JP5401117B2 - Water heater - Google Patents

Description

  The present invention relates to a water heater, and more particularly, to an electric water heater that automatically performs a cleaning operation of supplying fresh water to a heat exchanger and cleaning it.

  2. Description of the Related Art Conventionally, there is a water heater that automatically performs a cleaning operation for cleaning and supplying fresh water to a heat exchanger. For example, the water heater shown in Patent Document 1 includes a water level sensor that detects the water level of bathtub water, and starts a cleaning operation when the water level of the bathtub water becomes lower than a preset reference water level during drainage.

JP 2003-106643 A

  However, the water level of the bathtub water may greatly increase or decrease during the user's bathing, and may temporarily fall below the reference water level. Further, depending on the influence of the measurement error of the water level sensor and the state of the actually installed pipe, the correct water level may not always be detected accurately. In such a case, a malfunction may occur in which cleaning is performed although it is not the timing for cleaning. When a malfunction occurs, for example, automatic washing is performed during bathing, which causes problems such as uncomfortable feelings for bathers, and waste of water, which is not economical.

  Therefore, an object of the present invention is to provide a water heater that can suitably prevent or suppress the automatic cleaning operation of the reheating heat exchanger from being erroneously performed.

  The water heater according to the present invention includes a reheating circuit that heats the bathtub water taken out from the bathtub and returns it to the bathtub by a reheating heat exchanger, and a fresh water circuit that supplies fresh water to the bathtub. Connected to the circuit, the fresh water flowing through the fresh water circuit is configured to be supplied to the reheating heat exchanger, and is provided with a water level detection unit that detects the water level of the bathtub water. When the operation for supplying fresh water is performed and the water level of the bathtub water becomes equal to or higher than a preset reference water level, and the state where the water level of the bathtub water is lower than the reference water level is detected over a predetermined water level monitoring time. As a result of the drainage of the bath water, a cleaning operation is performed in which fresh water is replenished and supplied to the heat exchanger for cleaning.

  According to the water heater having the above-described configuration, the water level of the bathtub water is temporarily lower than the reference water level by detecting that the water level of the bathtub water is lower than the reference water level over a predetermined time. Factors can be eliminated.

  Further, the water heater according to the present invention includes a reheating circuit that heats the bathtub water taken out from the bathtub and heats it back to the bathtub by a heat exchanger, and a fresh water circuit that supplies fresh water to the bathtub, the reheating circuit And a fresh water circuit are connected so that fresh water flowing through the fresh water circuit is replenished and supplied to the heat exchanger, and has a water level detection unit that detects the water level of the bathtub water. After a state lower than a set reference water level is detected over a predetermined water level monitoring time, when a predetermined start delay time elapses, a cleaning operation is performed in which fresh water is supplied to the reheating circuit for cleaning. It is characterized by that.

  According to the water heater having the above-described configuration, the water level of the bathtub water is temporarily lower than the reference water level by detecting that the water level of the bathtub water is lower than the reference water level over a predetermined time. Factors can be eliminated. Further, since the bathtub water is drained during the predetermined start delay time, the water level of the bathtub water further decreases, and the bathtub water present in the reheating circuit is also discharged. Therefore, it is possible to suitably prevent a situation in which the water supplied to the reheating circuit by the cleaning operation is mixed with the bathtub water and flows back to the reheating circuit and the cleaning effect is destroyed.

  In addition, the water level of the bathtub water is detected a plurality of times during the predetermined water level monitoring time, and the water level of the bathtub water is lower than the reference water level when the water level of the bathtub water is lower than the reference water level at all time points. A configuration in which it is determined that the water level has been lowered is preferable.

  In this way, the possibility of malfunctioning can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the hot water supply machine which can prevent suitably or prevent that the automatic washing operation | movement of a reheating heat exchanger is performed accidentally is realizable.

It is a block diagram which shows the example of the water heater concerning 1st Embodiment of this invention. It is a circuit diagram which shows the hot water supply driving | operation of the water heater concerning 1st Embodiment with a thick line. It is a circuit diagram which shows the hot water filling circuit of the water heater concerning 1st Embodiment with a thick line. It is a circuit diagram which shows the circuit of the reheating of the water heater concerning 1st Embodiment with a thick line. It is a circuit diagram which shows the washing | cleaning operation | movement of the water heater concerning 1st Embodiment with a thick line. It is a flowchart which shows the automatic washing | cleaning control of the water heater concerning 1st Embodiment. It is the block diagram which showed the circuit at the time of hot water filling with the thick line in the example of the water heater concerning 2nd Embodiment of this invention. It is a circuit diagram which shows the washing | cleaning operation | movement of the water heater concerning 2nd Embodiment with a thick line. It is a block diagram which shows the example of the water heater concerning 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<< First Embodiment >>
FIG. 1 is a configuration diagram illustrating an example of a water heater S according to the first embodiment of the present invention.

<Overall configuration of water heater S>
As shown in FIG. 1, a water heater S according to the first embodiment includes a hot water storage tank 1 that stores hot water, and a heat source that heats water for storing hot water in the hot water storage tank 1. The water supply from the water supply source (for example, the water pipe 22) is supplied through the pipe 7. Specifically, the water heater S heats the low-temperature water supplied from the water supply source by the heat pump unit 8 and stores the heated hot water in the hot water storage tank 1. That is, the water heater S includes a tank unit 5 including the hot water storage tank 1 and a heat pump unit 8.

  The hot water heater S includes a hot water supply heat exchanger 4 that heats low temperature water from the water pipe 22 by exchanging heat with hot water in the hot water storage tank 1 to generate hot water for hot water supply. In this case, the hot water storage tank 1 functions as a storage tank that stores hot water as a heat medium that exchanges heat with low-temperature water. The water heater S also includes a reheating heat exchanger 24 that heats the bath water derived from the bathtub 2 by exchanging heat with hot water in the hot water storage tank 1. Furthermore, the water heater S is a hot water heater according to an operation command 60 from the operation unit 60 and the operation unit 60 such as the bath remote control 45 and the kitchen remote control 46 operated by the user for hot water filling, chasing, hot water supply and the like. And a controller 16 for comprehensively controlling the entire S.

  In addition, the hot water supply device S is supplemented with a hot water supply circuit that supplies fresh water heated to the hot water supply terminal, and hot water (in this case, functions as a heat medium) that is stored in the hot water storage tank 1 from the bathtub. A reheating circuit 2P that exchanges heat with a fired heat exchanger and returns it to the bathtub.

  The hot water supply circuit includes a general hot water supply circuit 2X that supplies hot water to a general hot water supply terminal (such as a faucet or a shower), and a hot water filling circuit 2Y that supplies hot water to a bathtub terminal provided in the bathtub. Further, as a supply source of fresh water supplied to the hot water supply circuit, in addition to an external water supply source such as a water pipe 22 and well water, a hot water storage tank 1 for storing fresh water can be considered.

  Here, fresh water refers to water before use that has not yet passed through a state in which the user can directly contact, and includes water from a water supply source and water stored in the hot water storage tank 1, while mixing. It is distinguished from water after use containing dirt such as that supplied to the stopper 19 and the bathtub 2 (particularly, the bath water once supplied to the bathtub 2).

