Originally Posted by coolmen
Turn off the fuel line valve between the fuel tank and the fuel filter. I use a metal painters roller pan to keep any dripping oil off the floor. Loosen the bolt on the top of the filter and remove the old filter and gasket. install new filter,rub some fuel oil on the new gasket before installing it to help soffen up the rubber to get a nice fit. tighten filter top and turn back on fuel line. on top of filter next to big bolt is a small screw(bleeder). loosen just enough to let air out of filter and it should fill with fuel once you see that oil start comeing out of screw this tells you oil filter is full of fuel and has NO AIR in the line. now you have to bleed the line to the furnace to remove any other air trapped in the line. if you have very short line from filter to furnace bledding may not be needed. This is the process BUT I highly recommend you call a pro. oil leaks can linger in the house for a long time and oil furnaces need inspecting and adjusting during the maintaince process. (This is not something that you simply change a air filter ) Starting a furnace with air in the line could damage the fuel pump, over tighten a screw can add to cost. major spills can get the EPA involved.
I appreciate the post and the words of warning however if you consider "a pro" to be a guy who leaves oily combustible rags all in my crawl, sketchy electrical connections, all sorts of assorted parts new and used. And my furnace in no more better shape than when they left then I will go with my own abilities.