JP2914865B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater for heating water in a combustor.

[0002]

2. Description of the Related Art Conventionally, the following water heaters are known. The water heater is composed of a heat exchange channel consisting of a water supply pipe, a heat exchanger, and a tapping pipe, a water tap attached to the outlet of the tapping pipe, a water flow sensor that detects the amount of water flowing through the heat exchange water path, and a heat exchange. A gas burner for heating the heater, a thermistor for detecting tap water temperature and supply water temperature, a proportional valve for controlling the amount of gas supplied to the gas burner, a water amount control device for controlling the amount of water flowing to the heat exchange water channel, and a detection of supply water temperature The apparatus includes a main body side microcomputer for controlling the proportional valve and the water amount control device so that the tap water temperature is maintained at the set temperature based on the water amount, and a hot water temperature indicator for displaying the set temperature. The set temperature is set by a remote controller connected by a communication line.

[0003]

However, the above-mentioned conventional water heater has the following problems. When the water supply temperature is high (for example, 25 ° C.) and the set temperature is low (for example, 37 ° C.), when the discharge amount of the hot water becomes small (for example, 3 liters per minute), the water heater can reduce the calorific value of the gas burner. The state (1) cannot be achieved, and the temperature of the discharged hot water becomes higher than the set temperature. In this state, hot water at a desired temperature cannot be obtained, and the user feels discomfort.

[0004] It is an object of the present invention to provide a water heater in which hot water at a substantially set temperature is obtained when the capacity is insufficient.

[0005]

In order to solve the above-mentioned problems,
The present invention employs the following configuration. (1) a water supply pipe-a heat exchanger-a heat exchange water passage formed by connecting a tapping pipe, a hot water tap provided at an outlet of the tapping pipe, a water flow sensor for detecting a water flow amount flowing through the heat exchange water passage, A combustor that heats the heat exchanger, a feedwater temperature sensor that detects a feedwater temperature, a tap water temperature sensor that detects a tap water temperature, and a calorific value of the combustor, the amount of water, or both the calorific value and the amount of water. An actuator to be operated and a microcontroller for controlling the actuator so that the combustor is brought into a combustion state when the detected water amount is equal to or more than a predetermined value and the tapping temperature is maintained at a set temperature based on the detected supply water temperature and the detected water amount. A water heater comprising: a microcomputer;
Is the predetermined value based on the set temperature and the detected feedwater temperature.
And the detected outlet temperature is set to the set temperature.
If the temperature exceeds the set value, the detected hot water temperature falls below the set temperature.
The combustion of the combustor is stopped until the temperature decreases .

(2) A water supply pipe-a heat exchanger pipe having a heat exchanger-a tapping pipe; a hot water supply passage provided at an outlet of the tapping pipe; and a water supply pipe or tapping water. A water amount sensor that detects the amount of water flowing through the pipe, a combustor that heats the heat exchanger, a water supply temperature sensor that detects a water supply temperature, a water supply temperature sensor that detects a water supply temperature, and a water amount that passes through the water supply pipe;
An actuator for controlling the ratio of the amount of heat exchange water passing through the heat exchanger and the amount of bypass water reaching the tapping pipe through the bypass pipe, and an actuator for operating the heat generation amount of the combustor; with the combustor to the combustion state based on the detection sheet temperature and the detection amount of water, in a water heater comprising a body-side microcomputer for controlling said actuator so as to hot water temperature is maintained at the set temperature, the microcomputer , The set temperature and
The predetermined value is determined based on the supply and discharge water temperature, and when the detected discharge water temperature is equal to or higher than the set value with respect to the set temperature.
Stops the combustion of the combustor until the detected outlet temperature falls below the set temperature.

[0007]

[0008]

[Action]

[Claim 1] The hot water tap is opened and the amount of water flowing through the heat exchange water channel is set to a predetermined value or more. The water amount sensor detects the amount of water flowing through the heat exchange channel, the supply water temperature sensor detects the supply water temperature, and the tap water temperature sensor detects the tap water temperature.

The microcomputer puts the combustor into a combustion state and, based on the detected supply water temperature and the detected water amount,
The actuator is controlled so that the tapping temperature is maintained at the set temperature. The actuator operates the calorific value of the combustor, the amount of water flowing through the heat exchange channel, or both the calorific value and the amount of water.

