JP2003090608A - Hot water/water mixing unit for hot water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly supply low temperature water to a purposed position when operation of supplying the low temperature water is re-opened after it is temporarily interrupted, in a hot water/water mixing unit for a hot water supplier in which it includes a mixed water circuit (29) which is communicated to a hot water supplier connection port (18) from the junction of a cold water circuit (15) and a warm water circuit (14), and on which a mixed water temperature sensor (33) is provided; and a hot water/water mixer (20) for adjusting a mixing ratio of the warm water and cold water from the cold water circuit (15), wherein, when there is not on a low temperature water switch (953) operated upon the low temperature water being supplied to the purposed position from a hot water supplier (7) in the state where a gas burner of the hot water supplier (7) is extinguished, mixed water at hot water supply set temperature is forced to flow out from the hot water/water mixer (20), while when the low temperature water switch (953) is turned on, low temperature water is forced to flow out from the hot water/water mixer (20). SOLUTION: After the foregoing low temperature water switch (953) is turned on, low temperature water is forced to flow out until there is outputted from the side of the hot water supplier (7) a signal indicative of the low temperature water having been supplied by a set amount or over a set time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply unit for connecting a hot water supply device utilizing natural energy such as a solar water heater or a hot water supply device utilizing various kinds of waste heat to a water heater. It is a thing.

[0002]

2. Description of the Related Art A solar water heater has a hot water supply system in which hot water of a desired temperature cannot be taken out due to the weather or the like, so that a water heater is connected as an auxiliary heat source to enable effective use of energy resources. There is, for example, the one described in FIG. The upstream hot water circuit (56) drawn out from the solar water heater (5) is connected to the hot water circuit (14) of the hot water mixing unit (1) for a water heater.

The water supply circuit (10) connected to the water supply system is the cold water circuit (1) of the hot and cold water mixing unit (1) for water heaters which is the subject of the present invention.
A hot water mixer (20) is provided at the confluence of the cold water circuit (15) and the hot water circuit (14) while being connected to the hot water mixer (20). A mixed water temperature sensor (33) is provided in the mixed water circuit (29) formed on the downstream side.
The mixed water circuit (29) is connected to the water inlet (77) of the water heater (7) by piping, and the hot water outlet (7) taps the tap (85).
Hot water is supplied to the bathtub (81).

In this case, when the hot water supply temperature is set by the remote control device (71) for the hot water supply device (7), the set temperature (hereinafter referred to as "hot water supply set temperature") is set to the hot water supply water mixing unit (1). ) Unit controller (11). In this state, for example, when the hot water tap (85) is opened, the hot water mixer (20) operates to adjust the mixing ratio of hot water from the solar water heater (5) and cold water from the water supply circuit (10). , This allows
The temperature of the mixed water detected by the mixed water temperature sensor (33) is matched with the hot water supply set temperature. Then, the mixed water flowing out of the hot water / water mixing unit (1) for a water heater is supplied to the hot water tap (85) via the water heater (7) maintained in the combustion stopped state.

On the other hand, for example, when a low temperature water switch (not shown) provided in the remote control device (71) is turned on in order to perform the water supply (the operation of warming the bath water in the bathtub (81)), the remote control device The low-temperature water request signal output from the (71) is transmitted to the unit controller (11) of the hot-water mixing unit (1) for water heaters, and the unit controller (11) causes the hot-water mixer ( 20) is controlled so that the hot water mixer (20) fully opens the opening on the cold water circuit (15) side.
On the other hand, the water heater (7) is maintained in a fire extinguishing state due to the low temperature request signal, which causes the hot water mixing unit for the water heater.
The low-temperature water flowing out from (1) is supplied to the bathtub (81) as it is without being heated by the water heater (7), and the water supply operation proceeds, whereby the temperature inside the bathtub (81) decreases.

[0006]

However, in the above-mentioned conventional apparatus, when the hot water supply operation for opening the hot water tap (85) is performed during the water supply operation, the water heater responds to the hot water supply operation.
A hot water request signal is output from (7) and is transmitted to the unit controller (11) of the hot water mixing unit (1) for a water heater. Then, the hot water mixer (20) is controlled by the unit controller (11) so that the mixed water of the hot water supply set temperature set by the remote control device (71) flows out, while the hot water tap (85) is closed. Up to this, the water supply operation is temporarily interrupted, and after the hot water tap (85) is closed, the water supply operation is restarted. Therefore, at the initial stage of restarting the water supply operation, during the hot water supply operation, the water heater / hot water mixing unit (1) moves the water heater (7).
There was a problem in that the hot water of the set temperature for hot water supply filled in the connection pipe (79) connected to the tank flows into the bathtub (81), and the temperature in the bathtub (81) does not drop rapidly.

