JPH09318153A - Hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-water supplier, capable of converging a discharging hot-water temperature to an objective discharging hot-water temperature as soon as possible. SOLUTION: A hot-water supplier is provided with a gas amount regulating valve 16, capable of changing freely the amount of combustion of a burner 8 for heating a heat exchanger 7 for heating water, a discharging hot-water temperature thermistor 12, detecting a discharging hot-water temperature, a temperature setting switch 20, for setting an objective discharging hot-water temperature, and a control unit 4, controlling the gas amount regulating valve 16 based on a temperature difference between the objective discharging hot-water temperature and the detected discharging hot-water temperature. In this case, the control unit 4 operates the amount of feedback operation under a condition that the integration of a temperature difference is operated and an integrated term obtained by producing the same by a control constant is contained, to control the gas amount regulating valve 16. The control unit 4 is constituted so as to set the control constant at a predetermined initial value upon starting hot-water supplying operation and when the detected discharging hot-water temperature is changed from a condition lower than the objective discharging hot-water temperature into a condition higher than the objective temperature or when a hunting condition, wherein the detected discharging hot-water temperature is changed from a condition higher than the objective discharging hot-water temperature into a condition lower than the same, is generated, the control unit 4 changes the control constant into a small value to operate the integrated term.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for heating water, which heats water supplied through an inlet channel by combustion of a burner to discharge hot water from a hot water outlet channel, and a combustion amount of which burner combustion amount can be freely changed. Adjusting means, hot water temperature detecting means for detecting the temperature of hot water discharged from the hot water passage, target temperature setting means for setting a target hot water temperature, target hot water temperature set by the target temperature setting means, and Control means for controlling the combustion amount adjusting means is provided based on the temperature deviation from the detected hot water temperature detected by the hot water temperature detecting means, and the control means performs integral calculation of the temperature deviation and integrates the temperature deviation. In a state including an integral term obtained by multiplying the value by a control constant, the feedback operation amount of the combustion amount adjusting means is calculated so that the detected hot water temperature becomes the target hot water temperature, and the combustion amount is calculated based on the calculation result. Key It relates hot water supply device configured to control the unit.

[0002]

2. Description of the Related Art In the above hot water supply apparatus, the hot water discharge temperature is controlled by adjusting the burner combustion amount based on the temperature deviation between the detected hot water temperature detected by the hot water temperature detecting means and the target hot water temperature. Although the feedback control is performed so as to reach the temperature, in such a water heater, conventionally, the control constant for the integral term has been fixed at a preset value.

[0003]

In the hot water supply apparatus having the above-mentioned structure, the residual deviation when the steady state is reached from the transient state by using the above-mentioned integral term for the feedback operation amount for the combustion amount adjusting means ( Although the steady-state deviation) can be suppressed to be as small as possible, the conventional technique has the following disadvantages because the control constant for the integral term is constant.

That is, if the control constant is set to a large value in advance in order to improve the responsiveness at the start of hot water supply to reach the target hot water temperature as quickly as possible, the hot water discharge temperature reaches the target hot water temperature. In this case, when so-called hunting in which the state where the outlet heated water temperature exceeds the target outlet heated water temperature and the state where the outlet heated water temperature is lower than the target outlet heated water temperature are alternately repeated takes a long time until the outlet heated water temperature converges to the target outlet heated water temperature. It has the disadvantage that the temperature of the hot water is not stable for a long time.
Even when the above-mentioned hunting occurs, if the control constant is set to a small value in order to suppress the time until it converges to the target hot water temperature as short as possible, At the start, the rise response time until the outlet heated water temperature rises to near the target outlet heated water temperature will take a long time.

Therefore, in order to avoid such a disadvantage,
The time during which a hunting condition in which the hot water temperature exceeds the target hot water temperature or falls below the target hot water temperature continues (duration when the hot water temperature fluctuates and is unstable), or the number of times the hunting condition occurs Measure, based on the measurement result, if the time is long or the number of occurrences is large, modify the control constant to a small value, and then execute control based on the modified control constant. A configuration that is designed to do so was considered.