When the water supply temperature is high, the set temperature is low, the amount of hot water discharged is small, or the capacity becomes insufficient due to two or more of these factors, and (detected hot water temperature-set temperature) ≥set value, the microcomputer (Detected hot water temperature-
The combustion of the combustor is stopped until the set temperature) <set value.
The predetermined value is set based on the set temperature and the detected feedwater temperature.
The microcomputer decides.

[Claim 2] The hot water tap is opened and the amount of water flowing through the water supply pipe is set to a predetermined value or more. A water amount sensor detects a water amount, a water supply temperature sensor detects a water supply temperature, and a tap water temperature sensor detects a tap water temperature.

The microcomputer puts the combustor into a combustion state and, based on the detected supply water temperature and the detected water amount,
The actuator is controlled so that the tapping temperature is maintained at the set temperature. The actuator controls the amount of water passing through the water supply pipe, the ratio of the amount of heat exchange water passing through the heat exchanger to the amount of bypass water reaching the tapping pipe through the bypass pipe, and the amount of heat generated by the combustor. .

When the supply water temperature is high, the set temperature is low, the amount of hot water discharged is small, or the capacity becomes insufficient due to two or more of these factors, and if (detected hot water temperature−set temperature) ≧ set value, the microcomputer (Detected hot water temperature-
The combustion of the combustor is stopped until the set temperature) <set value.
The predetermined value is set based on the set temperature and the detected feedwater temperature.
The microcomputer decides.

[0014]

[0015]

According to the first aspect of the present invention, in a non-bypass mixing type water heater having a heat exchange water channel in which a water supply pipe, a heat exchanger, and a tapping pipe are connected, a set temperature is set.
And the microcomputer determines based on the detected feedwater temperature.
Determine the value and (detected hot water temperature-set temperature) ≥ set value
And (combustion stop of the combustor until (detected hot water temperature−set temperature) <set value).

For this reason, even when the supply water temperature is high, the set temperature is low, the discharge amount of hot water is small, or the capacity is insufficient due to two or more of these factors, the user can use the hot water at the substantially set temperature. It is easy to use. Also,
The predetermined value of the amount of water detected to bring the baking oven into the combustion state
The microcomputer determines based on the detected feedwater temperature.
The heat exchanger overheats or passes through the heat exchanger
Problems such as boiling of water can be prevented.

According to a second aspect of the present invention, in a bypass mixing type water heater provided with a bypass pipe that bypasses a water supply pipe to a tapping pipe, a set temperature and detection are provided.
Microcomputer determines predetermined value based on feedwater temperature
And, - if the (detected hot water temperature set temperature) ≧ set value (detected hot water temperature - set temperature) until the <set value, is configured to burn stop combustor.

For this reason, even when the supply water temperature is high, the set temperature is low, the discharge amount of hot water is small, or the capacity is insufficient due to two or more of these factors, the user can use the hot water of approximately the set temperature. It is easy to use. Also,
The predetermined value of the amount of water detected to bring the baking oven into the combustion state
The microcomputer determines based on the detected feedwater temperature.
The heat exchanger overheats or passes through the heat exchanger
Problems such as boiling of water can be prevented.

[0019]

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention ( corresponding to claim 2 )
This will be described with reference to FIGS.

As shown in the figure, a water heater system A includes a water heater main body K installed outdoors, a main remote controller M installed in a kitchen, and a two-wire wire N connecting between the water heater main body K and the main remote controller M. It is composed of

As shown in FIG. 1, the water heater main body K has a water supply pipe 111 and a heat exchanger pipe 112 having a heat exchanger 112a.
A heat exchange channel 11 having a series of tapping pipes 113 and a hot water tap C
₁ , a water amount sensor 11a, a gas burner 12, a tap water temperature thermistor 118 for detecting tap water temperature, a feed water temperature thermistor 119 for detecting feed water temperature, and an actuator.
Switching electromagnetic valve 131, governor proportional electromagnetic valve 132, electric water flow control device 133 with distributor, and main body side communication circuit 14
And a main body side microcomputer 15 and the like.

The water supply pipe 111 has an upstream side connected to a water supply system (not shown) and a downstream side connected to the electric water flow controller 1 with a distributor.
33 are connected to the entrance. In this water supply pipe 111,
Water filter / water tap m ₁ from upstream, water flow sensor 11
a, and a water supply temperature thermistor 119.

The upstream side of the heat exchanger tube 112 is connected to one outlet of the electric water flow controller 133 with a distributor, and the downstream side is connected to the mixer g. Further, the heat exchanger 112a located in the middle is disposed in the combustion drum 120 above the gas burner 12, and heats water passing therethrough.

