JPH09210348A - Combustion controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion controller capable of setting to the utmost a reference communication rate becoming a reference of correction of the amount of ventilation to a proper value irrespective of an external environment and conditions of use of an apparatus. SOLUTION: This combustion controller comprises a fan control means 105 for adjusting a communication rate of a fan 4 such that a target revolution number Ns is attained, a reference communication rate setting means 107 for setting a reference communication rate Ds of the fan 4 corresponding to the target revolution number Ns based upon the controlled communication rate, and a correction means 108 for correcting the target revolution number Ns based upon a deviation between the controlled communication rate and the reference communication rate. A set target rationalization means 109 is provided in which an upper limit and a lower limit of the reference communication rate are previously set corresponding to the conditions of the use of an apparatus, and if the communication rate controlled by the fan control means 105 exceeds the upper limit, the upper limit is used as a set target of the reference communication rate, and if the communication rate does not exceed the upper limit and is not less than the lower limit, the communication rate is used as a set target.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target rotation speed setting means for setting a target rotation speed of a fan that ventilates combustion air to the burner on the basis of the required combustion amount of the burner, and The fan control means for adjusting and controlling the drive power of the fan so as to reach the target rotation speed, and the target rotation speed based on the drive power controlled by the fan control means based on the command of the command means. A reference power setting means for setting a reference drive power of the fan corresponding to the above, a correction for correcting the target rotation speed based on a deviation between the drive power controlled by the fan control means and the reference drive power. And a combustion control device provided with the means.

[0002]

2. Description of the Related Art A combustion control device having the above-described structure changes its ventilation characteristic due to a decrease in fan capacity or obstruction of a supply / exhaust passage to a burner as the device is used. Since there is a risk of degrading the combustion characteristics by deviating from the initial setting value, the change in the ventilation characteristics as described above is determined based on the deviation between the fan driving power and the preset reference driving power, and By correcting the target rotation speed of the fan based on the determination result, it is possible to always obtain an appropriate ventilation characteristic.

By the way, in the above-mentioned combustion control device, conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-302711, the operating time of the device is a first set time (5 hours).
Fan drive power (commutation rate) controlled by the fan control means when the time has passed, and a fan controlled by the fan control means when the operation time has passed the second set time (6 hours). The larger one of the drive powers (conduction rate) of the above is set as the reference drive power.

[0004]

However, in the above-mentioned conventional configuration, when the operating time of the device exceeds the set time as described above, the current condition is always maintained regardless of the external environment at that time and the use condition of the device. Since the drive power of the fan is set as the reference drive power, as a result, there are the following disadvantages.

When the drive power controlled by the fan control means is set as the reference drive power, for example, a strong wind from the outside air is blown to the exhaust port or the air supply port of the ventilation path. In such a case, the work of the fan becomes lighter or heavier than that in a state where such a strong wind does not occur.
The drive power of the fan may not be controlled to an appropriate value.

Further, the reference drive power setting operation is often performed in a state in which the combustion of the burner is stopped in order to minimize the fluctuation associated with the combustion of the burner. In the case where the setting operation of the reference drive power is performed immediately after the stop, it is considered that the burner has a short burn time before that and the burner has a long burn. Here, when the burner burns for a long time, it means that the temperature of the air inside the device and the surrounding air is rising due to the burner burning, and the air expands with the temperature rise and the air density becomes thin. Will be there. As a result, the load on the fan is reduced, and the drive power for achieving the target rotation speed becomes a small value. When the burner combustion time is short, there is almost no such temperature rise in the air, so the load on the fan is greater than when the burner time is long. As described above, depending on the usage status of the device, there are disadvantages such that the reference drive power has different values even if the state of the air supply / exhaust path is the same.

As described above, there is a possibility that a value different from the appropriate drive power may be set as the reference drive power depending on the external environment and the usage situation, and the subsequent fan control may not be performed in an appropriate state. There was a disadvantage.

