Furnace works, but only a couple times.....

I may have a stumper here. First, a little background. We bought our camper this past spring. Since then, we have mostly camped places that have electric hookup, so we have relied on a small electric space heater on the occasional chilly night. However, last week, we went on a late fall campout, and the temps got BRISK (below freezing one night). So, we fired up the propane heater, also. It worked great, heated up the pup, cycled off for a while, kicked back on, warmed up again, cycled off...... and wouldn't fire back up again.

Of course this was the middle of the night, so I get up, get bundled up, and go out to check the gas tanks. Plenty of gas. So I check the fuses. Good. I check the thermostat. Cold, turned on, all set properly. I open up the furnace cover, shut off the reset switch, and wait a minute.... getting colder all the while. As soon as I flipped the switch back to the ON position, the heater kicked on and warmed up the camper again. It ran two or three cycles again, then would not run. I had to get up again and reset the switch.

Any idea what the problem may be, and what I could do to fix it? The camper is a 2007 Fleetwood Sun Valley, and is in like-new condition. The battery is brand new (I installed it new at the beginning of September, and leave it on a battery tender when it is parked in our garage). The tanks are both full and the propane flows through all the lines without issue. I am out of ideas.

 

No fault codes. The only time I've seen any was the one time I ran out of propane

You think it may be the t-stat, Hacksaw? I was thinking about putting in a digital one anyway...... we'll see if that does it....