The electric water flow control device 133 with the distributor includes a water flow amount passing through the water supply pipe 111, a heat exchange water amount passing through the heat exchanger pipe 112, and a hot water supply pipe 113 without passing through the heat exchanger pipe 112.
This is a device for controlling the ratio of the amount of bypass water flowing through the bypass pipe 114 to the bypass pipe 114.

The upstream side of the bypass pipe 114 is connected to the other outlet of the electric water flow controller 133 with a distributor, and the downstream side is connected to the mixer g.

The hot water pipe 113 has an upstream side connected to the outlet of the mixer g, hot water temperature thermistor 118, overpressure relief valve and drain tap m _2, and the hot-water tap C ₁ are sequentially arranged.

The mixer g mixes the water that has passed through the bypass pipe 114 and the hot water heated by the heat exchanger pipe 112 to increase the temperature to make hot water having a substantially uniform temperature. The mixer g is provided with a water tap m ₃ and a freeze prevention heater h.

The hot water tap C ₁ is a hot water tap for adjusting the amount of hot water discharged from a faucet provided in the kitchen.

The water amount sensor 11a is of an impeller type and detects the amount of water flowing through the water supply pipe 111.

The gas burner 12 of the two-stage switching type has a combustion cylinder 1 into which secondary air is sent by a combustion fan 122.
The gas is supplied by a gas pipe 121 and is forcibly burned. This gas pipe 121 has an original solenoid valve 1
23, a governor proportional solenoid valve 132, a gas solenoid valve 124, and a switching solenoid valve 131 are provided.

Reference numeral 125 denotes an ignition electrode; 126, an igniter; 127, a frame rod for detecting a combustion flame;
28 is a thermal fuse, 129 is an embers safety device, and 130 is a low temperature detection switch.

The tap water temperature thermistor 118 detects the tap water temperature, and the feed water temperature thermistor 119 detects the feed water temperature. The can body thermistor p is connected to the heat exchanger 112a.
It is provided to detect the boiling of water passing through.

The switching solenoid valve 131 switches the gas supply amount to the gas burner 12 in two stages by opening (energizing) and closing (non-energizing) the valve.

The governor proportional solenoid valve 132 indicates an opening in accordance with the amount of energization, and continuously varies the amount of gas flowing through the gas pipe 121.

The main body side communication circuit 14 shown in FIG. 2 converts the operation information relating to the presence / absence of combustion, whether or not the operation is in progress, and the set temperature into a down-converted digital signal Dd. An operation command related to an operation start / stop instruction and a set temperature change instruction is demodulated from the upstream digital signal Du sent from the remote control communication circuit 21 while being sent to the circuit 21.

When the power cord of the water heater main body K is plugged into the outlet, the main body side microcomputer 15 is supplied with operating power and starts operating. Based on the following equation, the fire extinguishing water amount W _OFF , The differential water amount Dif and the fire extinguishing water amount W _ON are obtained.

Fire extinguishing water amount W _OFF = 64 / (set temperature T _SET
-Detected supply water temperature T _IN ) 64: Q _IN × 0.85 (kcal / min); fixed value However, fire extinguishing water amount W _OFF ≧ 2.0 (l / min)

Fire extinguishing water amount W _ON = Fire extinguishing water amount W _OFF + Differential water amount Dif However, if (Set temperature T _SET −Detected feed water temperature T _IN ) ≦ 0, no ignition is performed. However, Fire extinguishing water amount W _ON ≧ 2.7 (l / min)

Differential water amount Dif = 128 /
(T _SET -T _IN ) ² 128: Qmin × 0.85 × 2 (kcal / min);
Fixed value However, differential water amount Dif ≧ 0.7 (l / m
in)

When the detected water amount W is equal to or greater than the fire extinguishing water amount W _ON , an instruction is made to energize the combustion fan 122 and the gas burner 12
And the switching solenoid valve 131 and the governor proportional solenoid valve 13 so that the detected tap water temperature T _out is maintained at the set temperature T _SET based on the detected feed water temperature T _IN and the detected water amount W.
2 and controls the electric water flow control device 133 with a distributor.

The main remote controller M includes a remote controller communication circuit 21, push button switches 22 and 23 for instructing to change the set temperature, an operation switch 24 for instructing start and stop of operation, and a remote controller microcomputer 25. ,
Display circuit 26, operation lamp 261, hot water temperature indicator 26
3 and a combustion lamp 264.