However, in the above improved configuration, when the hunting state as described above occurs, the control constant is corrected after the hunting state has converged, so that the initial hunting state is suppressed. In addition to the disadvantage that it is impossible to do, the situation of occurrence of such a hunting state may change when, for example, the target outlet hot water temperature or the incoming water temperature changes. The constant cannot always be said to be an appropriate value, and there is a disadvantage in that the duration of the hunting state and the number of occurrences cannot be reliably suppressed in the hot water supply operation thereafter. Moreover, when the control constant is corrected as described above, the control is executed based on the corrected control constant after that, so that the tapping temperature rises near the target tapping temperature at the start of tapping. The disadvantage that it takes a long time to start up could not be avoided, and there was still room for improvement.

The present invention has been made in view of such a point, and an object thereof is to provide a hot water supply apparatus which can converge the hot water discharge temperature to a target hot water discharge temperature as quickly as possible.

[0008]

According to the characterizing feature of claim 1, the control means detects the target hot water temperature set by the target temperature setting means and the detection detected by the hot water temperature detecting means. Integral calculation of the temperature deviation from the hot water temperature, and in a state that includes an integral term obtained by multiplying the integrated value by a control constant, so that the detected hot water temperature becomes the target hot water temperature, the feedback operation amount is calculated, Based on the calculation result, the combustion amount adjusting means, that is, the combustion amount of the burner is controlled.

At the start of the hot water supply operation, the control means sets the control constant to a predetermined initial value, and the detected hot water temperature is higher than the target hot water temperature. Or the hunting state in which the temperature changes from a state larger than the target hot water temperature to a state smaller than the target hot water temperature, the control constant is changed to a small value and the integral term is calculated.

Therefore, at the start of the hot water supply operation, a rising time is required until the hot water outlet temperature rises from a low temperature close to the water inlet temperature to the target hot water outlet temperature. Since the set initial value is set, if the initial value is set to a large value, the response characteristic can be improved and the rise time can be made as short as possible.

Then, the outlet heated water temperature rises near the target outlet heated water temperature, and the detected outlet heated water temperature changes from a state lower than the target heated outlet temperature to a higher state or from a state higher than the target heated outlet temperature to a lower state. If it changes, the control constant will be changed to a value smaller than the previous value and the calculation will be executed accordingly. Therefore, the proportion of the integral term that contributes to the feedback manipulated variable based on the temperature deviation becomes small, Fluctuations in the hot water temperature can be suppressed to such small values.

As a result, when the hunting state occurs, the rising time to reach the target hot water temperature at the start of hot water supply can be made as short as possible, and
Along with this, by changing the control constant in the integral term to a small value, fluctuations in the outlet heated water temperature can be suppressed to a small value, and the time until the outlet heated water temperature converges to the target outlet heated water temperature can be shortened as much as possible. Become.

According to a second aspect of the present invention, the control means is configured to successively decrease the control constant and calculate the integral term each time the hunting state is established.

As a result, when the hunting state repeatedly occurs a plurality of times, each time the hunting state occurs, the control constant is successively reduced to a value smaller than the previous value. The fluctuation of the tapping temperature can be further suppressed, and the time taken for the tapping temperature to converge to the target tapping temperature can be shortened.

According to the third aspect of the present invention, the control means multiplies the present control constant by a coefficient smaller than "1" to change the control constant to a small value. It is configured.

Therefore, it is only necessary to carry out an operation of multiplying the control constant by a constant coefficient in accordance with the above-mentioned hunting state. For example, a plurality of different values are stored in advance in the storage means, and the hunting state is stored. As a result, the current control constant is determined, and a simple calculation may be performed without performing complicated control such as reading a small value of data from the storage means, and the control configuration can be simplified. At the same time, the processing time can be short.

