JP4230462B2 - Combustion control device - Google Patents

Description

  The present invention relates to a control device for a combustion apparatus. The present invention is suitable as a control device for a combustion apparatus having a hot water supply function.

  A combustion apparatus typified by a gas hot water supply apparatus includes a control device having a microcomputer mounted in the control center thereof, a gas electromagnetic valve for switching supply / stop of fuel gas by the microcomputer, and a fuel gas supply amount. Control of the operation of various actuators such as a proportional valve for adjusting the air flow, and a fan motor for adjusting the air flow rate of the combustion air is performed.

Therefore, if the microcomputer runs away, the amount of fuel gas supplied or the amount of air blown becomes uncontrollable, which may cause a situation where the amount of combustion becomes excessive or misfires occur. Therefore, Patent Document 1 discloses a measure for dealing with this problem.
JP 2002-318003 A

  The control device disclosed in Patent Document 1 includes a main microcomputer and a sub-microcomputer in the device. Then, the microcomputers runaway are detected by causing the microcomputers to communicate with each other to communicate with each other. When the sub microcomputer detects the runaway of the main microcomputer, the fuel supply solenoid valve is closed.

By the way, although safety is naturally required for the combustion apparatus, in recent years, higher safety is required than ever before. Therefore, it is necessary to take double and triple protection measures to prevent the occurrence of excessive flames, misfires when fuel is injected, or hot water discharged from the hot water supply system. Don't be.
From this viewpoint, when the control device described in Patent Document 1 is viewed, there are still problems to be improved. That is, according to the configuration of Patent Document 1, the sub-microcomputer stops the combustion apparatus when the main microcomputer is abnormal. Whether or not a stop signal is effectively transmitted from the sub-microcomputer. There is no function to check in advance.
In view of the above, an object of the present invention is to provide a combustion control device having a function of checking in advance that a stop signal is effectively transmitted and having higher safety than the conventional one.

  The invention according to claim 1 for achieving the above object comprises a main control device, a sub-control device, and a shut-off confirmation means for directly or indirectly confirming that the fuel supply is shut off, Both control devices can execute a shut-off operation that shuts off the fuel supply. Before the start of combustion, the shut-off operation by the main control device and the shut-off operation by the sub-control device are individually performed, and the respective shut-off operations are performed. It is the combustion control device characterized by confirming that the engine is effective by the shut-off confirmation means.

  The combustion control device of the present invention separately performs the shut-off operation by the main control device and the shut-off operation by the sub-control device before the start of combustion, and confirms that the respective shut-off operations are effective by the shut-off confirmation means. For this reason, the supply of fuel can be surely cut off if any abnormality occurs during combustion.

  According to a second aspect of the present invention, the combustion device controlled by the combustion control device includes a blower that supplies fuel to the combustion unit for combustion and blows air to the combustion unit, and the combustion control device operates the blower. The pre-purge process and the fuel supply start process for starting the fuel supply to the combustion section are sequentially executed, and before the pre-purge process, the shut-off operation is executed by one control device and the control device or another control device Confirming that the shut-off operation is valid, performing the shut-off operation by the other control device during the pre-purge process, and confirming that the shut-off operation is valid by the control device or another control device The combustion control device according to claim 1.

  Combustion devices often perform pre-purge before starting combustion. Here, the pre-purge is a process of blowing air into the combustion device before supplying fuel and exhausting unburned components remaining in the combustion device, and is also referred to as a scavenging process. In the pre-purge process, it is necessary for the air to pass through the combustion device, and since this is a physical process, it takes a certain amount of time. Therefore, in the present invention, the shutoff operation is confirmed using the pre-purge period.

  The invention according to claim 3 is the combustion control device according to claim 2, wherein when it is determined that the shut-off operation is not effective, the process does not proceed to the fuel supply start process.

  The combustion control device of the present invention does not supply fuel when it is found that the shut-off operation is not effective. Therefore, the combustion apparatus that employs the combustion control apparatus of the present invention has high safety.

  The invention according to claim 4 is the combustion control device according to any one of claims 1 to 3, wherein it is confirmed that the cutoff confirmation means functions effectively during combustion.

Since the combustion control device of the present invention can check the effectiveness of the shutoff confirmation means, the safety is higher.
Further, since the effectiveness of the shutoff confirmation means is checked during combustion, time is effectively used. That is, if the check operation is performed before the start of combustion, the user is kept waiting during that time, which gives the user an irritation.
Therefore, in the present invention, the above check is performed during combustion.

  The invention according to claim 5 is the combustion control apparatus according to claim 4, wherein when it is found that the shutoff confirmation means is not functioning effectively, the combustion is stopped.

  In the combustion control device of the present invention, when it is found that the shutoff confirmation means is not functioning effectively, the combustion is stopped. Therefore, the combustion apparatus that employs the combustion control apparatus of the present invention has high safety.

  According to the sixth aspect of the present invention, the main controller is responsible for overall control of the combustion apparatus, and a signal for knowing the operating state of the combustion apparatus is input to the main controller and the sub-control apparatus, The sub-control device performs a shut-off operation when the signal becomes a predetermined stop condition, and the stop condition when the sub-control device performs an emergency shut-off operation is the stop condition when the main control device executes the shut-off operation The combustion control device according to any one of claims 1 to 5, wherein the combustion control device is gentler than the stop condition.

In the combustion control device of the present invention, the functions of the main control device and the sub-control device are clearly separated, and the main control device is responsible for overall control of the combustion device. For this reason, the performance required for the sub-control device is relatively low, and the selection range of devices to be employed as the sub-control device is wide.
In the present invention, not only the main control device but also the sub-control device performs an emergency shut-off operation when a predetermined stop condition is met. can do.
Furthermore, in the present invention, the stop condition when the sub-control device executes the emergency shut-off operation is gentler than the stop condition when the main control device executes the shut-off operation, so that it is erroneously detected during normal operation. There is no problem that combustion stops.
That is, in recent years, since the combustion apparatus is burned under various combustion conditions, the amount of combustion may increase for a short period of time, or the amount of blown air may increase or decrease. Since such an operation is restored in a short time, it cannot be said to be abnormal combustion and is not in a dangerous state. For this reason, in the main control device, settings and programs are often performed so that the device does not stop at such an expected range of shake. For this reason, if the threshold value for determining an abnormality in the sub-control device is lower than that of the main control device (in a direction in which it is easily determined to be abnormal), the shut-off operation is frequently executed even in a state where it should not be stopped. There is a concern that it will be unusable.
On the other hand, a measure to install the same program as the main control device can be considered for the sub-control device, but a measure to install the same programgram as the main control device is to reduce the required performance of the sub-control device. Contrary to the purpose.
Therefore, in the present invention, the stop condition when the sub-control device performs the emergency shut-off operation is made gentler than the stop condition when the main control device executes the shut-off operation, and the shut-off operation by the sub-control device is performed. Restricted to improve both safety and compatibility.

