Furnace

Vancil wrote:
I'm not sure if this matters, but the trailer is a 50amp unit, but we're currently at a 30amp site using an adapter. That wouldn't affect the furnace from working, would it?

No, it operates on 12VDC. Verify that you have 12V power at the furnace's circuit board (meter necessary).

Forum member Chris Bryant has a library of services manuals available for download here. Scroll down to your model of furnace and DL the manual. It will have a trouble-shooting section to diagnose any issues.

These small RV furnaces are actually somewhat durable. Most issues involve a clogged exhaust/combustion air port, a stuck sail switch, a failed circuit board (blown fuse), or lack of 12V power/gas delivery. A user should take some time every few years to clean up inside the furnace, tending the burner tube, the flame sensor/thermocouple, sail switch, and the blower.

I can't seem to access the sail switch without pulling the entire unit out.

I'm not sure if this matters, but the trailer is a 50amp unit, but we're currently at a 30amp site using an adapter. That wouldn't affect the furnace from working, would it?

It is a suburban furnace, model number SF-35FQ

Fan control on thermostat is for the A/C Unit NOT furnace (Place FAN in Auto----otherwise A/C Fan may run when operating furnace)

Furnace fan is part of furnace function
Furnace needs good source of 12V DC power

Some furnace circuit boards have a 'check/verify' circuit that will not allow furnace function if 'Sail Switch' is still closed prior to fan operation.
Sail Switch should only close when fan is running up to speed.

Could also be lack of 12V DC to furnace (blown fuse, tripped on/off switch on furnace, circuit board issue, thermostat issue etc.)

What BRAND/MODEL is your furnace ?? (Info should be on data sheet in drawer, cabinet door, folder/info pack, on furnace)

The blower setup also has a safety feature called a sail switch. This is there to shut down your propane feeding the furnace in the event the blower is not working... The air from the blower makes it operate... Sometimes if it gets debris in it and doesn't operate like it should... Shoot some WD40 into it to free it up again...

Just another thought...
Roy Ken

is your battery hooked up? Is your power converter plugged in and providing 12v powering? The furnance requires 12v to run... if it isn't getting it from your battery, it has to get it from the converter.