JPH0345854A - Temperature control device of hot water feeder - Google Patents

Abstract

PURPOSE:To prevent an influence of a disturbance of a variable resistor and to enable all temperatures within a settable range to be set by a method wherein in the case that a set resistance value is more than a predetermined resistance value, a target temperature is set to a minimum temperature and as the set resistance is lower, the target temperature is set to its high temperature and in the case that a connected state between the two terminals and the variable resistor is not connected, the target temperature value is set to a high value. CONSTITUTION:As a user sets a hot water feeding temperature by a variable resistor circuit 51 or 61 of a selected remote controller 50 or 60, voltages of terminals 36, 37 or 38, 39 corresponding to a variable resistance circuit are read as the set temperature signals. At this time, in the case that a connected state of the selected remote controller is normal and a resistance value of a variable resistor VR1 or VR2 is more than a specified resistance value, its minimum temperature becomes a set temperature and in turn in the case that it is less than that, as the resistance value is lower in response to the resistance value, a higher temperature is set. In that case that the connected condition is not normal due to a poor connection of the main remote controller 50 or a short-circuited condition between the terminals 36 and 37 or the like, it is operated as an automatic mode and then the specified temperature set at a higher temperature is applied as a set temperature.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a water heater that includes a variable resistor for setting the hot water temperature, and sets a target temperature according to the resistance value of the variable resistor. The present invention relates to a temperature control device for a water heater.

[Prior Art] A temperature control device for a water heater that sets the hot water temperature according to the operating state of a variable resistor is designed to set the temperature at a location away from the main body of the water heater. Some remote control units (hereinafter referred to as ``operation units'') that are connected by real wires are equipped with variable resistors.

In such a control device, a constant voltage is applied from the control device to a variable resistor in the operating section, and the control device detects the voltage that changes depending on the resistance value of the variable resistor to determine the target temperature of hot water. do.

In this case, in many water heaters, the temperature can be freely set between about 35° C. and about 70° C. depending on the operating state of the variable resistor.

By the way, variable resistors, etc. have a tolerance of about ±10% for the total resistance value of the variable resistor, and generally speaking, if the resistance value of the variable resistor is set to a large value, the error value will be growing.

For this reason, in the temperature control device of a water heater, the target temperature can be set using all variable resistors within the tolerance, and in order to improve the operation feeling of the variable resistors, the maximum resistance value can be adjusted depending on the error. In order to be able to set the same value even if there is a difference, the minimum temperature is set for all cases where the resistance value is higher than the predetermined resistance value, the set temperature is set higher when the resistance value is small, and the set temperature is set higher when the resistance value is large. A device with a lower set temperature is being considered.

[Problems to be Solved by the Invention] As described above, as a temperature control device in which the set temperature is determined according to the resistance value of the variable resistor, if the variable resistor is provided in the operating section, the operating section and the control device may be connected to each other. Disconnection of the electric wire for connection between the terminals and the disconnection within the operation unit is likely to occur.

If a disconnection occurs, the control unit detects the resistance value of the variable resistor as if it were the maximum resistance value, and determines that the resistance value is higher than the predetermined resistance value, so the minimum temperature is set. When hot water is supplied, hot water with a minimum temperature of about 35°C is supplied. For this reason, for example, the hot water temperature is too low to take a bath, and there is a problem in that the user cannot take a bath while waiting for repair by a professional.

The present invention is a temperature control device for a water heater that uses a variable resistor to set the temperature, when an electric wire or the like between the variable resistor and the variable resistor used to set the hot water temperature is disconnected, and the temperature cannot be set using the variable resistor. To provide a temperature control device for a water heater that does not cause any practical problems, such as allowing you to at least take a bath without lacking the function of the water heater even if a repair company cannot repair it in time. purpose.

[Means for Solving the Problems] The present invention provides a temperature control device for a water heater that sets a target temperature according to a set resistance value of a variable resistor connected between two terminals by two electric wires. If the set resistance value is greater than or equal to a predetermined resistance value, the target temperature is set to the lowest temperature,
The smaller the set resistance value is, the higher the target temperature is set, and when the connection state between the two terminals and the variable resistor is disconnected, the target temperature is set to a higher temperature. Use technical means.