The present invention has been made paying attention to such a point, and an object thereof is to set the reference drive power to a proper value as much as possible, irrespective of the external environment, the use condition of the apparatus and the like. It is a point to provide another combustion control device.

[0009]

According to the characterizing feature of claim 1, in the drive power controlled by the fan control means, a proper adjustment region set in advance corresponding to the usage condition of the device. In order not to set an abnormal drive power value that is out of the range as the reference drive power in the reference power setting means, the detected value of the drive power is made appropriate as a setting target in the reference power setting means. Since the setting target optimization means is provided, for example, when setting the reference drive power, the drive power abnormal value is caused by changes in the external environment such as the condition of the outside air and the usage conditions such as the burner combustion time. It is possible to avoid the problem that is erroneously set as the reference drive power, and it is possible to set the reference drive power as a proper value as much as possible.

As a result, the fan control can be executed in the most appropriate condition, and the disadvantage that the burner is incompletely burned due to the air-fuel ratio largely deviating from the set value can be avoided.

According to the second aspect of the present invention, the setting object optimizing means receives the drive power controlled by the fan control means, which is detected based on the instruction of the instruction means, from the apparatus. If the upper limit value of the reference drive power preset corresponding to the usage situation is exceeded, the upper limit value is set as the setting target, and the drive power is preset according to the usage situation of the device. If the lower limit value of the reference drive power is below, the lower limit value is set as the setting target, and the drive power does not exceed the upper limit value, and if it is not below the lower limit value, the drive power is It is configured to be set.

That is, the reference drive power to be set is set to an intermediate value between the upper limit value and the lower limit value set in advance in accordance with the usage status of the apparatus, and the upper limit value is exceeded. The disadvantage that an abnormal value or an abnormal value below the lower limit value is set is avoided.

According to the third aspect of the present invention, the setting object optimizing means supplies the drive power controlled by the fan control means based on the instruction of the instruction means with the passage of time. Then, the detection is performed a plurality of times, and the average value thereof is set as the setting target.

As a result, an average value of a plurality of driving electric powers detected a plurality of times is calculated, and one of them is caused by a change in the external environment such as the condition of outside air and the use condition such as the burner burning time. Even if there is an abnormal drive power value, it is possible to set a value closer to a more appropriate value as the reference drive power by averaging the detected values in other normal states. .

According to a fourth aspect of the present invention, the fan control means is configured to execute post-purge for continuing the ventilation operation by the fan for a set time after the combustion operation of the burner is stopped. The setting object optimizing means is configured to detect the drive power after a set time has elapsed since the start of post-purge.

When the set time elapses after the combustion of the burner is stopped, for example, even when the temperature of the air inside or around the apparatus is rising by continuing the combustion of the burner for a long time, Since the temperature of the air decreases as the set time elapses, it is possible to reduce the error in the drive power due to the increase in the temperature of the air.

Further, when the burner burns for a very short time and immediately shifts to post-purge, the temperature of the fan gradually rises due to energization of the fan as the post-purge is executed. Along with this, the electric resistance changes and the current value changes, but when the set time elapses and such current value change stabilizes and reaches a steady value, the reference drive power Will be set.

As described above, in the state where the error caused by the transient change of the air temperature, the electric resistance, etc. is minimized,
This makes it possible to set an appropriate reference drive power.

According to a fifth aspect of the present invention, the fan control means is configured to execute post-purge for continuing the ventilation operation by the fan for a set time after the combustion operation of the burner is stopped. The setting object optimizing means is configured to detect the drive power as the post-purge is executed, and the elapsed time from the start of the post-purge to the detection of the drive power, The detected driving power is corrected based on a preset correction characteristic, and the corrected driving power is set as the setting target.

In this configuration, as in the characteristic configuration of claim 4, the detection is performed based on the preset correction characteristic without waiting until the set time elapses after the combustion of the burner is stopped. By correcting the driving power, it becomes possible to set an appropriate value. In other words, transient changes in air temperature, electrical resistance, etc. can be measured in advance by experiments, etc., so the correction characteristics are set based on these measurement data, and burner combustion It is possible to correct the value to an appropriate value according to the time from the stop to the detection of the driving power.