According to the fourth aspect of the present invention, when the target hot water temperature set by the target temperature setting means changes by the set value or more, the control means returns the control constant to the initial value and the feedback operation amount is adjusted. The integral term will be calculated.

When the target hot water temperature set by the target temperature setting means changes by a set value or more, the deviation between the current hot water discharge temperature and the target hot water discharge temperature increases, but at this time, the control constant is changed to a small value. In such a state, the response time is poor and a response time is required until the temperature approaches the target hot water temperature, but by returning the control constant to the initial value, the hot water temperature can be set to the target hot water temperature as quickly as possible. It is possible to get close to the temperature.

According to the fifth aspect of the present invention, when it is detected that the water flow rate of the heat exchanger has changed by the set water flow rate or more based on the detection information of the water flow rate detection means, the control means causes the control means to: The control constant is returned to the initial value and the integral term in the feedback manipulated variable is calculated.

When the amount of water passing through the heat exchanger changes by more than the set amount of water, the deviation between the current hot water outlet temperature and the target hot water outlet temperature increases with the change in the amount of water, but at this time, the control constant is a small value. If the state is changed to, response time is poor and response time is required until the temperature approaches the target hot water temperature, but by returning the control constant to the initial value,
The tap water temperature can be brought close to the target tap temperature as quickly as possible.

According to the sixth aspect of the present invention, when the state in which the water flow to the heat exchanger is not detected continues for the set time or longer, the control means returns the control constant to the initial value and the feedback operation amount is adjusted. The integral term will be calculated.

The combustion of the burner is stopped when water is not flowing to the heat exchanger. Therefore, when the state in which the water is not detected continues for a set time or longer, hot water in the heat exchanger is used. Since the temperature of has decreased to a low temperature close to the inlet water temperature, when hot water supply is restarted after that, it takes a rising time from the start of hot water supply until the outlet temperature reaches the target outlet temperature. At this time, if the control constant is changed to a small value, the response is poor and it takes time to reach a temperature close to the target hot water temperature, but by returning the control constant to the initial value, the hot water temperature can be controlled. It is possible to approach the temperature close to the target hot water temperature as quickly as possible.

According to the seventh aspect of the present invention, the control means is based on a temperature deviation between the target hot water temperature set by the target temperature setting means and the incoming water temperature detected by the incoming water temperature detecting means. Then, the feedforward operation amount of the combustion amount adjusting means is calculated, and the combustion amount adjusting means is controlled based on the feedforward operation amount and the feedback operation amount.

Therefore, after the hot water supply is started, the combustion amount adjusting means is controlled on the basis of the feedforward manipulated variable. Therefore, immediately after the hot water supply is started, the required amount of combustion to bring the hot water discharge temperature to the target hot water temperature is set. The burner will burn,
As compared with the configuration in which only the feedback operation amount is used for control, the rise time from the temperature at which the tapping water temperature is low close to the inlet water temperature to the target tapping temperature or a temperature close thereto can be made shorter.

As a result, for example, when the hot water supply is started after the burner has been stopped for a long time, or when the deviation between the hot water discharge temperature and the target hot water temperature is larger than the set amount, the hot water discharge temperature is set to the target hot water temperature as quickly as possible. The temperature can be close to the target temperature, and when the temperature rises close to the target hot water temperature, fluctuations in temperature due to hunting can be suppressed, and the time until the hot water temperature converges to the target hot water temperature can be minimized. Thus, the time required from the start of hot water supply to the target hot water temperature can be shortened.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The water heater according to the present invention will be described below. As shown in FIG. 1, the hot water supply device includes a hot water supply unit 3 that heats water supplied through a water inlet passage 1 to supply hot water to a hot water tap (not shown) through a hot water outlet passage 2.
4, a control unit 4 as control means for controlling the operation of the
It is configured by including a remote control operation unit 5 for instructing control information to the.