  The circuit that supplies fresh water supplied from the water supply source to the reheating heat exchanger and the circuit that supplies fresh water stored in the storage tank to the reheating heat exchanger supply fresh water to the bathtub. It can be specified as a fresh water circuit.

The general hot water supply circuit 2X, the pressure of the water in the hot water storage tank 1 (e.g., about 2 kg / cm ²⁾ pressure higher than (e.g., about 6~8kg / cm ²⁾ intended to be fluidly constituting fresh water It is. Specifically, the general hot water supply circuit 2X distributes tap water that has not been decompressed as the fresh water. However, the general hot water supply circuit 2X is not limited to this, and the heat medium (that is, water) in the hot water storage tank 1 may be boosted and supplied using a pump or the like. Moreover, the said general hot water supply circuit 2X is comprised so that fresh water can be distribute | circulated by the faster flow velocity than the said reheating circuit 2P. Specifically, for example, fresh water flows into the general hot water supply circuit 2X at about 2 m / s, for example, while the reheating circuit 2P receives bath water at about 1.0 to 1.5 m / s during reheating. Washed away.

  Specifically, the general hot water supply circuit 2X causes fresh water supplied from a water supply source to exchange heat with hot water stored in the hot water storage tank 1 (in this case, it functions as a heat medium) by a hot water supply heat exchanger ( That is, it is heated and supplied to a general hot water supply terminal. The hot water filling circuit 2Y supplies hot water from the hot water storage tank 1 to the bathtub terminal.

  Hereinafter, the structure of each part of the water heater S will be described in detail.

<Heat pump unit 8>
The heat pump unit 8 shown in FIG. 1 absorbs the external heat with a refrigerant such as expanded low-temperature carbon dioxide, and then heats it with the refrigerant compressed to a high temperature and the low-temperature water from the hot water storage tank 1 flowing through the pipe 34. It is a device that exchanges and heats low-temperature water. The heat pump unit 8 repeatedly expands and compresses the refrigerant, absorbs heat from the outside and heats the low-temperature water, and a circulation pump (not shown) that circulates the low-temperature water in the hot water storage tank 1 flowing through the pipe 34. And.

  The heat pump includes a compressor that compresses the refrigerant, a gas cooler (not shown) that heats the low-temperature water by exchanging heat between the compressed high-temperature refrigerant and the low-temperature water from the hot water storage tank 1, and decompresses the refrigerant by expanding the pressure. And an endothermic device that absorbs the heat of the outside air to the refrigerant whose pressure has been reduced and reduced in temperature. The circulation pump pumps the low-temperature water in the hot water storage tank 1 through the pipes 32 and 34, passes the gas cooler of the heat pump and heats it, and then returns the heated hot water to the upper part of the hot water storage tank 1 through the pipe 35. .

<Hot water storage tank 1>
In the hot water storage tank 1 shown in FIG. 1, tap water from the water pipe 22 is introduced through the pipe 7, the pipe 36 a, the pipe 23 a, the pressure reducing valve 6, and the pipe 23 b, and the water in the hot water storage tank 1 is supplied. The pipe 32, the three-way valve 33, and the pipe 34 are led to the heat pump unit 8 and heated by the gas cooler of the heat pump to become hot water, and then led to the upper part of the hot water storage tank 1 through the pipe 35 and stored in the hot water storage tank 1. ing.

  The temperature of the hot water in the hot water storage tank 1 is higher as it goes from the lower side to the upper side in the vertical direction, that is, the temperature distribution is relatively low, medium and high as it goes from the lower part to the upper part in the hot water tank 1. For example, the temperature inside the hot water storage tank 1 is about 90 ° C. and the middle portion is about 50 ° C. In addition, the warm water in the intermediate part of the vertical direction in the hot water storage tank 1 is called intermediate warm water.

  In the hot water storage tank 1, a plurality of temperature sensors 47, 48, 49, 50, 51, 52 for detecting the temperature of the hot water stored in the vertical direction are arranged from the upper part to the lower part. A detection signal indicating the temperature of the hot water in the hot water storage tank 1 detected by 47, 48, 49, 50, 51, 52 is output to the controller 16 and used for controlling the water heater S.

<Water filling circuit 2Y>
A hot water filling circuit 2 </ b> Y shown in FIGS. 1 and 3 is a circuit for supplying hot water stored in the hot water storage tank 1 to the bathtub 2 and filling the bathtub 2 with hot water. The hot water filling circuit 2Y guides the hot water at the upper part of the hot water tank 1 to the first mixing valve 14 through the pipe 41a and the pipe 54 connected to the first take-out part 10 at the upper part of the hot water tank 1. 14 is mixed with the tap water that has passed from the water pipe 22 through the pipe 7, the pipe 36a, the pipe 23a, the pressure reducing valve 6 and the pipe 23b, and is disposed downstream of the first mixing valve 14 and is controlled to be opened. 28, through the first path passing through the pipes 29c, 29b, 29a, the pipe 29b, the connection part 30, the pipe 25, the pump 27, the flow regulating valve (or the circulation regulating valve) 31, and the bypass pipe 63, This is a configuration in which hot water is filled in the bathtub 2 through two paths including a second path connected to the pipe 3 at the junction 65.

  Here, the piping 29a is connected to the water circulation port 2i provided in the bathtub 2, and the piping 3 is connected to the water circulation port 2o of the bathtub 2, and through these water circulation ports 2i and 2o. The hot water filling is done. That is, in this case, the water circulation ports 2i and 2o function as bathtub terminals.

<Hot water supply heat exchanger 4>
FIG. 2 is a circuit diagram showing a hot water supply operation of the water heater S of the first embodiment by a bold line. The hot water supply heat exchanger 4 shown in FIG. 2 derives the tap water supplied through the water pipe 22 and the pipe 7 from the upper part of the hot water storage tank 1 by the hot water circulation pump 18 that is operated and controlled when the controller 16 has a hot water supply request. It is a device that heats and exchanges heat with high-temperature hot water to a predetermined temperature. The heated water is supplied to the mixing plug 19 and supplied with hot water.

  The mixing plug 19 is used for supplying hot water in a bathroom, for example. At the time of hot water supply, the tap water introduced into the hot water supply heat exchanger 4 from the water pipe 22 through the pipes 7, 36a, 36b is supplied by the hot water supply circulation pump 18 from the first take-out portion 10 above the hot water storage tank 1 through the pipes 41a, 41b. After being heated by the hot water at the upper part of the hot water storage tank 1 introduced into the heat exchanger 4, the hot water is supplied to the mixing plug 19 through the pipe 36 c, the accumulator 39 and the pipe 40.

  On the other hand, in the hot water supply heat exchanger 4, the water discharged from the hot water supply heat exchanger 4 after being heat exchanged with tap water is returned to the hot water storage tank 1 through the pipe 42 and the hot water supply circulation pump 18. In addition, although the water discharged from the hot water supply heat exchanger 4 is returned to the lower part of the hot water storage tank 1, it may be returned upward from the bottom of the hot water storage tank 1.