As a result, even if the burner is re-ignited after the combustion of the burner is stopped and before the set time elapses, the reference drive electric power can be properly adjusted within a short time after the combustion of the burner is stopped. It becomes possible to set the value, which improves convenience in use.

According to the sixth aspect of the invention, the fan control means is configured to control the conduction ratio of the current supplied to the fan as the drive power of the fan. It is possible to control the drive power with higher accuracy than in the case where the magnitude of the current value or the voltage value is changed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A hot water supply apparatus as an example of a combustion control apparatus 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 K for performing a hot water supply operation, a controller H for controlling the operation of the hot water supply unit K, and a remote control device as command means for instructing control information to the controller H. And R.

The hot water supply unit K is provided with a heat exchanger 2 for heating water and a gas combustion type burner 3 for heating the heat exchanger 2 in the combustion chamber 1, and is directed toward the inside of the combustion chamber 1. Burner 3
A fan 4 that ventilates the combustion air is provided. The fan 4 is configured to be driven by a DC electric fan motor 5, and is provided with a rotary encoder 6 as a rotation speed detection unit that detects the rotation speed of the fan 4. A water supply channel 7 for supplying water to the heat exchanger 2.
And a hot water outlet 8 for supplying hot water after heating to a hot water tap (not shown)
Are connected to each other, and the water supply passage 7 is provided with a water flow rate sensor 9 for detecting the water flow rate to the heat exchanger 2 and an incoming water temperature thermistor 10 for detecting the temperature of the water entering the heat exchanger 2. A hot water outlet temperature thermistor 11 for detecting the hot water outlet temperature of the heat exchanger 2 is provided in the passage 8.

In the fuel supply passage 12 for the burner 3, there are two electromagnetically operated on-off valves 1 for opening and closing the fuel supply passage 12.
3, 14 and an electromagnetically operated gas amount adjusting valve 15 for changing and adjusting the supply amount of the fuel gas to the burner 3. An igniter 16 that executes an ignition operation for the burner 3 and a frame rod 17 that detects whether or not the burner 3 is ignited are provided near the burner 3. The combustion gas of the burner 3 is discharged to the outside through the exhaust passage 18.

The remote controller R is connected to the controller H so that various information can be communicated, and the operation switch 1 for instructing the controller H to start / stop the operation of the hot water supply unit K.
9. A temperature setting switch 20 for switching and setting the target hot water supply temperature, a temperature display section 21 for displaying the hot water supply temperature, and an abnormality display lamp 22 for displaying an abnormal operation are provided.

The controller H includes a water flow sensor 9,
Detection information of the incoming water temperature thermistor 10, the outgoing hot water thermistor 11, the frame rod 17, the rotary encoder 6, etc. is input, and based on the command information of the remote controller R,
Each on-off valve 13, 14, gas amount adjusting valve 15, igniter 1
6 is configured to execute operation control. More specifically, when the hot water tap is opened after the operation switch 19 is turned on and the water flow rate sensor 9 detects a water flow rate equal to or more than the set value, the fan motor 5 is driven to cause the burner 3 to operate. Ventilation, each on-off valve 13, 14, gas amount adjusting valve 1
5 is opened, the burner 3 is ignited by the igniter 16, and then the gas amount adjusting valve 15 is controlled so that the outlet hot water temperature becomes the target hot water supply temperature and the fan motor 5 is controlled so as to attain the proper air-fuel ratio. Is configured to.

