JPH0718589B2 - Water amount control device for water heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water amount control device that controls a water valve that adjusts the amount of hot water supplied in a water heater, and particularly to a water valve that detects a hot water temperature and determines the heating capacity. The present invention relates to a water amount control device for a water heater having an opening degree correction function for correcting the opening degree.

[Prior Art] In a water heater, the maximum hot water supply amount lmax that can be heated is calculated from the inlet temperature Tin of water flowing into the heat exchanger provided in the water heater and the maximum heating capacity Qmax of the heating means such as a burner. It can be calculated by the following formula.

lmax = Qmax / (Tset-Tin) ... Here, Tset is a fixed hot water discharge target temperature predetermined in the water heater or a hot water discharge target temperature set by the user.

For this reason, the opening of the water valve is adjusted and the amount of water flowing into the heat exchanger is adjusted so that the maximum hot water supply amount lmax obtained by the equation is reached.

Further, in an actual water heater, there is a manufacturing error in the water valve that adjusts the amount of water, and in the heating means that determines the maximum heating capacity Qmax, for example, in the case of a burner using gas as fuel, the supplied fuel There are fluctuations in the gas pressure and manufacturing errors in the proportional valve that adjusts the fuel supply amount. Therefore, even if the heating means is controlled to output the maximum heating capacity Qmax and the water valve is controlled so as to obtain the maximum hot water supply amount lmax obtained by the formula, the actual hot water outlet temperature Tout becomes equal to the hot water outlet target temperature Tset. It may not be. Therefore, the temperature of the hot water discharged from the heat exchanger
Detects Tout and taps temperature To according to the tapping temperature Tset
The opening of the water valve is corrected so that ut can be obtained.

[Problems to be Solved by the Invention] However, the temperature of water supplied from a waterworks or the like to a water heater is rarely constant. There is a case where the temperature of water is supplied and the temperature of the supplied water gradually decreases while the hot water supply is continued. Therefore, the desired temperature for tapping
Even if Tset is constant, the heating capacity relatively changes with the change of the water temperature Tin. Therefore, in the conventional water heater, in order to set the outlet hot water temperature Tout to the hot water outlet target temperature Tset, the maximum hot water supply amount lmax is once calculated according to the new water inlet temperature Tin, and the water valve is controlled based on the calculated value. Further, the outlet heated water temperature Tout is detected, and the opening degree of the water valve is corrected again. Therefore, when the incoming water temperature Tin changes, it takes time for the outgoing hot water temperature Tout to reach the outgoing hot water target temperature Tset, and the outgoing hot water temperature Tout is difficult to stabilize.

The present invention is a water amount control for a water heater, which quickly adjusts the amount of hot water so that when the temperature of the water supplied to the water heater changes, hot water having a hot water discharge temperature according to the target hot water temperature can be quickly obtained. The purpose is to provide a device.

[Means for Solving the Problems] The present invention is directed to a water inlet temperature of water flowing into a heat exchanger for heating water passing through the inside, an inflow water amount, a hot water outlet temperature and hot water outlet from the heat exchanger. A heating control unit that determines the heating amount of the heating unit based on the target temperature is detected, and heating of the heating unit that heats the heat exchanger by detecting the inflow of water into the heat exchanger is started. In the water amount device of the water heater for controlling the water amount adjusting means for adjusting the amount of water passing through the heat exchanger, the hot water outlet target temperature, the maximum heating capacity of the heating means, and the incoming water temperature into the heat exchanger are set. The first step of determining the maximum opening degree of the water amount adjusting means based on the first step, and the first step of determining the opening degree of the water amount adjusting means.
Initially set to an initial opening smaller than the maximum opening determined in the step of, from the initial opening to an opening larger than the maximum opening in the range until the heating amount of the heating means reaches the maximum heating amount. A second step in which the heating amount of the heating means is the maximum heating amount and the hot water temperature is lower than a predetermined temperature lower than the hot water discharge target temperature in the second step in which the heating amount of the heating means is changed stepwise at predetermined time intervals. When the hot water comes out, the water entering temperature, and the maximum heating capacity of the heating means, the third step of obtaining the amount of hot water flowing out from the heat exchanger, and the step obtained in the third step. A fourth step of obtaining the equivalent opening degree of the water amount adjusting means based on the equivalent hot water discharge amount, and the maximum opening degree determined in the first step and the maximum opening degree of the water amount adjusting means. A fifth step of obtaining an opening difference from the corresponding opening obtained in step 4 and a sixth step of using the opening difference obtained in the fifth step as an opening correction value of the water amount adjusting means. In the step of FIG. 7, the maximum opening capacity of the water amount adjusting means is determined based on the maximum heating capacity of the heating means and the temperature of the water entering the heat exchanger. The technical means is to control the water amount adjusting means in accordance with the maximum opening degree and the opening degree correction value.

