Furnaces are built to purposely be almost impossible to service or test without removing them from the trailer.
There are so many safety features to prevent an accidental explosion that sometimes I think it is a miracle they ever do work.
I picked up a new Flagstaff on Nov 15. Furnace was working great during pickup demo by dealer. Went to a Good Sam group campout that weekend - turned on the furnace, ran 30 seconds of cold air - and turned off. Could hear the igniter, but no heat. Unit shuts off.
Propane good, everything else good.
Lucky it was only down to about 30 degrees for two nights at a FHU 50A site - small electric space heater and 'fireplace' in trailer kept it warm enough for us. Wasn't cold enough to worry about the tanks.
Back to the dealer Tuesday morning. Turns out the 'sail' switch had snapped. This senses exhaust air flow, and if there isn't enough will not allow the propane valve to open.
But the simple fix required removal of the furnace from the unit and testing on a bench.
Here is a YouTube video on some of the key things about fixing a furnace. Personally I would not pull the furnace out of any trailer less than five years old - but I understand you might have to do that.
http://www.youtube.com/watch?v=foPtSXWNrXc
Get your installation manual out and check it carefully before trying to remove the furnace.
Full-Time 2014 - ????
โNot all who wander are lost.โ
"You were supposed to turn back at the last street."
2012 Ram 2500 Mega Cab
2014 Flagstaff 832IKBS TT