When the fuel supply is insufficient, with the strength and weakness of the flame, the burner is often accompanied by "wheezing, wheezing" sound. At this time, the liquid in the oil supply pipeline may be accompanied by bubbles so that the injection pressure is unstable and the combustion is unstable. In addition, when there are bubbles in the oil pipe, the operation resistance of the oil pump will then go up and down, and when the fire is unstable, it is often accompanied by black smoke. This is because the oil pressure cannot be established when the oil supply is insufficient, so that the diesel oil atomization is not good and can not be completely burned.
Common causes of fire instability are:
1) When the suction pipe leaks and absorbs oil, the external air then enters the pipe to form bubbles;
2) the suction pipe is narrow, blocked and deflated, so that the oil circuit is not smooth and the diesel oil supply is insufficient;
3) Oil supply system filter (including suction pipe inlet filter, diesel filter element, oil pump filter, etc.) blocked.


In winter, the oil supply system is often blocked, because of the poor fluidity of diesel oil when the temperature is low, it is easy to precipitate wax, plug the pipeline, diesel filter, oil pump filter, nozzle filter, etc., so that the oil supply system is not smooth, resulting in unstable fire or fire. If the temperature in the workshop is low, the oil supply pipeline can be heated by drying lamp, and the oil pump, filter element and other parts can be heated. When ignition is difficult, the air intake door can be baked to preheat the air intake.