Puzzler on our Furnace I have an Attwood furnace, old obsolete etc. It failed a couple of years ago during the bomb cyclone in the Texas Pan handle. I went to Walmart and bought a Mr Heater Little Buddy and a case of propane tanks. It worked so well that when I got home and fought with the furnace (As an FYI the sail switch is to make sure the fan is blowing.) Apparently over time the combustion chamber got clogged with soot. Cleaned it out, replaced burner parts, finally got it to work on a bench outside the RV but when re-installed, wouldn't work.
I got a Mr Heater Big Buddy and using a Natural Gas hose, direct connected it to the RV propane system. (The connector in the heater uses Natural Gas fittings instead of Propane connectors.) At the end of heating season, I disconnect the quick connect, slide the hose into the furnace area through a little door, and the heater goes under the bed or in the garage. We like to sleep cool so we always have a window cracked and I invested in a carbon monoxide detector as well as the normal smoke alarm.
Some day I'll just dump the furnace and gain some more storage room. I have to figure out a work around for the stupid fan controller setup. Without the connection to the furnace, the AC won't run. Apparently the two stage fan controller for both the furnace and the AC are built into the furnace boards.
It also doesn't my batteries overnight like the furnace fan would do!