My espar heater finally crapped out. Thankfully we were headed for home so no cold nights. I paid 150 bucks for it (used) almost 4 years ago. I serviced it once prior just for the lack of history on it. What I found this time is a plugged fuel pump filter and a plugged filter in the combustion chamber. These are very tiny filters and very very fine mesh. I have a separate tank for the diesel fuel. (van is gas) I pulled the tank drained it, cleaned it blow the lines out. Very very little in the bottom. My pickup tube is an inch off the bottom. So the clogged filters I have to assume are from the diesel fuel itself. In Europe they say the fuel in the states is "dirty fuel". I tend to believe that. I try and run kerosene when I can but it's not always available. A good cleaning new filters and she's running like new. I also changed the glow plug, although there was no problems with it other than unknown age. Glow plug, gaskets and filters were a 100 bucks on eBay. It's an easy job so don't be afraid to dive into it. Very simple machine. I think every two years will be a good service schedule on it for me. Going to add a filter before the pump as well. Can't imagine being without it.