<Hot water supply circulation pump 18>
The hot water supply circulation pump 18 shown in FIG. 1 uses an inverter circuit (not shown) of the controller 16 so that the hot water temperature detected by the hot water temperature sensor 37 in the pipe 36c becomes the hot water temperature set by the operation unit 60. The rotation speed is freely controlled (feedback control).

  That is, when the hot water temperature detected by the hot water temperature sensor 37 is lower than the hot water temperature set by the operation unit 60, the controller 16 determines the rotational speed of the hot water circulation pump 18 that circulates hot hot water in the hot water storage tank 1. Increase the amount of heat given to the tap water to increase the hot water supply temperature. On the other hand, when the hot water temperature is higher than the hot water temperature set by the operation unit 60, the controller 16 reduces the amount of heat applied to the tap water by lowering the rotational speed of the hot water circulation pump 18 to lower the hot water temperature. The hot water supply circulation pump 18 is controlled.

<Reheating heat exchanger 24>
The reheating heat exchanger 24 shown in FIG. 1 has, on the inlet 24i side, a pipe 29a, a pipe 25, a pump 27, a flow rate adjustment valve 31, and a pipe 58 from which the bath water in the bathtub 2 is led, and an outlet. On the side of 24 o, a pipe 26 is connected to which hot water that has been heat-exchanged with the hot water in the upper part of the hot water storage tank 1 in the reheating heat exchanger 24 and returned to the bathtub 2.

<Turning circuit 2P>
The reheating circuit 2 </ b> P indicated by the thick line in FIG. 4 is a circuit for retreating the bath water stretched on the bathtub 2. When reheating, the bath water in the bathtub 2 is led out from the water flow port 2i of the bathtub 2 and connected to the water flow port 2i, as shown by the arrow in FIG. 4, and connected to the water flow port 2i. , Pump 27, flow control valve 31, pipe 58, reheating heat exchanger 24, pipe 26, pipe 3 arranged in the hot water at the top of hot water storage tank 1, and water distribution port 2 o connected to pipe 3 It is comprised so that it may return to the bathtub 2 via.

  In addition, the low-temperature bath water in the bathtub 2 is indirectly heat-exchanged with the high-temperature hot water in the upper part of the hot water storage tank 1 in the reheating heat exchanger 24 so that the reheating is efficiently performed in a short time. It is configured.

  Here, the reheating temperature is set by the user using the operation unit 60 such as the bath remote controller 45 or the kitchen remote controller 46. The temperature sensor 56 detects the temperature of the hot water before passing through the pipe 29a, and the temperature sensor 59 detects the temperature of the hot water passing through the pipe 26 after being driven, and each detection signal is input to the controller 16. Is done. Then, in the controller 16, a pump 27 that recirculates the bath water in the bathtub 2 and circulates it to the heat exchanger 24 until the temperature sensor 56 detects that the temperature of the hot water in the bathtub 2 has reached the set temperature of the user. To control the operation and continue the chasing mode. Then, when the temperature of the hot water in the bathtub 2 reaches the set temperature of the user, the operation of the pump 27 is stopped and the reheating mode is ended.

<Operation unit 60>
An operation unit 60 shown in FIG. 1 is a device that allows a user to perform input operations to perform hot water filling, chasing, hot water supply, etc. with the hot water heater S, and is disposed in a bath remote controller 45 or a kitchen disposed in the bathroom. Kitchen remote control 46 and the like.

  The operation unit 60 can select a hot water filling mode for filling the bathtub 2, a reheating mode for replenishing the bath water in the bathtub 2, a hot water supply mode for supplying hot water from the mixing tap 19, and the like. The temperature can be set such as the temperature of hot water during hot water filling, the temperature of hot water during reheating, the temperature of hot water during hot water supply, and the like. The operation unit 60 is connected to the controller 16 by wire or wirelessly, and an input operation to the operation unit 60 by a user is input to the controller 16 as an operation signal.

<Controller 16>
The controller 16 is a control device that electronically controls the water heater S, and includes a microcomputer that performs control according to signals detected by various sensors such as the operation unit 60 and the temperature sensor 48, and an operation unit. 60. An input interface such as an amplifier circuit or an A / D converter circuit that converts detection signals detected by various sensors into input signals suitable for the microcomputer 3, and hot water supply according to an output signal of a control signal from the microcomputer A drive circuit for driving an actuator such as the circulation pump 18 and an output interface such as a relay drive circuit are provided.

  This controller 16 controls various actuators such as the solenoid valve 28, the hot water pump 27, the circulation pump 18 and the heat pump unit 8 of the hot water supply device S according to a program stored in a ROM (Read Only Memory) of the microcomputer. Controls various modes such as reheating, hot water supply, etc.

≪Details of operation of piping system of water heater S≫
Next, the operation | movement detail of the piping system of the water heater S is demonstrated.

<Storage of hot water in hot water storage tank 1>
The tap water is supplied to the hot water storage tank 1 as shown by an arrow along the thick line in FIG. 1 by tap water in the water pipe 22, for example, by a water pressure of about 6 to 8 kg / cm ^2. Water is introduced from the pipe 7 to the pressure reducing valve 6, and is reduced to a predetermined pressure, for example, about 2 kg / cm ² by the pressure reducing valve 6, and then introduced into the lower part of the hot water tank 1 through the pipe 23 and the check valve 20. Is done. The check valve 20 plays a role of preventing the backflow of tap water from the hot water storage tank 1.

  The tap water introduced into the hot water storage tank 1 is introduced into the heat pump unit 8 through the pipe 32, the three-way valve 33, and the pipe 34, and heated by a gas cooler (not shown) of the heat pump unit 8 as hot water. It is introduced into the upper part of the hot water storage tank 1 through the pipe 35 and stored in the hot water storage tank 1.

<Hot water supply mode from the mixer tap 19>
Next, hot water supply from the mixing plug 19 in the hot water heater S will be described with reference to FIG. As shown by a broken line in FIG. 2, the hot water heater S includes a circulation circuit in which hot hot water in the hot water storage tank 1 circulates through the hot water supply heat exchanger 4, and hot water from the mixing plug 19 is supplied to the hot water supply heat exchanger 4. The tap water is heated by exchanging heat between the tap water from the water pipe 22 and the hot hot water from the hot water storage tank 1.

  When the user uses the bath remote controller 45 to select the hot water supply mode, for example, a hot water supply mode selection signal is input to the controller 16, the hot water circulation pump 18 is operated by the signal from the controller 16, and the hot water in the upper part of the hot water storage tank 1 is operated. 2 is led out from the first outlet 10 to the hot water supply heat exchanger 4 through the pipes 41a and 41b, and the hot water supply heat exchanger 4 exchanges heat with low-temperature tap water to lower the temperature. Hot water is returned to the lower part of the hot water storage tank 1 through the pipe 42. A check valve 44 on the way from the outlet of the hot water heat exchanger 4 to the lower part of the hot water tank 1 serves to prevent natural circulation of the hot water tank 1 and hot water of the hot water tank 1 when the hot water circulation pump 18 is replaced. Plays a role in preventing backflow.

