used in the hot water storage tank 61 within a predetermined time is less than the capacity of the hot water storage tank 61, the solenoid valve 70 is opened to supply an amount of hot water corresponding to the capacity of the hot water storage tank 61. It is good also as a structure discharged | emitted to a drain pipe.
Thereby, by discharging the entire amount of hot water in the hot water storage tank 61, the hot water staying in the hot water storage tank 61 can be reliably discharged, and the hot water storage tank 61 can be reliably kept hygienic.

In this embodiment, when the amount of hot water used in the hot water storage tank 61 is less than the capacity of the hot water storage tank 61 within a predetermined time, the solenoid valve 70 is opened to drain unused hot water in the hot water storage tank 61. It is good also as a structure discharged | emitted to the pipe | tube 41. FIG.
Thereby, only the unused hot water in the hot water storage tank 61 is discharged, so that hot water staying in the hot water storage tank 61 can be reliably discharged, and the hot water storage tank 61 can be reliably kept hygienic. . Furthermore, since only unused parts are discharged, water can be saved.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 10 ... Control part 11 ... Hot water storage type water heater 41 ... Drain pipe 61 ... Hot water storage tank 69 ... Mixing part 70 ... Solenoid valve (open / close valve)
71 ... Heater 83 ... Expansion water discharge pipe (drainage)

Claims (4)

A hot water storage tank for storing hot water,
A heater that is provided in the hot water storage tank and heats the hot water in the hot water storage tank;
A drainage channel for discharging expansion water generated by heating by the heater to a drainage pipe;
A mixing section for mixing the hot water in the hot water storage tank with water and discharging it to the drain pipe;
An on-off valve that is provided on the outflow side of the mixing section and can be opened and closed;
A drainage device provided in the drainage pipe and having a sealing portion;
A control unit that performs heater control for controlling energization to the heater, performs opening / closing control of the on-off valve, and discharges water from the tank when it is determined that no sealing water is supplied to the sealing unit And comprising
Wherein, until a predetermined time elapses, when it is determined that the and the on-off valve without executing the heater control was not opened, by opening the on-off valve a prescribed time, the mixture A hot water storage type water heater that discharges water in the hot water storage tank to the drain pipe through a section.   When the amount of hot water used in the hot water storage tank within a predetermined time is less than the capacity of the hot water storage tank, the control unit opens the on-off valve to open the hot water tank in the hot water storage tank via the mixing unit. The hot water storage water heater according to claim 1, wherein a predetermined amount of hot water is discharged to the drain pipe.   The hot water storage water heater according to claim 2, wherein the control unit discharges an amount of hot water corresponding to a capacity of the hot water storage tank to the drain pipe.   The hot water storage water heater according to claim 2, wherein the control unit discharges an amount of hot water corresponding to a difference between a capacity of the hot water storage tank and the usage amount to the drain pipe.

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