Coke or smoke in the furnace
Zhongde LYF2.0/300-0.7, composite boiler (oil-fired and exhaust gas)
Possible cause
Burner out of adjustment
What to do
Manufacturer's manual, p. 93Re-adjust the burner and clean the furnace
See the assembly on the 3D model
Other Zhongde LYF2.0/300-0.7 faults
Water level below the lowest visible part of the gaugeFeed failure or level control faultBrown water in the gauge glass / primingOil or dirt in the boiler waterSafety valve does not lift at set pressureSticking or wrongly set valveHeating surface red-hot or deformedOverheating, low water or scaleWater level gauge leaksLoose nuts or worn cock packing
From the manufacturer's manual “EM-3 ZHONGDE BOILER”. Check against the original on board before work.