Taking the proportional gas burner as an example, its working process has four stages: preparation stage, pre-purge stage, ignition stage and normal combustion stage.
Preparation stage: After the program controller is powered on, it starts the internal program self-test. At the same time, the servo motor drives the damper to the closed state. After the program self-test is completed, it is in the standby state. When the thermostat, over-high or low gas pressure switch, steam boiler steam When the pressure switch and other limit switches allow, the program controller starts and enters the pre-purge stage. If the solenoid valve group is equipped with a leakage detection system, the system will first perform valve leakage detection when the above-mentioned limit switch allows it. After the detection passes, it will enter the pre-purge stage.
Pre-purge stage: The servo motor drives the damper to the high fire opening state, and at the same time the fan motor starts to blow in air for pre-purge. According to the program controller, after about 20 to 40 seconds of purging, the servo motor drives the damper to the ignition state. Open state, ready to ignite. During the entire pre-purge stage, the air pressure switch measures the air pressure. Only when the air pressure is maintained at a high enough level can the pre-purge process continue.
Ignition stage: After the servo motor drives the damper to the ignition opening state, the ignition transformer cuts in and outputs high voltage to the ignition electrode to generate ignition sparks. After about 3 seconds, the program controller sends power to the safety solenoid valve and proportional solenoid valve. , after the valve is opened, the gas reaches the combustion head, mixes with the air provided by the fan, and then is ignited. Within 2 seconds after the valve is opened, the ionization electrode should detect the presence of flame. Only in this way, the program controller will continue the subsequent program. Otherwise, the program controller will lock and disconnect the solenoid valve to stop the gas supply and alarm at the same time.
Normal combustion stage: After the ignition is normal and the combustion is stable for a few seconds, the servo motor drives the damper to the high fire opening state. At the same time, the servo motor of the proportional gas regulating valve cuts in and adjusts the gas valve behind the gas valve according to the air pressure and furnace back pressure. Gas pressure is used to adjust the gas volume to achieve stable and efficient combustion. Thereafter, the burner automatically switches between small and large fires and shuts down according to the requirements of each limit switch. In addition, an ionization electrode and an air pressure switch monitor the burner throughout the combustion process.
Common fault phenomena, causes and solutions
In the event of a malfunction, you must first check whether the conditions for normal operation of the burner are met:
1. Is the power supply normal?
2. Is the fuel supply system normal? For example, is the gas pressure on the gas supply pipeline normal and is the ball valve open (gas machine)? Is there oil in the tank and is the valve on the oil supply and return pipe open (oil engine)?
3. Are the adjustments and interlocking controls of all regulators and controllers normal? Such as temperature regulator, water flow switch, water level switch, oil level switch, gas pressure switch, etc.
4. Has the amount of air, gas or fuel during combustion been changed?
If it is determined that the fault is not caused by the above reasons, the relevant functions of the burner must be checked and tested. The general method is to remove some interlock controls, turn on the burner, and then accurately observe the following working processes. According to the phenomenon, the problem can be quickly discovered and eliminated.
Taking the proportional gas burner as an example, its working process has four stages: preparation stage, pre-purge stage, ignition stage and normal combustion stage.
Preparation stage: After the program controller is powered on, it starts the internal program self-test. At the same time, the servo motor drives the damper to the closed state. After the program self-test is completed, it is in the standby state. When the thermostat, over-high or low gas pressure switch, steam boiler steam When the pressure switch and other limit switches allow, the program controller starts and enters the pre-purge stage. If the solenoid valve group is equipped with a leakage detection system, the system will first perform valve leakage detection when the above-mentioned limit switch allows it. After the detection passes, it will enter the pre-purge stage.
Pre-purge stage: The servo motor drives the damper to the high fire opening state, and at the same time the fan motor starts to blow in air for pre-purge. According to the program controller, after about 20 to 40 seconds of purging, the servo motor drives the damper to the ignition state. Open state, ready to ignite. During the entire pre-purge stage, the air pressure switch measures the air pressure. Only when the air pressure is maintained at a high enough level can the pre-purge process continue.
Ignition stage: After the servo motor drives the damper to the ignition opening state, the ignition transformer cuts in and outputs high voltage to the ignition electrode to generate ignition sparks. After about 3 seconds, the program controller sends power to the safety solenoid valve and proportional solenoid valve. , after the valve is opened, the gas reaches the combustion head, mixes with the air provided by the fan, and then is ignited. Within 2 seconds after the valve is opened, the ionization electrode should detect the presence of flame. Only in this way, the program controller will continue the subsequent program. Otherwise, the program controller will lock and disconnect the solenoid valve to stop the gas supply and alarm at the same time.
Normal combustion stage: After the ignition is normal and the combustion is stable for a few seconds, the servo motor drives the damper to the high fire opening state. At the same time, the servo motor of the proportional gas regulating valve cuts in and adjusts the gas valve behind the gas valve according to the air pressure and furnace back pressure. Gas pressure is used to adjust the gas volume to achieve stable and efficient combustion. Thereafter, the burner automatically switches between small and large fires and shuts down according to the requirements of each limit switch. In addition, an ionization electrode and an air pressure switch monitor the burner throughout the combustion process.
Common fault phenomena, causes and solutions
In the event of a malfunction, you must first check whether the conditions for normal operation of the burner are met:
1. Is the power supply normal?
2. Is the fuel supply system normal? For example, is the gas pressure on the gas supply pipeline normal and is the ball valve open (gas machine)? Is there oil in the tank and is the valve on the oil supply and return pipe open (oil engine)?
3. Are the adjustments and interlocking controls of all regulators and controllers normal? Such as temperature regulator, water flow switch, water level switch, oil level switch, gas pressure switch, etc.
4. Has the amount of air, gas or fuel during combustion been changed?
If it is determined that the fault is not caused by the above reasons, the relevant functions of the burner must be checked and tested. The general method is to remove some interlock controls, turn on the burner, and then accurately observe the following working processes. According to the phenomenon, the problem can be quickly discovered and eliminated.