JPH0713537B2 - Flow control device for water heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water heater flow rate control device having a flow rate control valve for controlling the flow rate of water passing through a water circuit including a heat exchanger.

[Prior Art] A water heater is provided with a flow rate control valve that drives a valve body by a gad motor in order to adjust a flow rate passing through a heat exchanger to a flow rate that matches a heating capacity of a burner or the like.

In addition, a water solenoid valve is installed in the piping to the bathtub to automatically start filling the bathtub and automatically stop filling when the set amount of water or the set water level is reached. Some have.

In such a device that performs automatic filling, a water hammer is likely to occur when opening and closing the water solenoid valve, so the water solenoid valve is opened or closed while the flow rate is regulated by the flow rate control valve.

In this case, as a water flow control valve to control the flow rate,
A gad motor is used because the valve must be driven reliably against the high water pressure of the waterworks.When the water volume control valve reaches the maximum opening and the minimum opening related to the opening / closing operation of the water solenoid valve. When the gad motor is driven, the gad motor is driven in order to stop the driving of the gad motor immediately in order to detect the maximum opening or the minimum opening. The drive is stopped when each opening limit is detected.

[Problems to be Solved by the Invention] However, when an abnormality occurs in the opening limit detection means for detecting each opening limit, the gad motor will continue to operate even if the valve body of the water flow control valve becomes immovable. When the gad motor is driven and the gad motor is in a locked state, an excessive current flows, so that a driver including a transistor or an IC for energizing the gad motor may generate heat and be damaged.

When the abnormality of the opening limit detection means cannot be recovered,
Since the motor is repeatedly energized each time the motor is driven, the driver heats up each time and the possibility of damage is further increased.

The present invention provides a driver for driving a motor in a flow control device of a water heater including a means for detecting the opening limit of a flow rate control valve, when some abnormality occurs in the opening limit detection means. The object of the present invention is to protect water and to quickly supply hot water without wastefully driving the flow rate control valve when the abnormality is continuous and cannot be returned to normal operation.

[Means for Solving the Problems] The present invention provides a flow control valve driven by a motor in a water circuit including a heat exchanger, and sets the maximum opening limit or the minimum opening limit of the flow control valve. In a flow rate control device for a water heater, which comprises an opening limit detection means for detecting, and which stops driving the motor when the opening limit detection means detects the opening limit of the flow rate control valve, If there is no detection by the opening limit detection means after the energization of No. 1 is started, the energization to the motor is stopped when the energization time to the motor exceeds a predetermined time, and the number of times the suspension is stopped. When the number of times exceeds the predetermined number, the technical means is not to energize the motor thereafter.

[Operation] According to the present invention, even if an abnormality occurs in the opening limit detection means of the flow rate control valve and the flow rate control device is driven beyond the opening limit, a predetermined amount is maintained after the energization of the motor is started. When the time has passed, even if there is no detection by the opening limit detection means,
Power supply to the motor stops halfway.

Therefore, even if the motor is fixed and an excess current is supplied, the motor is not energized for a predetermined period of time, so that it is possible to suppress overheating of the energization element for energizing the motor.

Further, when the number of times of intermediate stop exceeds a predetermined number, the motor is not energized and the flow rate control valve is not driven at all.

Therefore, the water heater operates regardless of the operation of the flow rate control valve.

[Effects of the Invention] In the present invention, since the motor is not energized for more than a predetermined time, the energizing element (motor driver) for energizing the motor is not overheated and damage can be prevented.

Further, when the midway stop repeatedly occurs and the number of times exceeds a predetermined number, the hot water supply operation is performed regardless of the operation of the flow rate control valve, so that there is no problem in the hot water supply operation.

EXAMPLES Next, the present invention will be described based on examples.

The gas water heater 1 with a hot water filling function shown in FIG. 2 performs hot water filling to several hot water inlets equipped with hot water taps and automatic hot water filling to the bathtub B. A heat exchanger 10 for heating water supplied from a water supply source such as water supply, and two sets of burner groups 3 and 3a in which a plurality of plate-shaped burners are arranged as a heating source are provided. 2 is provided with a blower 4 for supplying combustion air to the burner groups 3 and 3a.

