JP3718651B2 - Hot water mixing unit for water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hot water supply unit for connecting a hot water supply device using natural energy, such as a solar water heater, or a hot water supply device using various types of waste heat, to a water heater (7).
[0002]
[Prior art]
Solar water heaters have a hot water supply system in which hot water at the target temperature cannot be taken out due to the weather, etc., so that the hot water supply system (7) can be connected as an auxiliary heat source so that energy resources can be used effectively. A device described in Japanese Patent Laid-Open No. 10-196983 is known.
[0003]
This has the schematic structure shown in FIG. 3, and the upstream hot water passage (56) drawn out from the solar water heater (5) is connected to the hot water passage (14) of the hot water mixing unit (1) for the water heater. It is connected. The water supply passage (10) connected to the water supply is connected to the cold water passage (15) of the hot water mixing unit (1) for the water heater, and at the junction of the cold water passage (15) and the hot water passage (14). A hot water mixer (20) is provided. The hot water passage (14) and the cold water passage (15) are provided with a hot water temperature sensor (19) and a feed water temperature sensor (23), respectively. Further, a mixed water temperature sensor (33) is provided in the mixed water passage (29) formed on the downstream side of the hot water mixer (20).
The mixed water passage (29) is connected to the water inlet (77) of the water heater (7) by piping, and the hot water is supplied from the water heater (7) to the hot water tap (85) and the bathtub (81). It has become.
[0004]
In this device, when the hot water supply temperature is set by the remote controller (71) for remote control of the water heater (7) , the set temperature (hereinafter referred to as “set temperature S”) is the hot water mixing unit for the water heater. It is transmitted to the control device (11) of (1). And, for example, when a water flow is generated in the water passage in the water heater (7) by opening the tap hot water tap (85), the water flow rate sensor provided in the water heater (7) outputs a water flow presence signal for the water heater. The hot-water mixer (20) of the hot-water mixing unit (1) starts to be controlled. That is, the hot and cold water passages (14) are connected to the hot water and cold water passages (15) by the hot and cold water mixer (20) operating based on the detected temperatures of the hot water temperature sensor (19) and the feed water temperature sensor (23) and the set temperature S. The mixing ratio of the cold water is adjusted, whereby the temperature of the mixed water flowing out of the hot water mixer (20) is adjusted to the set temperature S. Then, hot water flowing out from the hot water mixing unit for hot water heater (1) is supplied to the hot water tap (85) or the like through the hot water heater (7) maintained in the combustion stopped state.
[0005]
In this case, the detected flow rate of the water heater flow sensor incorporated in the water heater (7) and used for calculating the combustion amount of the gas burner is expressed by a predetermined number of bits. Accordingly, when the detected flow rate expressed by a predetermined number of bits is transmitted from the communication cable to the control device (11) of the hot water mixing unit for hot water heater (1), the ratio occupied by the transmission and reception of the detected flow rate in the communication As a result, the smooth transmission / reception of other information becomes difficult. For this reason, in the above-mentioned conventional apparatus, a signal indicating whether or not water has passed (which can be expressed by 1 bit) detected by the flow sensor for the water heater is transmitted from the communication cable to the control device (11), and the signal is used for the water heater. It is used only as a start signal for starting control of the hot / cold water mixing unit (1). Therefore, in this case, it is not possible to perform various controls of the hot water mixing unit (1) for the hot water heater based on the flow rate of the mixed water flowing through the mixed water passage (29) (equal to the flow rate detected by the flow sensor for the hot water heater). .
[0006]
Therefore, by arranging an independent mixed water flow sensor in the mixed water passage (29), it is possible to realize the following fine control considering the correlation with the operation of the water heater (7). It is done.
[0007]
That is, when the temperature detected by the hot water temperature sensor (19) (temperature of hot water supplied from the solar water heater (5) side) is slightly lower than the set temperature S set by the remote controller for water heater (71), Even if the gas burner of the water heater (7) is burned with the minimum combustion amount (burning amount with the minimum gas amount that can ensure smooth ignition to the gas burner), the temperature of the hot water discharged from the water heater (7) exceeds the preset temperature S Calculate the temperature of the mixed water (hereinafter referred to as the “target mixing temperature”, but this mixing target temperature needs to be lower as the flow rate of the mixed water decreases). An independent mixed water flow sensor (32) for determining the flow rate of the mixed water necessary for this calculation is disposed in the mixed water passage (29).