[Operations] According to the present invention, when a wire breakage is not detected, the target temperature is set according to the resistance value of the variable resistor, and the target temperature is set higher as the resistance value becomes smaller, and gradually lower as the resistance value becomes larger. If the resistance value is set and the resistance value is equal to or higher than the predetermined resistance value, the minimum temperature is set.

On the other hand, if a disconnection is detected, regardless of the resistance value,
A high temperature is set as the target temperature.

[Effects of the Invention] In the present invention, when the resistance value of the variable resistor is small, the set temperature is high, when the resistance value is large, the set temperature is low, and when the resistance value is above a predetermined value, the lowest temperature is set. Therefore, all temperatures within the settable range can be set without being affected by variations in the variable resistor.

In addition, if a disconnection is detected, the target temperature is set to a high temperature even though the apparent resistance value of the variable resistor increases, so the minimum function as a water heater cannot be achieved. It can be used even if repairs by a repair company are delayed.

[Example] Next, the present invention will be explained based on embodiments shown in the drawings.

Inside the combustor case 10 of the gas water heater 1 shown in FIG.
A burner group 11 including a plurality of burners is arranged, and a blower 12 for supplying combustion air to the burner group 11 is provided below the combustor case 10. A wood-tube heat exchanger 13 is provided above the burner group 11 in the combustor case 10, and water passing through the interior is heated by combustion heat from the burner group 11. A sparker 14 for igniting the burner group 11 is provided near the burner group 11 in the combustor case 10, and a flame rod 15 for detecting ignition of the burner group 11 is provided to confirm the operation of the gas water heater 1.
is provided. An exhaust port 2 for discharging combustion exhaust gas to the outside is provided above the combustor case 10.

A nozzle pipe 16 for supplying fuel gas is provided below the burner group 11.
A plurality of fuel injection ports 16a for ejecting fuel gas are provided corresponding to each burner.

The fuel pipe 20 that guides the fuel gas to the nozzle pipe 16 includes two electromagnetic valves 21 and 22 that allow the fuel gas to pass when energized, and a governor that adjusts the amount of fuel gas supplied by controlling the supply pressure according to the energized current. Proportional valves 23 are provided in order from the upstream side.

A water supply pipe 17 that leads water from a water supply source (not shown) to the heat exchanger 13 includes an electric water flow control bag W, 18 for adjusting the amount of hot water supply, and a water flow switch that detects the amount of water passing through the heat exchanger 13. 19 are provided sequentially from the upstream side, and a hot water supply pipe 17a that guides hot water flowing out from the heat exchanger 13 to a hot water supply port (not shown) includes a hot water outlet temperature thermistor 25 that detects the outlet temperature of hot water flowing out from the heat exchanger 13. is provided.

The gas water heater 1 having the above configuration is controlled by a control device 30 shown in FIG.

The control device 30 is mainly a microcomputer that has a sequence control section 31, a temperature control section 32, a combustion control section 33, a fishery control section 34, and a display control section 35 according to a program in a ROM. Main remote controllers (hereinafter referred to as "main remote controllers") each driven by remote controller drive circuits 40 and 40a 5
0 and a sub-remote controller (hereinafter referred to as "sub-remote controller") 60.

The control device 30 is provided with terminals 36 and 37 for connecting the main remote controller 50 and terminals 38 and 39 for connecting the sub remote controller 60.

The main remote control 50 has a terminal 36.3 of the control device 30.
Terminals 50A and 50B are provided for connection between the control wave 230 and the main remote controller 50, and two electric wires 40A and 40B are connected between each terminal of the control wave 230 and the main remote control 50. In this case, since the polarity is not particularly determined, the terminals 5OA and 50B of the main remote control 50 are connected to the terminal 3 of the control wave f30.
6.37 may be reversely connected.

Similarly, the sub remote controller 60 has terminal 3 of the control device 30.
Terminals 60A and 60B are provided for connection between the terminals 8 and 39, and each terminal is connected by two electric wires 40C and 140D. Similarly, the sub remote controller 60
The terminals 60A and 60B are the terminals 38.3 of the control device 30.
9 may be connected in reverse.

First, the configuration of the main remote controller 50 will be explained.