  When hot water is supplied using the hot water supply heat exchanger 4, tap water from the water pipe 22 is introduced to the hot water supply heat exchanger 4 through the pipes 7, 36 a, 36 b by the water pressure, and is heated by the hot water supply heat exchanger 4. The tap water thus heated is supplied to one side of the mixing plug 19 through the pipe 36c, the hot water supply temperature sensor 37, the hot water supply flow rate sensor 38, the accumulator 39, and the pipe 40. And in the mixing plug 19, a user mixes the tap water from the water pipe 22 connected to the other side of the mixing plug 19 and the supplied hot water, and adjusts the temperature of the hot water supply.

  Note that the accumulator 39 has a small amount of hot water remaining in the accumulator 39 in order to prevent an overshoot phenomenon in which hot water blows out from the faucet of the mixer tap 19 when the hot water flow rate is about 2 to 3 liters / minute. It is arranged to mix with water and cool to an appropriate temperature.

  The temperature of the hot water supplied from the hot water supply heat exchanger 4 to the mixing plug 19 is determined by using the controller 16 in the hot water storage tank unit 5, the temperature of the hot water detected by the tank top temperature sensor 47, and the pipe 7 from the water pipe 22. Based on the temperature detected by the water temperature sensor 53 of the tap water passing through the hot water supply heat exchanger 4 and the flow rate detected by the hot water flow sensor 38, it is set by the operation unit 60 such as the kitchen remote controller 46 and the bath remote controller 45. Then, the rotational speed of the hot water circulation pump 18 is controlled so that the predetermined hot water temperature is reached, and the flow rate of hot water from the hot water storage tank 1 flowing on the primary side that gives heat to the tap water is controlled in the hot water supply heat exchanger 4. doing.

  According to this structure, since the high water pressure of the tap water from the water pipe 22 can be utilized, for example, a shower on the third floor is possible, and a pressure reducing valve and a negative pressure breaking valve can be dispensed with. In addition, by using a sealed hot water supply system that introduces tap water depressurized via the pressure reducing valve 6 into the hot water storage tank 1, parts such as a cistern tank, an overflow switch, and a level switch are unnecessary, and the system is simplified. , Noise during water supply is also eliminated.

<Water filling mode for bathtub 2>
Next, the hot water filling to the bathtub 2 in the water heater S will be described with reference to FIG. FIG. 3 is a circuit diagram showing a hot water filling circuit of the water heater S by a thick line. When the user selects the hot water filling mode with the operation unit 60 such as the kitchen remote controller 46 and the bathroom remote controller 45, the hot water filling to the bathtub 2 is performed in the water heater S. When the user selects the hot water filling mode with the operation unit 60, the hot water filling mode selection signal is input from the operation unit 60 to the controller 16, and the normally closed electromagnetic valve 28 is controlled to open by the control of the controller 16. At the same time, the first mixing valve 14 and the flow rate adjustment valve 31 are each controlled in the hot water filling mode.

  When the electromagnetic valve 28 is controlled to open, the tap water supplied from the water pipe 22 is decompressed by the pressure reducing valve 6 and supplied to the hot water tank 1 through the pipe 23b as shown in FIG. The hot hot water in the hot water storage tank 1 is pushed out from the first take-out part 10 at the upper part of the hot water storage tank 1. And the warm water pushed out from the 1st extraction part 10 is guide | induced to the 1st mixing valve 14 through the piping 54 branched from the piping 1, as shown by the thick line of FIG. The pipes 29c and 29b are mixed with the tap water passing through the pipe 36a, the pipe 23a, the pressure reducing valve 6 and the pipe 23b from the pipe 7 connected to the pipe 18 through the electromagnetic valve 28 disposed downstream of the first mixing valve 14. , 29a and hot water is supplied to the bathtub 2 using two paths, the first path passing through the pipe 29b, the pipe 25, the pump 27, the flow rate adjusting valve 31, and the second path following the pipe 3. Tensioning is performed.

  Here, regarding the temperature of the hot water supplied to the bathtub 2, the controller 16 controls the temperature of the hot water detected by the temperature sensor 56 to be a predetermined bath temperature set by the operation unit 60. That is, the temperature of the hot water filling is controlled so as to be the set temperature of the hot water filling set by the user using the operation unit 60 such as the bath remote control 45 or the kitchen remote control 46. Specifically, the temperature sensor 56 detects the temperature of hot water passing through the pipe 29a when filling with hot water. The detection signal of the detected temperature is input to the controller 16, and the controller 16 compares the temperature set by the user with the detected temperature of the temperature sensor 56. And the mixing ratio of the hot water from the hot water storage tank 1 in the 1st mixing valve 14 and the tap water supplied from the piping 23c etc. is adjusted so that both may become equal.

  Regarding the amount of hot water supplied to the bathtub 2, the flow rate sensor 55 detects the flow rate, inputs this flow rate detection signal to the controller 16, and the controller 16 calculates the predetermined hot water amount. Then, the amount of hot water is controlled, and when the predetermined amount of hot water is reached, the solenoid valve 28 is closed and the supply of hot water is stopped.

  Further, the water level of the bathtub 2 is detected by a water level detection unit (water level sensor) 57. Specifically, the water level detection part 57 detects the pressure of the hot water in the piping 25, and detects the water level of the bathtub 2 based on the detected pressure. Specifically, a pressure detection signal is input to the controller 16, and the controller 16 calculates the water level based on the head and the like. However, the water level detection part 57 is not limited to this, You may detect the water level of the bathtub 2 directly. And the solenoid valve 28 etc. are controlled so that it may become a predetermined setting water level. Moreover, the water level detection part 57 can detect a water level with a predetermined precision, when a water level is more than the water circulation port 2i. However, when the water level is lower than the water circulation port 2i, the water level cannot be detected.

  In the automatic cleaning described later, since the water level in the bathtub is lower than the predetermined water level is one of the conditions for starting the automatic cleaning, the reference water level is used as the reference water level in this water heater. Is set. Specifically, hot water is stored in the bathtub 2 stepwise or continuously, and the water level first detected by the water level detection unit 57 is set as the reference water level.

  In this way, the bathtub 29 is filled with water by passing through the pipe 25 on the downstream side of the connecting portion 30 and the flow rate adjusting valve 31 and through the pipe 3 on the downstream side of the pipe 26 on the outlet side of the reheating pipe. The hot water filling is performed with two pipes together with the hot water filling from, and the hot water filling is performed at a constant water pressure via the pressure reducing valve 6. For this reason, the hot water filling time can be set to about 13 minutes, for example, at a preset temperature of 42 ° C. and 200 liters, and the hot water filling time can be shortened by about 7 minutes compared to the conventional case.