Next, the combustion control configuration of the controller H will be described based on the block diagram of the combustion control configuration shown in FIG. Water flow sensor 9, incoming water temperature thermistor 1
0, heating amount calculation means 100 for calculating the required heating amount (combustion amount, that is, gas supply amount) by the burner 3 based on the detection information of the hot water temperature thermistor 11 and the setting information of the target supply temperature in the remote control device R. A gas amount control means 101 for controlling the gas amount adjusting valve 15 so that the gas supply amount corresponds to the calculation result of the heating amount calculation means 100,
Based on the characteristics preset as shown in FIG. 3 and the combustion amount calculated by the heating amount calculation means 100 so that the ventilation amount of the fan 4 becomes an appropriate value corresponding to the combustion amount,
Target speed setting means 1 for setting the target speed of the fan 4
02, turn on the DC power supply 103 to the fan 4
The switch unit 104 is turned off so that the actual rotation speed of the fan 4 detected by the rotary encoder 6 becomes the target rotation speed, and the switch unit 104 is switched to flow the current supplied from the DC power supply 103 to the fan motor 5. The fan control unit 105 controls the rate (an example of drive power) based on the commands from the fan control unit 105 and the command unit 106.
The standard flow rate setting unit 107 (an example of the standard power setting unit) that sets the standard flow rate of the fan 4 corresponding to the target rotation speed based on the flow rate controlled by the fan control unit 1.
The use condition of the device, out of the flow rate controlled by the fan control unit 105, the correction unit 108 that corrects the target rotation speed based on the deviation between the flow rate controlled by 05 and the reference flow rate. An abnormal value of the flow rate outside the proper adjustment area set in advance corresponding to the above-mentioned reference flow rate setting means 107.
In order not to be set as the reference flow rate, the setting target ratio adjustment means 1 for making the detected value of the flow rate appropriate as the setting target in the reference flow rate setting means 107.
Each of 09 is provided.

In other words, in this hot water supply device, when the ventilation ability of the fan 4 is lowered as the device is used, or when the air supply / exhaust path is clogged with dust or the like and is blocked, the ventilation characteristics are deteriorated. By correcting the target rotation speed of the fan 4 to an appropriate value, it is possible to always ensure an appropriate ventilation amount.

The setting object optimizing means 109 determines that the flow rate controlled by the fan control means 105 exceeds the upper limit value of the reference flow rate set in advance corresponding to the usage status of the apparatus. If the upper limit value is the setting target, and the flow rate is below the lower limit value of the standard flow rate set in advance corresponding to the usage status of the device, the lower limit value is set and the flow rate is set. However, if the upper limit value is not exceeded and the lower limit value is not exceeded, the flow rate is set as the setting target. The upper limit value and the lower limit value of the standard flow rate as described above are predetermined values based on the installation conditions of this water heater and the experimental data conducted in a state corresponding to the configuration of this water heater. Will be used. still,
The command unit 106 is configured to instruct the reference flow rate setting unit 107 to set the reference flow rate when the accumulated operating time of the apparatus reaches a set time (for example, 5 hours).

Next, the control operation of the controller H will be described with reference to the control flowcharts shown in FIGS. When the hot water tap is opened while the operation switch 19 is turned on, and the detected value Qx by the water flow rate sensor 9 exceeds the set value Qs, ignition control for the burner 3 is executed (steps 1, 2, 3). That is, each on-off valve 13, 1
4. The gas amount adjusting valve 15 is opened, and the ignition operation by the igniter 16 is started, and the flame rod 17
When ignition is confirmed by, the ignition operation is stopped. Next, based on the detection information of each of the incoming water temperature thermistor 10, the water flow rate sensor 9, the hot water temperature thermistor 11 and the target hot water supply temperature information set by the temperature setting switch 20 in the remote control device R, the required heating amount by the burner 3 Is calculated (step 4), and the required heating amount is calculated as shown in FIG.
Based on the preset characteristics as shown in FIG.
The target rotation speed Ns is set (step 5).