The main remote controller 50 has a terminal 5 as shown in FIG.
A variable resistance circuit 51, an operation switch circuit 52, and a display circuit 53 are provided in parallel between 0A and 50B.

The variable resistance circuit 51 includes variable resistors VRI connected in parallel.
and a resistor R1 are connected in series with a resistor R2, and the set temperature is determined according to the resistance value of the variable resistance circuit 51 which changes when the user operates the variable resistor VRI.

The operation switch circuit 52 consists of an operation switch SWI for instructing the start and stop of operation of the gas water heater 1, and a resistor R3 connected in series with the operation switch SWI. A switch is used and the circuit is closed only when operated.

The display circuit 53 has terminals 50A and 50B connected to the control device 30.
As in 5, it may be reversely connected to terminals 36 and 37 of
A bridge circuit 54 consisting of six diodes D1 to D6 forming a full-wave rectifier circuit, a combustion lamp circuit Fr456 and an operating lamp circuit 57 provided in parallel on the output side of the bridge circuit 54 via a switching circuit 55. Become.

In the bridge circuit 54, the voltage applied between the terminals 5OA and 50B is connected to the switching circuit 55 and the combustion lamp circuit 56.
The rising voltage of the display circuit 53 is set high by connecting the diode D3 and the diode D4, and the diode D5 and the diode D6 in series, respectively. The current flowing to the display circuit 53 is reduced when the drive voltage to the display circuit 53 is not supplied.

The switching circuit 55 is a circuit for supplying lamp lighting power to the combustion lamp circuit 56 and the operating lamp circuit 57 when the voltage supplied from the bridge circuit 54 is equal to or higher than a predetermined voltage. transistor Q
When the voltage applied to the Zener diode ZDI connected to the base of the Zener diode ZD1 exceeds the breakdown voltage of the Zener diode ZD1, both the transistor Q1 and the transistor Q2 are turned on, and power is supplied to each lamp circuit 56 and 57.

The combustion lamp circuit 56 is supplied with power for lighting the lamp from the switching circuit 55, and at that time, the diode D7
The DC voltage applied to the resistor R5 via the AC component includes an AC component, and when the AC component is equal to or higher than a predetermined voltage, the combustion lamp L1 made of a light emitting diode (LED) is turned on.

Here, the AC component of the DC voltage applied to the resistor R5 passes through the capacitor C1, is voltage doubled and rectified by the diodes D8 and D9, and is then charged to the capacitor C2 via the resistor R6. When the charging voltage of capacitor C2 is above a certain voltage, the charge of capacitor C2 is transferred to resistor R.
7 to the transistor Q3 as a base current,
At this time, transistor Q3 is turned on, and combustion lamp L1 connected to the collector of transistor Q3 is lit.

The operating lamp circuit 57 lights the operating lamp L2 made of a light emitting diode when power for lamp lighting is supplied from the switching circuit 55 and the effective value of the DC voltage at that time is equal to or higher than a predetermined voltage.

Here, when the potential of the capacitor C3, which is charged by the supply voltage from the switching circuit 55 via the resistor R8 and discharged by the diode DIO when the supply voltage is lower than the charging voltage, is equal to or higher than a predetermined voltage, the resistor R9 A base current flows through the transistor Q4 to turn on the transistor Q4, and the operating lamp L2 connected to the collector of the transistor Q4 lights up.

Next, the sub remote control 60 will be explained.

The sub remote controller 60 has a terminal 60 as shown in FIG.
A variable resistance circuit 61 and a display circuit 63 are provided in parallel between A and 60B.

Similar to the variable resistance circuit 51, the variable resistance circuit 61 includes a variable resistor VR2 and a resistor R11 connected in parallel.
12, and a rotary priority switch SW2 is further connected in series to these. The priority switch SW2 is a switch for performing temperature adjustment control in the control device 30 based on the set temperature of the sub-remote controller 60. In the control device 30, when the priority switch SW2 is in the on state, the sub-remote controller 60 is selected. , the main remote controller 50 is selected when it is in the off state.

The display circuit 63 has the same configuration as the display circuit 53 in the main remote controller 50, and includes a bridge circuit 64 and a combustion lamp circuit 66 provided in parallel with the output side of the bridge circuit 64 via a switching circuit 65 and equipped with a combustion lamp L3. It consists of an operation lamp circuit 67 equipped with an operation lamp L4, and furthermore, a priority display circuit 68 is provided on the output side of the bridge circuit 64 in parallel with the switching circuit 65.