The hot water supply unit 3 is provided with a heat exchanger 7 for heating water and a gas combustion type burner 8 for heating the heat exchanger 7 in the combustion chamber 6, and the lower side of the combustion chamber 6 is provided. A burner 8 is provided with a fan 9 for ventilating combustion air.
The heat exchanger 7 is connected to a water inlet passage 1 to which water is supplied and a hot water outlet passage 2 for discharging heated hot water toward a hot water tap, and the water inlet passage 1 is connected to the heat exchanger 7. A water flow rate sensor 10 as a water flow rate detection means for detecting the water flow rate and an incoming water temperature thermistor 11 as an incoming water temperature detection means are provided.
A hot water outlet temperature thermistor 12 is provided in the hot water outlet path 2 as a hot water outlet temperature detecting means. A fuel supply passage 13 for supplying fuel (gas) to the burner 8 has two electromagnetically operated on-off valves 14 and 15 and a gas amount as a combustion amount adjusting means capable of changing and adjusting the fuel supply amount. A control valve 16 is provided. The gas amount control valve 16 is provided electromagnetically and is configured so that the valve opening, that is, the fuel supply amount can be changed and adjusted in proportion to the supplied current value. An igniter 17 that performs an ignition operation for the burner 8 and a frame rod 18 that detects an ignition state are provided near the burner 8.

The remote controller operating section 5 displays an operation switch 19 for instructing the control section 4 to start and stop the hot water supply operation, a temperature setting switch 20 as a target temperature setting means for switching and setting a target hot water supply temperature, a hot water outlet temperature and the like. A temperature indicator 21 and a combustion lamp 22 for displaying the combustion state of the burner 8.
And the like.

The control section 4 comprises a microcomputer, and the water flow rate sensor 10, the incoming water temperature thermistor 11, the hot water temperature thermistor 12, and the frame rod 18 are provided.
Each of the detection information is input, and based on the detection information and the operation command from the remote controller operation unit 5, the on-off valves 14 and 15, the gas amount control valve 16, the fan 9, the igniter 17 and the like are controlled. Is configured. That is,
When water flow is detected in the hot water supply operation state, the control unit 4 executes ignition control for the burner 8 and burns the burner 8 so that the hot water discharge temperature reaches the target hot water discharge temperature. Combustion control means 100 for controlling the operation amount of the fan 9 so as to obtain the ventilation amount obtained from the preset control characteristics corresponding to the combustion amount of the burner 8, and the incoming water temperature thermistor 11. , The hot water temperature thermistor 12, the water flow rate sensor 10, and the target hot water temperature set by the temperature setting switch 20, the required combustion amount of the burner 8, specifically, the adjustment of the gas amount control valve 16. The calculation means 101 for calculating the manipulated variable is provided in the form of a control program.

The calculation means 101 calculates the target outlet temperature Ts.
And the feedback operation amount F based on the temperature deviation between the hot water temperature thermistor 12 and the detected hot water temperature To.
In addition to calculating B, the feedforward manipulated variable FF is calculated based on the deviation between the target hot water temperature Ts and the incoming water temperature Ti detected by the incoming water temperature thermistor 11, and the water flow rate Qx detected by the water flow rate sensor 10. Then, the feedforward operation amount FF and the feedback operation amount FB are added to calculate the adjustment operation amount of the gas amount adjustment valve 16. More specifically, the feedforward manipulated variable FF is calculated based on the following [Equation 1]. However, K _F is a feedforward control constant.

[0031]

[Formula 1] FF = K _F · (Ts−Ti) · Qx

The feedback operation amount FB is calculated based on the following [Equation 2].

[0033]

[Formula 2] FB = K _p · (Ts−To) + K _i · ∫ (Ts
-To) dt

In the above [Equation 2], the first half is a proportional term proportional to the temperature deviation, and K _p is a control constant for the proportional term. The latter half is an integral term which is the temporal total of the temperature deviation, and K _i is a control constant for the integral term.
Therefore, feedback control by so-called proportional integral (PI) control is performed.