<Chance mode>
Next, replenishment of the bath water in the bathtub 2 in the water heater S will be described with reference to FIG. As shown in FIG. 4, reheating of the bath water in the bathtub 2 is performed using a reheating heat exchanger 24. In the reheating heat exchanger 24, the pipe 25 from the bathtub 2, the pump 27, the flow rate adjusting valve 31, and the pipe 58 are connected to the inlet 24i side, and the pipe 26 returning to the bathtub 2 is connected to the outlet 24o side. Has been. When the reheating heat exchanger 24 is used, the pump 27 is driven by the controller 16, and bath water is introduced into the reheating heat exchanger 24 through the flow rate adjusting valve 31 from the pipe 25, and the reheating heat exchanger 24. In 24, heat exchange is performed between the hot water in the upper part of the hot water storage tank 1 and the introduced bath water.

  When the user selects the reheating mode with the operation unit 60 such as the kitchen remote control 46 or the bathroom remote control 45, the hot water in the bathtub 2 is reheated in the water heater S. That is, when the reheating mode is selected by the operation unit 60, a reheating mode selection signal is input from the operation unit 60 to the controller 16. Under the control of the controller 16, the water in the bathtub 2 is retreated and the heat exchanger 24 is turned on. The pump 27 for circulation is operated, and the flow rate adjustment valve 31 is controlled to the reheating mode.

  As shown by the arrow in FIG. 4, the bath 27 operated by the command of the controller 16 causes the bath water from the water flow port 2 i of the bathtub 2 to be connected to the pipe 29 a, the connecting portion 30, the pipe 25, After being led to the reheating heat exchanger 24 through the flow rate adjusting valve 31 and the pipe 58 and heated in the reheating heat exchanger 24 by heat exchange with the hot water at the upper part of the hot water storage tank 1, the piping 26 and the piping 3. The water is returned to the bathtub 2 through the water distribution port 2o of the bathtub 2.

  Here, since the boiling water led to the reheating heat exchanger 24 is heat-exchanged with the hot water at the upper part of the hot water storage tank 1 in the reheating heat exchanger 24, a large amount of heat is given to the reflowing water, and the efficiency is increased. Can be repulsed.

  In this case, since the reheating heat exchanger 24 is disposed at the upper part of the hot water storage tank 1, high-temperature hot water may be supplied to the bathtub 2 at the start of reheating. In order to prevent this, the heating returned to the bathtub 2 using the temperature of the heated hot water flowing out from the reheating heat exchanger 24 at the start of reheating and the temperature detection signal of the temperature sensor 56 for detecting the return temperature. The temperature of the subsequent bath water is predicted, and the opening degree of the flow rate adjusting valve 31 is controlled so that the predicted temperature is 60 ° C. or less. Specifically, the temperature detection signal of the temperature sensor 59 and the temperature detection signal of the temperature sensor 56 are input to the controller 16, and the controller 16 controls the opening degree of the flow rate adjustment valve 31.

  According to this configuration, at the start of reheating, the temperature detection signal of the temperature sensor 59 that detects the temperature of the heated hot water flowing out from the reheating heat exchanger 24 and the temperature of the temperature sensor 56 that detects the return temperature. Based on the detection signal, the opening degree of the flow rate adjusting valve 31 is controlled so that the temperature of the heated fountain returned to the bathtub 2 is equal to or lower than a predetermined temperature. It can prevent that the high temperature water which stays discharges directly to a bathtub.

  Further, by circulating the hot water in the bathtub 2 to the reheating heat exchanger 24, heat is indirectly exchanged with the hot water at the upper part in the hot water storage tank 1, and the hot water in the bathtub 2 is chased. By providing a circulation circuit that is heated for heating, it is possible to prevent heat from being wasted from the reheating heat exchanger 24 during reheating and to prevent waste of heat energy.

<Fuel heat exchanger cleaning mode>
Next, the cleaning mode of the reheating circuit 2P in the water heater S will be described with reference to FIG. In the cleaning mode, fresh water is passed through the reheating circuit 2P, and dirt on the piping and the reheating heat exchanger 24 is washed away.

  The cleaning operation will be described with reference to FIG. First, the first mixing valve 14 is controlled so that the water side is fully opened. As a result, the reheating heat exchanger 24 is mainly supplied with water from the water supply source, and the hot water in the hot water storage tank 1 is not supplied.

  Next, the solenoid valve 28 is controlled to open. Then, the water from the water supply source starts to flow downstream. That is, fresh water is supplied to the pipes 29c and 29b and the pipe 29a. The supplied water flows from the water circulation port 2i of the bathtub to the bathtub 2 while washing the pipe 29a, and is drained from a drain port in the bathtub 2 (not shown).

  Further, the pump 27 is driven and controlled. Then, a part of the fresh water that has flowed through the pipe 29c flows into the pipe 25 and flows from the water circulation port 2o of the bathtub to the bathtub 2 while washing the pipes downstream from the pipe 25c. Drained from.

  At this time, if the flow path to the pipe 58 side of the flow regulating valve 31 is open, the supplied water flows through the pipe 58, the reheating heat exchanger 24, and the pipes 26 and 3, Wash. Moreover, if the flow path to the pipe 63 side of the flow rate adjusting valve 31 is open, the supplied water flows through the pipes 63 and 3 and cleans these pipes.

  In this way, the pipes 29a, 25, 58, the reheating heat exchanger 24, and the pipes 26, 3, 63 constituting the reheating circuit 2P are washed with fresh water. The opening control of the electromagnetic valve 28 and the drive control of the pump 27 may be performed simultaneously, or the pump 27 may be driven and controlled after the opening of the electromagnetic valve 28.

  Here, control of the flow rate adjustment valve 31 will be described. In order to clean the piping 29a, 25, 58, 26, 3 and the reheating heat exchanger 24 constituting the reheating circuit 2P, the flow adjustment valve 31 may be controlled to be opened largely on the piping 58 side. However, when hot water (for example, 80 ° C.) is present in the upper part of the hot water storage tank 1, it is assumed that the hot water of the same level is also present in the reheating heat exchanger 24. Therefore, at the start of cleaning, high-temperature hot water in the reheating heat exchanger 24 may pass through the pipes 26 and 3 and be discharged to the bathtub 2 from the water distribution port 2o of the bathtub.

  For this reason, at the time of cleaning, based on the temperature detected by the temperature sensors 59 and 56 (particularly, the temperature sensor 59), the flow rate adjusting valve 31 is set so that the water temperature discharged to the bathtub 2 becomes a predetermined temperature (for example, 60 ° C.) or less. The high temperature water flowing through the pipe 26 and the water flowing through the pipe 63 are mixed at the junction 65. This control is basically the same as in the case of chasing. However, in the case of reheating, the opening degree of the flow rate adjustment valve 31 is controlled so as to be as close to the predetermined temperature as possible while keeping the temperature below the predetermined temperature, whereas in the case of cleaning, As long as the temperature is equal to or lower than the predetermined temperature, it may be repeated any number of times, and control is performed so that water flows into the reheating heat exchanger 24 at a ratio as large as possible.

  The washing operation ends after a predetermined amount of water has been poured. Specifically, the process ends when the integrated value of the flow rate detected by the flow rate sensor 55 reaches a predetermined amount. However, the time for performing the cleaning operation may be set in advance, and the cleaning may be terminated after this time has elapsed.