The priority display circuit 68 includes a display switch SW3 and a resistor R1.
3. The 0 display switch SW3, which is a series connection of priority lamps L5 consisting of light emitting diodes, is connected to the priority switches SW2 and 3! ! It is a rotary switch that moves
When giving priority to the sub-remote controller 60, the circuit is closed together with the priority switch SW2, and the priority lamp L5 is turned on.

In the control device 30, when the control device 3o is connected to a power line, a 5V power supply (not shown) is always operating, and the microcomputer is operating in a standby state.

In the sequence control m31, when the control device 30 is connected to the power line, it is always in a startup standby state, and the resistor 4
1.41a respectively detected terminals 36.37
, and each terminal voltage V, between terminals 38 and 39. , v6°, the predetermined operating mode is determined.

In the sequence control unit 31, each terminal voltage V,. , V6°, as shown in Figure 5 or Figure 6, respectively, read 0.5 to 2.5V as the set temperature voltage, and
．． 5~5V is read as disconnection detection voltage, 0.05V
The following is read as the short circuit detection voltage between terminals 36 and 37 and between terminals 38 and 39.

Also, the terminal voltage on the main remote controller 50 side. For this, a voltage of 0.05 to O-3V, which is lower than the lowest voltage of 0.5V read as the set temperature voltage and higher than 0.05V as the short circuit detection voltage, is read as the operation switch operation voltage.

On the other hand, regarding the terminal voltage V6° on the sub-remote controller 60 side, the set temperature voltage of 0.5 to 2.5 is detected only when the priority switch SW2 is closed. The time when the voltage is detected is the time when the sub-remote controller 60 is used preferentially.

Conversely, when the priority switch SW2 is in the open state, the terminal voltage ■6° is higher than the set temperature voltage of 0.5 to 2.5V, so the case where 3.5 to 5V is detected is When in use.

In this way, the terminal voltage V 6 (3.5 to 5 for 1
When the voltage (2) is detected, it cannot be determined whether it is due to a disconnection or the like or because the priority switch SW2 is open, but in either case, the variable resistance circuit 61 of the sub remote controller 60 Since the setting state has no bearing on control, there is almost no problem in practice.

The operation mode is determined by each terminal voltage V. , V6o are determined by determining whether they are connected, conductive, or short-circuited based on whether they are the disconnection detection voltage or the set temperature voltage set as described above.

The operating modes include a multi mode in which the main remote controller 50 and sub remote controller 60 are both connected, an automatic mode in which neither remote controller is connected, and a single mode in which only the main remote controller 50 is connected. be.

In cases other than automatic mode, the sequence control W unit 31
When an operation signal from the operation switch SW1 is detected, the machine enters a standby state, and in the automatic mode, it is always in a standby state.

In the case of multi-mode, based on the terminal voltage ■6° on the side of the sub-remote controller 60 equipped with the priority switch SW2, which remote controller is to be controlled based on the set temperature information is determined, and the operation signal of the operation switch SWI is determined. When the controller detects this and enters the operation standby state, the set temperature from the selected remote controller is transmitted to the temperature control controller 32.

In addition, in the operation standby state, the operation standby state and
The selected remote controller selection information is transmitted to the display control unit 35.

In the standby state, the power to the drive circuits for driving the blower 12 of the gas water heater 1 and the answering device is turned on.
When water flow to the heat exchanger 13 is detected by the water flow switch 19, combustion is started by performing predetermined ignition sequence control, and when water flow stop is detected, combustion is stopped by fire extinguishing sequence control.

On the other hand, each terminal voltage ■,. , v6° detects a short circuit between each terminal, it is assumed to be an abnormality detection state, and an abnormality display signal is sent to the remote controller for which the short circuit has not been detected. If there is a short circuit between the terminals, it will operate in automatic mode.

When the temperature control unit 32 enters the operation standby state and the operation state, the temperature control unit 32 reads the set temperature voltage from the selected remote controller before the water flow is detected, and starts heating based on the temperature information detected by the outlet hot water temperature thermistor 25. The amount is determined and transmitted to the combustion control section 33.