The above-mentioned control constants K _F , K _P , and K _I are optimally set in advance based on experimental data and the like in consideration of the characteristics (thermal efficiency and the like) of the hot water supply unit 3 at the time of initial installation of the hot water supply device. It will be set to the initial value.

Then, the calculating means 101 changes the detected hot water outlet temperature To from a state smaller than the target hot water outlet temperature Ts to a higher state or from a state higher than the target hot water outlet temperature Ts to a lower state. As the hunting state changes, the control constant K for the integral term
_I is changed to a small value and is configured to calculate the integral term. When hunting occurs, the influence of the integral term is reduced, and fluctuations in the outlet heated water temperature are suppressed. Specifically, each time the hunting state is entered, the current control constant K _I is multiplied by a coefficient α smaller than “1”, and the control constant K _I is changed to a small value and gradually decreased. Has been done. The control constant K _I changed in this way is written and stored in a storage means such as a memory, and the initial values are separately stored in a non-volatile memory (EEPROM), so that a power failure or the like may occur. Can also hold that value. In this way, the hunting state is repeated for a long time, and it is prevented that the hot water discharge temperature fluctuates and takes time to converge to the target hot water discharge temperature Ts, and the hot water discharge temperature is stabilized as quickly as possible.

When the target hot water outlet temperature Ts changes by a set value or more, or when the water flow rate to the heat exchanger 7 changes by a set amount or more, the computing means 101 passes water to the heat exchanger 7. When the state where is not detected continues for a set time or longer, the control constant K _I is returned to the initial value K _I (0) and the integral term is calculated. When the temperature deviation is large, It is configured so as to approach the target hot water outlet temperature Ts quickly.

Next, the control operation of the control unit 4 will be described based on the control flowchart of FIG. When the operation switch 19 of the remote control operation unit 5 is turned on and a start of the hot water supply operation is instructed, a flag described later is reset to OFF (steps 1 and 2), and after the start of the hot water supply operation is instructed, When it is detected that the water flow amount Qx detected by the water amount sensor 10 exceeds the set water amount Qs and the water flow is started by opening the hot water tap, the ignition control for the burner 8 is executed (steps 3 and 4). That is, the opening / closing valves 14 and 15 and the gas amount adjusting valve 16 are opened, and the ignition by the igniter 17 is started to cause the flame rod 1
When ignition is confirmed by 8, the ignition operation of the igniter 17 is stopped.

Then, the gas amount control valve 16 as described above
The operation amount calculation control for calculating the adjustment operation amount is executed (step 5), and the gas amount adjustment valve 16 is adjusted and controlled to the calculated adjustment operation amount, and a ventilation amount suitable for the gas amount is obtained. Thus, the combustion control for controlling the ventilation amount of the fan 9 is executed (step 6). This step 5 (manipulation amount calculation control) and step 6 (combustion control) are the detected water flow rate Qx
Is below the set water volume Qs and water flow is stopped, or
The operation is repeated every set time until the operation switch 19 is turned off (steps 5-8). When the detected water flow rate Qx falls below the set water flow rate Qs and the water flow is stopped, the on-off valves 14 and 15 are shut off to stop the combustion of the burner 8, and the process proceeds to step 2 to prepare for the next hot water supply (step 9). When the operation switch 19 is turned off, the on-off valves 14 and 15 are shut off to stop the combustion of the burner 8 and stop the hot water supply operation (step 10).

Next, the manipulated variable calculation control will be described with reference to FIG. First, it is determined whether or not the flag is ON (step 51), but immediately after the hot water supply operation is started,
Since the flag has been reset to OFF, step 52
The time from the stop of the hot water supply last time to the start of the hot water supply this time, that is, the time when the state in which the water flow to the heat exchanger 7 is not detected continues, for example, It is judged whether or not it is a set time or more for lowering the temperature to a low temperature close to it, and if the set time or more has elapsed, the initial value K _I (0) is set as the control constant K _I for the integral term. Set (step 53). At this time, when the initial value K _I (0) is set, the flag is turned on (step 54).