In the gas supply path 5 for supplying the fuel gas to each of the burner groups 3 and 3a, the source solenoid valve 5a for controlling the supply of the fuel gas, the opening degree is adjusted according to the target combustion amount, and the supply amount of the fuel gas is adjusted. A governor proportional valve 5b is provided for this purpose, the gas supply path 5 is branched downstream of the governor proportional valve 5b, and a small solenoid valve 6 that opens at the time of combustion and closes when stopped is provided on the burner group 3 side. The
A small solenoid valve 6a that is opened and closed according to the target combustion amount is provided on the side of the burner group 3a, and fuel gas is ejected downstream of each small solenoid valve 6 and 6a corresponding to each burner group 3 and 3a. And a manifold 7 which is divided into two chambers 7a and 7b.

Further, in the combustion case 2, ignition electrodes 8 of the burner groups 3 and 3a and a frame rod 9 for flame detection are provided.

On the other hand, a water supply pipe 11 for supplying water to the heat exchanger 10 is connected to a water supply pipe or the like, and a filter 12 for preventing mixing of foreign matters and the like is provided in the most upstream part, and is supplied downstream thereof. Water temperature thermistor 13 and flow sensor 14
Is provided.

The hot water outlet pipe 15 from which the hot water flows out of the heat exchanger 10 has a heat exchanger.
Hot water temperature thermistor 16 that detects the temperature of water heated by 10
Is provided further downstream, and a hot water servo 17 for adjusting the flow rate of hot water passing through the heat exchanger 10 is provided.

As shown in FIG. 10, the hot water servo 17 has a taper-shaped valve body 17 at the tip of the rotary shaft supported by the feed screw mechanism.
a is fixed, this valve body 17a is arranged in the opening, and the rotating shaft is connected to the output shaft of the gad motor 17b.
When 7b rotates, the feed screw mechanism described above causes the valve body 17a to move.
Moves in the opening to adjust the opening, thereby adjusting the passing flow rate.

The hot water outlet pipe 15 is branched downstream of the hot water amount servo 17, and one is a hot water supply pipe 18 connected to several hot water supply ports (not shown).
The other is a filling pipe 19 connected to the bathtub B.

The hot water supply pipe 18 is connected to a bypass pipe 20 branched from the water supply pipe 11 downstream of the incoming water temperature thermistor 13, and the bypass pipe 20
A bypass solenoid valve 21 for controlling the communication between the water supply pipe 11 and the hot water supply pipe 18 by opening and closing the bypass pipe 20 and the bypass pipe 20.
A water flow switch 22 is provided for detecting the water flow flowing through.

A bypass solenoid valve 21 is provided at the connection between the hot water supply pipe 18 and the hot water supply pipe 15.
Check valve 23 for preventing the inflow of water from the bypass pipe 20 side communicating with the water supply pipe 11 to the water filling pipe 19 when the
In addition, the hot water supply pipe 18 is provided with a pressure relief valve for protecting the heat exchanger 10 and the like from high pressure generated by an abnormality such as an afterfire.
24 is provided integrally with the check valve 23.

The water filling pipe 19 has a water filling solenoid valve for controlling the water filling.
25 and a check valve 26 for preventing the backflow of hot water from the bathtub B are provided. The check valve 26 operates upstream of the check valve 26 when a negative pressure is generated due to water supply interruption or the like, and the hot water outlet pipe 15 A negative pressure actuating valve (vacuum breaker) 27 that opens the air to the atmosphere is provided.

The gas water heater 1 with a water filling function of the present embodiment having the above configuration is controlled by the control device 30 provided in the water heater case 1A.

The control device 30 includes a microcomputer 31 and a drive circuit, and includes a combustion control unit for controlling the combustion state of each burner group 3, 3a and the flow rate of hot and cold water passing through the heat exchanger 10 and automatic hot water filling or high temperature soldering. It has a function part with a water amount control part for controlling water flow for hot water, and the control device 30 has a bath remote control 41 and a main remote control to set and operate an operating state.
42 are equipped.

The control device 30 performs a hot water supply operation when water passage in the hot water supply pipe 18 is detected by opening a hot water supply tap (not shown), and also by operating a hot water switch or a hot water switch (not shown) provided on the bath remote controller 41. An automatic filling operation and a high temperature hot water operation are performed, and combustion control and water amount control are performed in each operation.

First, the hot water supply operation will be described with reference to FIG.