[Operation] In the present invention, when the inflow of water into the heat exchanger is detected,
The heating of the heating means is started.

On the other hand, in the control of the water amount adjusting means, in step 1, the maximum opening degree of the water amount controlling means is determined based on the hot water outlet temperature, the maximum heating capacity of the heating means, and the incoming water temperature flowing into the heat exchanger.

In step 2, the opening of the water amount adjusting means is initially set to an initial opening smaller than the maximum opening determined in the first step, and the heating amount of the heating means reaches the maximum heating amount within this range. From the initial opening to an opening that is larger than the maximum opening, the opening is changed stepwise at predetermined intervals.

In this step 2, the hot water outlet temperature reaches a predetermined temperature until the heating amount of the heating means reaches the maximum heating amount even if the opening degree of the water amount adjusting means becomes large. When the opening degree of the adjusting means becomes large and the hot water discharge amount increases, the heating power is insufficient with respect to the hot water discharge amount, so that the hot water discharge temperature does not reach the predetermined temperature and becomes equal to or lower than the predetermined temperature.

Therefore, in step 3, in addition to the detected inflow water amount, the equivalent outflow amount of hot water flowing out of the heat exchanger can be obtained based on the hot water output temperature, the incoming water temperature, and the maximum heating amount of the heating means at that time.

Further, in addition to the maximum opening of the water amount adjusting means determined in the first step, the equivalent opening of the water amount adjusting means can be obtained based on the equivalent hot water discharge amount obtained in the third step. At this time, if the actual heating capacity of the heating means or the actual opening degree of the water amount adjusting means is different from the heating capacity or opening degree for control, the equivalent opening degree of the water amount adjusting means obtained in the fourth step is The maximum opening of the water amount adjusting means determined in the first step is different. Therefore, these opening differences are obtained, and thereafter, the maximum opening of the water amount adjusting means obtained in step 7 is corrected by this opening difference, whereby the capacity error of the heating capacity and the opening error of the water amount adjusting means are corrected. The corrected opening can be obtained.

Therefore, thereafter, by using this difference in opening degree as the opening degree correction value of the water amount adjusting means, it is possible to perform the water amount control according to the actual heating capacity of the heating means and the actual opening characteristic of the water amount adjusting means.

[Effect of the Invention] In the present invention, the opening degree of the water amount adjusting means is determined based on the hot water outlet temperature, the maximum heating capacity of the heating means, and the incoming water temperature flowing into the heat exchanger in the initial stage of hot water supply. A smaller initial opening is determined. For this reason, the amount of hot water discharged does not exceed the maximum heating capacity of the heating means and becomes smaller than the heating capacity. Therefore, the apparent heating capacity at the initial stage of hot water supply is improved, and hot water having the desired hot water discharge temperature can be quickly obtained.

Further, in the initial stage of hot water supply, an opening correction value corresponding to the error of the heating capacity of the heating means and the opening error of the water quantity adjusting means is obtained, and thereafter, the water quantity adjusting means is controlled with the opening correction value. Therefore, when the inflow temperature of the water flowing into the heat exchanger changes, the maximum opening degree of the water amount adjusting means is determined according to the new inflow temperature, and the water amount adjusting means responds to the determined maximum opening degree. Controlled. At this time, since the control is performed with the opening correction value, the water amount adjusting means promptly exhibits the maximum opening according to the target hot water temperature. Therefore, even if the inflow water temperature changes, the hot water having the desired hot water outlet temperature is quickly supplied.

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

The gas water heater of this embodiment, which is schematically shown in FIG.
And a fuel pipe 20, a water pipe 30, and a control circuit 50.

