You make a good point Joe. My friends truck burned to the ground due to an espar under the bunk. Burnt his foot pretty bad too. Entire truck melted.
Just bought a FL Cascadia with a battery APU. The cooling is good but the heater is useless. Fierce when working but unreliable. So I had my Tri Pak switched from my old truck to my new one this last week. A right performance but that is another story. Anyhow the espar has been giving me a fit for about 3 winters and it is annoying because I paid a lot of money for that pos. I had the original one replaced in 2014. I had given up with it and gone over to a 20lb propane bottle and a Mr Buddy heater. That worked pretty well. In the switcheroo I asked if they would look at the espar. They did. Apparently I had a kitchen towel stuffed up the intake port !! I couldn't see it because it had a long vent attached and it never occurred to me. They bench checked it and ran kerosene through it. It is working fantastic now. I love it. The battery one is a webasto apparently and will need to go to FL. I'll get around to it when I win the lottery.
Just d###! I would have never looked either. Until I took the whole thing apart. Something to keep in mind though.