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jerjersmith's avatar
jerjersmith
Explorer
Feb 03, 2017

Propane Furnace Stopped Working, No Fan, No Heat

New to Forum. All feedback appreciated

Ok, so my heater stopped working. I lean towards thermostat but would like to know for sure before ordering $120 plus another $25 for adapter (old model is replaced by new model which requires some extra to do)

Here is the troubleshooting I have gone through so far:
-When I turn thermostat to heat I get nothing, no fan, no heat.
-When I turn thermostat to A/C I get nothing, no fan, no cooling.(I did turn temp setting down so thermostat would tell A/C to turn on FYI)
-Propane stove works, flames are strong and blue
-Heat pump works, fan kicks on like it should
-If I turn thermostat to "off" and turn Fan to "on" the fan will run
-Batteries are all good (I am plugged into power meter)
-No tripped breakers
-Couldn't locate any additional breakers by the unit itself

Thermostat Model number: 6535-335 is a True Air Coleman-Mach
I tried to manually bypass the thermostat and connect the red and white wires but I didn't get anything nor was I sure I did this correctly, I'm not that tech savy and the thermostat wiring was more complicated than a typical thermostat in a house would be.
It has a 9 pin plug and a 3 pin plug etc. So I am not really taking this into account that I can rule the thermostat out.

Please help!
  • fairway2002's avatar
    fairway2002
    Explorer
    Feb 04, 2017
    Sounds like no 12volt. Board does have a code light on it. 30 amp fuse someware i think. Guy next to me borrowed a 30amp for his.
  • BFL13's avatar
    BFL13
    Explorer II
    Feb 04, 2017
    You got the fan to run so the T-Stat must be getting power?

    But nothing works as in the OP. Only trouble I had with that was the slider setting to change the temperature the furnace comes on and shuts off got wonky. I had to keep setting it higher and higher to get the furnace to come on. You get a click. Had to get a new same type thermostat(Dometic)

    Yours is a different brand, but the thing remains that they are sort of tricky.
  • enblethen's avatar
    enblethen
    Nomad
    Feb 03, 2017
    Should start by checking for 12 volts DC at the furnace. If 12 volts DC is present check for circuit breaker. Many furnaces have a circuit breaker to protect the motor. It is located on fan housing. About one inch square 1/2 inch thick with a red or white reset button.
    No 12 volts DC could indicate a blown fuse in the 12 volt DC distribution panel.
  • jerjersmith's avatar
    jerjersmith
    Explorer
    Feb 03, 2017
    Good idea on the oil filled electric heater. I do have an electric heat dish which is ok, but its not holding up when temps are in the teens or lower.

    As for checking for loose wires, I poked around a little, things looks to be ok. Hard to really tell, not too good with an ohm meter but maybe its time to learn.

    Just want to make sure Scott, when you say "it really does sound like stat is bad" did mean to say "Doesn't"?
  • RoyB's avatar
    RoyB
    Explorer II
    Feb 03, 2017
    My PLAN B is to always carry an Oil Filled Electric Heater (LOWES-WAKMART $35) as you never know when you are going to need to use one haha...

    I had a total failure one time and it turned out to be the fan SAIL SWITCH had hair and junk in it from the floor area.. This is safety feature that if yo have a failed blower motor it shuts down the furnace.

    Roy Ken
  • ScottG's avatar
    ScottG
    Nomad
    Feb 03, 2017
    The furnace would not have any breakers protecting it, it would have fuses.
    It really does sound like the stat is bad.
    Have you check it to see if any wires have come loose?

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