Here, as shown in Fig. 12, the actual resistance value r of the variable resistor in the variable resistance circuit of the remote control is smaller than the standard resistance value r0, and the resistance value 1"t is the limit on the smaller tolerance side of the variable resistor. (Resistance value r, = standard resistance value roX
0.9), a constant resistance value r2 can always be obtained by setting the contact position of the variable resistor to the maximum resistance value.
is defined as the limit resistance value for setting the minimum temperature cosin, and as shown in FIG.
iin is set, and as the resistance value r of the variable resistor becomes smaller than this constant resistance value r2,
The temperature is set high.

That is, when the resistance value r of the variable resistor is a constant resistance value r2, the constant voltage v given as the terminal voltage of the remote control
In the case of 2 or more, the set temperature is the lowest temperature Titn,
As the terminal voltage becomes lower than this constant voltage v2, the set temperature is set higher.

Note that this constant voltage 2 is equal to 2, which is shown as the highest voltage as the set temperature voltage in FIGS. 5 and 6.
The voltage is lower than 5V, and the terminal voltage is 2.5V when the resistance value is r3.

Further, the maximum temperature TlaX of the set temperature is set when the terminal voltage is 0.
Set when the voltage is 5V.

In automatic mode, the system is always on standby, and when water flow is detected, it operates at a constant high temperature (e.g. 60°C or 75°C) set in advance by a dip switch (not shown), and in standalone mode. Then, it enters a startup standby state, and operates only according to the operation status of the main remote controller 50, similar to when the main remote controller is prioritized in the multi mode described above. Terminal 36.3
If the connection status is abnormal, such as a short circuit between 7,
It operates as in the case of automatic mode, and operates with the constant temperature set at the above-mentioned high temperature as the set temperature.

The combustion control section 33 controls the blower 12 and the governor proportional valve 23 according to the heating amount determined by the temperature control section 32 to control the combustion amount of the burner group 11 .

The display control unit 35 controls each lamp of each remote controller 50, 60 to turn on, turn off, or blink based on the information of the selected remote controller and the combustion information detected by the flame rod 15, depending on the respective operating conditions. The remote control drive circuit 40 . - Send each to 40a.

In the remote control drive circuit 40.40a, the supply voltage from 5 Veil is applied to each terminal 36.40 through a resistor 42.42a.
38, and is constantly supplied as a detection voltage v rent to each remote control 50.60 connected to each terminal 36.38.

The remote control drive circuit 40.40a has a detection voltage V r
In addition to oI, the DC voltage from the 5V power supply is applied to each terminal 36.3.
8 and directly to each remote control 50.60, a switching transistor 43.43a
are connected to each terminal 36.38 via a diode 44.44a.

Furthermore, switching transistors 45.45a are connected to each terminal 36.38 in order to directly supply DC voltage from a 12V power supply (not shown) to each remote controller 50.60.

Note that a switching transistor 46.46a is provided before the transistor 45.45a, and each transistor 43.43a, 46.46a is connected to the display control unit 35.
each controlled by

In the remote control drive circuit 40, each switching transistor 43.45 applies a respective voltage to the terminal 36 only when turned on by a control signal, and when both transistors 43.45 are turned off, voltage is applied from the 5V power supply. Only the voltage of the resistor 4 is used as the detection voltage V rel.
2 to terminal 36.

When the transistor 43 that directly supplies power from the 5V power supply and the transistor 45 that directly supplies power from the 12V power supply are both off, the detection voltage V rem from the 5V power supply is controlled by the variable resistance circuit in the main remote controller 50. A voltage is applied to a series circuit consisting of a parallel circuit of 51 and operation switch circuit 52 and a resistor 42, and a divided voltage corresponding to the combined resistance is applied to the terminal 36 according to the operating state of the variable resistance circuit 51 in the main remote control 50. Terminal voltage Vri. appears as

Also in the remote control 1IWjJ circuit 40a, similar to the remote control drive circuit 40, respective voltages are applied,
When both transistors 43a and 45a are off,
A voltage corresponding to the operating state of the remote controller 60 appears at the terminal 38 as a terminal voltage V60.