The remote-control-side communication circuit 21 converts an operation command for changing a set temperature or starting / stopping the operation into an upstream digital signal Du and sends it to the main-unit communication circuit 14 via the two-wire N. The operation information is demodulated from the downstream digital signal Dd sent from the side communication circuit 14,
It is sent to the remote control microcomputer 25.

The push-button switches 22 and 23 are unlock-type push-button switches whose contacts are switched to a closed state during the operation when the push operation is performed. When the set temperature change operation is performed, the operation signals 220 and 230 are generated. It is sent to the remote control microcomputer 25 described later.

When the operation switch 24 is pressed,
An unlock-type push-button switch whose contact switches to a closed state during operation.
40 is sent to the remote controller microcomputer 25 described later.

The microcomputer 25 on the remote control side
The operation command for changing the set temperature and starting / stopping the operation is sent to the remote control communication circuit 21, and the operation information demodulated by the remote control communication circuit 21 is converted into a display signal 250.

The operation lamp 261 is a backlight that lights up during operation, the hot water temperature indicator 263 is a seven-segment LED that displays the set temperature T _SET by a numerical value, and the combustion lamp 264 is an LED that lights up when the gas burner 12 is in a combustion state. is there.

Next, the operation of the water heater system A will be described with reference to FIG.
This will be described based on the flowchart shown in FIG.

When the user presses the operation switch 24,
The water heater body K to the operating state (operation lamp 261 is illuminated), opening the water tap C ₁ needed. In the initial state when the plug is inserted, the set temperature T _SET is set to 40 ° C. At the start of the second and subsequent operations, the set temperature T
_{For the SET,} the previous value is read from the memory 150.

In step s1, detected water amount W ≧ fire extinguishing water amount W
_The main body side microcomputer 15 determines whether or not it is _ON , and if the detected water amount W ≧ the fire extinguishing water amount W _ON (YES), the process proceeds to step s2.

In step s2, the main body side microcomputer 15 instructs the combustion fan 122 to start operating, and proceeds to step s3.

In step s3, the main body side microcomputer 15 instructs the ignition operation of the gas burner 12, and proceeds to step s4. The ignition operation causes the igniter 126
Is activated, spark discharge occurs at the ignition electrode 125, the original solenoid valve 123, the gas solenoid valve 124, and the switching solenoid valve 13
1 is in the valve open state.

In step s4, the main microcomputer 15 determines whether or not a flame is detected (the frame rod 12).
7), and when the flame is detected (YES), the process proceeds to step s5. When the flame is not detected (NO), the process proceeds to step s12.

In step s5, the main body side microcomputer 15 turns on the combustion lamp 264 of the main remote controller M. The set temperature T _SET is displayed on the hot water temperature indicator 263.
Is displayed. Further, based on the detected feed water temperature T _IN and the detected water amount W, the detected tap water temperature T _out is set to the set temperature T.
_The switching solenoid valve 131, the governor proportional solenoid valve 132, and the electric water flow controller with distributor 133 are controlled so as to be maintained at _SET .

In step s6, the main body side microcomputer 15 determines that (detected hot water temperature T _out -set temperature T _SET ) ≧
It is determined whether or not the temperature is 3 ° C., and if (T _out −T _SET ) ≧ 3 ° C. (YES), the process proceeds to step s8 and (T _out −
If (T _SET ) <3 ° C. (NO), the flow proceeds to step s7.

In step s7, detected water amount W <fire extinguishing water amount W
_The microcomputer 15 determines whether or not it is _OFF ,
If detected water amount W <fire extinguishing water amount W _OFF (YES), the process proceeds to step s11. If detected water amount W ≧ fire extinguishing water amount W _OFF (NO), the process returns to step s4.

In step s8, the main body side microcomputer 15 performs a fire extinguishing operation of the gas burner 12, and proceeds to step s9. By the fire extinguishing operation, the original solenoid valve 123, the gas solenoid valve 124, the switching solenoid valve 131, and the governor proportional solenoid valve 132 are closed, the combustion lamp 264 is turned off, and the post-fan operation for 10 seconds is completed. Thereafter, the combustion fan 122 stops.

In step s9, the main body side microcomputer 15 determines whether or not the detected outlet temperature T _out <set temperature T _SET . If T _out <T _SET (YES), the flow proceeds to step s10.

[0059] In step s10, detecting water amount W <extinguishing water W whether the microcomputer 15 is _OFF, it is determined, if the detected water amount W ≧ extinguishing water W _OFF (NO) returns to step s2, detecting water amount W < In case of fire extinguishing water amount W _ON (Y
ES) returns to step s1.