  The invention described in claim 7 is provided with a device drive circuit for operating a device for supplying fuel, and the shutoff confirmation means confirms whether or not the device drive circuit is energized. It is a combustion control apparatus in any one of 1 thru | or 6.

  In the combustion control device of the present invention, the structure for confirming whether or not the device drive circuit is energized is adopted as the shut-off confirmation means, so that the structure is simple.

  The invention according to claim 8 is the combustion control device according to any one of claims 1 to 7, wherein the main control device and the sub-control device are connected by communication means.

  In the combustion control device of the present invention, since the main control device and the sub control device are connected by the communication means, information that one control device is performing the shut-off operation can be transmitted to the other control device. You can also check for runaway control devices.

  Since the combustion control device of the present invention can check in advance that the fuel supply cutoff operation is effective, it is safer than the conventional one.

Embodiments of the present invention will be further described below.
FIG. 1 is a circuit block diagram when the combustion control device of the present invention is used as a control device for a hot water supply device. FIG. 2 is a circuit diagram when the combustion control device of the present invention is utilized as a control device for a hot water supply device. FIG. 3 is a conceptual diagram of a hot water supply apparatus controlled by the control apparatus of the present invention. FIG. 4 is a flowchart showing a part of the operation of the combustion control device shown in FIG. FIG. 5 is a circuit diagram showing the connection relationship of each solenoid valve in FIG.

The combustion control device 27 of this embodiment is used in a hot water supply device 1 as shown in FIG. The hot water supply apparatus 1 uses gas as fuel, and supplies the gas to the burner group 2 to burn it. The hot water supply apparatus 1 of the present embodiment has three burners 5, 6, and 7, and gas solenoid valves 10, 11, and 12 are provided in the respective gas supply paths.
Each supply path is integrated into one and connected to the gas supply source 13, and the proportional valve 15 and the original electromagnetic valve 16 are interposed therebetween. The gas solenoid valves 10, 11, 12 and the original solenoid valve 16 are normally closed solenoid valves that are closed when the current supply to the solenoid is interrupted.

  The hot water supply device 1 includes a heat exchanger 18 and heats the water in the heat exchanger 18 with a flame generated by the burner group 2. A blower 9 for blowing air to the burner group 2 is provided.

  The hot water circuit includes a high temperature hot water circuit 22 that extends from the water supply source 20 through the heat exchanger 18 to the hot water outlet 21, and a bypass water passage 23 that bypasses the heat exchanger 18 and is connected to the high temperature hot water circuit 22. The bypass water passage 23 is provided with a water amount adjustment valve 25, which adjusts the amount of water flowing through the bypass water passage 23 to adjust the temperature of the hot water discharged from the hot water outlet section 21.

The hot water supply device 1 is provided with various sensors. That is, the high-temperature hot water circuit 22 is provided with a water amount sensor 29. A high temperature hot water temperature sensor 28 is provided on the outlet side of the heat exchanger 18 of the high temperature hot water circuit 22, and a hot water temperature sensor 26 is provided on the downstream side of the connecting portion with the bypass water channel 23.
Further, a frame rod 30 and a burner sensor 31 are provided in the vicinity of the burner group 2. The flame rod 30 detects the presence of a flame, and the burner sensor 31 detects the temperature of the flame.
A rotation speed detection sensor 32 for detecting the rotation speed of the blower 9 is provided.

  Next, an outline of the combustion control device 27 of the present embodiment will be described with reference to FIG. The combustion control device 27 includes two microcomputers (control devices) 35 and 36 as shown in FIG. Each of the microcomputers 35 and 36 is one microcomputer, and each includes an MPU, a RAM, and a ROM. In addition, an interface circuit (not shown) is provided as in a known microcomputer. However, the performance of one microcomputer 36, that is, the processing speed of the MPU and the capacity of the RAM and ROM are inferior to those of the other microcomputer 35.

In this embodiment, the microcomputer 35 with higher performance functions as the main control device 35, and the microcomputer 36 with lower performance functions as the sub-control device 36.
The main control device 35 performs the same function as a control device built in a known combustion control device, and bears the main control of the combustion control device 27. That is, ignition to the burner group 2, adjustment of the hot water temperature and gas, opening and closing of each solenoid valve, control of the blower 9, and the like are performed. When a remote controller is connected to the hot water supply device 1, it communicates with the remote control, receives various commands from the remote control, and performs processing such as transmitting the operation status of the hot water supply device 1 to the remote control. . That is, the main control device 35 has all the basic functions provided in the control device of the conventional gas hot water supply device.
In contrast, the sub-control device 36 performs only a shut-off operation for shutting off the fuel supply. That is, the sub-control device controls only opening and closing of the original solenoid valve 16 and the gas solenoid valves 10, 11, and 12.

  Further, the two control devices 35 and 36 include a communication terminal (not shown) for performing data communication in both directions. These terminals are connected to the microprocessor (MPU) and the memory of the main control unit 35 via an interface (communication means) (not shown) via a bus. The microprocessor of the main control unit 35 and the sub-control unit 36 are connected to each other. Data is transmitted and received between the microprocessors.

The main control device 35 and the sub-control device 36 have a flame detection circuit 55, a water amount detection circuit 56, a tapping temperature detection circuit 57, and a blower rotation as signals for knowing the operation state of the combustion device via the bus line 37. The number detection circuit 58, the burner sensor detection circuit 59, the proportional valve current detection circuit 60, the original solenoid valve monitoring circuit 61, and the gas solenoid valve monitoring circuit 62 are connected.
That is, signals from the sensors and the like are input in parallel to both the main controller 35 and the sub controller 36.

  Further, the combustion control device 27 of the present embodiment has a device drive circuit 42 that supplies power from the power source V1 to the solenoid valve drive circuit 46. In the present embodiment, the device drive circuit 42 is a power supply line that operates a device that supplies fuel, and relays RL10, RL11, and RL12 that operate the solenoid valves 10, 11, 12, and 16 as shown in FIG. , There is a line for supplying electric power to the coil of RL16 and a line for supplying electric power to the solenoids of the electromagnetic valves 10, 11, 12, 16 as shown in FIG. In any case, by shutting off the electric power flowing through the circuit, each solenoid valve 10, 11, 12, 16 is closed and the fuel supplied to the burner group 2 is shut off. Accordingly, if the combustion is in progress, the combustion is stopped, and if the combustion is stopped, the start of the combustion is prevented.