[0008]
However, when a mixed water flow sensor (32) different from the water heater flow sensor provided in the water passage of the water heater (7) is provided, the occurrence rate of abnormality increases as the number of parts increases. And when abnormality of each said flow sensor generate | occur | produced, there existed a problem that normal operation | movement of the water heater (7) or the hot water mixer (20) could not be ensured.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of such points.
`` Mixed water that is extended from the junction where the cold water passage (15) through which the cold water from the water supply flows and the hot water passage (14) through which the hot water from the hot water supply device joins and is piped to the downstream water heater (7) Passage (29),
A mixed water temperature sensor (33) and a mixed water flow sensor (32) disposed in the mixed water passage (29);
Hot water that adjusts the mixing ratio of the hot water and the cold water so that the detected temperature of the mixed water temperature sensor (33) matches the mixed target temperature that is set and changed based on the detected flow rate of the mixed water flow sensor (32). In a solar connection unit comprising a mixer (20),
It is an object to make it possible to determine the abnormality of the mixed water flow sensor (32) so that appropriate measures can be taken.
[0010]
[Means for Solving the Problems]
[1]
The technical means of the present invention for solving the above problems are as follows:
"Water flow of the water heater flow sensor (78) that detects the flow of the mixed water in the water heater (7) under the condition that the mixed water flow sensor (32) outputs a water flow stop signal. When there is a flow rate sensor abnormality where a presence signal is transmitted via a communication cable, the flow rate sensor for mixed water (32) includes an abnormality determination means for outputting an abnormality signal indicating that the abnormality is present,
When the flow sensor is abnormal, the hot water / water mixer (20) sets the cold water passage (15) to the maximum opening degree and sets the hot water passage (14) to the minimum opening degree .
[0011]
According to the above technical means, the suitability of the operation of the mixed water flow sensor (32) is monitored by the hot water heater flow sensor. That is, the water flow rate sensor (32) of the former mixed water is mixed even though the water passing signal output from the latter water heater flow sensor is sent to the hot water hot water mixing unit via the communication cable. When the flow rate sensor that has not detected the flow of water (including both water flow and flow rate) is abnormal, the mixed flow rate sensor (32) is judged to be in an abnormal state, and an abnormality is detected. A signal is output.
When the flow sensor is abnormal , the cold water passage (15) is set to the maximum opening degree in the hot water / mixer (20) , while the hot water passage (14) is set to the minimum opening degree, thereby mixing. The temperature of water is lowered.
[0012]
[2]
In the above item 1,
“If the abnormality signal is output, the communication cable sends a notification request signal for notifying the water heater remote controller of the water heater (7) that the mixed water flow sensor (32) is in an abnormal state. `` Having a means for delivering to the water supply '', by informing the user that the mixed water flow sensor (32) is in an abnormal state to the remote controller for hot water heater, the user can repair the mixed water flow sensor (32). Recognize the need for
When the abnormal signal disappears, that is, when the mixed water flow sensor (32) returns to a state in which the mixed water flow is detected, the notification request signal is not sent to the communication cable. The anomaly notification operation by is also stopped.
[0013]
[3]
In the above item 1 or 2,
`` A part of the cold water passage (15) located on the upstream side of the hot water mixer (20) and a bypass passage (28) connecting the mixed water passage mixed water passage (29);
Provide a safety valve to keep the bypass passage (28) closed,
When the abnormal signal is output, the safety valve is opened.
When it is determined that the mixed water flow sensor (32) is in an abnormal state, the safety valve is opened, so that a large amount of cold water flows from the cold water passage (15) into the mixed water passage (29). As a result, the temperature of the mixed water decreases. Therefore, more reliably prevented not convenient to dangerous high temperature water is supplied to the water heater (7) side. Then, the water whose temperature has been lowered by the large amount of cold water is supplied to the hot water heater (7) side, and this is heated to the hot water supply set temperature by the original function of the hot water heater.
[0014]
When the abnormal signal disappears, that is, when the mixed water flow sensor (32) returns to the state of detecting the flow of mixed water, the control for opening the safety valve is also released, thereby again. The safety valve shuts off the bypass passage (28) and returns to the initial state.
[0015]
[Section 4]
In the above item 1 or 2,
`` A safety valve is provided to keep the warm water passage (14) open,
In the case where the abnormal signal is output, the safety valve is closed. '' If the mixed water flow sensor (32) is determined to be in an abnormal state, it is provided in the hot water passage (14). The safety valve thus closed is closed, whereby the hot water from the hot water supply device such as the solar water heater (5) is shut off. Thereby, only the cold water is supplied to the hot water heater (7) side without the hot water from the hot water supply device being mixed with the cold water from the cold water passage. Therefore, thereafter, the cold water is heated to the hot water supply set temperature and an appropriate hot water supply operation can be performed by the original function of the water heater (7) .
