Heating oil filters, also known as inline filters, filter out inpurities from the oil in a heating system. This contributes to safe and effective operation of the oil pump and the burner nozzle. What do heating oil filters do? Heating oil filters filter out particles found in the oil, preventing the nozzle from clogging and reducing any potential impurities from collecting in the oil. In most cases, the heating oil filter is found on the heating tank and looks similar to an oil filter found on a car. In order to maintain a working system and prevent damage, heating oil filters need to be cleaned on a regular basis and replaced often. What are the different kids of heating oil filter? Heating oil filters can be made with metal or plastic, as long as the fluids being filtered are not aggressive to the plastic casing. They can also contain different kinds of filter element, again depending on what is being filtered out of the system.