A power cutoff signal is output from the main control device 35 and the sub control device 36. The power cutoff signal is input to the logical sum circuit 40, and the output of the logical sum circuit 40 is output to the device drive circuit 42 side and input to the power cutoff circuit 43.
Here, the power shut-off circuit 43 is inserted in a circuit extending from the drive power supply 45 to the solenoid valve drive circuit 46, and shuts off the voltage supplied to the original solenoid valve 16 and the gas solenoid valves 10, 11, and 12. is there.
As described above, since the original solenoid valve 16 and the gas solenoid valves 10, 11, and 12 are normally closed, when the power supply cutoff circuit 43 functions and the voltage supplied to each solenoid valve is shut off, The solenoid valve is closed and the gas supply to the burner group 2 is stopped.

  A voltage detection circuit 47 is provided between the power cutoff circuit 43 and the solenoid valve drive circuit 46, and a signal from the voltage detection circuit 47 is input to the main controller 35.

As described above, the main controller 35 and the sub controller 36 output a power shut-off signal, and this signal is input to the power shut-off circuit 43 via the OR circuit 40. When a power shut-off signal is output from any of the devices 36, the power shut-off circuit 43 is activated, the voltage supplied to each solenoid valve is shut off, and the gas supply to the burner group 2 is stopped.
Further, whether or not the energization from the drive power supply 45 is cut off can be determined by the main controller 35 confirming the signal of the voltage detection circuit 47. In other words, the voltage detection circuit 47 is a circuit for determining whether or not electric power is supplied to the electromagnetic valve drive circuit 46, and is a circuit (interruption confirmation means) for indirectly knowing whether fuel is supplied to the burner group 2. is there.
Further, whether or not a current flows through each solenoid valve can be determined by the main controller 35 and the sub controller 36 confirming signals from the original solenoid valve monitoring circuit and the gas solenoid valve monitoring circuit.

The schematic configuration of the control device 27 has been described above using the block diagram, but the actual circuit is as shown in FIG. That is, the main control device 35 and the sub control device 36 are provided with stop signal output terminals 50 and 51.
Here, the stop signal output terminal 50 on the main control device 35 side outputs an H signal when the hot water supply device 1 is operating normally, and outputs a Lo signal when it is detected that it is in an abnormal state.
On the other hand, the stop signal output terminal 51 of the sub-control device 36 is Lo when the hot water supply device 1 is operating normally, and is opened (open) when it is detected that it is in an abnormal state.

  The device drive circuit 42 is a circuit that supplies power to the coils of the relays RL10, RL11, RL12, and RL16 from the drive power supply V1 shown in FIG. A part of the device drive circuit 42 includes a solenoid valve drive circuit 46.

  The solenoid valve drive circuit 46 is a circuit for controlling energization to the gas solenoid valves 10, 11, 12 and the original solenoid valve 16, and as shown in FIG. 2, the coils of relays RL10, RL11, RL12, RL16 and these Transistors Q10, Q11, Q12, and Q16 that drive and control the relays RL10, RL11, RL12, and RL16 are configured as main parts. Each relay number corresponds to each solenoid valve number. Note that the relays RL10, RL11, RL12, and RL16 all have their contacts closed by energizing the coils.

  A relay drive signal is input from the main controller 35 to the base terminals of the transistors Q10, Q11, Q12, and Q16. Then, when a relay drive signal is given from the main control device 35, the transistors Q10, Q11, Q12, Q16 are turned on, and the relays RL10, RL11, RL12, RL16 are energized, whereby relay contacts (FIG. 5). Is activated to energize the solenoids of the gas solenoid valves 10, 11, 12 and the original solenoid valve 16. As described above, since each solenoid valve is normally closed, the solenoid valve is opened by energizing the solenoid. In other words, the relay contact is activated by energizing RL10, RL11, RL12, and RL16, but the relay contact is connected in series with the coil of each solenoid valve to the power supply for the gas solenoid valve. Is energized, and each solenoid valve is opened.

  The power cut-off circuit 43 is a circuit that cuts off the power supply to the device drive circuit 42. Specifically, the power cut-off circuit 43 is a circuit that can cut off the power supplied to each of the relays RL10, RL11, RL12, RL16 all at once. It is. In the present embodiment, the power cut-off circuit 43 is mainly configured by a transistor Q2 interposed between the drive power supply V1 of the relays RL10, RL11, RL12, and RL16 and the relay. Specifically, the transistor Q2 is a PNP transistor, and has an emitter terminal connected to the drive power supply V1 and a collector terminal connected to the other end of each of the relays RL10, RL11, RL12, and RL16. When the power supply cut-off signal is given to the base terminal, the transistor Q2 is turned off and the voltage supply to each relay is cut off.

  In the present embodiment, the collector terminal of the transistor Q3 is connected to the base terminal of the transistor Q2 constituting the power supply cutoff circuit 43, and the transistor Q2 is also turned off when the transistor Q3 is turned off. That is, when the transistor Q3 is turned off, a power supply cutoff signal is given to the transistor Q2.

The OR circuit 40 shown in FIG. 1 includes a transistor Q3 and a transistor Q4. That is, the transistor Q3 and the transistor Q4 are provided between the main control device 35 and the sub control device 36 and the transistor Q2 which is the power cutoff circuit 43. The stop signal output terminal 50 of the main control device 35 is connected to the emitter terminal of the transistor (PNP type) Q4, and the stop signal output terminal 51 of the sub control device 36 is connected to the base terminal.
The collector terminal of the transistor (PNP type) Q4 is connected to the base terminal of the transistor (NPN type) Q3.
Further, the emitter terminal of the transistor (NPN type) Q3 is grounded.

  As described above, the stop signal output terminal 50 on the main control device 35 side outputs an H signal when the hot water supply device 1 is operating normally, and outputs a Lo signal when it detects an abnormal state. (Lo active signal), the stop signal output terminal 51 of the sub-control device 36 is Lo when the hot water supply device 1 is operating normally, and is opened when it detects an abnormal state. Therefore, when the hot water supply apparatus 1 is operating normally, the base is Lo, the transistor (PNP type) Q4 is turned on, and the emitter of the transistor (PNP type) Q4 is H. Therefore, when the water heater is operating normally, the transistor (PNP type) Q4 is turned on, the transistor Q3 is turned on, the transistor Q2 is also turned on, and current is supplied to the relays RL10, RL11, RL12, and RL16. Thus, each solenoid valve 10, 11, 12, 16 is opened.