[0017]
【The invention's effect】
The present invention has the following specific effects.
In the first aspect of the invention, the operation of the mixed water flow sensor (32) is monitored by the hot water heater flow sensor, and the abnormality / normality of the mixed water flow sensor (32) can be determined.
When the mixed water flow sensor (32) is determined to be abnormal (when the flow sensor is abnormal), the chilled water passage (15) is set to the maximum opening degree while the hot water passage (14) is set to the minimum opening degree. The temperature of the mixed water is lowered. Therefore, there is no inconvenience that dangerous hot water is supplied to the hot water heater (7) side.
[0018]
In the invention of item 2, the fact that the mixed water flow sensor (32) is in an abnormal state can be notified by the remote controller for the water heater, and the necessity of repairing and inspecting the mixed water flow sensor (32) is urged. Can do.
[0019]
For items 3 and 4, when the mixed water flow sensor (32) is judged to be in an abnormal state, the danger of dangerous high-temperature water being supplied to the hot water heater (7) side is more reliably prevented. There are advantages you can do.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, the above-described embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram of a hot water supply system using a hot water mixing unit (1) for a hot water heater according to an embodiment of the present invention. The solar water heater (5) is hot water supplied via a hot water mixing unit (1) for a hot water heater. Pipe connected to vessel (7). Details of each part will be described below.
[0022]
[About solar water heater (5)]
The solar water heater (5) includes a heat storage pipe (52) formed so as to circulate between the heat collector (50) that absorbs solar heat and the hot water storage tank (51), and the heat storage pipe (52 ) Is provided with an expansion tank (53) and a circulation pump (54).
A water supply pipe (55) for supplying cold water from the water supply and a water drainage passage (58) having a water drain plug (57) are connected to the bottom of the hot water storage tank (51), and the hot water storage tank (51). An upstream hot water passage (56) is drawn from the top of the.
[0023]
[About water heater (7)]
The water heater (7) is composed of a water heater body (70) having a heat exchanger (69) heated by a gas burner (not shown) and water flowing into the heat exchanger (69) (a hot water mixing unit (1 A water heater flow sensor (78) for measuring the flow rate of the mixed water) and a water heater remote control (71) electrically connected to the water heater body (70), and the water heater remote control ( 71) includes an operation switch (72), a hot water switch (73) and a hot water temperature setting device (75) that are operated when hot water is filled in the bathtub (81), and the operating state of the water heater (7). A display section (74) for displaying is provided.
In addition, the water heater main body (70) and the bathtub (81) are connected by a forward pipe (82) and a return pipe (83) used for hot water filling and reheating, and further, a water heater main body A hot water tap (85) is provided in the hot water supply passage (84) drawn from (70).
[0024]
[About the hot water mixing unit (1) for water heaters]
The hot water mixing unit (1) for hot water heaters, which is the subject of the present invention, has a hot water pipe connection port (16) to which an upstream hot water passage (56) through which hot water from the solar water heater (5) flows is connected, as described above. A water supply pipe connection port (17) to which the water supply passage (10) branched from the solar water supply pipe (55) is connected, and a water heater connection port connected to the water inlet (77) of the water heater body (70). (18) is provided.
[0025]
In the hot water passage (14) formed on the downstream side of the hot water pipe connection port (16), a vacuum breaker (12), a check valve (13), and a hot water temperature sensor (19) are arranged in this order. It is arranged from the upstream side. Further, near the upstream end of the hot water passage (14), there is provided a water drain plug (21) having a function of removing dust in the water flow and a function of draining the passage.