The combustor 10 includes a water heater case 1 in which a burner plate 11 having a large number of flame holes is provided, and a blower case 2 including a blower 12 that supplies combustion air. The water heater case 1 forms a combustion chamber 1a and a mixing chamber 1b with the burner plate 11 as a boundary. In the inlet 2a of the blower case 2,
An air supply duct 3 is connected to reduce noise during combustion, and a nozzle 13 for ejecting fuel gas is provided inside the air supply port 3a.
Is provided.

The fuel gas ejected from the nozzle 13 is mixed with the combustion air supplied by the blower 12 in the mixing chamber 1b, all primary air combustion is performed on the upper surface of the burner plate 11, and the combustion gas is discharged from an exhaust port (not shown). It

Above the burner plate 11 in the combustion chamber 1a, there are provided a sparker 14 for spark discharge for ignition, a frame rod 15 for flame detection, and a thermocouple 16, respectively.

The fuel pipe 20 is a gas pipe for supplying fuel gas to the nozzle 13,
A source solenoid valve 21, a main solenoid valve 22, and a proportional valve 23 for adjusting the supply amount of fuel gas are respectively provided in order from the upstream side thereof, and further a solenoid valve 24 is provided downstream of the proportional valve 23, and a solenoid valve 24 The upstream side and the downstream side are communicated with each other by a bypass pipe 20a obtained by branching the fuel pipe 20, and the branched fuel pipe 20 and bypass pipe 20a are provided with orifices 25 and 26, respectively.

The water pipe 30 is composed of a supply pipe 31 and a hot water supply pipe 32 which are respectively connected to a water supply source and a hot water supply port (not shown), and a heat exchanger 33 and a bypass pipe 34 which are provided in communication with each other. Are arranged in the combustion chamber 1a.

At the branch portion of the heat exchanger 33 of the supply pipe 31 and the bypass pipe 34,
A bypass valve 35 for adjusting the ratio of the amount of water supplied to each of the heat exchanger 33 and the bypass pipe 34 is provided. Further, upstream of the supply pipe 31, an incoming water temperature thermistor 36 for detecting the supplied water temperature, a water amount sensor for detecting the supplied water amount.
37, a water amount control valve 38 for adjusting the amount of water supplied is provided. Each of the bypass valve 35 and the water amount control valve 38 is driven by a gad motor, and a potentiometer is provided to detect the opening of each valve.

The water pipe 30 downstream of the heat exchanger 33 is provided with a heat exchange thermistor 39 for detecting the temperature of the hot water flowing out of the heat exchanger 33, and the hot water supply pipe 32 is further provided with hot water flowing out of the heat exchanger 33. An outlet hot water temperature thermistor 40 for detecting the temperature of hot water mixed with water that has passed through the bypass pipe 34 is provided.

The control circuit 50 is mainly composed of a microcomputer and controls the operating state of the water heater according to the operating state of the controller 51 operated by the user, and performs sequence control, combustion control and water amount control.

As sequence control, when the operation switch of the controller 51 is turned on, combustion is started in a predetermined sequence, and when the combustion state or the hot water supply state is under a predetermined condition, the combustion is stopped.

In the combustion control, the blower 12, the proportional valve 23, and the solenoid valve 24 are controlled based on the temperature set by the controller 51, the detection signals from the thermistors 36, 39, 40, and the water amount sensor 37 to adjust the combustion amount. Here, the blower 12 is controlled based on the determined required combustion amount, and the current value to the proportional valve 23 is controlled based on the detected rotation speed of the blower 12. Also,
The air-fuel ratio is corrected based on the combustion temperature detected by the thermocouple 16, and the fuel gas supply amount and the combustion air supply amount are maintained at the stoichiometric air-fuel ratio.

In the water amount control, the proportion of water passing through the heat exchanger 33 and the bypass pipe 34 is adjusted by the bypass valve 35.
Here, the incoming water temperature Ti detected by the incoming water temperature thermistor 36
Determine the amount of bypass water to the bypass pipe 34 based on n,
The bypass valve 35 is controlled based on it.