Then, it is judged whether or not the target hot water outlet temperature Ts has been changed and changed by a set amount or more, and if it has not changed, the opening amount of the hot water supply tap is adjusted, etc. It is determined whether or not it has changed (steps 55 and 56). If it is determined that the target hot water outlet temperature Ts has changed by a set amount or more, or if the water flow rate has changed by a set amount or more, the initial value K _{I is} set as the control constant K _I for the integral term. (0) is set (step 57). After that, as shown in FIG. 4, for example, the hot water outlet temperature approaches the target hot water outlet temperature Ts as the burner 8 burns, and the detected hot water outlet temperature To changes from a state smaller than the target hot water outlet temperature Ts to a higher state. , The sign of the deviation between the target hot water temperature Ts and the detected hot water temperature To changes from “positive” to “negative” as the hunting state changes from a state larger than the target hot water temperature Ts to a smaller state. Or, the counter is incremented each time it changes from “negative” to “positive”, and the current control constant K _I is multiplied by a coefficient α smaller than “1” every time the hunting state is set, The control constant K _I is set to a small value K
The value is changed to _I (n) and the value is stored in the memory (steps 58 to 61). Then, as described above, the feedforward operation amount FF and the feedback operation amount FB are calculated based on [Equation 1] and [Equation 2] (step 6).
2). At this time, either the initial value K _I (0) or the small value K _I (n) changed in step 60 is selectively used as the control constant K _I of the integral term. That is, when the hunting state as described above is not detected, the initial value K _I (0) is used as it is, and when the hunting state is repeated, as shown in FIG. 4, the coefficient is calculated every time the hunting state is detected. The control constant K _I (n), which is multiplied by α and changed to a small value that is gradually decreased, is used to calculate the integral term in the feedback control input FB, and the fluctuation of the tapping temperature due to the integral term is calculated. It is possible to shorten the time taken for the sticking to be suppressed and to converge to the target hot water outlet temperature Ts. If the target hot water temperature Ts changes by more than the set amount or the water flow rate Qx changes by more than the set amount during hot water supply, the control constant K _I is set to the initial value K _I.
It will be returned to _I (0) (step 57). The operation amount calculation control operation is repeated every set short time, but if hot water supply is continued, it is determined in step 51 that the flag is ON and the process proceeds to step 55. If the initialization process of the control constant K _I in 57 is not executed, the value stored in the memory will be used.

[Other Embodiment] (1) In the above embodiment, the current control constant K _I is “1”.
The smaller coefficient α is multiplied to change the value to a smaller value. However, instead of such a configuration, the current control constant K _I
It may be changed to a smaller value by subtracting the set amount from, or a value smaller than the current value may be appropriately selected from a plurality of data strings previously obtained by experiments, etc., and integration based on that value may be performed. The terms may be calculated.

(2) In the above-described embodiment, the control constant K _I is gradually decreased and changed to a small value each time the hunting state is set. However, instead of such a configuration, when the hunting state is set, the control is controlled. The constant K _I may be changed from the initial value to a value smaller by a preset amount, and thereafter, the integral term may be calculated with the changed value.

(3) In the above embodiment, the heat exchanger 7
When the state in which water passage to the chamber is not detected continues for a set time or longer, the control constant K _I is returned to the initial value and the integral term is calculated. However, instead of such a configuration, the combustion of the burner 8 is stopped. And when I start burning again, always,
The control constant K _I may be set to the initial value K _I (0).

(4) In the above embodiment, the target hot water outlet temperature T
The control constant K _I is set to an initial value when s changes by more than the set amount or when the water flow changes by more than the set amount of water. However, even if the initialization process is not executed during such hot water supply, Good.

(5) In the above embodiment, not only the feedback operation amount but also the feedforward operation amount is added to calculate the adjustment operation amount of the gas amount control valve 16. However, the feedback operation does not use the feedforward operation amount. The adjustment operation amount may be calculated based on only the control.

