How to Convert Engine Oil to Boiler Fuel Oil

Place a 1-5 micron felt filter on top of a large, empty jar. Carefully pour the engine oil into the jar through the filter, until the jar is full. Wash the filter thoroughly in warm water. Place the filter on a second jar. Pour the contents of the first jar into the second jar, through the filter. Pour the second jar into a storage tank. Repeat the filtering process until all the oil is filtered.

Pour the filtered oil from the tank into the furnace's oil burner to pre-heat the oil to 120 degrees Fahrenheit. If the oil burner does not automatically feed oil into the oil pump on your boiler, carefully pour the heated oil into the oil pump for use in the boiler. Set the oil pump to feed the oil through at 150 psi.

Adjust the band heaters on the collar of the furnace to heat the oil to between 275 and 300 degrees. Turn the valve on the burner nozzle to reduce the speed at which the oil flows from the nozzle, as engine oil burns hotter than fuel oil. When the heated oil enters the furnace through the burner nozzle, it will atomize and combust.