Further, the opening degree of the water amount control valve 38 is appropriately controlled so that the amount of hot water supplied does not exceed the heating capacity of the combustor 10 with respect to the hot water outlet target temperature Tset set by the controller 51. Here, in particular, the error in the heating capacity of the combustor 10 and the water amount control valve 38
When the water tap is opened and hot water supply control is started in order to eliminate the error in the hot water outlet temperature Tout due to the opening error and to quickly supply the hot water at the hot water outlet target temperature Tset even when the water inlet temperature Tin changes. Only by performing the following control,
The opening degree of the water amount control valve 38 can be promptly corrected according to the change of the incoming water temperature Tin.

Next, the water amount control will be described with reference to FIGS. 2 to 8.

When the user opens a water tap (not shown) (step 1 in FIG. 2), water flows from the supply pipe 31 into the heat exchanger 33 and the bypass pipe 34, and the amount of water is detected as the detected water amount l _{F, which} is the water amount sensor 37.
Detected by. When the detected water amount l _F is equal to or greater than the starting reference water amount l _O determined for starting combustion (Yes in step 2), hot water supply control is started by the microcomputer. When the detected water amount l _F is smaller than the starting reference water amount l _O (No in step 2), the hot water supply control is not started until the detected water amount l _F reaches the starting reference water amount l _o .

When the hot water supply control is started, the maximum hot water supply amount lmax that can be taken out is based on the hot water output target temperature Tset set by the controller 51, the water input temperature Tin detected by the water input temperature thermistor 36, and the maximum heating capacity Qmax of the combustor 10. Is calculated by the above equation (step 3). However, when the calculated maximum hot water supply amount lmax is large and the water amount control valve 38 is controlled accordingly, the flow velocity in the heat exchanger 33 may become too large depending on the control state of the bypass valve 35, and at that time. ,
Bubbles may be generated in the heat exchanger 33, which may be dangerous. Therefore, to prevent such a danger, the maximum hot water supply amount lmax
Is larger than the safe flow rate ln predetermined by the relationship with the bypass valve 35 (Yes in step 4),
Apart from the calculated maximum hot water supply amount lmax, the maximum hot water supply amount lmax is reduced to the safe flow rate ln to be equal to the safe flow rate ln (step 5). When the maximum hot water supply amount lmax is less than or equal to the safe flow rate ln (No in step 4), the calculated value is set as the maximum hot water supply amount lmax.

Then, it is determined whether or not the calculation of the maximum hot water supply amount lmax is performed in the hot water supply control for the first time by a predetermined flag indicating the first time (step 6).

If there is no flag indicating the first time (No in step 6)
Is a coefficient N for changing the opening degree of the water flow control valve 38.
Set to 85 (step 7). This is because in the initial stage of hot water supply, the temperature of the heat exchanger 33 and the like in the combustor 10 is low and the passing water cannot be sufficiently heated, so that the shortage is compensated. As a result, the opening of the water amount control valve 38 is smaller than the opening for supplying the maximum hot water supply amount lmax, which is 85% of the maximum hot water supply amount lmax.
The opening is controlled to supply a flow rate corresponding to%, and the apparent heating amount increases.

If there is a flag indicating the first time (Yes in step 6)
In s), the maximum hot water supply amount lmax is calculated again due to the change of the outlet hot water target temperature Tset or the change of the incoming water temperature Tin. In particular, since the opening of the water flow control valve 38 is not changed, the coefficient N is set to It is set to 1.00 (step 8).

When the coefficient N is determined, the control flow rate 1 is determined according to the coefficient N by l = lmax * N ... (Step 9), and accordingly, the water flow control valve 38
The value P of the potentiometer for detecting the valve position of is calculated (step 10), and the gad motor of the water amount control valve 38 is driven based on the calculated value P of the potentiometer (step 11).

The calculation process of the potentiometer value P (step 10) and the gad motor drive process (step 11) are each performed in the third step.
This is separately processed by the subroutine shown in FIGS.

The subroutine for calculating the value P of the potentiometer starts its processing when there is a call command (step 1
2) The calculation is performed based on the predetermined formula (step 1
3) After the calculation is completed, the process returns to the called step (step 14).

Further, the subroutine for carrying out the drive processing of the gad motor is started when the calling instruction is issued (step 15), and the following processing is carried out.