[0026]
On the other hand, in the cold water passage (15), a check valve (22), a feed water temperature sensor (23), and a hot water mixer (20) are arranged in this order, and the hot water mixer (20) The hot water control valve (25) disposed at the junction of the hot water passage (14) and the cold water passage (15) and the cold water control valve (24) disposed in the cold water passage (15) on the upstream side thereof It consists of and. Then, the cold water control valve (24) and the hot water control valve (25) are arranged so that the valve bodies (241) and (251) at the front end are moved to the valve ports (26) (26) ( 27), the flow rate is adjusted by changing the opening degree of the valve ports (26) and (27). The bypass passage (28) drawn from between the feed water temperature sensor (23) and the hot water mixer (20) in the cold water passage (15) is a mixed water passage (29 )It is connected to the. The bypass passage (28) is provided with a normally-open electromagnetic valve (31) (a valve that is kept open when not energized) as a safety valve for opening and closing the bypass passage (28). The mixed water passage (29) is provided with a mixed water flow sensor (32) for measuring the mixed water flow rate, a mixed water temperature sensor (33), an overtemperature detection sensor (34), and a drain plug (35). The drain plug (35) also functions as a relief valve that opens when the water pressure in the mixed water passage (29) and the like is excessively increased to release the pressure. Further, near the upstream end of the cold water passage (15), a water drain plug (30) having both a dust removal function and a drainage function is provided.
[0027]
The hot water temperature sensor (19), feed water temperature sensor (23), hot water / water mixer (20), normally open solenoid valve (31), flow rate sensor for mixed water (32), mixed water temperature sensor (33), Electrical components such as the temperature rise detection sensor (34) are electrically connected to the control device (11), and the operation of the hot water / water mixer (20) is controlled by the control device (11).
[0028]
[Actual hot water operation]
Next, the operation of the hot water supply system will be described.
The control device (11) incorporated in the hot water mixing unit (1) for the water heater stores a microcomputer for executing the control operation shown in the flowchart of FIG. 2, and hereinafter, the hot water supply according to the present embodiment will be described. The operation of the system will be described with reference to the flowchart of FIG.
[0029]
First, when the operation switch (72) provided in the remote controller (71) for the hot water heater (7) of the water heater (7) is operated, the operation signal is controlled by the hot water mixing unit (1) for the water heater via the communication cable (79). This is sent to the device (11), thereby starting the control operation of FIG.
[0030]
Next, it is determined in step (ST1) whether or not the flow rate Q of the mixed water detected by the mixed water flow rate sensor (32) exceeds the base flow rate (2 liters / minute in the present embodiment). If the detected flow rate of the mixed water flow rate sensor (32) is less than the base flow rate, a step (ST2) corresponding to the abnormality determining means as the above-described invention specific matter is further executed. That is, in step (ST2), the mixed water flow rate sensor (32) outputs a detected flow rate “0” as a water flow stop signal, and the water heater flow rate sensor (78) detects a water flow (water flow). If it is confirmed that a presence signal is being output), error processing in steps (ST3) and (ST4) is performed. That is, in such a case, it is determined that the mixed water flow sensor (32) is in an abnormal state such as disconnection, and in step (ST3), the hot water control valve (25) is set to the minimum opening, and the cold water control valve (24) is turned on. In addition, the normally open solenoid valve (31) is kept open at the maximum opening. Accordingly, a large amount of cold water supplied from the water supply passage (10) is supplied from the cold water passage (15) and the bypass passage (28) to the mixed water passage (29). Therefore, dangerously high temperature water is prevented from being supplied to the hot water heater (7) from the hot water mixer (20), which has become unable to perform accurate control due to the mixed water flow sensor (32) being in an abnormal state. be able to. In step (ST4), a notification request signal for displaying on the display unit (74) of the water heater remote control (71) that the mixed water flow sensor (32) is in an abnormal state is sent to the communication cable (79 ) To the water heater remote controller (71). As a result, “flow rate sensor for mixed water: error” is displayed on the display section (74), and the necessity of repair / inspection of the flow rate sensor for mixed water (32) is urged. A signal for notifying the mixed water flow rate sensor (32) in an abnormal state by voice or the like may be transmitted to the water heater remote controller (71). Further, in the water heater (7) of the type in which the currant mark indicating that the tap faucet (85) has been opened is displayed on the display section (74) of the remote controller for water heater (71), a signal for displaying the curran mark is displayed. It may be handled as the signal with water flow.
[0031]
Next, control is returned to step (ST1) after step (ST4), and mixed water with a flow rate Q exceeding the basal flow rate flows by opening the tap tap (85) or turning on the hot water switch (73). If it is confirmed in step (ST1) that “flow sensor for mixed water: error” is displayed on the display section (74) of the remote controller for hot water supply (71), the display is deleted (step (See ST5).