The present invention has been made in view of the above-mentioned point. "The chilled water circuit whose upstream end is a water supply pipe connecting port connected to a water supply circuit through which chilled water flows and the upstream end from a hot water supply device are provided. A hot water circuit serving as a hot water pipe connection port connected to an upstream hot water circuit through which hot water flows, and a mixed water temperature sensor that is connected from a confluence point of the cold water circuit and the hot water circuit to a water heater connection port on the downstream side thereof are provided. A mixed water circuit, and a hot and cold water mixer for adjusting the mixing ratio of the cold water and the hot water at the confluence, and the gas burner of the water heater connected to the water heater connection port is extinguished in a state of being extinguished. When the low temperature water switch operated when supplying low temperature water from the water heater to the destination is not turned on, the hot water mixer is controlled so that the temperature detected by the mixed water temperature sensor becomes equal to the hot water set temperature of the water heater. It That one, the cold water switch is ON
When the hot water mixer is controlled so that the low temperature water lower than the hot water set temperature can be supplied to the mixed water circuit when operated, the low temperature water from the water heater to the target location When the operation of supplying water is resumed after being temporarily interrupted, it is an object of the invention to enable the low temperature water to be rapidly supplied to a destination.

[0008]

[Means for Solving the Problem] [1] The technical means of the present invention for solving the above-mentioned problem is, “After the low-temperature water switch is turned on, the low-temperature water is delivered to the destination. The hot water mixer is controlled so that the low temperature water can be supplied to the mixed water circuit until a signal indicating that the supply of the set amount or the set time has been completed is output from the water heater side. .

The above technical means operates as follows. When the low-temperature water switch is operated, the low-temperature water flowing out from the hot-water mixer is supplied to the target location such as a bathtub as it is without being heated by the water heater as in the conventional one.

When the water heater starts the hot water supply operation while supplying the low-temperature water, the hot-water mixer of the hot-water mixing unit for the water heater of the present invention continues to supply the low-temperature water to the downstream side. This is because the hot-water mixer is configured to continue mixing the low-temperature water until a signal indicating that the low-temperature water has been supplied to the destination at the set amount or for the set time is output from the water heater side. As a result, the low-temperature water is maintained in the connection pipe connecting the hot water / water mixing unit for a water heater of the present invention and the water heater even during the hot water supply operation.

During the hot water supply operation, the low temperature water supplied from the hot water mixer is heated up to the hot water supply set temperature by the original function of the water heater connected to the hot water supply connection port to be supplied. .

When the hot water supply operation is completed, the low-temperature water filled in the connecting pipe connecting the hot-water mixing unit for the water heater and the water heater of the present invention is quickly supplied to the water heater, and the low-temperature water is supplied to the destination. Operation is restarted.

[2] In the above item 1, the low temperature water is
It may be mixed water that flows out from the hot / cold water mixer when the mixing ratio of cold water is maximized, but "the destination is in the bathtub (81) of the bathroom, and the temperature of the low temperature water is 30 ° C or lower. (Please check) is the set temperature ”.

By doing so, even if the temperature of the cold water supplied from the water supply changes due to the change of seasons, the low temperature water of the set temperature is supplied to the bathtub (81). Therefore, the bather can empirically predict the rate at which the temperature inside the bathtub (81) will drop with a single watering operation, improving usability.

[0015]

The present invention, having the above-mentioned structure, has the following unique effects. Even when the operation of supplying low-temperature water to the hot-water supply place is interrupted and the hot-water supply operation is performed, the low temperature water is maintained in the connection pipe connecting the hot-water mixing unit for the water heater and the water heater. Therefore, when the operation of supplying the low-temperature water to the destination is restarted, the low-temperature water filled in the connection pipe connecting the hot-water mixing unit for the water heater and the water heater of the present invention is supplied to the water heater, and the low-temperature water is supplied to the destination. Can be quickly supplied.

