Iaian, I really can't believe there's any way that any problem with the thermostat could cost a couple hundred dollars to fix, unless that was allowing for hours of RV shop time. If it were me, I would just pull the wires off of the thermostat (in my own cheap spare time) and connect the appropriate ones together as if I were a thermostat telling the furnace to come on, and see if the furnace works... if it does, then it's a cheap thermostat fix... if not, then it's time to troubleshoot the furnace (which would
be hundreds of dollars to replace, and could even be expensive to just fix).
There are manuals in the FiberglassRV Document Center
(see link on the left side of the page, and work your way down through Appliances
and then Furnaces/Heaters
) to assist with the thermostat wiring and furnace troubleshooting, for your particular furnace. Mine's a Suburban, but there's no way to be sure what's in any particular trailer other than looking at it and reading the label (usually inside, behind the front cover).
Even though there may be faster and easier ways to get heat (like plugging in a portable electric heater), I think it is valuable to have the option of using a nicely built-in propane-fueled furnace, especially when camping without outside power available.
If your Boler
was built by Vanguard in Winfield like mine (thus, Okanagan Egg"), it's really close to home in Kelowna. Too bad Boler
isn't around anymore, and even Vanguard moved out of B.C.