The display control section 35 controls each remote control 50.60 according to the control state of the sequence control section 31 via the remote control drive circuit 40.40a configured as described above.

The lighting, flashing, and extinguishing of each lamp depends on the operating status of the gas water heater 1: whether it is in standby mode, whether it is in combustion mode, and whether an abnormality is occurring. , and a separate display is performed for each remote controller 50, 60 depending on whether or not that remote controller is in the priority state.

The relationship between the display state on each remote controller 50, 60 and the operating state of the gas water heater 1 is summarized in Table 1.

(The following is a blank space.) In the table below, control of the remote control drive circuit 40 by the display control unit 35 will be explained. Note that the remote control drive circuit 40a will be described in parentheses 0.

■When lighting only the operation lamp L2 (L4) without lighting the combustion lamp LL (L3), turn on the transistor 45 (45a) and turn on the transistor 45 (45a).
Power from the 2V power supply is supplied almost continuously.

In this case, since the set temperature signal is read from the remote controller that receives this control, the power supply from the 12V power supply is stopped for a short period of time, and only the detection voltage V rel is supplied from the 5V power supply. The time is set at intervals of 30m5, each BmS.

■If you want to blink only the operation lamp L2 (L4) without lighting the combustion lamp LL (L3), turn on and off the transistor 45 (45a) according to the blinking cycle.
As shown in FIG. 8, power is supplied intermittently from a 12V power supply. At this time, the blinking cycle is, for example, 2.7SeC
On, 2.73eC off.

■ Combustion lamp Ll (L3) and operation lamp L2 (L
4), when both transistors 43 (
43a> is turned on to continuously supply power from the 5V power source, and the transistor 45 (45a> is controlled to turn on for 5mS and turn off for 5mS with continuous constant pulses with a pulse period of 10m5, for example. This is repeated, and as shown in FIG. 9, the power from the 12V power source converted into pulses is supplied overlappingly with the power from the 5.times. power source.

In this case as well, the time period during which both the power from the 5Vtfi and the power from the 12V power source are stopped and only the detection voltage Vrel is supplied is provided at intervals of 30m5, BmS each.

■If only the combustion lamp Ll (L3) is lit continuously and the operation lamp L2 (L4) is blinked,
For example, as shown in FIG. As shown in
5. Control the power from the power supply so that it changes according to the blinking cycle.

■If you want to blink only the combustion lamp LL (L3) without lighting the operation lamp L2 (L4), turn off the transistor 43 (43a), stop the power from the 5V power supply, and As shown, pulse period 10m
The power from the 12V power supply converted into 5 continuous constant pulses is supplied intermittently according to a blinking cycle in which, for example, ISeC is turned on and ISec is turned off.

5 ■ Transistor 43 that directly supplies power from the power supply
(43a) and the transistor 45 (45a) for directly supplying power from the 12V power supply are both off, and when only the detection voltage Vrem from the 5V power supply is continuously supplied, the combustion lamp LL (L3 ) and operation lamp L2 (L4) are not lit.

In addition, in each of the cases of ■ to ■ above, even if each lamp is lit or blinking, the remote control 50
In order to be able to read the operating status of (60), as in the case of ■, the detection type J from the 5V power supply is
The time when only JVrelfi is supplied is 3 mS each, 3
They are placed at intervals of 0m5.

In this case, since only the detection voltage v rcn+ is supplied for a very short time of 3 mS, each lamp can be lit and blinked without any visual problem.

Note that in the sequence control section 31 described above, the terminal 36
．． If 0.05V or less is detected as the short circuit detection voltage between 37 and 37, control is performed so that each transistor 43.45 in the remote control drive circuit 40 is not turned on in order to protect each transistor 43.45 from damage etc. to stop power supply.

Similarly, the short circuit detection voltage between terminals 38 and 39 is 0.0.
If 5V or less is detected, the remote control drive circuit 40
The power supply by each transistor 43a, 45a in a is stopped.

The water 1 control unit 34 controls the electric water flow rate control bag W18 based on the temperature information detected by the outlet hot water temperature thermistor 25 to limit the flow rate exceeding the heating capacity from passing through the heat exchanger 13.

Next, the operation of temperature setting in the gas hot water supply 31 of this embodiment having the above configuration will be explained.