First, the correction value Pb1 is added to the value P of the potentiometer calculated in step 10 to obtain the correction control value Pb (step 16). Here, the correction value Pb1 is obtained by a correction value calculation subroutine described later. The controllable opening of the water amount control valve 38 is predetermined, and the potentiometer value is accordingly set to the minimum value Pmin and the maximum value Pmax.
Has been decided. Therefore, when the correction control value Pb is smaller than the minimum value Pmin (Yes in step 17) and larger than the maximum value Pmax (Yes in step 18), the correction value Pb is not corrected and the correction control value Pb is not changed. Is changed to the minimum value Pmin and the maximum value Pmax, respectively (steps 19 and 20).

After that, the correction control value Pb and the value detected by the potentiometer
Pbn is compared (step 21), and as a result, when the opening of the water amount control valve 38 is small (Yes in step 21), the gad motor is driven to increase the opening (step 22), and the opening is increased. If larger (N in step 21
At step o), the gad motor is driven so as to reduce the opening (step 23), and when the detection value Pbn falls within the predetermined range of the correction control value Pb by each driving (step 24), the gad motor is stopped (step 25). , And then returns to the called step (step 26).

During this period, the combustor 10 is ignited to supply the fuel gas and the blower 12 to supply the combustion air.

When the opening control of the water amount control valve 38 is completed by the driving process of the gad motor and there is an ignition signal from the frame rod 15 (Yes in step 27), the connector A shifts to the control of FIG.

When the combustor 10 ignites, a process of fetching each data of the outlet heated water temperature Tset set by the controller 51 and the water temperature Tin by the water temperature thermistor 36 (step 28)
Is performed by the subroutine shown in FIG.

This will be described below.

The data acquisition process starts when there is a call command (step 60), and the outlet hot water target temperature Tset and the incoming water temperature Tin are set.
In the capturing process of 1, each temperature data is captured 1 second after the start of the process. Therefore, in step 61, it is determined whether or not the 1-second timer is operating, and if it is not operating (No in step 61), the 1-second timer is started (step 62), and the calling command is issued from step 63. Return to the step where there was. If the one-second timer is operating (Yes in step 61), the process is repeated through step 63 to the step in which the calling instruction is given until one second has elapsed (No in step 64).

After 1 second has elapsed and the 1-second timer has finished operating (step
(Yes in 64), each data of the outlet heated water temperature Tset and the inflow water temperature Tin is sequentially fetched (steps 65 and 66), and when there is no change in each fetched data (No in step 67)
Then, after step 63, it turns to the step where the calling instruction is given.

On the contrary, if each of the fetched data has been changed (Yes in step 67), the process returns to step 3 via the connector E, and the maximum hot water supply amount lmax is calculated again.

In FIG. 5, when the process for taking in the hot water outlet temperature Tset and the incoming water temperature Tin (step 28) is completed, it is judged whether or not the combustion amount of the combustor 10 is the maximum heating capacity Qmax (step 29), and maximum heating is performed. If the capacity is Qmax (Yes in step 29), the data of the outlet hot water temperature Tout detected by the outlet hot water temperature thermistor 40 is fetched (step 30), and whether the outlet hot water temperature Tout has reached a temperature 1 degree lower than the hot water outlet target temperature Tset. It is determined whether or not (step 31). This determination is made every 10 seconds, and therefore, when the outlet heated water temperature Tout has not reached the temperature 1 degree lower than the outlet heated water target temperature Tset (Yes in step 31), the 10 second timer is operating. It is determined whether or not (step 32), and if the 10-second timer is operating (Yes in step 32).
In step s), it is determined whether or not the operation of the 10-second timer has ended (step 33). If the operation of the 10-second timer has not ended (No in step 33), the process returns to step 28.

When the hot water outlet temperature Tout is sufficiently high and is heated to a temperature one degree lower than the hot water outlet target temperature Tset (No in step 31)
Return to step 28.

If the 10-second timer is not running (in step 32
No), it is determined in step 34 whether the 30-second timer is operating. If the operation of the 10-second timer has ended (Yes in step 33), a flag indicating the first time is written (step 35).

On the other hand, if the 30-second timer is not running (No in step 34), the 30-second timer is started (step 3
6). Also, if the 30-second timer is running (step 3
If Yes in 4), it is determined in Step 37 whether or not the operation of the 30-second timer has ended. If it has not ended (No in Step 37), merge with the processing in Step 36. Then, the procedure returns to step 28 via connector C, and when the processing is completed (Yes in step 37), step 3
It merges with after the process of 5, and shifts to the correction value calculation process (step 38).

