Never add air to a dark, smoky furnace. First, trip the unit to remove the ignition source, purge thoroughly, and then correct the problem. A lean mixture, which results in more air than necessary, while not efficient, is not dangerous. Poor atomization of oil can cause an accumulation in the furnace and create a localized volatile mixture of unburned fuel, which can result in an explosion. To prevent this situation, the oil gun sprayer assembly must be free of debris and the atomizing steam or air and fuel oil pressures must be properly adjusted.
Improper purge can leave a combustible mixture in a boiler.
Many explosions occur during attempts to relight a burner after it has tripped because of another problem. The pilot then ignites the large inventory of unburned combustible gases in the furnace, which produces the explosion. This scenario can be avoided by investigating the cause of the trip and allowing the furnace to purge thoroughly before any attempt to relight. Boiler safety operation and maintenance practices Frequently observe the burner flame, especially when firing oil, to identify plugged sprayer tips and other combustion problems. This approach provides an early warning.