Forum Discussion

Mikesr's avatar
Mikesr
Explorer
Jun 28, 2016

Furnace and or thermostat problem

Currenly on a trip and running A/C and not furnace.
The furnace started to make a fan noise and the sound like it's trying to fire the gas.
Moved thermostat to off and back and forth to heat with no change the noise is there yet.
I removed the 15 amp fuse marked furnace and the noise stopped. Problem solved right ? No the thermostat must run off that fuse because then the A/C does not work.
Took access panel off of furnace and can't see any easy fix, that's over my pay grade.
I'm thinking to disconnect a wire to the thermostat that controls the furnace? Which one ?
Furnace is Suburban
Thermostat is Coleman Mach





Thanks for any help
  • ....Moved thermostat to off and back and forth to heat with no change the noise is there yet.

    .....After turning thermostat off and on and pulling fuse the original problem has stopped.

    BEFORE you start going all crazy about wiring etc.
    You can NOT flip those levers 'on and off' and 'on and off' because there is a delay switch on them.

    The ac and furnace has a delay. Some have a real long delay on them.
    You turn it on it takes a while to start because of the delay switch and when you turn it off there is also a delay on them for safety.

    You flipping that switch 'on and off' and 'on and off' your are screwing up the delay producing the problems you are experience.

    Wait and then Start all over and turn it on ONCE. Wait for the delay and the unit to start THEN see if there is a problem.
  • rockhillmanor wrote:
    ....Moved thermostat to off and back and forth to heat with no change the noise is there yet.

    .....After turning thermostat off and on and pulling fuse the original problem has stopped.

    BEFORE you start going all crazy about wiring etc.
    You can NOT flip those levers 'on and off' and 'on and off' because there is a delay switch on them.

    The ac and furnace has a delay. Some have a real long delay on them.
    You turn it on it takes a while to start because of the delay switch and when you turn it off there is also a delay on them for safety.

    You flipping that switch 'on and off' and 'on and off' your are screwing up the delay producing the problems you are experience.

    Wait and then Start all over and turn it on ONCE. Wait for the delay and the unit to start THEN see if there is a problem.

    Good tip thank you
  • Mike, did you get this fixed? I'm having the same problem and would love to know what you found out.

    Paul
  • I have a Coleman Mach in mine. It started to do some crazy things, not what yours is doing but odd stuff. I replaced it in about ten minutes and it's worked fine ever since.
  • I replaced the thermostat with the Coleman Mach digital and the problems we're resolved. Great thermostat and it's much more accurate.