When the combustion amount of the combustor 10 does not reach the maximum heating capacity Qmax (No in step 29), in order to bring the combustion amount of the combustor 10 to the maximum heating capacity Qmax, the temperature is changed through the connector B to the condition shown in FIG. Perform the control shown.

If the 30-second timer is already running (Yes in step 42), restart the 30-second timer (step 4
3), determine whether there is a first time flag (step 4
Four). When the 30-second timer is not operating (No in step 42), the process directly proceeds to the determination in step 44. If there is an initial flag (Yes in step 44)
Then, the process returns to step 28 via the connector C. If there is no initial flag (No in step 44), it is determined in step 45 whether or not the 10-second timer is operating. If the 10-second timer is not operating (no in step 45),
The 10 second timer is started (step 46), and the process returns to step 28 via the connector C. If the 10-second timer is operating (Yes in step 45), it is determined whether or not the 10-second timer has finished operating (step 47), and if the 10-second timer has not finished operating (step 47). If No in 47, the process returns to step 28 via the connector C.

If the operation of the 10-second timer has ended (Yes in step 47), 0.05 is added to the coefficient N (step 4).
8). When the value of coefficient N after addition is 1.25 or less (step 4
(Yes in 9) returns to step 9 through the connector D, and thereafter, the same control is repeated until the value of the coefficient N becomes 1.25, and when the value of the coefficient N exceeds 1.25 (No in step 49). For this, the coefficient N is set to 1.00 (step 50), and the process returns to step 9 via the connector D.

In step 38, the correction value Pb for controlling the water volume control valve 38
1 is calculated. This is processed by the subroutine shown in FIG. 8 and is started when the calling instruction is issued in step 38 (step 70).

In the correction value calculation subroutine, first, the hot water temperature thermistor
The data of the outlet hot water temperature Tout detected by 40 is taken in (step 71), and the outlet hot water temperature Tout and the incoming water temperature Tin
Based on the temperature difference between and, and the maximum heating capacity Qmax of the combustor 10, the equivalent hot water discharge amount la is obtained (step 72). Then, in step 73, the value P is calculated by calling the subroutine for calculating the value P of the potentiometer shown in FIG. Further, the flow rate difference between the equivalent hot water discharge amount la obtained in step 72 and the detected water flow rate l _F is calculated, and the water flow control valve 38 is calculated from the flow rate difference.
Obtain the equivalent opening value Pn of the potentiometer indicating the opening of
The potentiometer correction value Pb1 is obtained from the difference between the equivalent opening value Pn and the value P (step 74).

When the water amount control valve 38 is controlled by the obtained correction value Pb1, the water amount adjusted by the water amount control valve 38 is
The correction value Pb1 is discriminated so that it does not become below the predetermined minimum water amount or above the maximum water amount (step 7
5, 76), if it is smaller than the value a indicating the minimum water amount (Yes in step 75), the correction value Pb1 is corrected to the value a indicating the minimum water amount (step 77), and is larger than the value b indicating the maximum water amount. (No in step 75, and step 76
If Yes), the correction value Pb1 is corrected to the value b indicating the maximum water amount (step 78).

After the correction value Pb1 is obtained or corrected if necessary, the process returns to the called step (step 7
9).

In step 38, the correction value is
When Pb1 is calculated, the coefficient N is set to 1.00 (step 3
9), return from connector D to step 9.

The gas water heater of the present embodiment having the above configuration operates as follows.

When the user sets the hot water outlet target temperature Tset by the controller 51 and starts the operation, and when a water tap (not shown) is opened, water flow is detected by the water amount sensor 37, and hot water supply control is started in a predetermined sequence.

In the ignition control, the blower 12 starts rotating, and when the predetermined number of rotations is reached, the sparker 14 is operated, and when the operation of the sparker 14 is detected, the original solenoid valve 21 and the main solenoid valve 22 are opened, Combustion air and fuel gas are supplied to the combustor 10.

In the water amount control, the bypass amount is determined based on the incoming water temperature Tin flowing into the heat exchanger 33, and the bypass valve 35 is controlled.