Then, the gas amount control for adjusting the gas amount adjusting valve 15 is executed so that the amount of fuel supplied to the burner 3 becomes a value corresponding to the required heating amount, and the fan 4 detected by the rotary encoder 6 is executed. Is the target speed N
Fan control is executed to control the current flow rate to the fan motor 5 so as to be s (steps 6 and 7). When the hot water tap is closed and the value Qx detected by the water flow rate sensor 9 falls below the set value Qs, the fuel supply to the burner 3 is stopped and the combustion of the burner 3 is stopped (steps 8 and 9).

The fan 4 remains even after the combustion of the burner 3 is stopped.
The post-purge that keeps the ventilation operation by the set time is executed. In this post-purge,
Fan control is performed to adjust the current flow rate so that the rotation speed of the fan 4 becomes the maximum rotation speed.

When the post-purge is started in this way,
As will be described later, it is determined whether or not the reference flow rate Ds for correcting the target rotation speed Ns is set (steps 10 and 11). The standard flow rate Ds is not set,
Moreover, the cumulative time t of the operating time of the water heater is set to the set time t.
Beyond the _S (5 hours), and, after the elapsed time T from the post-purge is started has elapsed settling time T _at, setting of the reference duty ratio Ds is made (step 12, 1
3).

Stabilization time T_atWait until
For the following reasons. For example, if the burner 3 burns
If the combustion time before stopping is long, the burner 3
With the combustion, the temperature of the air in the combustion chamber 1 and the surrounding air rises,
As the air expands and the air density becomes thin, the fan
The load on 4 is lighter by that amount, and the flow rate is decreasing.
However, the temperature of the air gradually decreases as the combustion stops.
So the air density becomes thicker and the fan 4 is gradually approached.
Load increases and the flow rate gradually increases (see Fig. 6).
In L1), stabilization time T_atThere is little fluctuation after passing
It becomes. If the burning time is very short (a few seconds)
There is no increase in air temperature as described above, but
Along with the execution of the purge, the coil of the fan motor 5
When the energization is started, the coil gradually warms due to the energization.
Temperature rises and the coil resistance increases, reducing the flow rate.
After a while (see line L2 in FIG. 6), the stabilization time T _atOver
Fluctuations will be less if you do. In other words, such a temperature rise
Error due to transient fluctuations associated with
In order to stabilize time T_atAfter the passage of
The setting of Ds is performed.

To set the reference flow rate Ds, first, the flow rate Dx actually controlled at that time is detected and read as the setting flow rate (step 14). If the setting conduction ratio Dx exceeds the preset upper limit value D _MAX , the upper limit value D _MAX is set as the reference conduction ratio Ds (steps 15 and 16). If the read setting conduction rate Dx is below the preset lower limit value D _MIN , the lower limit value D _MIN is set as the reference conduction rate Ds (steps 17 and 18). Then, the setting flow rate D
If x does not exceed the upper limit value D _MAX and is not below the lower limit value D _MIN , the detected setting conduction ratio Dx is set as the reference conduction ratio Ds (step 19). When the setting of the reference flow rate Ds is completed and the set time elapses, the post purge is completed and the fan 4 is stopped.

In this way, when strong wind of the outside air is blown in the opposite direction to the exhaust port portion of the exhaust passage 18 and the ventilation by the fan 4 is obstructed,
When the outside air breeze is blown to the air intake of the fan, the load of the fan 4 becomes extremely large or extremely large, which is impossible under normal use conditions, such as when it acts to promote ventilation. Therefore, an abnormal value of the conduction ratio is detected, and such an abnormal value is prevented from being set as the reference conduction ratio Ds.

