Trouble with furnace

[cledet]

The past few weeks I tried the furnace out and it worked fine. Put out nice warm heat. Now that it is cold it will not light. I can hear it clicking but no ignition. My stove works
fine. I cooked in the oven and stove top at the same time last night. Could it be a regulator? Any help or suggestions would be greatly appreciated. 3/4 full time RV living. By the way this is a 2006 Bighorn.

Thanks,
Craig

 

[danemayer]

Hi Craig,

When the thermostat calls for heat, it sends 12V DC to the furnace control board and to the blower motor. The blower should run for about 20-25 seconds before there's an ignition attempt.

I'm not sure about your 2006, but on newer trailers, the thermostat signals a relay located above the return for the living room A/C unit. So you may hear an overhead click, followed by the blower motor starting.

If the blower doesn't start, you're not getting 12V to the blower motor. If the blower runs for 25 seconds and you hear the ignition click, you may have a gas flow problem, or a control board problem, or possibly a problem with igniter or gas valve, although the last 2 are less common failures.

 

[cledet]

Thanks for the reply. The fan motor does run and there are about 3 clicks in the furnace. I haven't noticed one overhead. A couple of weeks ago when we started having 60ish
degree weather I tried it out just to make sure it was working and it was working fine. Now it is in the 40's and won't come on.

 

[danemayer]

Try closing the valves on the propane tanks and re-opening verrrrrry slowly. They have overflow protection devices that can restrict flow of propane. If that doesn't help, try switching the dual regulator from one tank to the other.

 

[cledet]

I will try that when I get home. I am running off of a 25 gallon propane bottle. I haven't touched it since August when I had it last filled. The only thing that has changed in
the last couple of weeks when it was working until now is the colder weather and I just don't know how that can affect it.

 

[danemayer]

If not a propane flow problem, it could be low voltage, although that usually shows up as a blower/sail switch problem that prevents an ignition attempt. After that, likely causes are lose wires, failing control board, failing igniter, failing gas valve.