JPH0449012B2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a temperature control device for a water heater.

<Prior art and its issues> In general, in water heaters, it is necessary to operate the hot water storage can at a low temperature for the purpose of preventing freezing, etc., and conventional water heaters have a configuration in which the hot water supply volume is set to a low temperature range. This was the most common. However, in a water heater that performs controlled combustion operation of a burner so that the temperature of the hot water in the hot water storage can becomes a constant high temperature setting value, and also adjusts the temperature of hot water discharged through the hot water supply pipe to the temperature set by an electric mixing valve, Setting both the temperature of the hot water storage can and the temperature of the electric mixing valve, as well as switching the hot water storage can between low-temperature operation and high-temperature operation, cannot be done using conventional temperature control controls. There was a drawback that it could not be achieved. In addition, in order to obtain such a function, when switching to low-temperature operation, it is necessary to memorize the hot water temperature control from the previous high-temperature operation, and ensure that hot water is discharged at the original hot water temperature when returning to high-temperature operation. be.

<Purpose> Therefore, the present invention solves the drawbacks of the above-mentioned prior art,
The temperature control of the hot water storage can body, that is, the can temperature control, can be easily switched from the high temperature setting value in normal times to the low temperature setting value when freezing prevention is required, and the hot water temperature control can be adjusted at the same temperature as in normal times. The purpose of the present invention is to provide a temperature control device for a water heater that can store information.

<Means for Solving the Problems> In order to achieve the above object, the water heater temperature control device of the present invention normally maintains the water temperature in the hot water storage can at a constant high temperature setting value by controlling the combustion of the burner. This is a water heater temperature control device that operates at a high temperature so that the temperature is fixed at an operation switch for performing a combustion control operation, and a hot water outlet temperature setting device for setting the hot water outlet temperature to a desired temperature;
In addition, a low-temperature operation switch is provided for switching the combustion control operation of the burner from the normal high-temperature operation to low-temperature operation, and the control section includes a burner combustion control circuit, a can temperature adjustment circuit, and the low-temperature operation. When the switch is turned on, the can temperature adjustment circuit changes the can temperature adjustment from the normal high temperature set value to the fixed low temperature set value, and when the low temperature operation switch is turned on, the valve drive output of the electric mixing valve is controlled. It is characterized by the provision of a circuit that turns off the valve and maintains the valve position corresponding to the previous hot water temperature control.

<Function> When the low temperature operation switch is off, the burner is operated under combustion control so that the hot water storage can reaches the high temperature set value determined by the can temperature adjustment circuit of the control section by turning on the operation switch. On the other hand, the electric mixing single valve adjusts the hot water to the hot water temperature set by the hot water temperature controller. During operation, when the low temperature operation switch is operated and turned on, the temperature adjustment set temperature of the hot water storage can is switched from the high temperature setting value to the low temperature setting value in the control section, and the low temperature operation is performed.
At the same time, the valve drive output of the electric mixing valve is turned off, so that the valve position of the electric mixing valve continues to be maintained at the position corresponding to the hot water temperature control set by the hot water temperature control setting device during high temperature operation.

<Example> Hereinafter, preferred examples of the present invention will be described in detail based on the drawings.

First, to explain the overall configuration with reference to FIG. 2, a water supply pipe 2 and a hot water supply pipe 3 are connected to a hot water storage can body 1 which is a hot water storage tank, and an electric mixing valve 4 is provided at the outlet of this hot water supply pipe 3. There is. Hot water storage can body 1
The hot water temperature is detected by the can body hot water temperature detector 5, and based on this detected temperature, the control unit 6 controls the burner controller 7, and the burner controller 7 maintains the hot water temperature of the hot water storage can body 1 at the set temperature. to control the burner. Further, the temperature of the hot water discharged through the hot water supply pipe 3 is controlled by an electric mixing valve 4 automatically adjusting the hot water temperature to a set hot water temperature. 8 is an operation unit for performing various operations by remote control.