In the hot water supply operation, when it is detected that the flow rate L detected by the flow rate sensor 14 is equal to or more than the operation start water amount when the hot water tap (not shown) is opened (YES in step 1), the water flow detection state is determined and a predetermined value is determined. Ignition control is performed in sequence (step 2).

Here, the operation start water amount is a water amount selected at each operation according to the feed water temperature detected by the incoming water temperature thermistor 13 from the water amount values set in advance in eight stages, and one of them is 2.6 / Minutes are set.

Subsequent to the ignition control, the hot water supply set temperature set by the remote controller is read as the target temperature in the temperature control.

When the burner groups 3 and 3a are ignited by the ignition control and the flame rod 9 detects ignition, temperature control is performed based on the target temperature, the thermistors 13 and 16, and the detection signals from the flow rate sensor 14 (step 3). ).

In the temperature control, feedforward control is performed based on the target temperature, the temperature detected by the incoming water temperature thermistor 13 and the flow rate L detected by the flow rate sensor 14, and the hot water temperature detected by the hot water temperature thermistor 16 reaches a predetermined condition. In that case, feedback control is further performed based on the temperature detected by the hot water temperature thermistor 16.

Thereafter, in the hot water supply operation, when it is detected that the hot water supply plug is closed and the flow rate L detected by the flow rate sensor 14 becomes equal to or less than the amount of water in which operation is stopped (YES in step 4), predetermined digestion control is performed (step 5). ).

This operation stop water volume was set in the same way as the operation start water volume.
It is selected from among the stages according to the feed water temperature detected by the incoming water temperature thermistor 13.

When 2.6 / min is selected as the operation start water amount, 1.9 / min is selected as the operation stop water amount.

In the hot water supply operation, in the automatic hot water filling operation and the high temperature hot water operation described later, even when it is detected that the hot water tap of the hot water inlet is opened by the water flow switch 22 of the bypass pipe 20, The hot water supply operation is preferentially performed by interrupting the hot water supply operation.

Therefore, after the digestion control in the hot water supply operation is finished, it is determined whether or not the hot water supply operation was caused by an interrupt operation in another automatic hot water filling operation or high temperature hot water supply operation.

In the case of the interrupt operation during the automatic filling operation (YES in step 6), the process proceeds to step 13 in the automatic filling operation described later.

In addition, the automatic filling operation is not in progress (in step 6
NO), in the case of high temperature hot water operation (in step 7
YES), Step 4 in high temperature hot water operation shown in Fig. 7
Move to 3.

Next, the automatic filling operation will be described with reference to FIG.

The automatic filling operation is performed according to the filling instruction from the filling switch of the bath remote control 41, and when the operation of the filling switch is detected (YE in step 11).
S), whether the hot water supply operation is being performed or not
It is determined based on the value of the detected flow rate L and the ignition detection signal.

In this determination, if the detected flow rate L is equal to or less than the operation stop water amount, it is determined that the hot water supply operation is not performed regardless of the ignition detection signal. If there is a detection signal, it is determined that the hot water supply operation is being performed, and if there is no ignition detection signal, it is determined that the hot water supply operation is not being performed.

When it is determined that the hot water supply operation is not performed (NO in step 12), the automatic hot water filling operation in step 13 and subsequent steps is continued as follows.

When it is determined that the hot water supply operation is being performed (YES in step 12), a message to that effect is displayed on the display device of the bath remote controller 41, and the process proceeds to step 4 to wait until the hot water supply operation is completed.

In step 13, valve opening control for opening the water filling solenoid valve 25 is performed.

The valve opening control is a control for driving the hot water amount servo 17 in association with the hot water filling solenoid valve 25 in order to prevent a water hammer when the hot water filling solenoid valve 25 is opened, and the details will be described later.

When the water filling solenoid valve 25 is opened by the valve opening control, the water normally passes through the water filling pipe 19 accordingly, and the flow sensor
By 14, the detected flow rate L exceeds the operation start water amount, and water flow is detected.

When water flow is detected (YES in step 14), ignition control is performed in a predetermined sequence as in the hot water supply operation (step 15), and temperature control is further performed after ignition detection by the frame rod 9. Is performed (step 16).

With this temperature control, the bath remote control 41
Control is performed by using the water filling temperature set in step 1 as the target temperature.

During this automatic hot water filling operation, if the user opens the hot water tap at the hot water inlet to supply hot water, the bypass pipe 20
The water flow switch 22 inside detects that and is turned on, and as described above, the hot water supply operation is performed prior to the automatic water filling operation.

