Easiest way I have found. Drain filter housing, replace filter and o-ring. Once the new filter is in place and the cap is tight loosen the supply line on the VP44, bump starter and let LP run, when fuel comes out of the supply line tighten it back up. My truck will start with the first try, sometimes it takes a couple, darn thing has a mind of its own. There are numerous ways and opinions on how to do this, this is how I do mine and I do it every 6k along with the oil and oilfilter.