In the item of item 2, as described above, the bather can empirically predict the rate at which the temperature in the bathtub (81) will drop by one watering operation regardless of the season. This makes it possible to provide a hot water mixing unit for a water heater that is easy to use.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the embodiments of the present invention described above 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 / water mixing unit (1) for a water heater according to an embodiment of the present invention, in which a solar water heater (5) supplies hot water through the hot water / water mixing unit (1) for a water heater. It is piped to the vessel (7). The details of each unit will be described below. [About solar water heater (5)] The solar water heater (5) includes a heat storage pipe (52) formed so as to circulate between a heat collector (50) that absorbs solar heat and a hot water storage tank (51). The heat storage pipe (52) is provided with an expansion tank (53) and a circulation pump (54).

Further, the bottom of the hot water storage tank (51) is connected to a water supply pipe (55) for solar water for supplying cold water from a water pipe and a drain circuit (58) having a drain plug (57), An upstream hot water circuit (56) is drawn out from the top of the hot water storage tank (51).

[About the water heater (7)] In the water heater body (70) of the water heater (7), the water amount sensor (62), the hot water heat exchanger (61) and the hot water temperature sensor (64) are arranged in this order. A water passage (63) is provided sequentially from the upstream side, and a hot water tap (85) is provided in the hot water supply passage (65) drawn from the water passage (63) to the downstream side. ing. The hot water supply gas burner (66) for heating the hot water supply heat exchanger (61) is supplied with gas from the hot water supply gas valve (67).

Further, the reheating circuit (69) formed so as to circulate in the water heater body (70) and the bathtub (81) has a circulation pump (91).
And a heat exchanger (68) for bath, and the reheating circuit (69) is equipped with a water filling valve (42).
It is connected to the above waterway (63) via 1). Furthermore, a gas burner (92) for reheating that heats the bath heat exchanger (68)
A gas valve (93) for reheating is provided in the gas circuit to the.

Further, the hot water supply controller (90) built in the water heater main body (70) includes a main remote controller installed in the kitchen.
(94) and a bath remote control device (95) arranged in the bathroom are connected via a communication cable (78). The main remote control device (94) includes an operation switch (940) that is turned on when operating the water heater (7), a hot water temperature setting device (941) that sets the hot water set temperature, and a bathtub (81). A water filling switch (944) that is turned on when filling water to the set water level is provided. On the other hand, the bath remote control device (95) is provided with an operation switch (950), a hot water supply temperature setting device (951), and a water filling switch (954) as in the main remote control device (94). (81) A reheating switch (952) to be thrown in when reheating the inside, and a low temperature water switch (5) to be thrown in when pouring a set amount (for example, 10 liters) of low temperature water into the bathtub (81). 953) is provided.

[About hot-water mixing unit (1) for water heater]
The hot and cold water mixing unit (1) for a water heater as an object of the present invention,
The hot water pipe connection port (16) to which the upstream hot water circuit (56) in which hot water from the solar water heater (5) flows is connected, and the water supply circuit (10) branched from the above-mentioned solar water supply pipe (55). The water supply pipe connection port (17) to be connected, and the water inlet (7
A water heater connection port (18) connected to 7) is provided.

The hot water circuit (14) formed on the downstream side of the hot water pipe connection port (16) has a vacuum breaker (120),
Normally closed solenoid valve (31), check valve (13), and hot water temperature sensor (1
9) are arranged in this order from the upstream side. Further, near the upstream end of the hot water circuit (14), a water drain plug (21) having both a function of removing dust in the water flow and a function of draining the circuit is provided.

On the other hand, in the cold water circuit (15), the check valve (22), the feed water temperature sensor (23), and the hot water mixer (20) are arranged in this order, and the hot water mixer ( 20) is the hot water circuit (14)
And a cold water control valve (25) arranged at the confluence of the cold water circuit (15) and a cold water control valve (24) arranged in the cold water circuit (15) on the upstream side. . Then, the cold water control valve (24) and the hot water control valve (25), the corresponding pulse motor (240) (250) by the rotation of the tip valve body (241) (251) valve opening (26) ( 27), which results in valve openings (26) (27)
The flow rate is adjusted by changing the opening degree of.