A heat exchange coil 10a for reheating the bathtub 9 is arranged in the hot water storage can 1, and one hot water storage can 1 can supply hot water through the hot water pipe 3,
It is equipped with two types of heat circuits capable of reheating the bathtub 9 or circulating hot water to the heat radiating part of the heater 11 through a circulation path constituted by the heat exchange coil 10a and the piping 10. It has a circuit configuration.

Next, details of the operation section 8 and the control section 6 will be explained based on FIG. 1. The operation unit 8 includes an operation switch 12, a low temperature operation switch 13, and a hot water outlet temperature control setter 1 consisting of an up temperature control switch 14a and a down temperature control switch 14b for setting the hot water temperature.
4, and a desired hot water temperature is set in the hot water temperature adjustment setting circuit 15 by operating the hot water temperature adjustment setting device 14.

Then, when the operation switch 12 is turned on while the low-temperature operation switch 13 is in the off state, the DC power supply 16 is connected to the first to third resistors R1 to R3 and the fourth to sixth resistors, respectively, which are connected in series via the operation switch 12. As well as being applied to R4 to R6,
It is applied to a can body water temperature detector 5 consisting of a thermistor. The resistors R1 to R3 constitute a can temperature adjustment setting circuit. And the first resistor R1 and the second and third resistors R2,
A voltage obtained by dividing the power supply voltage of the DC power supply 16 by R3 is applied to the positive terminal + of the voltage comparator 17 as a fixed high temperature setting value for regulating the can temperature. The can body hot water temperature detector 5 is connected to the negative terminal of the voltage comparator 17 via a fifth resistor R5. Therefore, when the detected hot water temperature of the hot water storage can 1 is lower than the high temperature setting value, the input voltage of the positive terminal + of the voltage comparator 17 is higher than that of the negative terminal -, so the output of the voltage comparator 17 is When the signal becomes high level, the combustion control circuit 18 is turned on, a combustion command signal is output to the burner controller 7, the burner controller 7 is driven, and the hot water storage can 1 is heated.

When the temperature of the hot water in the hot water storage can 1 rises due to heating and exceeds the above-mentioned high temperature setting temperature, the input voltage at the negative terminal - of the voltage comparator 17 becomes higher than that at the positive terminal +. The output signal of the comparator 17 changes to a low level, the combustion control circuit 18 is turned off, a combustion stop command signal is output to the burner controller 7, and the drive of the burner controller 7 is stopped. As a result, when the water temperature in the hot water storage can body 1 decreases to below the high temperature setting temperature, the above-mentioned operation is repeated and this on/off operation causes the hot water temperature in the hot water storage can body 1 to
The temperature is regulated to maintain the high temperature set by the input voltage of the positive terminal + of the voltage comparator 17.

In this state, a temperature control signal corresponding to the hot water temperature set in the hot water temperature adjustment setting circuit 15 is sent to the hot water temperature adjustment setting circuit 15 by the operation of the hot water temperature adjustment setting device 14.
This output hot water temperature control signal becomes the valve drive output of the electric mixing valve 4 in the hot water temperature adjustment circuit 19, and the electric mixing valve 4 moves its valve position to a position corresponding to the hot water temperature adjustment signal. As a result, the hot water at the high temperature set value from the hot water storage can 1 is automatically adjusted to the hot water temperature adjustment setting temperature set by the hot water temperature adjustment setting device 14.

Next, when the low temperature operation switch 13 is turned on while the operation switch 12 is on, the DC power supply 16
The power supply voltage of the seventh
This divided voltage is applied to the base of the transistor Q to turn on the transistor Q, and the voltage is applied to the second and third resistors R2 and R2 through the first diode D1 and the transistor Q.
Since the connection point of R3 is grounded, voltage comparator 1
The input voltage of the positive side terminal + of the voltage comparator 17 becomes the value obtained by dividing the power supply voltage by the first and second resistors R1 and R2, and becomes lower, and the positive side terminal + becomes the reference voltage of the voltage comparator 17.
The input voltage is switched from the high temperature setting to a fixed low temperature setting. Then, as in the case of the high temperature setting described above, the combustion control circuit 18 is repeatedly turned on and off by the output signal of the voltage comparator 17, and the hot water temperature in the hot water storage can body 1 is set to the positive side terminal of the voltage comparator 17. It is controlled to maintain the low temperature set by the input voltage. That is, the resistors R7 and R8, the transistor Q, and the first diode D1 constitute a circuit that switches the can temperature adjustment from the normal high temperature set value to another low temperature set value.