When it is detected that the water flow switch 22 is in the ON state (YES in step 17), the closing control for closing the water filling solenoid valve 25 is performed to change the hot water supply operation based on the hot water supply set temperature by the remote controller. Perform (step 18) and move to step 2.

On the other hand, during the automatic hot water filling operation, if there is no operation for the hot water supply operation (NO in step 17), the bath remote control 41
Until the amount of filling water set in advance is reached (NO in step 19), the filling operation at the filling temperature set by the bath remote controller 41 is continued.

When the integrated value of the flow rate L detected by the flow temperature sensor 14 reaches the set amount of filling water (YE in step 19)
S), the valve closing control for closing the water filling solenoid valve 25 is performed (step 20).

The valve closing control in step 20 is the same as step 18 described above.
The sequence is almost the same as the valve closing control in (1), and the details will be described later.

When the flow rate is decreased by the valve closing control and the flow rate L detected by the flow rate sensor 14 is less than the amount of water for which operation is stopped (YES in step 21), it is determined that the water flow has ended, and the predetermined fire extinguishing control is performed. Perform (step 22) and finish the automatic filling operation.

Next, the valve opening control in step 13 will be described with reference to FIG.

The valve opening control is for preventing a large amount of water from passing when the water filling solenoid valve 25 is opened, and the bypass solenoid valve 21 is first opened (step 31). This is, as mentioned above,
In order to prioritize hot water supply operation over automatic hot water filling operation,
The hot water supply pipe 18 and the water supply pipe 11 are connected by a bypass pipe 20 so that the hot water supply can be detected during the automatic hot water filling operation.

Then, in order to limit the passage flow rate, the opening degree of the hot water servo 17 is minimized (step 32).

After this, the water filling solenoid valve 25 is opened (step 33). At this time, since the flow rate is limited by the hot water amount servo 17, the passing flow rate is small, and the occurrence of water hammer can be eliminated.

After that, the opening degree of the hot water servo 17 is increased (step 3
4) Increase the flow rate again. This allows the flow sensor 1
Make sure to increase the flow rate passing through 4 to make the detected flow rate L equal to or higher than the operation start water amount.

Next, the valve closing control in steps 18 and 20 will be described with reference to FIG.

The valve closing control is for preventing the occurrence of water hammer similarly to the above-mentioned valve opening control, and when the detected flow rate L at the time of performing the valve closing control exceeds the water filling stop water amount (N in Step 35).
O), decrease the opening of the hot water servo 17 (step 36)
The process proceeds to step 35, and steps 35 and 36 are repeated until the detected flow rate L becomes equal to or less than the amount of water to stop filling with water.

When the flow rate L detected by the flow rate sensor 14 is less than or equal to the amount of water to stop filling (YES in step 35), the flow rate is sufficiently small so that water hammer does not occur, so the filling solenoid valve 25 is closed. (Step 37), the bypass solenoid valve 21 is also closed (step 38).

Here, when switching to hot water supply operation, the water filling solenoid valve 25
Even if is closed, hot water can flow out from the hot water supply port, so that a water hammer is unlikely to occur. On the other hand, when hot water filling is completed, there is no escape for hot water, so a water hammer is likely to occur.

Therefore, the amount of water to stop filling the water is set to about 10 / min in step 18 so as to switch to the hot water supply operation as soon as possible, and in step 20, it is set to about 4.5.
/ Minute is set for each.

Next, the high temperature hot water operation will be described with reference to FIG.

High-temperature hot water operation is performed when the temperature of the hot water in bathtub B decreases.
It is an operation operation for heating hot water instead of reheating with a bath kettle, and supplies hot water of 80 ° C to the bathtub B for 5 minutes at a preset condition, for example, for 3 minutes only. is there. At this time, the bath remote control 41
Can be set arbitrarily.

Here, when the hot water switch of the bath remote controller 41 is operated to give an instruction, hot water is hotly supplied for a predetermined time in response.

When the operation of the hot water switch is detected (YES in step 41), it is determined whether or not the hot water supply operation is being performed based on the detected flow rate L of the flow rate sensor 14 and the ignition detection signal as in the case of the automatic hot water filling operation. When the hot water supply operation is not performed (NO in step 42), the high temperature hot water operation is continued.