After the reference flow rate Ds is set in this way, based on the deviation between the reference flow rate Ds and the correction flow rate read every time the post-purge is executed, The target rotation speed Ns of the fan 4 is corrected to an appropriate value. That is, as the post-purge is started, the flow rate Dx actually controlled at that time is
Is read as the correction flow rate (step 20), and if the correction flow rate Dx is smaller than the reference flow rate Ds and their deviation exceeds the set value ΔD, the target of the fan 4 is obtained. The rotation speed Ns is corrected to the increasing side (step 21,
22), if the correction flow rate Dx is larger than the reference flow rate Ds, and their deviation exceeds the set value ΔD,
The target rotation speed Ns of the fan 4 is corrected to the decreasing side (steps 24 and 25). The correction of the target rotation speed Ns will be specifically described. As shown by a broken line in FIG. 3, the target rotation speed Ns for the maximum combustion amount is increased by a predetermined value ΔN, and the target rotation speed Ns for the minimum combustion amount is increased by the predetermined value ΔN. Is multiplied by a coefficient α smaller than “1”, and the broken line connecting these two points with a straight line becomes the corrected target rotational speed Ns. This corresponds to one increase side correction operation, and is similarly performed on the decrease side. When the number of corrections C reaches the set number of times Cs on both the increasing side and the decreasing side, it is determined that there is an abnormality and abnormality processing (for example, the abnormality display lamp 2) is performed.
2 is turned on) (steps 23, 26, 27,
28). In such a case, there is a possibility that the ventilation path is blocked and ventilation by the fan 4 is difficult, or an abnormality such as damage to the exhaust passage 18 has occurred.
This is to prompt the user to carry out repair inspection. Number of corrections C
When the set time elapses in a state where is less than the set number of times Cs, the post purge is ended and the operation of the fan 4 is stopped (steps 29 and 30).

[Other Embodiments] (1) In the above embodiment, in setting the reference flow rate Ds, as a setting object optimization means, the preset upper limit value D _MAX and the lower limit value D _MIN are compared with each other. Although the reference flow rate Ds is set, the following configuration may be used instead of such a configuration. As shown in FIG. 7, if the standard flow rate Ds is not set, the cumulative time t of the operating time of the water heater is the first set time t _s1 (5 hours) and the second set time t _s2 (6 hours). , And the third set time t _s3 (10 hours)
Each time, after the stabilization time T _at has elapsed since the post-purge was started, the set flow rate at that time is read (steps 11, 12a to 16a), and the average value of each flow rate is read. May be calculated and the average value thereof may be set as the reference flow rate Ds (steps 17a, 18a). The control operation before and after the reference flow rate setting operation is the same as steps 1 to 10 and steps 21 to 30 in FIGS. In this embodiment, the number of times of reading the flow rate is set to three, but the number of times is not limited to three and may be two or more, and the more the number of times of reading, the more uniform the proper reference flow rate. It can be set.

(2) In the above embodiment, the flow rate is read after the stabilization time T _at has elapsed after the start of the post-purge, but such stabilization time T _at has elapsed. The reading may be performed without waiting until it is done. If the burn time of the burner 3 before the post-purge is short, the flow rate should be corrected according to the reading time as follows. May be.

That is, when the combustion time is short, the flow rate decreases with the execution of the post-purge as shown by the line L2 in FIG. 6, but this decreasing line is a straight line as shown in FIG. Approximately, based on the maximum change amount e, the elapsed time t ₁ until the flow rate is read, and the stabilization time T _at ,
By obtaining the correction value a of the conduction ratio as described below, the reference conduction ratio Ds can be set with a small error without waiting until the stabilization time T _at elapses.

[0043]

## EQU1 ## a = e (1-t ₁ / T _at ).

Therefore, the flow rate is obtained as a value obtained by subtracting the correction value a from the detection value Dx ₁ .

(3) In the above embodiment, the command means 106
As a configuration, when the integrated time of the operating time reaches the set value, the setting of the reference flow rate Ds is instructed. However, instead of this configuration or in addition to such a configuration, the remote controller is provided. A configuration may be adopted in which a maintenance switch is provided in the device R or the like and a command for setting the reference flow rate Ds is issued based on the operation of the maintenance switch. When the command configuration based on the accumulated time and the command configuration based on the maintenance switch are used together, the command based on the accumulated time is set at the initial stage of installation of the device, and repair inspection etc. can be performed with long-term use. After the completion, an appropriate reference flow rate Ds can be set by instructing with the maintenance switch.