Furthermore, by turning on the transistor Q, the control terminal of the hot water temperature adjustment circuit 19 for determining the valve position of the electric mixing valve 4 is connected to the second diode D2.
and grounded via the transistor Q, and the valve drive output of the hot water temperature control circuit 19 is short-circuited to be in the OFF state, and as a result, the electric mixing valve 4
retains its original setting position. In other words, the original hot water setting temperature set by the hot water temperature adjustment setting device 14 is stored as a result. Therefore, next, low temperature operation switch 1
3 is turned off and the high temperature operation mode is restored, the electric mixing valve 4 resumes control of the tapped water temperature at the position corresponding to the original hot water temperature. In this way, even during low-temperature operation, the electric mixing valve 4 is used to memorize the hot water setting temperature during the previous high-temperature operation, so that low-temperature operation and high-temperature operation can be switched by one-touch operation of turning on the low-temperature operation switch 13. Can be switched. The second diode D2, transistor Q, and resistor
R7 and R8 constitute a circuit that turns off the valve drive output of the hot water temperature adjustment circuit 19 and maintains the previous valve position.

It should be noted that the present invention is not limited only to the above-mentioned embodiments, and it goes without saying that various embodiments are possible without departing from the scope of the claims. Alternatively, in a one-can two-circuit system that includes two circuits for hot water supply and a bathtub, it is easy to configure the system to switch between a high-temperature priority sequence and a low-temperature operation sequence for the heater or bathtub.

<Effects of the Invention> The present invention has the above configuration and operation, and according to the temperature control device for a water heater of the present invention described in the claims, the temperature control of the hot water storage can can be set by turning on the low temperature operation switch. Since the temperature can be switched from a high temperature set value to a low temperature set value, the hot water storage can can be operated at a low temperature when necessary with a very simple one-touch operation.
Freezing party can be prevented. Moreover, even when the can temperature control is switched from high-temperature operation to low-temperature operation, the electric mixing valve that adjusts the hot water outlet temperature can maintain the valve position corresponding to the set hot water outlet temperature during high-temperature operation. When the operation returns to high temperature operation, hot water can be resumed at the original hot water temperature, which is very convenient.

In addition, the temperature control set temperature of the electric mixing valve is set by a temperature control setter, and the temperature control set temperature of the hot water storage can is changed by a low temperature operation switch, so the circuit configuration is extremely simple and can be manufactured at low cost.

Moreover, in a one-can, two-circuit system in which heating and hot water supply or hot water supply and reheating of a bath are performed by a single hot water storage can, there is an advantage that switching between these sequences and a low-temperature operation sequence can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of an embodiment of the temperature control device for a water heater according to the present invention, and FIG. 2 is a block diagram showing the overall configuration. 1: Hot water storage can body, 3: Hot water supply pipe, 4: Electric mixing valve, 6: Control section, 8: Operation section, 12: Operation switch, 13: Low temperature operation switch, 14: Hot water temperature control setting device, 17: Voltage comparison 18: Combustion control circuit, Q: Transistor.

Claims (1)

[Claims] 1 Under normal conditions, high-temperature operation is performed to fix the hot water temperature in the hot water storage can at a constant high temperature setting value by combustion control of the burner, and the temperature of hot water discharged through the hot water supply pipe is set by the electric mixing valve. This is a water heater temperature control device that automatically adjusts the temperature of the water heater. A setting device and a low temperature operation switch for switching the combustion control operation of the burner from the normal high temperature operation to low temperature operation are provided, and the control section includes a burner combustion control circuit;
a can temperature adjustment circuit; a circuit for switching the can temperature adjustment by the can temperature adjustment circuit from a normal high temperature setting value to a fixed low temperature setting value when the low temperature operation switch is turned on; A temperature control device for a water heater, comprising: a circuit for turning off the valve driving output of the electric mixing valve and maintaining the valve position corresponding to the hot water temperature control up to that point.