Forum Discussion

kode9's avatar
kode9
Explorer
Nov 12, 2021

No heat / Furnace not working

Hi.

I bought in August a Grand Design 297QB brand new and while I did test everything there - on the RV lot - and then, nowadays when temperatures start to drop, the heater is not working.

It did work for a couple of hours back in September, but now. Nothing. Nada. NONE.

And all I did then was to just to increase the temperature of the thermostat from 75 to 82( or something like that ) and heater would work.

Now if I do the same, the only thing that comes out is cold air.

The thermostat is a Coleman-Mack.

Must mention that I am complete noobie when it comes to RV/Traver trailers and so on.

Thank you.
  • Are you hooked up to shore power? If not, your battery may be low. For the furnace to go on the fan must blow hard enough to operate the sail switch, which tells the furnace to ignite and that you have enough air to circulate the heat. Battery should be at least 12.3 volts.
  • Access you furnace, varies between makes and models, locate the two blue wires. Connect them together. Furnace should start and produce heat. Separate the wires, furnace should go into cool down mode.
    If it operates in that manner, thermostat is bad.
  • WayneAt63044 wrote:
    The furnace heats using propane; are the tank valves open?


    it's not just "are the tanks open?" it's also is the excess flow valve closed? Easiest way to have propane problems with tanks made in the last 15 years or so is to open the propane valve to fast. SLOWLY is the word of the day. To check if there is enough flow, light the stove burners. if you get a good flame on high your ok. If all you get is a weak flame, turn off the propane tank, disconnect the hose, reconnect the hose and make sure it is ALL the way tightened. then SLOWLY open the valve. Check the stove.

    Oh, and make sure you have propane in the tanks!

    Next, on the thermostat make sure it is set to heat, not cool or fan.
  • WayneAt63044 wrote:
    The furnace heats using propane; are the tank valves open?


    And are they full ??? Have you used the stove or any other propane item ? Have you tried the stove to see if it will light ??
  • Like most noobs who come on here lately. we will probably never know the outcome. :R
  • I would also check to make sure the fresh air intake from the outside is clear of any debris. I had a pop up camper years ago that I tried everything to get heat on. Finally on the day I sold it, literally, I found a 2 wasp nest in there. It was very small but heat kicked on right after, doh…
  • It's new. Take it back to the dealer. I had a furnace in a class C that worked fine until the temp got below freeziing. Then fan would run but only cold air. Stove worked. Turns out it was moisture in the regulator. The regulator would freeze. It would allow enough propane for the stove to work but, not the furnace.Had to replace the regulator and purge the tank to get the moisture out.
  • Each time I've had a furnace failure, had to replace the sail switch.