[0032]
Next, it is determined whether or not a water passage signal from the water heater flow sensor (78) is transmitted from the communication cable (79) to the control device (11) (see step (ST6)). If the presence signal is not received (if no water stop signal is output from the water heater flow sensor (78)), the water heater flow sensor (69) is in an abnormal state in step (ST7). A notification request signal to be displayed on the display section (74) of the water heater remote control (71) is transmitted from the communication cable (79) to the water heater remote control (71). Thereby, “flow rate sensor for hot water heater: error” is displayed on the display section (74), and the necessity of repair / inspection of the flow sensor for hot water heater (69) is urged. It should be noted that a signal for notifying that the flow rate sensor for water heater (69) is in an abnormal state by voice or the like may be transmitted to the remote controller for water heater (71). On the other hand, if it is determined in step (ST6) that the water heater flow sensor (69) is outputting a water flow detection signal, the display (74) of the water heater remote control (71) will indicate “Water heater flow sensor: Error”. If "" is displayed, the display is deleted (see step (ST8)).
[0033]
Next, whether or not the detected temperature of the hot water temperature sensor (19) is lower than the set temperature S set by the hot water temperature setting device (75) after the normally open solenoid valve (31) is closed in step (ST9). Is determined in step (ST10).
[0034]
When the detected temperature of the hot water temperature sensor (19) is lower than the set temperature S, the mixed water of the flow rate Q determined from the output of the mixed water flow sensor (32) is changed to the minimum combustion amount (the lower limit combustion amount of the gas burner). ) Is calculated (step (ST11)). That is, when the heat generation amount of the water heater (7) operating at the minimum combustion amount is the minimum heat generation amount Wmin, the minimum rise temperature ΔT = the minimum heat generation amount Wmin / flow rate Q is calculated.
[0035]
When the minimum rise temperature ΔT is calculated, the mixed water (discharge of the hot water mixer (20) is reduced to the mixing target temperature MT that is lower than the set temperature S set by the hot water temperature setter (75) by the minimum rise temperature ΔT. If the temperature of water) can be adjusted, it can be seen that the temperature of the hot water flowing out of the water heater (7) operating at the minimum combustion amount becomes the set temperature S set by the hot water temperature setter (75). Therefore, in step (ST12), the mixing target temperature MT = the set temperature S−the minimum rise temperature ΔT is calculated.
[0036]
Next, when the detected temperature of the hot water temperature sensor (19) is equal to or lower than the calculated mixing target temperature MT, the control shifts from step (ST13) to step (ST14) and the cold water is mixed from the cold water passage (15). The hot and cold water mixer (20) is controlled so that the ratio is minimized. That is, the opening degree of the cold water control valve (24) constituting the hot water mixer (20) is set to the minimum and the hot water control valve (25) is fully opened. Then, hot water below the mixing target temperature MT is supplied from the mixed water passage (29) of the hot water mixing unit for hot water heater (1) to the water heater main body (70), and the hot water is set by the hot water temperature setting device (75). The temperature of the water heater body (70) is raised to the set temperature S, and the hot water is supplied to the hot water tap (85) and the bathtub (81).
[0037]
On the other hand, when the detected temperature of the hot water temperature sensor (19) exceeds the mixing target temperature MT when the above step (ST13) is executed, the steps (ST15) to (ST17) are executed. The opening degree of the cold water control valve (24) and the hot water control valve (25) of the hot water mixer (20) is adjusted so that the temperature of the mixed water mixed in the mixer (20) becomes the mixing target temperature MT. . That is, the temperature of the mixed water flowing out from the hot water mixer (20) is monitored by the mixed water temperature sensor (33), and if the detected temperature of the mixed water temperature sensor (33) exceeds the above mixing target temperature MT, step (ST16) The degree of opening of the cold water control valve (24) and the hot water control valve (25) is adjusted so that the mixing ratio of the hot water from the hot water passage (14) decreases. When the detected temperature of the mixed water temperature sensor (33) is lower than the above mixing target temperature MT, in step (ST17) the chilled water control valve (24) or hot water is adjusted so that the mixing ratio of hot water from the hot water passage (14) increases. The opening degree of the control valve (25) is adjusted.
[0038]
Thereby, the mixed water of the mixing target temperature MT is supplied from the hot water mixing unit for hot water heater (1) to the hot water heater (7). Then, the gas burner incorporated in the water heater (7) burns with the minimum combustion amount, and as a result, the mixed water at the above mixing target temperature MT is heated and heated by the minimum rise temperature ΔT in the water heater (7). Hot water of S is supplied to the hot water tap (85) and the bathtub (81).
[0039]
On the other hand, if the detected temperature of the hot water temperature sensor (19) is equal to or higher than the set temperature S when the above-described step (ST10) is executed, steps (ST18) to (ST20) are executed. The opening degree of the cold water control valve (24) and the hot water control valve (25) of the hot water mixer (20) is adjusted so that the temperature of the mixed water mixed in the water tank (20) becomes the set temperature S.