In step s11, the main body side microcomputer 15 performs a fire extinguishing operation of the gas burner 12, and returns to step s1. In addition, the original solenoid valve 123,
The gas solenoid valve 124, the switching solenoid valve 131, and the governor proportional solenoid valve 132 are closed, the combustion lamp 264 is turned off, and after the post-fan operation for 10 seconds is completed, the combustion fan 122 is stopped.

In step s12, the main microcomputer 15 closes the original solenoid valve 123, the gas solenoid valve 124, the switching solenoid valve 131, and the governor proportional solenoid valve 132, turns off the combustion lamp 264, and turns off the combustion. An error stop operation for stopping the fan 122 is instructed. The restart is performed by once pressing the operating switch 24 to stop the operation, removing the cause of the error, and then pressing the operating switch 24 again to bring the water heater body K into the operating state.

Next, advantages of the water heater system A will be described. [A] In a bypass mixing type water heater provided with a bypass pipe 114 that bypasses the water supply pipe 111 to the hot water pipe 113, (detected hot water temperature T _out -set temperature T _SET ) ≧ 3 ° C.
{YES in step s6}, the main body side microcomputer 15 returns (detected hot water temperature T _out <set temperature T
_SET )) until the gas burner 12 is extinguished until YES in step s9.

For this reason, the water supply temperature is high in summer (for example, 2
5 ° C.), the set temperature T _SET is low (for example, 37 ° C.),
Discharge amount of hot water is low (e.g., per minute 3 l), or even if the capacity under these two or more factors, because the hot water substantially set temperature T _SET be discharged from the hot-water tap C _1, usability Excellent.

[I] The body-side microcomputer 15 determines the amount of fire extinguishing water W _{ON for} starting the combustion of the gas burner 12 and the amount W _OFF of fire extinguishing water for extinguishing the gas burner based on the set temperature T _SET and the detected feed water temperature T _IN. Since the determination is made, occurrence of troubles such as overheating of the heat exchanger 112a and boiling of water passing through the heat exchanger 112a can be prevented.

Next, a second embodiment (corresponding to claim 1) of the present invention will be described with reference to FIG. 4 (see also FIGS. 2 and 3). In FIG. 4, those having the same numbers as the water heater system A have the same configuration, and the water heater system B differs from the water heater system A in the following points.

The heat exchange channel 11 is formed by connecting a water supply pipe 115, a heat exchanger 116 and a tapping pipe 117 without using a bypass pipe or a mixer.

The water supply pipe 115 has an upstream side connected to a water supply system (not shown) and a downstream side connected to an inlet of the electric water flow control device 134.

The heat exchanger 116 has an upstream side connected to the outlet of the electric water flow control device 134 and a downstream side connected to the tapping pipe 117.

The actuators are a switching solenoid valve 131, a governor proportional solenoid valve 132, and an electric water flow control device 134. The electric water flow control device 134 is a device that controls the amount of water passing through the water supply pipe 115.

In this embodiment, the extinguishing water amount W _ON and the extinguishing water amount W _OFF are set to the following values (fixed values).

Fire extinguishing water amount W _ON = 2.7 (l / min) Fire extinguishing water amount W _OFF = 2.0 (l / min)

The operation of the water heater system B is based on the flowchart shown in FIG.
And different.

In step s1, detected water amount W ≧ fire extinguishing water amount W
_The main body side microcomputer 15 determines whether or not it is _ON (2.7 liters per minute), and the detected water amount W ≧ the fire extinguishing water amount W
If it is _ON , go to step s2.

At step s5, the main body side microcomputer 15 turns on the combustion lamp 264 of the main remote controller M. The set temperature T _SET is displayed on the hot water temperature indicator 263.
Is displayed. Further, based on the detected feed water temperature T _IN and the detected water amount W, the detected tap water temperature T _out is set to the set temperature T.
_The switching solenoid valve 131, the governor proportional solenoid valve 132, and the electric water flow control device 134 are controlled so as to be maintained at _SET .

In step s7, the main body side microcomputer 15 determines that the detected water amount W <the fire extinguishing water amount W _OFF (2.0 per minute).
Liter) is determined. If W <W _OFF (YES), the process proceeds to step s11. If W ≧ W _OFF (NO), the process returns to step s4.

In step s10, the main body side microcomputer 15 determines that the detected water amount W <the fire extinguishing water amount W _OFF (2.
0 W), and if W <W _OFF (YES), the process returns to step s1. If W ≧ W _OFF (NO), the process returns to step s2.