  That is, the hot water heater S has a reheating circuit 2P that exchanges heat of the bathtub water taken out from the bathtub 2 with a high-temperature heat medium by a reheating heat exchanger 24 disposed in the storage tank and returns the water to the bathtub, and fresh water to the bathtub. And the fresh water circuit 2P is connected to the fresh water circuit, and the fresh water flowing through the fresh water circuit is supplied to the fresh heat exchanger 24 to wash the fresh heat exchanger 24. The water heater is configured to perform water heating, and is configured to be able to mix water having a temperature lower than that of the water that has exited the reheating heat exchanger 24. For this reason, even if the water used for cleaning the reheating heat exchanger 24 has a high temperature, the temperature can be lowered by mixing the low-temperature water. Therefore, it is possible to realize a water heater that can clean the reheating heat exchanger without discharging water used for cleaning the reheating heat exchanger to the bathtub in a high temperature state.

  Further, the reheating circuit 2 </ b> P is divided into a first path passing through the reheating heat exchanger 24 and a second path bypassing the reheating heat exchanger 24 on the upstream side of the reheating heat exchanger 24. It is provided so as to branch and merge on the downstream side of the reheating heat exchanger 24, and is configured to be able to adjust the flow rate ratio flowing through each path. Therefore, it is possible to adjust the flow rate of the water flowing through each path so that the temperature of the combined water does not become high (for example, 60 ° C. or less).

  Further, in the reheating circuit 2P, the flow rate ratio flowing through each path is adjusted according to the temperature of the water that has exited the reheating heat exchanger 24. Therefore, it can adjust so that the temperature of the water after joining (namely, returned to a bathtub) may not become high temperature.

  The water heater S includes a pump 27 for introducing water into the reheating heat exchanger 24, and the fresh water circuit is connected to the reheating circuit 2P on the upstream side of the reheating heat exchanger 24 and the pump 27. The pump 27 is connected to drive the fresh water flowing through the reheating circuit 2P to the reheating heat exchanger 24 when the reheating heat exchanger 24 is cleaned. Therefore, fresh water can be efficiently introduced into the reheating heat exchanger when the reheating heat exchanger is cleaned. Note that the pump 27 may be on the downstream side of the reheating heat exchanger 24.

  Further, the fresh water circuit is connected so as to join the reheating circuit 2P, and the fresh water introduced into the reheating circuit 2P has a path from the connecting portion 30 between the fresh water circuit and the reheating circuit 2P toward the downstream side. It flows into the bathtub 2 through the path | route which goes upstream from the said connection part 30, and the reheating circuit 2P is wash | cleaned. Therefore, the entire reheating circuit 2P can be cleaned.

<Automatic cleaning control>
Incidentally, the water heater S is configured to automatically perform the above-described cleaning operation. Next, automatic cleaning start control will be described with reference to FIG.

  First, when the user pulls out the drain plug in the bathtub 2 after bathing or the like, the water level in the bathtub is lowered. This is detected by the water level detection unit 57, and when it is detected that the water level is equal to or lower than a predetermined specified water level, it is determined that the bathing has ended. At this time, if the user has previously set the automatic cleaning mode with the operation unit 60 such as the kitchen remote controller 46 and the bathroom remote controller 45, automatic cleaning is performed. Thereby, the water containing the dirt which remained in the reheating circuit 2P by bathing etc. is discharged | emitted out of a circuit from the water distribution opening (2i, 2o) of a bathtub. If the automatic cleaning mode is not set in advance, automatic cleaning is not performed.

  The washing operation needs to be performed after the user uses the bathtub (that is, takes a bath) and drains the hot water from the bathtub. In order to do this automatically, the water heater assumes that the user has used the bathtub by performing a hot water filling operation, so that the hot water filling operation is performed and other operations related to bathing (for example, adding hot water) , Hot water, hot water, chasing, etc.) is regarded as a state in which the use of the bathtub has ended, and then the hot water is regarded as being drained by the drop in the water level of the bathtub.

  First, in step S11, it is determined whether or not a hot water filling operation is being performed. When the hot water filling operation is not being performed (No in step S11), in step S12, it is detected whether the hot water filling operation has been completed normally. The case where the hot water filling operation does not end normally is, for example, the case where the drain plug in the bathtub 2 is not closed and hot water does not accumulate in the bathtub. When the hot water filling operation is normally completed (Yes in step S12), it is determined in step S13 whether an operation other than the hot water filling operation is performed.

  When the operation other than the hot water filling is not performed (No in step S13), the water level detection by the water level detection unit 57 is performed. Here, in order to accurately detect the water level, it is preferable that the water surface in the bathtub 2 is stable, for example, not wavy. For this reason, after completion of the hot water filling operation and other operations related to bathing, the water level is measured after a predetermined time. This predetermined time is a water level stabilization waiting time, and is set to 30 seconds, for example. Specifically, it is determined in step S14 whether the water level stabilization wait time has elapsed. However, if accurate water level detection is not necessary at this stage, step S14 is unnecessary.

  Next, in step S15, it is determined whether or not the current water level in the bathtub 2 is higher than the reference water level.

  By the way, the water level of the bathtub may rise or fall greatly when the user goes out of the bathtub, etc., except when the hot water is drained, and the water level temporarily falls below the reference water level. Can do. Therefore, for example, if the current water level is about the same as the reference water level, if it is considered that drainage has been performed immediately based on the determination in step S15, a malfunction may occur such as a cleaning operation being performed during bathing, There may be inconveniences such as discomfort to the user. In addition, such a situation may occur due to the measurement error of the water level detection unit 57, and the water level of the bathtub 2 cannot always be accurately detected depending on the state of the actually installed piping. Can also occur.

  For this reason, in step S16, it is determined that hot water has been drained when a state in which the water level is equal to or lower than the reference water level is continuously detected over a predetermined time. This predetermined time is the water level continuous monitoring time, and is set to 10 seconds, for example. Then, if the water level is detected a plurality of times within this water level continuous monitoring time and the current water level has never exceeded the reference water level during that time, it is determined Yes in step S16. Specifically, the water level is detected at intervals of 0.5 seconds within the continuous water level monitoring time.

  Here, even if it is detected by the water level detection unit 57 that hot water has started to be drained (Yes in step S16), when the cleaning operation is started immediately, the water that has once returned to the bathtub is replenished by the pump 27 or the reheating circuit 2P. There is a possibility of being drawn into the soaking heat exchanger 24. Such a situation may occur, for example, when the amount of water supplied to the bathtub by the cleaning operation is larger than the amount of drainage of the bathtub 2 and the water level of the bathtub 2 becomes higher by the cleaning operation, or at the position of the water level detection unit 57. This occurs, for example, when the remaining water is drained but still remains in the reheating circuit 2P.

  For this reason, in step S17, the cleaning operation is started after a predetermined time has elapsed. This predetermined time is a cleaning operation start delay time, and is set to 5 minutes, for example.

