Our 5’er has a Dometic furnace with Airexcell thermostat. It has been short-cycling recently.
The problem is worse when it is cold (first turned on) and seems to improve when it runs for a while. When first turned on, it will only fire for a couple seconds at a time. As it warms up, it will improve to 4-5 minutes before cutting the gas and then re-fires 30 seconds or so later.
I’ve replaced the sail switch and control board (Dinosaur) with no change. Is there an easy way to isolate the furnace from the thermostat? I know I need to look into the high limit switch and propane pressure next, but trying to be smart before I keep throwing parts/money at it.
I’d expect the high limit switch to not be the problem since it’s worse starting from cold then gets better, but who knows?