On the contrary, when the hot water supply operation is being performed (YES in step 42), the process proceeds to step 4 and waits until the hot water supply operation is completed.

When the high-temperature hot-water supply operation is performed by the determination in step 42, the valve opening control shown in FIG. 5 is performed as in the case of the automatic hot-water filling operation (step 43).

When water flow starts with valve opening control and water flow is detected when the detected flow rate L of the flow rate sensor 14 is equal to or higher than the operation start water amount (YES in step 44), ignition control (step 45) and high temperature control are performed. It continues (step 46).

In the high temperature temperature control, the target temperature for temperature control is set to 80 ° C regardless of the temperature set by the main remote controller 42 or the bath remote controller 41, and the detected temperature of the hot water temperature thermistor 16 provided in the hot water pipe 15 is set to 80 ° C. The combustion amount of the burner groups 3 and 3a is determined so that the temperature becomes ℃, and the governor proportional valve is correspondingly determined.
The drive control of the blower 4 and the small solenoid valves 6 and 6a and 5b.

The high-temperature hot-water movement is a relatively short-time operation, but if the hot-water tap is opened for hot-water supply operation during this operation, it is detected by the water flow switch 22.

If the ON state of the water flow switch 22 is detected during the high-temperature hot water operation (YES in step 47), step 52
As shown below, the hot water supply operation is changed.

If the ON state of the water flow switch 22 is not detected during the high-temperature hot water operation (NO in step 47), it is determined whether or not the hot water according to the predetermined condition is completed, and if it is not completed (step No in 48), the process proceeds to step 46.

As a pre-determined condition, when the hot water operation is completed after the operation time of 3 minutes has passed (step
If YES in 48), first perform fire suppression control (step 4
9) When the solenoid valve is closed to stop the combustion of the burner to stop the heating and then the hot water temperature detected by the hot water temperature thermistor 16 becomes 50 ° C or lower (YE in step 50).
S), valve closing control is performed and the water filling solenoid valve 25 is closed (step 51).

As a result, even if hot water is supplied immediately after the high-temperature hot-water operation is completed, the hot water that has cooled to 50 ° C. or less only flows out to the hot-water supply port, so there is no risk of burns and it is safe.

On the other hand, when hot water supply is detected in step 47 and hot water supply operation is performed during high temperature hot water operation (YES), in order to prevent hot water from flowing out of the hot water supply port against the intention of the user, It is controlled as follows.

First, the target temperature for temperature control, which was determined to be 80 ° C. in the high-temperature hot water operation, is changed to the hot water supply set temperature set by the remote controller (step 52).

Normally, the hot water supply set temperature is lower than the target temperature of 80 ° C. in the high temperature hot water operation, so the opening degree of the hot water amount servo 17 is further increased to increase the flow rate (step 53), and the hot water temperature is quickly lowered. Try.

After that, it is determined whether or not the hot water temperature detected by the hot water temperature thermistor 16 is lower than the switching temperature Ta determined based on the hot water supply set temperature set by the remote controller, and the hot water temperature is lower than the switching temperature Ta. If so (YES in step 54), the valve closing control is performed (step 55), the process proceeds to step 2, and the hot water supply operation is performed.

Next, the determination of the switching temperature Ta in step 54 will be described with reference to FIG.

This switching temperature Ta is intended to ensure safety at the hot water supply port and to supply hot water as quickly as possible when the hot water supply operation is switched to the hot water supply operation.

Here, when the user sets the hot water supply set temperature Tset to a relatively high temperature of 50 ° C. or higher (YES in step 61), sufficient attention is paid to the risk of burns and the like. Therefore, Ta = Tset + 15 [° C], that is, the switching temperature Ta, in order to quickly supply hot water.
As a result, a temperature 15 ° C higher than the hot water supply set temperature Tset is determined (step 62), and when the temperature not reaching 50 [° C] is set as the hot water supply set temperature Tset (NO in step 61), the temperature of the hot water is high. Since it is considered that sufficient attention has not been paid, Ta = 57 [° C], which is a safe temperature even if a hand or the like touches hot water, that is, 57 [° C] is uniformly set as the switching temperature Ta (step 63).

The above relationship between the hot water supply set temperature Tset and the switching temperature Ta is
Shown in the figure.