On the other hand, when the main control device 35 or the sub control device 36 detects the stop condition, the power supply to the device drive circuit 42 is cut off. Specifically, the transistor (PNP type) Q4 is turned off, the transistors Q3 and Q2 are turned off, and the current supplied to each relay RL10, RL11, RL12, RL16 is cut off.
That is, when the main control device 35 detects an abnormality or a dangerous state or the cause thereof, the stop signal output terminal 50 becomes Lo, the base of the transistor Q3 becomes Lo, and the transistor Q3 is turned off. Therefore, the transistor Q2 is also turned off, and the current supplied to the relays RL10, RL11, RL12, RL16 is cut off.

  Further, also when the sub control device 36 detects a stop condition, the power supply to the device drive circuit 42 is cut off. Specifically, the stop signal output terminal 51 is opened (open), the base of the transistor Q4 is opened, the transistor Q4 is turned off, the subsequent transistors Q3 and Q2 are also turned off, and the relays RL10, RL11, RL12 , The current supplied to RL16 is cut off.

The voltage detection circuit (shut-off confirmation means) 47 is composed of a transistor (NPN type) Q5.
That is, it is a supply line of the drive power source V1, and the downstream side of the transistor Q2 is branched in parallel and connected to the base terminal of the transistor (NPN type) Q5. The collector terminal of the transistor (NPN type) Q5 is connected to the voltage detection signal connection terminal 52 of the main controller 35. The collector terminal of the transistor (NPN type) Q5 is connected to a signal power source 53 via a resistor.
The emitter terminal of the transistor (NPN type) Q5 is grounded.

When the supply line of the drive power supply V1 is turned on, a current flows through the base of the transistor (NPN type) Q5, the transistor Q5 is turned on, and the voltage detection signal connection terminal 52 of the main controller 35 becomes Lo.
Conversely, when the supply line of the drive power supply V1 is turned off, no current is supplied to the base of the transistor (NPN type) Q5, the transistor Q5 is turned off, and the signal voltage is applied to the voltage detection signal connection terminal 52 of the main controller 35. It takes.

The original solenoid valve monitoring circuit 61 and the gas solenoid valve monitoring circuit 62 detect whether the gas solenoid valve or the like is open or closed by monitoring the drive voltage supplied to the gas solenoid valve or the like. When the gas solenoid valves 10, 11, 12, etc. are open, a valve monitoring signal is output. Specifically, the gas solenoid valve monitoring circuit 62 is configured by a circuit that monitors the voltage applied to both ends of the coils of the gas solenoid valves 10, 11, and 12. The gas solenoid valve monitoring circuit 62 only needs to be able to detect whether the solenoid valve is open or closed. For example, other configurations such as monitoring the energization current of the coil can be adopted. is there.
The flame detection circuit 55 detects the presence / absence of combustion with the flame rod 30 disposed in the vicinity of the burners 5, 6 and 7, and outputs a flame detection signal when burning. Further, the water amount detection circuit 56 detects a water flow rate based on a detection signal obtained from a water amount sensor 29 provided upstream of the heat exchanger 18, and detects water flow when there is water flow exceeding the minimum working water amount. Output a signal.
The hot water temperature detection circuit 57 is a circuit that detects the temperature of hot water finally discharged from a currant or the like based on a signal from the hot water temperature sensor 26. The burner sensor detection circuit 59 is a circuit that detects the flame temperature based on a signal from the burner sensor 31. The proportional valve current detection circuit 60 is a circuit that detects an electrical signal input to the proportional valve and detects the opening degree of the proportional valve.
The blower rotational speed detection circuit 58 is a circuit that detects the rotational speed of the blower 9 from the signal of the rotational speed detection sensor 32.

Next, functions of the combustion control device of the present embodiment will be described.
In the present invention, the main control device 35 and the sub-control device 36 are used as the control means of the hot water supply device 1, and the main control device 35 controls the operation of each part of the hot-water supply device including opening and closing of the electromagnetic valve. Controls only the opening and closing of the original solenoid valve 16 and the gas solenoid valves 10, 11, 12.
The combustion control device 27 of the present embodiment is characterized by opening / closing control of the original solenoid valve 16 and the gas solenoid valves 10, 11, and 12, and therefore will be described with emphasis on this portion.
The original solenoid valve 16 and the gas solenoid valves 10, 11, and 12 are closed when an abnormality occurs in the hot water supply device 1 or when a dangerous driving situation occurs, but the hot water supply device 1 is operating normally. Of course it is opened and closed.
Therefore, when the original electromagnetic valve 16 and the gas electromagnetic valves 10, 11, and 12 are closed, there are cases where the hot water supply device 1 is operating normally and cases where there is an abnormality, which will be described separately.

First, the opening / closing operation of the original solenoid valve 16 and the gas solenoid valves 10, 11, 12 when the hot water supply device 1 is operating normally will be described.
In the combustion control device 27 of the present embodiment, of the control of each part of the hot water supply device performed by the main control device 35, the sub-control device 36 also shares the processing with respect to the combustion stop processing associated with the normal hot water supply operation. It is configured.

In this type of hot water supply device 1, in the normal hot water supply operation, the tip plug is closed during the combustion of the burners 5, 6, 7, etc. When certain conditions are satisfied, such as when the operation switch of the remote control is turned off, the combustion stop processing of the burners 5, 6 and 7 is executed. However, since the conditions for the normal combustion stop are well known, a detailed description will be given. Is omitted.
In the combustion control device 27 of the present embodiment, the two control devices 35 and 36 perform data communication in both directions, and the sub-control is also performed from the main control device 35 side for the combustion stop request when the normal operation is performed. Transmitted to the device 36.
In sharing the above-described combustion stop processing, the sub control device 36 transmits a stop signal from the stop signal output terminal 51 when receiving the execution command of the combustion stop processing given from the main control device 35 by the data communication described above. Specifically, the stop signal output terminal 51 is opened (opened), and the current supplied to each relay RL10, RL11, RL12, RL16 is cut off. That is, the power supply to the device drive circuit 42 is cut off by the sub-control device 36.

  On the other hand, when the main controller 35 needs to stop the combustion in the burner due to the closing operation of the tip plug, etc., which of the main controller 35 and the sub controller 36 performs the combustion stop process? A program to determine the system is installed. When the combustion stop process is performed on the sub-control device 36 side, the execution command for the combustion stop process is transmitted from the main control device 35 to the sub-control device 36.