(4) In the above embodiment, the reference flow rate Ds is set when the post-purge is executed. However, when the operation is stopped, for example, the integrated time of the operation time is set. May be configured to be automatically executed when reaches the set value.

(5) In the above embodiment, the duty factor of the DC power source is used as the driving power of the fan 4, but the present invention is not limited to this, and the magnitude of the current value or the voltage value is used, for example. Alternatively, the firing angle for the AC motor may be used.

(6) In the above embodiment, the hot water supply device is illustrated as the combustion control device, but the present invention can be applied to other combustion control devices such as a fan heater.

It should be noted that reference numerals are added to the claims for facilitating the comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a controller

FIG. 3 is a diagram showing a change characteristic of a target rotation speed with respect to a combustion amount.

FIG. 4 is a flowchart of a control operation.

FIG. 5 is a flowchart of control operation

FIG. 6 is a diagram showing a transitional change in the flow rate.

FIG. 7 is a flowchart of a control operation according to another embodiment.

FIG. 8 is an operation explanatory view of another embodiment.

[Explanation of symbols]

 3 burner 4 fan 102 target speed setting means 105 fan control means 106 commanding means 107 reference power setting means 108 correcting means 109 setting object optimizing means

Claims (6)

[Claims] 1. Based on the required combustion amount of the burner (3),
A fan (4) that ventilates combustion air to the burner (3)
Target rotation speed setting means (102) for setting the target rotation speed (Ns), and driving power of the fan (4) so that the rotation speed of the fan (4) becomes the target rotation speed (Ns). The target rotation speed (Ns) corresponding to the fan control means (105) for adjusting and controlling, and the drive power controlled by the fan control means (105) based on the command from the command means (106). Based on the deviation between the reference power setting means (107) for setting the reference driving power of the fan (4), the driving power controlled by the fan control means (105), and the reference driving power. A combustion control device provided with a correction means (108) for correcting the number of revolutions (Ns), which corresponds to the usage status of the device in the drive power controlled by the fan control means (105). Preset The detected value of the drive power is set to the reference power setting means (107) so that the drive power abnormal value deviating from the appropriate adjustment range is not set as the reference drive power by the reference power setting means (107). ) A combustion control device provided with a setting object optimization means (109) for making the setting object appropriate in (1). 2. The setting object optimizing means (109) is detected based on an instruction of the instruction means (106),
If the drive power controlled by the fan control means (105) exceeds an upper limit value of the reference drive power preset corresponding to the usage status of the device, the upper limit value is set as the setting target, If the drive power is lower than a lower limit value of the reference drive power preset corresponding to the usage status of the device, the lower limit value is set as the setting target, and the drive power exceeds the upper limit value. If it is not below the lower limit, the combustion control device according to claim 1, wherein the drive power is set as the setting target. 3. The setting object optimizing means (109) supplies drive power controlled by the fan control means (105) based on an instruction of the instruction means (106) with the passage of time. The combustion control device according to claim 1, wherein the combustion control device is configured to be detected a plurality of times and to set an average value thereof as the setting target. 4. The fan control means (105) is configured to execute post-purge for continuing the ventilation operation by the fan (4) for a set time after the combustion operation of the burner (3) is stopped, The combustion control device according to claim 1, 2 or 3, wherein the setting object optimizing means (109) is configured to detect the drive power after a set time has elapsed after the post purge was started. 5. The fan control means (105) is configured to execute post-purge for continuing the ventilation operation by the fan (4) for a set time after the combustion operation of the burner (3) is stopped. The setting object optimizing means (109) is configured to detect the drive power as the post purge is executed, and the time from the start of the post purge to the detection of the drive power. The drive power detected is corrected based on time and a preset correction characteristic, and the corrected drive power is set as the setting target. 3. The combustion control device described in 3. 6. The fan control means (105) is configured to control a conduction ratio of a current supplied to the fan (4) as a driving power of the fan (4). The combustion control device according to 2, 3, 4, or 5.