After the hot water supply operation is completed, as described above, it is determined whether the automatic hot water filling operation or the high temperature hot water operation is in progress, and if there is an interrupt during each operation and each operation is interrupted. Restarts each operation.

In that case, when restarting the automatic hot water filling operation, the remaining hot water filling flow rate is integrated based on the stored flow rate integrated value, and in the high temperature hot water operation, the operation is performed only for the time that has already been deducted before the hot water supply operation. To be done.

Further, the flow rate control by the hot water amount servo 17 is performed in parallel with the temperature control in each operation described above. In this flow rate control, the actual maximum heating amount is calculated from the hot water temperature, the incoming water temperature and the flow rate detected by each thermistor and the flow rate sensor 14, and the control values of the burner groups 3 and 3a at the time of operation, and this is calculated. With respect to the maximum heating amount, the maximum flow rate at which hot water can be supplied or filled is calculated from the set temperature and the incoming water temperature, and the hot water servo 17 is controlled to adjust the opening degree so as to obtain this maximum flow rate. As a result, control can be performed that makes the most of the maximum capacity of each device, regardless of variations due to manufacturing.

Next, regarding the configuration for driving the hot water servo 17,
A brief description will be given based on FIG.

As described above, the hot water servo 17 drives the valve body 17a which is moved by the feed screw mechanism by the gad motor 17b, and the gad motor 17b is driven by the driver unit 32 controlled by the microcomputer 31 in the normal rotation drive or the reverse rotation drive. The electric current for is energized.

Here, the driver unit 32 is composed of a driver IC that energizes the gad motor 17b in response to a normal rotation signal or a reverse rotation signal from the microcomputer 31, and together with the microcomputer 31 forming the control device 30 and other drive circuits, the control board 30A. It is fixed to.

On the other hand, when the valve body 17a reaches a position where it reaches the maximum limit opening position where it becomes immovable by the feed screw mechanism when it is driven further, or when it reaches a position where it reaches the minimum limit opening position. A fully open position sensor 17c and a fully closed position sensor 17d for detecting the respective limit opening degrees are provided.

These position sensors 17c and 17d use Hall ICs, and when the valve body 17a reaches the position where the maximum limit opening shown by the solid line in FIG. 10 is reached, it is detected by the fully open position sensor 17c, and conversely the two When the position reaches the minimum limit opening indicated by the dotted line, it is detected by the fully closed position sensor 17d, and each detection signal is transmitted to the microcomputer 31.

The gad motor 17b, the driver unit 32, the position sensors 17c, 17d, and the microcomputer 31 are connected by connector terminals 30B, 30C provided on the control board 30A, respectively.

In the controller 30, based on the above configuration, when driving the hot water servo 17 to the minimum opening degree in step 32,
Alternatively, in step 34, when the hot water servo 17 is set to the maximum opening degree, in order to promptly drive to each opening, regardless of the flow rate detected by the flow rate sensor 14, as the limit opening control of the hot water servo, As shown in FIG. 1, control is performed as follows.

When an instruction to set the hot water servo 17 to the maximum opening or the minimum opening is given by the control in the microcomputer 31,
Gad motor 17 stored in the memory of the microcomputer 31
It is judged whether or not the number n of half-way interruptions of energization of b exceeds a predetermined number x times (step 71).

Here, the midway stop means the gad motor 17 as described later.
When the energization time to b exceeds a predetermined time, energization is stopped to protect the driver unit 32,
When the number n of half-way stops exceeds the predetermined number x, it is because the position sensors 17c and 17d provided for detecting the limit position of the valve body 17a of the hot water servo 17 are abnormal and the limit position cannot be detected. In this case, it is considered that the feed screw mechanism that supports the valve body 17a is fixed, and the hot water servo 17 cannot be driven. Further, the predetermined number of times x is set to 3 times in the present embodiment, but can be set to any value such as 2 to 5 times.

When the number n of half-way stops does not exceed x times (NO in step 71), the driver unit 32 starts energizing the gad motor 17b (step 72).

When it is detected by the position sensors 17c and 17d that the maximum opening amount or the minimum opening amount has been reached after the hot water servo 17 is started (YE at step 73
S), and stop energizing the gad motor 17b (step 7
4) Then, the number n of halfway stops stored in the memory is reset to "0" times (step 75), and the drive control of the hot water servo 17 is completed.

The hot water servo 17 normally operates when operating normally.
It is possible to change the maximum opening and minimum opening in 20 seconds.