[0040]
That is, the temperature of the mixed water flowing out of the hot water mixer (20) is monitored by the mixed water temperature sensor (33), and if the detected temperature of the mixed water temperature sensor (33) exceeds the set temperature S, the step (ST20) The opening degree of the cold water control valve (24) and the hot water control valve (25) is adjusted so that the mixing ratio of the hot water from the hot water passage (14) decreases. If the detected temperature of the mixed water temperature sensor (33) is lower than the set temperature S, the chilled water control valve (24) or the hot water control is adjusted so that the mixing ratio of the hot water from the hot water passage (14) increases in step (ST19). The opening of the valve (25) is adjusted. Thus, the mixed water having the set temperature S is supplied from the hot water mixing unit for hot water supply (1) to the hot water supply (7) (18) and the hot water tap (85).
[0041]
In the present embodiment, the normally open solenoid valve (31) provided in the bypass passage (28) of the hot water mixing unit (1) for the water heater is fully opened when an abnormal state such as a power failure occurs during hot water supply. Thereby, a large amount of cold water flows from the bypass passage (28) into the mixed water passage (29). Therefore, there is no fear that hot water having a risk of burns or the like is supplied to the hot water tap (85) or the bathtub (81).
[0042]
[Other]
(1) Without providing the bypass passage (28), a normally closed solenoid valve, which is a safety valve that maintains a closed state in a non-energized state, is disposed in the hot water passage (14), and the normally closed solenoid valve is placed in the step ( It is possible to prevent the hot water from being supplied to the hot water heater (7) side by performing the closing operation at ST3).
(2) As the hot water supply device, in addition to the solar water heater (5) using natural energy, a hot water supply device using various waste heats can be applied.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a hot water supply system illustrating an embodiment of the present invention. FIG. 2 is an operation explanatory diagram of a hot water mixing unit (1) for a water heater according to an embodiment of the present invention. Figure [Explanation of symbols]
(1) ... Solar connection unit
(5) ・ ・ ・ Solar water heater
(7) ... Water heater (7)
(14) ... Hot water passage (14)
(15) ... Cold water passage (15)
(19) ... Hot water temperature sensor
(20) ... Hot water mixer (20)
(29) ・ ・ ・ Mixed water passage

Claims (4)

A mixed water passage extending from the junction where the cold water passage (15) through which cold water from the water supply flows and the hot water passage (14) through which hot water from the hot water supply device joins is connected to the downstream water heater (7) by piping. (29) and
A mixed water temperature sensor (33) and a mixed water flow sensor (32) disposed in the mixed water passage (29);
Hot water that adjusts the mixing ratio of the hot water and the cold water so that the detected temperature of the mixed water temperature sensor (33) matches the target mixing temperature that is set and changed based on the detected flow rate of the mixed water flow sensor (32). In a solar connection unit comprising a mixer (20),
Under the condition that the flow rate sensor for mixed water (32) outputs a flow stop signal, the flow rate sensor for water heater (78) detects the flow of the mixed water in the water heater (7). When the flow rate sensor is being transmitted via a communication cable, the abnormality determination means for outputting an abnormal signal indicating that the mixed water flow rate sensor (32) is abnormal is provided.
When the flow sensor is abnormal , the hot water / water mixing unit for the hot water heater sets the cold water passage (15) to the maximum opening degree while the hot water passage (14) is set to the minimum opening degree by the hot water / water mixer (20) . In the hot water mixing unit for hot water heaters according to claim 1,
When the abnormal signal is output, a notification request signal for notifying the remote controller for the water heater of the water heater (7) that the flow rate sensor for mixed water (32) is in an abnormal state is sent to the communication cable. A hot water / water mixing unit for a water heater, comprising means for delivering. In the hot water mixing unit for hot water heater according to claim 1 or claim 2,
A bypass passage (28) connecting the portion located in the middle of the cold water passage (15) and upstream of the hot water mixer (20) and the mixed water passage mixed water passage (29);
Provide a safety valve to keep the bypass passage (28) closed,
A hot water mixing unit for a water heater that opens the safety valve when the abnormal signal is output. In the hot water mixing unit for hot water heater according to claim 1 or claim 2,
Provide a safety valve to keep the warm water passage (14) open,
A hot water mixing unit for a water heater that closes the safety valve when the abnormal signal is output.

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