  That is, the water heater S includes a reheating circuit 2P that heats the bathtub water taken out from the bathtub 2 by the reheating heat exchanger 24 and returns it to the bathtub, and a fresh water circuit that supplies fresh water to the bathtub 2, and the reheating operation. The circuit 2P and the fresh water circuit are connected so that the fresh water flowing through the fresh water circuit is supplied to the reheating heat exchanger 24 and includes a water level detection unit 57 that detects the water level of the bathtub water. After the operation or the operation of supplying fresh water to the bathtub 2 is performed and the water level of the bathtub water becomes equal to or higher than a preset reference water level, the state in which the water level of the bathtub water is lower than the reference water level is a predetermined water level monitoring time. When the water is detected over a period of time, it is assumed that the bathtub water has been drained, and a cleaning operation is performed in which fresh water is replenished and supplied to the heat exchanger 24 for cleaning.

  For this reason, by detecting over a predetermined time that the water level of the bathtub water is lower than the reference water level, it is possible to eliminate accidental factors such as when the water level of the bathtub water temporarily becomes lower than the reference water level. Can do. Therefore, it is possible to realize a water heater that can suitably prevent or suppress the automatic cleaning operation of the reheating heat exchanger 24 from being erroneously performed.

  The water heater S includes a reheating circuit 2P that heats the bathtub water taken out from the bathtub 2 by the reheating heat exchanger 24 and returns it to the bathtub, and a fresh water circuit that supplies fresh water to the bathtub. 2P and the fresh water circuit are connected so that the fresh water flowing through the fresh water circuit is replenished and supplied to the heat exchanger 24, and is provided with a water level detection unit 57 for detecting the water level of the bathtub water. Cleaning in which fresh water is supplied to the reheating circuit 2P for cleaning when a predetermined start delay time has elapsed after a state in which the water level is lower than a preset reference water level is detected over a predetermined water level monitoring time. Operation is performed.

  Therefore, by detecting over a predetermined time that the water level of the bathtub water is lower than the reference water level, it is possible to eliminate accidental factors such as when the water level of the bathtub water temporarily becomes lower than the reference water level. it can. Moreover, since drainage of bathtub water is performed during the predetermined start delay time, the water level of the bathtub water is further lowered, and the bathtub water present in the reheating circuit 2P is also discharged. Accordingly, it is possible to suitably prevent a situation in which the water supplied to the reheating circuit 2P by the cleaning operation is mixed with the bathtub water and flows back to the reheating circuit 2P, and the cleaning effect is destroyed.

  Further, the water heater S detects the water level of the bathtub water a plurality of times during the predetermined water level monitoring time, and when the water level of the bathtub water is lower than the reference water level at all time points, It is determined that the water level of the water was lower than the reference water level. Therefore, the possibility of malfunctions can be further reduced.

<< Second Embodiment >>
Next, a water heater 2S according to a second embodiment of the present invention will be described with reference to FIG. In addition, FIG. 7 is a configuration diagram in which a circuit at the time of filling is shown by a bold line in the example of the water heater 2S according to the second embodiment. Below, the same code | symbol is attached | subjected and shown about the structure similar to the water heater S which concerns on 1st Embodiment, and detailed description is abbreviate | omitted.

  As shown in FIG. 7, the hot water heater 2 </ b> S of the second embodiment does not necessarily require hot water as hot as in the upper part of the hot water tank 1 in the hot water filling of the bathtub 2. In addition, the second take-out portion 12 is provided, and the medium temperature water in the hot water storage tank 1 is led to the newly provided second mixing valve 11 through the pipe 13 connected to the second take-out portion 12. The hot water storage tank 1 is mixed with high-temperature hot water guided from the upper part, and the hot water filling of the bathtub 2 is performed.

  The hot water filling circuit 2 </ b> R in the water heater 2 </ b> S guides the hot hot water at the upper part of the hot water storage tank 1 to the second mixing valve 11 through the pipe 41 a and the pipe 9 connected to the first take-out part 10 at the upper part of the hot water storage tank 1. Then, in the second mixing valve 11, hot hot water from the upper part of the hot water storage tank 1 is mixed with intermediate hot water that has passed through the pipe 13 from the second take-out part 12 in the middle of the vertical direction of the volume of the hot water storage tank 1. The mixed hot water is further mixed in the first mixing valve 14 with tap water from the water supply pipe 7 through the pipe 36a, the pipe 23a, the pressure reducing valve 6 and the pipe 23c, and is distributed downstream of the first mixing valve 14. A first path passing through the pipes 29c, 29b, and the pipe 29a by opening the electromagnetic valve 28 provided, and a second path passing through the pipe 3 through the pipe 29c, the pipe 25, the pump 27, and the flow rate adjusting valve 31 Fill the bathtub 2 with two paths.

  According to the above-described configuration, the hot water storage tank 1 has, for example, the hot water storage tank 1 by providing the second take-out portion 12 for deriving and supplying the intermediate water at the intermediate temperature in the hot water storage tank 1 at the intermediate portion of the hot water storage tank 1 in the vertical direction. In the hot water filling of the bathtub 2 that does not necessarily require as high temperature water as in the upper part, the amount of tap water mixed from the pipe 23c in the first mixing valve 14 is reduced by actively using warm water of intermediate temperature. Thus, waste of heat energy can be suppressed, and high-temperature water necessary for the hot water supply heat exchanger 4 can be efficiently used. In this way, by actively using the intermediate water at the intermediate temperature, the high-temperature water required for the hot water supply heat exchanger 4 and the reheating heat exchanger 24 can be efficiently used.

  Also in the second embodiment, the bathtub 2 is filled with water through the pipe 25 on the downstream side of the connecting portion 30 and the pipe 3 on the downstream side of the pipe 26 on the outlet side of the reheating pipe through the flow rate adjusting valve 31. By performing the hot water filling with two pipes and performing the hot water filling with a constant water pressure via the pressure reducing valve 6, the hot water filling time can be shortened.

  Further, the temperature detection signal of the hot water detected by the top temperature sensor 47 of the hot water storage tank 1 and the temperature detection of the hot water detected by the temperature sensor 49 arranged in the middle of the volume of the hot water storage tank 1 in the vertical direction. A signal is input to the controller 16, and the controller 16 predicts the temperature of hot water flowing out from the second mixing valve 11 from these two temperatures and the like, and determines and controls the valve opening degree of the second mixing valve 11. . In addition, as a middle part in the vertical direction of the volume of the hot water storage tank 1, a position of about 2/5 to 3/5 from above the volume of the hot water storage tank 1 is preferable. Thereby, the member for detecting the mixing temperature downstream of the second mixing valve 11 can be eliminated, the system becomes easy, and the production cost can be reduced.

  Moreover, also in the water heater based on 2nd Embodiment, the washing | cleaning operation | movement similar to 1st embodiment can be implemented. Furthermore, in the water heater according to the second embodiment, a cleaning operation using medium-temperature water can be performed.