  By the way, in the present embodiment, this program is executed by the sub-control device 36 after the main control device 35 executes the combustion stop processing, and the next combustion stop after the sub-control device 36 executes the combustion stop processing. The processing is set so that the main control device 35 and the sub control device 36 alternately perform the combustion stop processing once, as the main control device 35 performs.

  This is because the stop function including the fuel control circuit such as the power shut-off circuit 43 and the solenoid valve drive circuit 46 is normal by causing the combustion stop process by the stop output to be periodically performed during the normal hot water supply operation. This is because it is effective for the main control device 35 and the sub control device 36 to alternately execute the combustion stop process once each time. Therefore, within such a purpose range, for example, the main control device 35 performs the combustion stop processing twice in succession, and then the sub control device 36 performs the combustion stop processing once. It may be. In short, as long as it is within a range where it can be confirmed whether or not the combustion stop function of the sub-control device 36 functions normally, the specific method of sharing the combustion stop process can be changed as appropriate.

  Then, when the combustion stop process is performed on the main controller 35 side by the determination of the program, the combustion stop process is performed by stopping the output of the relay drive signal and closing each solenoid valve by its own control. .

  Thus, when the combustion stop process is executed by either the main control device 35 or the sub-control device 36, the main control device 35 performs the fire extinguishing operation based on the valve monitoring signals from the electromagnetic valve monitoring circuits 61 and 62. Is determined to be normal (fire extinguishing judgment process), and if not normal, combustion is stopped by the following process.

  That is, if the combustion stop process performed on the main control device 35 side does not function normally, an execution command for the combustion stop process is output to the sub control device 36 by communication, and the combustion is performed on the sub control device 36 side. Stop processing is executed. On the other hand, when the combustion stop process performed on the sub-control device 36 side does not function normally, the output of the relay drive signal is stopped and the combustion stop process is executed on the main control device 35 side.

  In connection with the above-described allocation of the combustion stop process, the main controller 35 records in the memory a history of the combustion stop process by the main controller 35 itself and the transmission of the execution command of the combustion stop process to the sub-control unit 36. The alternate combustion stop process described above is executed based on the recording.

Next, the combustion stop process when an abnormality occurs in the hot water supply device 1 or when a dangerous driving situation occurs will be described.
In the combustion control device 27 of the present embodiment, the original solenoid valve 16 and the gas solenoid valves 10, 11, and 12 are closed when predetermined stop conditions are met. In the combustion control device 27 of the present embodiment, in order to further improve safety, there are a variety of stopping conditions, and these situations occur as well as when the combustion state is abnormal or when hot water is discharged. Combustion is stopped even when a factor to detect is detected.
The case of “abnormal” includes, for example, leakage of unburned gas (unburned fuel) and burning of a burner. Specifically, it can be said that there is leakage of unburned gas when the burner unit is not combusted even though fuel is supplied to the burner unit. In other words, the original solenoid valve 16 is open, and at least one of the gas solenoid valves 10, 11, 12 is open, but no flame is detected. Sometimes it is abnormal, even though unburned gas leaks.
Further, it can be said that the fuel is supplied to the burner unit, and the air is burned when the burner unit is in a combustion state and the heat exchanger has no water flow. In other words, at least one of the gas solenoid valves 10, 11, and 12 is open, and there is no water flow or no water flow even though a flame is detected. When there is only water flow that is less than the minimum operating water volume (MOQ) of the device, it can be said that it is empty and it is abnormal.
Furthermore, when the hot water temperature sensor 26 detects a high temperature such as 90 degrees or more, there is a risk of burns.
Further, if the rotational speed of the blower 9 does not increase, it cannot be said that it is immediately dangerous, but if this state continues for a certain period of time, it will cause abnormal combustion. Similarly, when the state in which the proportional valve 15 is fully opened continues for a certain period of time or the flame temperature is abnormal, it is one of the risk factors.

The abnormal state is determined based on the signals of the sensors input to the main control device 35 and the sub control device 36, and information and signals that the main control device 35 has. Since the information and signals that the main control device 35 has are sent to the sub-control device 36 by communication means, the sub-control device 36 makes a determination based on the information transmitted from the main control device 35 with respect to these signals. Will be.
Since the signal for detecting the operation state of the combustion device detected by the sensor or the like is input in parallel to the main control device 35 and the sub control device 36, the sub control device 36 utilizes the directly received signal. To determine abnormality.

The determination of abnormality or danger is performed independently by each of the control devices 35 and 36. The matter to be noted here is that the judgment criteria such as abnormality judgment performed by the main control device 35 and abnormality judgment performed by the sub control device 36 are different.
That is, in the present embodiment, the threshold value of the determination performed by the sub control device 36 is less than that of the main control device 35. In other words, the sub-control device 36 does not determine that there is an abnormality or a dangerous state unless a state with a higher degree of abnormality or danger is detected. The judgment criterion of the sub-control device 36 is loose about 10-30% with respect to that of the main control device 35.
More specifically, the main controller 35 determines that the hot water temperature sensor 26 detects 85 degrees, but the sub controller 36 determines that it is abnormal when 90 degrees is detected. At 85 degrees, the sub-control device 36 does not issue a stop signal.
If the detected temperature of the burner sensor 31 exceeds 800 ° C. for 150 seconds, the main controller 35 determines that an abnormality has occurred and issues a stop signal. Under this condition, the sub-controller 36 does not issue a stop signal. The sub-control device 36 determines that an abnormality occurs when the state exceeding 800 degrees continues for 200 seconds.
The main controller 35 determines that an abnormality occurs when the rotation speed of the blower 9 is 1000 rpm for 10 seconds, but the sub-control device 36 determines that it is abnormal if it continues for 20 seconds.
If the current value of the proportional valve 15 is high or low continues for 4 seconds continuously, the main controller 35 determines that it is abnormal, but the sub controller 36 determines that it is abnormal if it continues for 5 seconds.