In the mixed water circuit (29), a water amount sensor (32) for measuring the flow rate of the mixed water, a mixed water temperature sensor (33),
An abnormality monitoring sensor (34) and a water drain plug (35) are further provided.The water drain plug (35) opens when the water pressure in the mixed water circuit (29) or the like rises excessively. It also has a relief valve function to open the. Further, near the upstream end of the cold water circuit (15), a water drain plug (30) having both a dust removing function and a draining function for water passage is provided.

The hot water temperature sensor (19), the water supply temperature sensor (23), the hot water mixer (20), the normally closed solenoid valve (31), and the water amount sensor
Electrical components such as (32), mixed water temperature sensor (33) and abnormality monitoring sensor (34) are electrically connected to the unit controller (11), and the unit controller (11) allows the hot water mixer (20).
The operation of is controlled.

[Actual Operation] Next, the operation of the hot water supply system will be described. The unit controller (11) incorporated in the hot and cold water mixing unit (1) for a water heater stores a microcomputer that executes the control operation shown in the flowchart of FIG. The operation of the hot water supply system incorporating the hot and cold water mixing unit (1) for a water heater will be described separately for the water supply operation and the hot water supply operation with reference to the flowchart of FIG.

<Water Supply Operation> First, a signal indicating whether or not the operation switches (940) and (950) provided on the main remote controller (94) of the water heater (7) and the bath remote controller (95) are operated. Is transmitted from the water heater body (70) via the communication cable (78) to the unit controller (11) of the hot water mixing unit (1) for the water heater in step (ST1), and the above signal is controlled by the unit. Until it is sent to the device (11), the normally closed solenoid valve (3
Keep 1) closed (see step (ST2)).

When it is confirmed in step (ST1) that the operation switches (940) (950) are operated, the mixed water detected by the water amount sensor (32) provided in the hot water mixing unit (1) for the water heater is detected. It is determined in step (ST3) whether or not the flow rate Q exceeds the base flow rate (2 liters / minute in the present embodiment).

In this case, when the low-temperature water switch (953) of the bath remote control device (95) is turned on to fill the bathtub (81), the water filling valve (42) is opened to open the base. Water that exceeds the flow rate is a water channel (63) → a connection channel for hot water filling (41) →
It flows in the route that connects the reheating circuit (69) and the bathtub (81). Therefore, in this case, the mixed water having the flow rate Q exceeding the base flow rate flows into the mixed water circuit (29) of the hot water mixing unit (1) for the water heater. Therefore, the normally closed solenoid valve (31) is opened in step (ST4) based on the output of the water amount sensor (32) for detecting the flow rate Q. When the low temperature water switch (953) is turned on, the hot water supply gas burner (66) of the hot water supply device (7) is maintained in a fire extinguishing state.

Next, it is judged in step (ST5) whether or not the low temperature water switch (953) is turned on. Specifically, it is determined whether or not a signal indicating that the low temperature water switch (953) has been turned on is transmitted to the unit controller (11) via the communication cable (78). When it is confirmed in step (ST5) that the ON operation has been performed,
Mixing target temperature MT of the mixed water to be mixed in the hot water mixer (20)
Is set to 25 ° C. (see step (ST6)).

Next, in steps (ST7) to (ST9), the operation of the hot water mixer (20) is controlled so that the temperature detected by the mixed water temperature sensor (33) coincides with the target mixing temperature MT. That is, when the mixed water temperature detected by the mixed water temperature sensor (33) is lower than the mixed target temperature MT, steps (ST7) to (ST8)
The opening degree of the hot water control valve (25) and the cold water control valve (24) is adjusted to increase the mixing ratio of hot water in the mixed water flowing through the mixed water circuit (29), while the mixed water temperature is increased. If the above is higher than the mixed target temperature MT, step (ST7)
To Step (ST9), the opening degree of the hot water control valve (25) and the cold water control valve (24) are adjusted to reduce the mixing ratio of the hot water.

As a result, in the hot water mixer (20), the low temperature water adjusted to the target mixing temperature MT of 25 ° C. is supplied from the connecting pipe (79) to the water heater (7), and the low temperature water is also supplied. However, water passage (63) → hot water connection (41) → reheating circuit (69)
→ A set amount (10 liters is set in the present embodiment) is supplied to the bathtub (81) through a path connected to the bathtub (81). As a result, the inside of the bathtub (81) becomes slimy.