(6) In the above embodiment, the gas burner type burner 8 is used, but an oil burning type burner 8 may be used.

(7) In the above embodiment, all the water supplied from the water inlet 1 is passed through the heat exchanger 7. However, instead of such a structure, the water inlet 1 and the hot water outlet 2 are replaced. It may be configured to include a bypass path that short-circuits and.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a water heater.

FIG. 2 is a flowchart of a control operation.

FIG. 3 is a flowchart of a control operation.

FIG. 4 is a diagram showing changes in tapping temperature and control constants.

[Explanation of symbols]

1 Inlet Channel 2 Outlet Channel 4 Control Unit 7 Heat Exchanger 8 Burner 10 Water Flow Rate Detection Unit 11 Inlet Water Temperature Detection Unit 12 Outlet Hot Water Temperature Detection Unit 16 Combustion Amount Adjustment Unit 20 Target Temperature Setting Unit K _I Control Constant K _I (0) Initial Value FB Feedback manipulated variable FF Feedforward manipulated variable Ti Inlet water temperature To Detected hot water temperature Ts Target hot water temperature α coefficient

Claims (7)

[Claims] 1. A heat exchanger for heating water, which heats water supplied through an inlet passage by combustion of a burner and discharges hot water from an outlet passage, and a combustion amount adjusting means capable of changing a combustion amount of the burner, Hot water temperature detecting means for detecting the temperature of hot water discharged from the hot water passage, target temperature setting means for setting a target hot water temperature, target hot water temperature set by the target temperature setting means,
Based on a temperature deviation from the detected hot water temperature detected by the hot water temperature detection means, a control means for controlling the combustion amount adjusting means is provided, and the control means performs an integral calculation of the temperature deviation, and In a state including an integral term obtained by multiplying the integrated value by a control constant, the feedback operation amount of the combustion amount adjusting means is calculated so that the detected hot water discharge temperature becomes the target hot water discharge temperature, and based on the calculation result. A hot water supply device configured to control the combustion amount adjusting means, wherein the control means sets the control constant to a predetermined initial value at the start of the hot water supply operation, and A hunting state in which the detected hot water temperature changes from a state smaller than the target hot water temperature to a higher state or changes from a state higher than the target hot water temperature to a lower state. With the composed, by changing the control constant to a small value, Configured water heater to compute the integral term. 2. The hot water supply apparatus according to claim 1, wherein the control means is configured to successively decrease the control constant and calculate the integral term each time the hunting state is established. 3. The control means is configured to multiply the current control constant by a coefficient smaller than “1” to change the control constant to a small value. Hot water supply device described. 4. The control means, when the target hot water outlet temperature set by the target temperature setting means changes by a set value or more, returns the control constant to the initial value and calculates the integral term. The hot water supply device according to any one of claims 1 to 3, which is configured. 5. A water flow rate detecting means for detecting a water flow rate in the heat exchanger is provided, and the control means controls the water flow rate of the heat exchanger based on the detection information of the water flow rate detecting means. The water heater according to any one of claims 1 to 4, wherein when the change is detected, the control constant is returned to the initial value and the integral term is calculated. 6. A water flow state detecting means for detecting a water flow state to the heat exchanger is provided, and the control means is configured such that when a state in which water flow to the heat exchanger is not detected continues for a set time or more, 6. The control constant is returned to the initial value, and the integral term is calculated.
Hot water supply apparatus according to any one of 1. 7. An incoming water temperature detecting means for detecting a temperature of water supplied through the incoming water passage is provided, and the control means is a target hot water outlet temperature set by the target temperature setting means,
Based on the temperature deviation from the incoming water temperature detected by the incoming water temperature detecting means, a feedforward operation amount of the combustion amount adjusting means is calculated, and based on the feedback operation amount and the feedforward operation amount, the combustion The water heater according to any one of claims 1 to 6, which is configured to control the amount adjusting means.