The advantages of the water heater system B of this embodiment are as follows. [U] In a non-bypass mixing type water heater provided with a heat exchange channel 11 in which a water supply pipe 111, a heat exchanger 116, and a tapping pipe 117 are connected, (detected tap water temperature T _out -set temperature T
_SET ) ≧ 3 ° C. {YES in step s6}, and the main body side microcomputer 15 determines (detected tapping temperature T _out <
Set temperature T _SET ) (YES in step s9)
In this configuration, the gas burner 12 is set to a fire extinguishing state.

For this reason, the water supply temperature is high in summer (for example, 2
5 ° C.), the set temperature T _SET is low (for example, 37 ° C.),
Discharge amount of hot water is low (e.g., per minute 3 l), or even if the capacity under these two or more factors, because the hot water substantially set temperature T _SET be discharged from the hot-water tap C _1, usability Excellent.

The present invention includes the following embodiments in addition to the above embodiments. a. In the above-described embodiment, the setting temperature is variable, but may be fixed (for example, 40 ° C., 50 ° C., 55 ° C.).

B. In the above embodiment, the set temperature is set to 3 ° C., but may be appropriately set to 1 ° C., 2 ° C., 4 ° C., or the like.

C. In the above embodiment, one remote controller is shown, but a plurality of remote controllers (for example, two or three remote controllers) may be used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a water heater system according to a first embodiment of the present invention.

FIG. 2 is a block diagram of the water heater system.

FIG. 3 is a flowchart illustrating the operation of the water heater system.

FIG. 4 is a schematic diagram of a water heater system according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Heat exchange water channel 11a Water amount sensor 12 Gas burner (combustor) 15 Main body side microcomputer (microcomputer) 111, 115 Water supply pipe 112 Heat exchanger pipe 112a, 116 Heat exchanger 113, 117 Hot water pipe 114 Bypass pipe 118 Hot water temperature thermistor (Tap water temperature sensor) 119 Water supply temperature thermistor (water supply temperature sensor) 131 Switching solenoid valve (actuator) 132 Governor proportional solenoid valve (actuator) 133 Electric water flow control device with distributor (actuator) 134 Electric water flow control device (actuator) A, B water heater system C ₁ hot water tap

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shigeru Ogiso 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi Inside Linhai Corporation (56) References JP-A-5-93545 (JP, A) JP-A-60- 142115 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F24H 1/10 302 F23N 5/02 350

Claims (2)

(57) [Claims] 1. A heat exchange channel formed by connecting a water supply pipe, a heat exchanger, and a tapping pipe, a hot water tap provided at an outlet of the tapping pipe, and a water quantity sensor for detecting an amount of water flowing through the heat exchange waterway. A combustor that heats the heat exchanger; a feedwater temperature sensor that detects feedwater temperature; a tapwater temperature sensor that detects tap water temperature; and a calorific value of the combustor, the amount of water, or a value of the calorific value and the amount of water. An actuator for operating both of them, and when the detected water amount is equal to or more than a predetermined value, the combustor is set to a combustion state, and the actuator is controlled based on the detected supply water temperature and the detected water amount so that the tap water temperature is maintained at the set temperature. A water heater comprising a microcomputer that performs the set temperature and the detected water supply.
And it determines the predetermined value based on the water temperature, when the detected hot water temperature exceeds the setting value for the set temperature, test
A water heater characterized in that the combustion of the combustor is stopped until the outlet water temperature falls below a set temperature . 2. Water supply pipe-heat exchanger pipe with heat exchanger-
A heat exchange channel formed by connecting a tapping pipe; a hot water tap provided at an outlet of the tapping pipe; a water quantity sensor for detecting a quantity of water flowing through the tapping pipe or the tapping pipe; and a combustion for heating the heat exchanger. A water supply temperature sensor for detecting a water supply temperature; a water supply temperature sensor for detecting a water supply temperature; an amount of water passing through the water supply pipe, an amount of heat exchange water passing through a heat exchanger, and a water supply through the bypass pipe. An actuator for controlling the ratio of the amount of bypass water to be reached and the calorific value of the combustor; A water heater that includes a main body microcomputer that controls the actuator so that the temperature is maintained at the set temperature.
The predetermined value is determined based on the water temperature , and when the detected hot water temperature becomes equal to or higher than the set temperature, the combustion of the combustor is stopped until the detected hot water temperature falls below the set temperature. A water heater characterized by the following.