In this embodiment, the solar water heater (5)
2 obtained by mixing warm water from the water with cold water from the water supply circuit (10)
The mixed water of 5 ℃ is supplied to the bathtub (81), and the water supply circuit (10)
Do not supply cold water from the bathtub (81) only. This is because even if the temperature of the cold water supplied from the solar water supply pipe (55) changes due to seasonal changes, it is always 25 ° C.
This is because the low temperature water is supplied to the bathtub (81) so that the degree of temperature decrease in the bathtub (81) by one watering operation is substantially constant throughout the season.
This makes it possible to empirically predict the degree to which the temperature inside the bathtub (81) will drop due to a single water supply.
Further, by utilizing the hot water from the solar water heater (5), the effect that the thermal energy of the solar water heater (5) can be utilized can be obtained. Next, a case will be described in which the hot water tap (85) is opened (when hot water is supplied) during the water supply operation of supplying low temperature water of 25 ° C. to the bathtub (81).

When the tap water tap (85) is opened during the water supply operation, the flow rate detected by the water amount sensor (62) increases. Then, the hot water supply control device (90) of the hot water supply device (7) that detects the increase in the flow rate closes the water filling valve (42) to temporarily interrupt the water supply operation, and the hot water supply gas burner (66). Start burning.
As a result, the hot water of the hot water supply set temperature set by the hot water supply temperature setting devices (941) (951) of the main remote control device (94) and the bath remote control device (95) can be boiled at the hot water supply heat exchanger (61) part. The combustion amount of the hot water gas burner (66) is controlled.

On the other hand, the unit controller (11) of the hot water / water mixing unit (1) for the water heater sets the mixing target temperature MT unless the end signal of the water supply operation is received from the water heater (7) side in step (ST10). It is configured so that the step (ST11) for changing to the hot water supply set temperature (the temperature set by the hot water supply temperature setting device (941) (951) of the main remote control device (94) and the bath remote control device (95) is not executed. There is. Therefore, even if the hot water tap (85) is opened during the water supply operation, the hot water mixer (20) remains at the above 25 ° C.
Will continue to supply low temperature water to the water heater (7). Therefore, the connection pipe (79) connecting the hot water mixing unit (1) for the water heater and the water heater (7) is kept filled with the low temperature water of 25 ° C.

Then, when the tap water tap (85) is closed and the detected flow rate of the water amount sensor (62) becomes "0", the water heater (7) keeps the hot water gas burner (66) in a fire extinguished state. The tension valve (42) is opened to restart the water supply operation, whereby the low temperature water of 25 ° C. filled in the connecting pipe (79) is supplied to the bath (81) side. Therefore, even when the length L of the connecting pipe (79) is large, when the connecting pipe (79) is filled with hot water at the hot water supply set temperature (when the hot water at the hot water supply set temperature is interrupted when the water supply operation is interrupted, Compared with the case of flowing out from the hot water mixer (20), low temperature water can be quickly supplied to the bathtub (81). Then, the sum of the amount of low-temperature water supplied to the bathtub (81) before interruption of the water-feeding operation and the amount of low-temperature water supplied to the bathtub (81) after restarting the water-feeding operation is a constant amount (10 in the present embodiment). The water filling valve (42) is maintained in the open state until the water filling valve (42) is set, and then the water filling valve (42) is closed and the water supply operation is completed (10 liters of low temperature water). A signal indicating that the supply of water to the bathtub (81) has been completed (an end signal of the water supply operation) is transmitted from the hot water supply control device (90) to the unit control device (11).

Then, the unit controller (11) of the hot and cold water mixing unit (1) for the water heater confirms the end signal of the above-mentioned water supply operation in step (ST10) of FIG. 2, and thereby the main remote controller (94). And, the hot water supply temperature set by the hot water supply temperature setting device (941) (951) of the bath remote control device (95) is stored again as the mixing target temperature MT (see step (ST11)). After that, the control operation is returned to step (ST1).

<Hot water supply operation> When the hot water tap (85) is opened while the control is returned to the step (ST1) and the low temperature water switch (953) is not operated, the hot water mixing unit for the water heater. The detected flow rate Q of the water quantity sensor (32) of (1) becomes more than the base flow rate. Also, when the water filling valve (42) of the water heater (7) is opened by turning on the water filling switches (944) (954) of the main remote controller (94) or bath remote controller (95), The detected flow rate Q of the sensor (32) becomes equal to or higher than the base flow rate.