On the other hand, in the control of the water amount control valve 38, the maximum hot water supply amount lmax is determined, and the water amount control valve 38 is drive-controlled to 85% of the maximum hot water supply amount lmax to the opening degree for obtaining the hot water discharge amount.

When the flame is detected by the combustor 10 and the flame is detected by the flame rod 15, the sparker 14 is stopped, the incoming water temperature Tin, the detected water amount.
l _F , the combustion amount of the combustor 10 is determined based on the hot water outlet temperature Tset, and the blower 12, the proportional valve 23, and the solenoid valve are determined accordingly.
24 is controlled.

When the detected water amount l _F is small and the combustor 10 does not reach the maximum heating capacity Qmax, the heating power does not become insufficient, and the combustion amount is increased without performing correction control in particular, so that the tapping target temperature Tset Hot water is supplied.

If the combustor 10 has the maximum heating capacity Qmax, the outlet temperature Tout
Based on the above, the opening degree of the water amount control valve 38 is increased by 5% every 10 seconds, and drive control is performed up to an opening degree for obtaining a hot water discharge amount of 125% of the maximum hot water supply amount lmax.

During this increase in opening, the heating power of the combustor 10 is usually insufficient. The equivalent hot water discharge amount la based on the hot water discharge temperature Tout at this time
Is calculated and the value P of the potentiometer is calculated, and the correction value Pb1 is obtained by the difference from the equivalent opening value Pn.

The correction value Pb1 obtained here is used in step 16 of the gad motor driving subroutine for driving and controlling the water amount control valve 38 thereafter.
The correction control value Pb is determined by 1 and the influence of the error generated in each control amount due to the error of the water amount control valve 38, the proportional valve 23, etc. can be compensated.

Therefore, after that, the incoming water temperature Tin changes and the water volume control valve 38
When the opening degree of is changed, the driving control is performed by the correction control value Pb capable of compensating for the error, so that the appropriate opening degree can be quickly set. It is possible to reduce the fluctuation of the outlet heated water temperature Tout.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a gas water heater showing an embodiment of the present invention, and FIGS. 2 to 8 are flow charts for explaining the operation of the control circuit of the present embodiment. In the figure, 38 ... Water amount control valve (water amount adjusting means), 50 ... Control circuit (water amount control device).

Claims (1)

[Claims] Claim: What is claimed is: 1. A heating means of a heating means based on an incoming water temperature of a water flowing into a heat exchanger for heating water passing through the inside, an inflowing water amount, a hot water outgoing temperature of the hot water flowing out of the heat exchanger, and a hot water outgoing target temperature. It has a heating control means for determining a heating amount, detects the inflow of water into the heat exchanger, starts heating of the heating means for heating the heat exchanger, and passes through the heat exchanger. In a water quantity control device of a water heater for controlling a water quantity adjusting means for adjusting a water quantity, the hot water outlet target temperature, the maximum heating capacity of the heating means, and the water quantity adjusting means based on the incoming water temperature into the heat exchanger. A first step of determining a maximum opening, and an opening of the water amount adjusting means is initially set to an initial opening smaller than the maximum opening determined in the first step, and the heating amount of the heating means is Maximum heating amount reached The second step of changing the initial opening to an opening larger than the maximum opening stepwise at a predetermined time within the range up to the maximum opening amount, and the maximum heating amount of the heating means in the second step. The equivalent amount of hot and cold water flowing out from the heat exchanger based on the amount of heating and the hot water discharge temperature when the hot water discharge temperature falls below a predetermined temperature lower than the hot water discharge target temperature, the incoming water temperature, and the maximum heating capacity of the heating means. A third step of obtaining the amount of hot water, a fourth step of obtaining the equivalent opening degree of the water amount adjusting means based on the equivalent amount of hot water obtained in the third step, and the first amount of the water amount adjusting means The fifth step of obtaining the opening difference between the maximum opening determined in step 4 and the equivalent opening determined in the fourth step; And a sixth step of setting the opening difference as an opening correction value of the water amount adjusting means, and in a seventh step thereafter, the maximum heating capacity of the heating means and the input into the heat exchanger. A water quantity control device for a water heater, wherein the maximum opening of the water quantity adjusting means is determined based on the water temperature, and the water quantity adjusting means is controlled according to the opening degree correction value.