As soon as the main control device 35 or the sub control device 36 detects an abnormality, a fire extinguishing operation (shut-off operation) is executed. That is, the power supply to the device drive circuit 42 is cut off. The fire extinguishing operation is based on the premise that combustion is actually occurring, but in this embodiment, as shown in FIG. 4, the normally closed solenoid valves 10, 11, 12, and 16 that intermittently supply fuel are used. When energized, the flame detection circuit 55 detects the flame, and the water amount detection circuit 56 detects the passage of water, it assumes that combustion is occurring. That is, since it is necessary to execute a fire extinguishing operation even when the main control device 35 is in a runaway state, it does not wait for determination whether or not the combustion is in progress, and if the device is in the above-described state, it is assumed that it is in the combustion state. .
Note that there is an exception when there is leakage of unburned gas as described above, and when the flame detection circuit 55 does not detect a flame, a fire extinguishing operation (shutoff operation) is performed.

When the main control device 35 detects an abnormality or danger, a stop signal is issued from the main control device 35, and the solenoid valves 10, 11, 12, 16 are closed. That is, when the main control device 35 detects an abnormality, the energization to the device drive circuit 42 is interrupted by a signal from the main control device 35. Specifically, the stop signal output terminal 50 of the main controller 35 becomes Lo, the base of the transistor Q3 becomes Lo, and the transistor Q3 is turned off. Therefore, the transistor Q2 is also turned off, and the current supplied to the relays RL10, RL11, RL12, RL16 is cut off. As a result, the current supplied to each solenoid valve 10, 11, 12, 16 is cut off, and each solenoid valve 10, 11, 12, 16 is closed to stop the gas supply.
Further, whether or not the current supplied to each of the relays RL10, RL11, RL12, and RL16 is interrupted is confirmed by a signal from the voltage detection circuit (interruption confirmation means) 47. That is, when the supply line of the drive power supply V1 is in the ON state, the voltage detection signal connection terminal 52 of the main control device 35 is Lo, but the stop signal of the main control device 35 is normally transmitted and the fire extinguishing operation (shut off) When the operation) is executed and the supply line of the drive power supply V1 is turned off, the signal voltage is applied to the voltage detection signal connection terminal 52 of the main controller 35. Therefore, when a predetermined voltage is applied to the voltage detection signal connection terminal 52, it is confirmed that the supply line of the drive power source V1 is turned off.
Further, it is possible to determine whether or not the fire extinguishing operation is normally performed based on the valve monitoring signals from the electromagnetic valve monitoring circuits 61 and 62.

  When the sub-control device 36 detects an abnormality, a stop signal is output from the sub-control device 36, the power supply to the device drive circuit 42 is cut off, and the solenoid valves 10, 11, 12, 16 are closed. That is, when the sub controller 36 detects an abnormality, the stop signal output terminal 51 is opened (open), the base of the transistor Q4 is opened, the transistor Q4 is turned off, and the subsequent transistors Q3 and Q2 are also turned off. The current supplied to each relay RL10, RL11, RL12, RL16 is cut off. As a result, the current supplied to each solenoid valve 10, 11, 12, 16 is cut off, and each solenoid valve 10, 11, 12, 16 is closed to stop the gas supply.

  As described above, the criterion for determining that the sub-control device 36 is abnormal is less than that of the main control device 35. Therefore, if the main control device 35 is functioning normally, each of the signals sent from the main control device 35 is used. The solenoid valves 10, 11, 12, and 16 are closed. Therefore, the sub-control device 36 is prevented from reacting due to the fluctuation of the combustion state assumed by the main control device 35 in advance, and the combustion stop does not occur in a state where the main control device 35 should not be stopped.

Furthermore, the combustion control device 27 of the present embodiment has a specific combustion stop function. That is, in the control device of the present embodiment, the signal of each sensor input to the main control device 35 is compared with the signal of each sensor input to the sub control device 36, and if there is a certain difference between them, the gas The solenoid valves 10, 11, 12, etc. are closed.
In other words, in the present embodiment, signals from sensors and the like are input in parallel to the main control device 35 and the sub-control device 36, so that both signals match. Theoretically, they should be completely the same, but in reality, a slight error may occur when analog / digital conversion is performed. However, if the two signals differ beyond the range that can be assumed, problems such as disconnection and short circuit are suspected. Therefore, in this embodiment, the signal of each sensor input to the main control device 35 is compared with the signal of each sensor input to the sub-control device 36, and if there is a certain difference between the two, the gas electromagnetic valve 10 , 11, 12 etc. were closed.

  Here, the comparison of both signals is performed on the main controller 35 side. In the combustion control device 27 of the present embodiment, the two control devices 35 and 36 perform data communication in both directions, and information such as sensors acquired by the sub control device 36 is transferred to the main control device 35 side by data communication. Sent. Then, the main controller 35 compares the two, and if the difference between the two is opened, for example, by 20% or more, a stop signal is issued from the main controller 35 to close the solenoid valves 10, 11, 12, and 16. It is arbitrary whether the difference between the signals input to the two control devices 35 and 36 is determined to be abnormal. However, if there is a difference of about 10% to 30%, it is desirable to determine that there is an abnormality.

Although the cutoff operation of the combustion control device has been described above, the combustion control device 27 according to the present embodiment includes a program for checking the operation state of the cutoff operation advance check function and the function for confirming the cutoff operation.
That is, the combustion control device of the present embodiment has a function of performing so-called pre-check and pre-purge, and performs a pre-check of the shutoff operation during this period. Also, the operation state of the function for confirming the shut-off operation is checked during combustion. That is, the function of the voltage detection circuit (shutoff confirmation means) 47 is checked during combustion.
Hereinafter, a description will be given with reference to FIG.
FIG. 6 is a flowchart showing a flow of operations in the normal time of the combustion control device of the present embodiment.
That is, the combustion control device 27 waits for a combustion request and starts a series of operations in the same manner as a known one. Here, for example, when the user opens the currant, the combustion request is passed through the circuit passing through the heat exchanger 18 in FIG. 3, and based on the detection signal obtained from the water amount sensor 29 in FIG. Is sent when the water flow rate is detected.

  In accordance with the flowchart of FIG. If there is a combustion request in step 1, the process proceeds to step 2 and pre-check is started. Here, the pre-check is to confirm the operation state of each device, sensor, and heater (not shown) of the combustion apparatus 1 by energizing them. Although not shown in FIG. 6, if an abnormality is found by the pre-check, some kind of display is performed. If the degree of abnormality is high, the combustion device 1 itself is stopped.

Then, when the pre-check is started, the process proceeds to step 3, and first, the blocking operation by the sub-control device 36 is confirmed.
That is, a stop signal is transmitted only from the stop signal output terminal 51 of the sub-control device 36, and the voltage of the voltage detection circuit 47 is confirmed by the main control device 35. More specifically, the stop signal output terminal 51 of the sub-control device 36 is opened (opened), a stop signal is transmitted, and the main control device 35 is set in a normal state, that is, H. At the same time, information indicating that the sub-control device 36 has transmitted a stop signal is transmitted to the main control device 35 by data communication via the energization unit (FIG. 2).