Then, in step (ST12), the hot water supply set temperature set by the hot water supply temperature setting devices (941) (951) of the main remote control device (94) and the bath remote control device (95) is set as the mixing target temperature MT. Remember. In this state, step (ST7) ~ (ST
8) is executed, whereby mixed water having the mixing target temperature MT is supplied from the hot water mixer (20) to the hot water supply device (7).

When the reheating switch (952) provided in the bath remote control device (95) is turned on, the reheating gas burner (92) burns and the reheating pump (91) operates to activate the bathtub (91). Bath water in 81) is heated.

[Other]. In the above embodiment, the low temperature water switch (953) is turned on.
The low-temperature water set to 25 ° C. was supplied from the water heater (7) to the bathtub (81) during the operated water supply operation, but the hot water control valve (25) of the hot water mixer (20) was supplied during the water supply operation. ) Is maintained at the minimum opening, while the cold water control valve (24) may be maintained at the maximum opening.

.. In the above embodiment, the solar water heater (5) that uses natural energy is adopted as the hot water supply device, but in addition to the solar water heater (5), various hot water supply devices that use various waste heat are adopted. can do.

.. In the above embodiment, 10 liters of low temperature water is supplied to the bathtub (81) during the water supply operation, but low temperature water may be supplied to the bathtub (81) for a set time.

.. In the above embodiment, the low temperature water is supplied to the bathtub (81) during the water supply operation, but the low temperature water for washing may be supplied to the washing machine during the water supply operation. In this case, the washing machine is the destination of low temperature water supply.

.. The mixing target temperature MT of the mixed water to be mixed in the hot water mixer (20) during the water supply operation is not limited to 25 ° C. as described above, but may be 30 ° C. or less. Further, by setting the hot water control valve (25) of the hot water mixer (20) to the minimum opening and the cold water control valve (24) to the maximum opening, the cold water in the cold water circuit is used as the low temperature water in the bathtub ( Water may be added to 81).

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a hot water supply system including a hot and cold water mixing unit (1) for a water heater according to an embodiment of the present invention.

[Fig. 2] Operation explanatory diagram of the hot and cold water mixing unit (1) for a water heater

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

(10) ・ ・ ・ Water supply circuit (14) ・ ・ ・ Hot water circuit (15) ・ ・ ・ Cold water circuit (16) ・ ・ ・ Hot water pipe connection port (17) ・ ・ ・ Water supply pipe connection port (18) ・ ・ ・ Water heater connection port (20) ・ ・ ・ Hot water mixer (29) ・ ・ ・ Mixed water circuit (56) ... Upstream side hot water circuit (953) ・ ・ ・ Low temperature water switch

Continued front page    (72) Inventor Masakazu Ando             Rinnai 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi             Within the corporation (72) Inventor Yukihiro Suzuki             Rinnai 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi             Within the corporation

Claims (2)

[Claims] 1. A cold water circuit having an upstream end serving as a water supply pipe connecting port connected to a water supply circuit through which cold water flows, and a hot water pipe connection having an upstream end connected to an upstream hot water circuit through which hot water from a hot water supply device flows. The hot water circuit that became the mouth, the mixed water circuit that is connected to the water heater connection port on the downstream side from the confluence point of the cold water circuit and the hot water circuit, and the mixed water temperature sensor is provided, and the cold water at the confluence point A hot water mixer for adjusting the mixing ratio of hot water and hot water, and is operated when the low temperature water is supplied from the water heater to the destination with the gas burner of the water heater connected to the water heater connection port extinguished. When the low temperature water switch is not turned on, the hot water mixer is controlled so that the temperature detected by the mixed water temperature sensor becomes equal to the hot water supply set temperature of the water heater, while the low temperature water switch is turned on. In the case of a hot water mixing unit for a water heater in which the hot water mixer is controlled so that low temperature water lower than the hot water setting temperature can be supplied to the mixed water circuit, after the low temperature water switch is turned ON, Until a signal indicating that the low temperature water has been supplied to the destination at the set amount or for the set time is output from the water heater side,
A hot and cold water mixing unit for a water heater, wherein the hot and cold water mixer is controlled so that the low temperature water can be supplied to the mixed water circuit. 2. The hot-water / hot-water mixing unit for a water heater according to claim 1, wherein the destination is a bathtub in a bathroom, and the temperature of the low-temperature water is a set temperature lower than 30 ° C. Mixing unit.