The operation mode is determined according to each terminal voltage, and when the operation switch SW1 is operated to enter the operation standby state, the detection voltage V is sent to the selected remote controller at a predetermined period as shown in FIG. When only rel is applied and each lamp is lit or flashing, if the user sets the hot water temperature using the variable resistance circuit of the selected remote control, the terminal voltage will change according to the resistance value of the variable resistance circuit. Read as set temperature signal.

At this time, if the connection state of the selected remote control is normal and the resistance value of the variable resistor is equal to or higher than the constant resistance value r2, the lowest temperature becomes the set temperature, and if it is lower than that, each resistance value The smaller the resistance value is, the higher the temperature is set.

At this time, a detected temperature signal is also read from the outlet hot water temperature thermistor 25, and the combustion amount is determined using these as heating information.

Thereafter, when a hot water tap (not shown) is opened, ignition is performed in a predetermined sequence, and the burner group 11 is ignited.

After ignition, when you operate the variable resistor on the remote control, a new hot water temperature is set according to the resistance value.

On the other hand, when only the main remote control 50 is connected and is apparently operating in standalone mode, if the connection state is abnormal and a disconnection is detected, it will operate in automatic mode and The fixed temperature that has been tightened is set as the set temperature, and temperature control and combustion control are performed.

In this case, although the set temperature cannot be changed using the main remote control 50, a constant high temperature is set, which is the minimum I! ! ! Because of the ability to
Even if repairs are delayed, you can overcome the emergency situation.

Therefore, the user's dissatisfaction can be suppressed to some extent, and the repairer can have more time to deal with repairs, reducing the mental burden.

In this example, the supply voltage to the variable resistor was supplied through the resistor, and the voltage at the connection was detected and set as the set temperature voltage, but the voltage from the power supply section was directly supplied to the variable resistor. A resistor may be provided to allow the current supplied and passed through the variable resistor to flow to the ground circuit, and the divided voltage to this resistor may be used as the set temperature voltage.

In this embodiment, a sliding type variable resistor is shown, but a rotating type variable resistor may also be used.

In this embodiment, water flow is detected by the water flow switch, but water flow may be detected by a flow rate detection signal from a flow rate sensor.

In this example, the terminal voltage for connecting the remote control is detected, and the connection state is comprehensively determined to perform control. However, only the disconnection of the terminal voltage is determined by a separate circuit, and the Depending on the result, the set temperature may be set to a constant high temperature.

In the above embodiments, a gas water heater is shown, but it may also be a water heater equipped with a combustor that uses other fuels such as oil, or a water heater that uses electric heating, or a water heater that is equipped with a variable resistor for temperature setting. Any temperature control device may be used.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the functional configuration of the control device for the gas water heater of this embodiment, Fig. 2 is a schematic configuration diagram showing the gas water heater of this embodiment, and Fig. 3 shows the main remote control of this embodiment. 4 is a circuit diagram showing the sub-remote controller of this embodiment, FIG. 5 is a voltage explanatory diagram showing the discrimination voltage for the main remote controller in the control device of this embodiment, and FIG. 6 is a control diagram of this embodiment. A voltage explanatory diagram showing the discrimination voltage for the sub-remote controller in the device, Figures 7 to 11 are voltage waveform diagrams for lighting the lamps of each remote controller, and Figure 12 shows the contact position and resistance of the variable resistor in this example. FIG. 13 is a characteristic diagram showing the relationship between the resistance value of the variable resistor, the terminal voltage, and the set temperature in this embodiment. In the figure, 1... Gas water heater (water heater), 30... Control device (water heater temperature control device), 36.37... Terminal (two terminals), 40A, 40B... Electric wire (2 wires), 50... Main remote control (operation unit), VRl.
...Variable resistor.

Claims (1)

[Claims] 1) A temperature control device for a water heater that sets a target temperature according to a set resistance value of a variable resistor connected between two terminals by two electric wires, wherein the set resistance value is a predetermined value. When the resistance value is higher than the resistance value, the target temperature is set to the lowest temperature, and the smaller the set resistance value is, the higher the target temperature is set, and the connection state between the two terminals and the variable resistor is A temperature control device for a water heater, wherein the target temperature is set to a high temperature in the case of a disconnection state.