  As a result, if each part functions normally, the energization to the device drive circuit 42 should be cut off by the signal from the sub-control device 36. More specifically, if each part functions normally, the transistor Q2 of the power cutoff circuit 43 is turned off by a signal from the sub-control device 36, and the power supplied to the relays RL10, RL11, RL12, RL16 is shut off all at once. Should be done. A signal indicating that the voltage has disappeared should be input from the voltage detection circuit (shut-off confirmation means) 47 to the main controller 35. More specifically, a predetermined voltage should be applied to the voltage detection signal connection terminal 52 of the main controller 35.

  As a flow of control, the process proceeds to step 4 to check whether or not the above situation is present. That is, it is confirmed whether or not a signal indicating that the voltage applied to each of the relays RL10, RL11, RL12, and RL16 has disappeared is input from the voltage detection circuit (shut-off confirmation means) 47 to the main controller 35. Specifically, it is confirmed that a predetermined voltage is applied to the voltage detection signal connection terminal 52 of the main controller 35.

  When it is confirmed in step 4 that the voltages applied to the relays RL10, RL11, RL12, and RL16 have disappeared, the process proceeds to pre-purge. Actually, since the operation check of each part is executed in parallel at the pre-check stage, the condition that no abnormality is found in the check of other parts and the condition of step 4 are met. The pre-purge start signal is issued.

  On the other hand, when energization to the device drive circuit 42 is maintained, the interruption operation is not functioning, so that an abnormality process is performed. Specifically, when a signal indicating that the voltage applied to each of the relays RL10, RL11, RL12, and RL16 has disappeared is not input, that is, a predetermined voltage is applied to the voltage detection signal connection terminal 52 of the main controller 35. If not, the shut-off operation is not functioning, so the process proceeds to step 6 to display a predetermined abnormality and stop the subsequent control. That is, the combustion apparatus is stopped without supplying combustion gas.

  On the other hand, when it is confirmed in step 4 that the voltage applied to each relay has disappeared and a pre-purge start signal is issued in step 5, the process further proceeds to step 7, and the state opposite to that in step 3 described above is obtained. create. That is, a stop signal is transmitted only from the stop signal output terminal 50 of the main controller 35, and the sub controller 36 is brought into a normal state. Specifically, the stop signal output terminal 50 of the main control device 35 is set to Lo, and the stop signal output terminal 51 of the sub control device 36 is set to Lo.

  As a result, as described above, if each part functions normally, the transistor Q2 of the power shut-off circuit 43 is turned off by a signal from the main controller 35, and the power supplied to each relay RL10, RL11, RL12, RL16 Should be blocked all at once. A signal indicating that the voltage has disappeared should be input from the voltage detection circuit (shut-off confirmation means) 47 to the main controller 35. More specifically, a predetermined voltage should be applied to the voltage detection signal connection terminal 52 of the main controller 35.

  As a control flow, the process proceeds to step 8, and it is confirmed whether or not the above-described situation is present. That is, it is confirmed whether or not a signal indicating that the voltage applied to each relay RL10, RL11, RL12, RL16 has disappeared is input from the voltage detection circuit 47 to the main controller 35. Specifically, as in step 4 described above, it is confirmed that a predetermined voltage is applied to the voltage detection signal connection terminal 52 of the main controller 35.

  When it is confirmed in step 8 that the voltages applied to the relays RL10, RL11, RL12, and RL16 have disappeared, the process proceeds to step 9 and thereafter, and combustion is started according to a normal procedure. That is, in step 9, the solenoid valves such as the gas solenoid valves 10, 11, 12 are opened, and the routine proceeds to step 10 where the fuel gas is ignited by an igniter or the like.

Thereafter, the control shifts to the known combustion control, and the proportional valve 15 and the like are controlled.
On the other hand, when a signal indicating that the voltage applied to each of the relays RL10, RL11, RL12, and RL16 has been lost is not input in step 8, specifically, the voltage detection signal connection terminal 52 of the main controller 35 is predetermined. When there is no voltage, since the shut-off operation is not functioning, the routine proceeds to step 12, where a predetermined abnormality is displayed and the subsequent control is stopped. That is, the hot water supply device 1 is stopped without supplying the fuel gas.

In the combustion control device of this embodiment, when the combustion control is performed, in other words, while the burners 5, 6 and 7 are burning, the operation state of the function for confirming the shutoff operation is checked. That is, it is checked whether or not the voltage detection circuit (shut-off confirmation means) 47 is normal.
Specifically, until the combustion stop (fire extinguishing signal) is confirmed in step 102, it is continuously monitored in step 100 that there is a voltage applied to each relay RL10, RL11, RL12, RL16.
That is, since the electromagnetic valves such as the gas electromagnetic valves 10, 11, 12 are opened in step 9 and combustion is continued, energization to the device drive circuit 42 is continuously maintained from step 9 onward. In other words, there is a voltage applied to each relay RL10, RL11, RL12, RL16. Accordingly, the voltage detection circuit 47 detects the presence of the voltage applied to each of the relays RL10, RL11, RL12, RL16, and the voltage detection signal connection terminal 52 of the main controller 35 is applied to each of the relays RL10, RL11, RL12, RL16. A signal (Lo) indicating the presence of voltage should appear.

Therefore, although the combustion state is maintained, the signal (Lo) indicating the presence of the voltage applied to each of the relays RL10, RL11, RL12, RL16 that should appear at the voltage detection signal connection terminal 52 of the main controller 35 disappears. If the signal becomes H, the voltage detection circuit 47 is expected to be abnormal.
Here, in actuality, the signal appearing at the voltage detection signal connection terminal 52 may be H only for a short period of time in relation to other control signals. Therefore, in this embodiment, the voltage detection signal connection terminal 52 is used. The time when the signal appearing at H is H is measured, and when the time exceeds a certain value, it is determined that the voltage detection circuit 47 is abnormal.

Returning to the description of the flowchart of FIG. 6, as described above, in step 100, it is monitored that the voltage detection signal connection terminal 52 is a signal (Lo) indicating the presence of a voltage applied to each relay RL10, RL11, RL12, RL16. If this becomes H, the routine proceeds to step 103, where the timer starts counting.
Subsequently, the routine proceeds to step 104, where the above-mentioned timer is checked to check whether or not the measured time exceeds a predetermined time.
If the measured time is within the predetermined time (in the case of NO), the routine proceeds to step 106, where it is confirmed whether or not a signal to extinguish is issued.
If there is no fire extinguishing signal (in the case of NO), the process returns to step 100, and the signal (Lo) indicating the presence of the voltage applied to the relays RL10, RL11, RL12, RL16 by the voltage detection signal connection terminal 52 is confirmed again.

