How to Maintain an Oil Burning Furnace
Oil burning furnaces require maintenance, more than gas or propane burning furnaces need. My own experience says you can go as long as 3 years without servicing it, but that is not sensible because sometimes the failure that results is severe (electrode insulator cracks, and you get the Bessemer Process on the electrode mount, which is to say, it melts). You are far better off cleaning them yearly.
Cleaning and servicing them is no big deal, but it is disordered since that soot is tarry and stinky. Turn off power to the system. Eliminate the oil burner assembly, which will also have the electrodes on it. How you eliminate this assembly is very reliant on on the specific unit; follow the oil line out of the pump to where it goes into the furnace housing and that will give you a good clue. You can know about oil burner service and emergency heating oil delivery services via various online sources.
Often (regularly) you have to either eliminate or hinge back the high voltage transformer to get at this assembly. When you have the burner out, remove the spigot and replace it. Make sure you replace it with a spigot with the same spray pattern, though you can vary the gallons per hour (GPH) rating to rate the furnace up or down in capacity. You can hop over to this website to know more about home heating oil services.
Spray patterns are termed as solid, semisolid, or hollow – which refers to the distribution of oil in the spray cone, and have an explicit angle which defines the angle of the cone of oil that is shot into the furnace. Solid is the most common pattern in my experience and 75 degrees is the most common angle that I have seen.
Wipe the whole assembly down to get the oil and soot off of it. You will be required to position and gap the electrodes, but first do a visual inspection of them. If there are visible cracks in the insulators, replace them. If the ends are eroded and potholed, replace them. If in doubt, replace them.