On the other hand, if it is not detected by the position sensors 17c and 17d that the maximum opening amount or the minimum opening amount has been reached since the driving of the hot water servo 17 was started (step 73
(NO in step No.), and energization is continued until 30 seconds elapse, and the process waits until the limit opening is detected (step 76).
NO), if it is not detected that the limit opening has been reached even after 30 seconds have passed (YES in step 76), the power supply to the gad motor 17b is suspended (step 77),
One is added to the stored number n of half-way stops (step 78), and the drive control of the hot water servo 17 is completed.

As a result, when the valve body 17a of the hot water servo 17 is fixed and the current value of the gad motor 17b increases, the energization is stopped before the driver unit 32 is overheated. Therefore, the driver unit 32 can be protected.

On the other hand, when the number of half-way stops n exceeds x times (YES in step 71), the drive control of the hot water servo 17 is terminated without performing the above control for energizing the gad motor 17b, and the hot water servo is performed. The operation is performed assuming that 17 is not provided.

Therefore, even if an abnormality occurs in each position sensor that detects the limit opening, hot water heated to a certain temperature can be used as a minimum operation, and hot water cannot be supplied due to a failure.

Also, due to the abnormality of each position sensor, the valve body of the hot water servo 17
Since the current for driving does not flow to the gad motor 17b when 17a is fixed and the gad motor 17b does not operate, the driver unit 32
Does not overheat.

Further, if the hot water servo 17 is fixed, as described above, the driver unit 32 does not become defective, so there is no need to repair or replace the control board 30A having a complicated configuration. Repairs are simplified because only one needs to be replaced.

Note that the stored number n of half-way stops is determined by the hot water servo 17
When the replacement is performed, the power is turned off or the reset switch or the reset terminal (not shown) is reset to be "0".

In the above embodiment, the hot water amount servo serving as the flow rate adjusting valve is provided on the downstream side of the heat exchanger, but it may be provided on the upstream side of the heat exchanger.

Further, in the above-described embodiment, all the hot water supplied or hot-watered passes through the heat exchanger, but a part of the water in the water supply pipe may bypass the heat exchanger to be hot-watered or water-filled. .

In the above embodiments, the burner using gas as the fuel is used as the heating source, but a fuel using petroleum as the fuel or electric heating may be used.

[Brief description of drawings]

FIG. 1 is a flow chart relating to a limit opening control of a hot water amount servo in a gas water heater with a water filling function according to the present embodiment, and FIG. 2 is a configuration diagram showing an outline of a gas water heater with a water filling function according to the present embodiment. FIG. 8 to FIG. 8 are flow charts for explaining the control operation by the control device of the present embodiment. FIG. 3 is a flow chart of hot water supply operation, FIG. 4 is a flow chart of automatic filling operation, and FIG. Fig. 6 is a flow chart of valve opening control in tensioning operation, Fig. 6 is a flow chart of valve closing control in automatic hot water filling operation, Fig. 7 is a flow chart of high temperature hot water operation, Fig. 8 is a flow chart regarding determination of switching temperature, and Fig. 9 is FIG. 10 is a characteristic diagram for explaining a switching temperature with respect to the hot water supply set temperature in the present embodiment, and FIG. 10 is a configuration diagram showing a configuration of a hot water amount servo and a configuration of a control device relating to its driving. In the figure, 10 ... Heat exchanger, 15 ... Outflow pipe (hot water supply circuit), 17
...... Hot water servo (flow control valve), 17b ...... Gad motor (motor), 17c ...... Fully open position sensor (opening limit detection means), 17d ...... Fully closed position sensor (opening limit detection means), 3
0 ... Control device (flow controller for water heater).

Claims (1)

[Claims] 1. A flow control valve driven by a motor is arranged in a water circuit including a heat exchanger, and an opening limit detection for detecting a maximum opening limit or a minimum opening limit of the flow control valve. In a flow rate control device for a water heater, which comprises a means for stopping the drive of the motor when the opening limit of the flow rate control valve is detected by the opening limit detection means, after the energization of the motor is started, When there is no detection by the opening limit detection means, when the energization time to the motor exceeds a predetermined time, the energization to the motor is stopped halfway, and when the number of the half stop exceeds the predetermined number of times. Is a flow controller for a water heater, wherein the motor is not energized thereafter.