  Next, with reference to FIG. 7, a cleaning operation using medium-temperature water will be described. In the washing operation using the medium temperature water, the medium temperature water as fresh water is taken out from the second extraction portion 12 of the hot water storage tank 1, and the water passes through the pipe 13, the second mixing valve 11, the pipe 15, and the first mixing valve 14. Shed. The flow path downstream of the first mixing valve 14 is the same as in the first embodiment. The second mixing valve 11 is fully open on the pipe 13 side.

  By the way, the medium-temperature water may have a high temperature that is not preferably discharged directly to the bathtub 2. In such a case, the temperature is lowered by mixing the intermediate temperature water taken out from the hot water storage tank 1 with the low temperature water from the water supply source in the first mixing valve 14.

  Specifically, as the temperature of the intermediate temperature water, the temperature of the temperature sensor 49 of the hot water storage tank 1 disposed at the same height as the second extraction unit 12 is used. However, the temperature of the intermediate temperature water may be directly detected by arranging a temperature sensor in the second take-out portion 12 or the pipe 13. Further, the temperature of the mixed water is detected by a temperature sensor 56. In the first mixing valve 14, the temperature of the medium temperature water detected by the temperature sensor 49, the temperature of the low temperature water detected by the temperature sensor 53, and the temperature of the mixed water detected by the temperature sensor 56 are a predetermined temperature ( For example, the temperature is controlled to be 60 ° C. or less.

  In the first embodiment and the second embodiment, the case where the hot water filling time is shortened by using the piping used for reheating is described as an example. It can also be used to fill with water. Moreover, although the piping which fills up the bathtub 2 illustrated the case of two piping used for reheating, if it is plurality, the number will not be limited.

«Third embodiment»
Next, a water heater 3S according to a third embodiment of the present invention will be described with reference to FIG. Below, the same code | symbol is attached | subjected and shown about the structure similar to the water heater S which concerns on 1st Embodiment, and detailed description is abbreviate | omitted. As with the water heater S according to the first embodiment, the controller (not shown) controls the entirety of the water heater 3S according to the third embodiment in accordance with an operation command or the like from an operation unit (not shown). It is.

  Unlike the first embodiment and the second embodiment, the hot water heater 3 </ b> S has a reheating heat exchanger 124 arranged outside the hot water storage tank 101. The hot water storage tank 101 is provided with a cistern tank C. This hot water heater 3S is a so-called direct pressure type hot water supply apparatus that exchanges heat with the hot water supply heat exchanger 104 and supplies it to the mixing tap 19 that is a general hot water supply terminal without lowering the pressure of the high-pressure water supplied from the water pipe 22. is there.

  The pipe 125 is provided with a pump 127 having a function equivalent to that of the pump 27 according to the first embodiment. The pipe 136c is provided with a hot water flow rate sensor 138 having a function equivalent to that of the hot water flow rate sensor 38 according to the first embodiment. Further, the pipe 129b is provided with a water level sensor 157 having a function equivalent to that of the water level sensor 57 according to the first embodiment, and the pipe 129c has a function equivalent to that of the electromagnetic valve 28 according to the first embodiment. An electromagnetic valve 128 is provided. The pipe 129 e is a pipe that exchanges heat with the bath water in the hot water supply heat exchanger 104 and returns the cooled water discharged from the hot water supply heat exchanger 104 to the hot water storage tank 101.

<Fuel heat exchanger cleaning mode>
Next, cleaning of the reheating heat exchanger 24 in the water heater 3S will be described. At the time of cleaning, the first mixing valve 114 is fully opened on the pipe 129d side, the switching valve 117 is fully opened on the pipe 129c side, the electromagnetic valve 128 is controlled to open, and the pump 27 is driven. Then, the first path passing from the cistern tank C through the pipe 123c, the pipe 129d, the pipe 129c, the pipe 125, the reheating heat exchanger 124, the pipe 103a, and the pipe 103b, and the second path through the pipe 129b and the pipe 129a The fresh water flows, and the reheating circuit 2P is washed. In addition, the pipe 167 is also washed. In this case, the fresh water may be supplied from the hot water storage tank 101 instead of from the cistern tank C. That is, the storage tank in the hot water heater 3 </ b> S includes the hot water storage tank 101 and the cistern tank C that store hot water as a heat medium.

  The hot water heater 3S may be one that performs not only cleaning using low-temperature water but also cleaning using medium-temperature water. In this case, the removal of the medium-temperature water is the same as that in the second embodiment.

<Automatic cleaning control>
Furthermore, also in the water heater 3S, the automatic cleaning start determination is performed using the water level detection unit 157, and the flow thereof is the same as that of the first embodiment.

  In addition, this invention is not limited to the structure described in said each embodiment, The structure can be suitably changed in the range which does not deviate from the meaning.

  For example, as a heat source for heating hot water as a heat medium, in addition to the heat pump unit, a heater or the like arranged in a storage tank can be considered.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Bathtub 2i, 2o Water distribution port 2P Reheating circuit 2R, 2Y Hot water filling circuit 2X General hot water supply circuit 4 Hot water supply heat exchanger 6 Pressure reducing valve (hot water filling circuit)
8 Heat pump unit (heat pump part)
DESCRIPTION OF SYMBOLS 10 1st extraction part 11 2nd mixing valve 12 2nd extraction part 14 1st mixing valve 18 Hot water supply circulation pump 19 Mixing plug 22 Water pipe 24 Reheating heat exchanger 27 Pump 28 Solenoid valve 30 Connection part 31 Flow control valve 37 Hot water supply Temperature sensor 38 Hot water flow rate sensor 39 Accumulator 47 Tank top temperature sensor (first temperature sensor)
49 Temperature sensor (second temperature sensor)
53 Water temperature temperature sensor 55 Flow rate sensor 56 Temperature sensor (fourth temperature sensor)
57 Water level detector 58 Piping 59 Temperature sensor (Third temperature sensor)
S water heater

Claims (3)

A reheating circuit that heats the bathtub water taken out of the bathtub and heats it back to the bathtub by a heat exchanger, and a fresh water circuit that supplies fresh water to the bathtub,
The reheating circuit and the fresh water circuit are connected, and the fresh water flowing through the fresh water circuit is configured to be supplied to the reheating heat exchanger,
It has a water level detector that detects the water level of the bathtub water,
The reference water level is set corresponding to the height of the bathtub terminal where the water level detection unit can detect the water level of the bathtub water,
Operating supplies fresh water against reheating operation or tub is performed after the water level of the bathtub water is equal to or larger than the reference level, lower than the water level of the bathtub water is the reference water level state for a predetermined water level monitoring time If the water is detected, a hot water heater is provided which performs a cleaning operation in which fresh water is replenished and supplied to the heat exchanger as if the drainage of the bathtub water has been performed. Claims lower than the reference water level the water level of the bathtub water is preset state after being detected over a predetermined water level monitoring time, whereupon further elapses a predetermined start delay time, characterized in that the washing operation is carried out Item 2. A water heater according to item 1 . The water level of the bathtub water is detected a plurality of times during the predetermined water level monitoring time,
The water level of the bathtub water is determined to be lower than the reference water level when the water level of the bathtub water is lower than the reference water level in detection at all points in time. Water heater.

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