  If the voltage detection signal connection terminal 52 does not have a signal (Lo) indicating the presence of the voltage applied to each of the relays RL10, RL11, RL12, RL16 (H), the above steps 100, 103, 104, 106 are repeated. . If the time elapses in this state and the predetermined time elapses, step 104 becomes YES, and the routine proceeds to step 105 to forcibly stop combustion.

On the other hand, the signal (Lo) indicating the presence of the voltage appearing at each of the relays RL10, RL11, RL12, RL16 applied to the voltage detection signal connection terminal 52 is returned before the above time has elapsed (in the case of NO at step 104). In this case, since the fluctuation is in an expected range, the process proceeds to step 101 and the timer is reset. Then, the process further proceeds to step 102 to confirm the presence or absence of a fire extinguishing signal. If there is no fire extinguishing signal, the process returns to step 100.
If there is a fire extinguishing signal, a series of control is completed.

In the embodiment described above, the blocking operation is checked by the signal of the voltage detection circuit 47, but the blocking operation may be checked by a signal of the original solenoid valve monitoring circuit 61 or the gas solenoid valve monitoring circuit 62. Further, the signal of the voltage detection circuit 47 and the signal of the original electromagnetic valve monitoring circuit 61 or the gas electromagnetic valve monitoring circuit 62 may be used in combination.
In short, it is only necessary to check the shut-off operation by inspecting the device drive circuit that operates the device that supplies fuel and confirming whether or not the device drive circuit is energized.

In the flowchart shown in FIG. 6, the sub-control device 36 side is checked first, and the main control device 35 side is checked later, but this context is arbitrary.
In the flowchart shown in FIG. 6, one controller side check is performed at the time of the pre-check, and the other check is performed at the time of the pre-purge. However, the timing of the check and the timing of the pre-check and the pre-purge are not strict. Absent. However, since various signals are interlaced during the pre-check, it is not recommended to check both the main and the sub at this time. At the time of the pre-check, since the load applied to the main control device 35 is large, it is desirable to check the sub-control device 36 as shown in the flowchart of FIG.
Both chucks may be performed during pre-purge.

  Further, the above-described embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope thereof.

  For example, in the above-described embodiment, the case where the present invention is used in a gas hot water supply device has been described. However, the present invention is not limited to this, and can be applied to a hot water supply device using oil as fuel. Furthermore, the present invention can be applied to a combustion apparatus having a combustion section other than a hot water supply apparatus (for example, a heating single-function combustion apparatus).

  Further, in the above-described embodiment, the flame detection circuit 55, the water amount detection circuit 56, the tapping temperature detection circuit 57, the blower rotation speed detection circuit 58, the burner sensor detection circuit 59, the proportional valve current detection circuit 60, the original through the bus line 37. Although the solenoid valve monitoring circuit 61 and the gas solenoid valve monitoring circuit 62 are connected to the main control device 35 and the sub control device 36, all of these are not necessarily required. Of course, each circuit may be connected to the main control device 35 and the like through normal wiring instead of the bus line. In addition to these, a signal for detecting the temperature of the heat exchanger 18, a signal for detecting the temperature of the combustion can body (not shown), a signal for the high-temperature hot water temperature sensor 28, etc. 36 may be input.

It is a circuit block diagram at the time of utilizing the combustion control apparatus of this invention as a control apparatus of a hot water supply apparatus. It is a circuit diagram at the time of utilizing the combustion control apparatus of this invention as a control apparatus of a hot water supply apparatus. It is a conceptual diagram of the hot water supply apparatus controlled by the control apparatus in this invention. 2 is a flowchart showing a part of the operation of the combustion control device shown in FIG. 1. It is a circuit diagram which shows the connection relation of each solenoid valve of FIG. It is a flowchart which shows the flow of operation | movement at the normal time of the combustion control apparatus of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water supply apparatus 10, 11, 12 Gas solenoid valve 16 Original solenoid valve 27 Combustion control apparatus 35 Main control apparatus 36 Sub-control apparatus 47 Voltage detection circuit (shut-off confirmation means)
55 Flame detection circuit 56 Water volume detection circuit 57 Hot water temperature detection circuit 58 Blower rotation speed detection circuit

Claims (8)

The main control device, the sub-control device, and a shut-off confirmation means for directly or indirectly confirming that the fuel supply has been shut off are provided, and both control devices execute a shut-off operation to shut off the fuel supply. The shut-off operation by the main control device and the shut-off operation by the sub-control device are separately performed before the start of combustion, and the shut-off confirmation means confirms that each shut-off operation is effective. Combustion control device. The combustion device controlled by the combustion control device includes a blower that supplies and burns fuel to the combustion unit and blows air to the combustion unit, and the combustion control device includes a pre-purge process that operates the blower and fuel supply to the combustion unit. The fuel supply start process is started sequentially, and before the pre-purge process, the shut-off operation is executed by one control device, and it is confirmed that the shut-off operation is effective by the control device or the other control device. 2. The combustion control according to claim 1, wherein during the pre-purge step, the shut-off operation by the other control device is executed and it is confirmed by the control device or another control device that the shut-off operation is effective. apparatus. 3. The combustion control device according to claim 2, wherein when it is determined that the shut-off operation is not effective, the process does not proceed to the fuel supply start process. The combustion control device according to any one of claims 1 to 3, wherein it is confirmed that the cutoff confirmation means functions effectively during combustion. The combustion control device according to claim 4, wherein when it is determined that the shut-off confirmation unit does not function effectively, combustion is stopped. The main control unit is responsible for overall control of the combustion device, and a signal for knowing the operating state of the combustion device is input to the main control unit and the sub control unit. When the stop condition is met, the shut-off operation is executed, and the stop condition when the sub-control device executes the emergency shut-off operation is milder than the stop condition when the main control device executes the shut-off operation. The combustion control device according to any one of claims 1 to 5, wherein The combustion according to any one of claims 1 to 6, further comprising a device drive circuit that operates a device that supplies fuel, wherein the shut-off confirmation means confirms whether or not the device drive circuit is energized. Control device. The combustion control device according to any one of claims 1 to 7, wherein the main control device and the sub control device are connected by communication means.

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