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Furnace and or thermostat problem

Mikesr
Explorer
Explorer
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
Mike and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH
15 REPLIES 15

Mikesr
Explorer
Explorer
I replaced the thermostat with the Coleman Mach digital and the problems we're resolved. Great thermostat and it's much more accurate.
Mike and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH

campigloo
Explorer
Explorer
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.

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

Paul

Mikesr
Explorer
Explorer
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 and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH

rockhillmanor
Explorer
Explorer
....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.

We must be willing to get rid of the life we've planned,
so as to have the life that is waiting for us.

bobndot
Explorer II
Explorer II
Mikesr, just a thought ,
if the fan comes on, on the furnace while you are running the a/c, i would start tapping the furnace in various places to see if it stops. Then you know, its something on the furnace itself.
A loose wire, switch or solenoid ?

I just noticed 'O-B's" post re: the circuit board and that makes perfect sense.

wanderingbob
Explorer II
Explorer II
What brand thermostat ? On my thermo if on auto setting weird things happen . Every thing fine when on speed # 1 or speed # 2 .

Mikesr
Explorer
Explorer
Old-Biscuit wrote:
'WHITE' wire is for Furnace

Thermostat circuit board shorted-----sending DC to furnace and A/C

Thank you
Mike and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH

jetcare
Explorer
Explorer
Coleman makes a direct replacement digital thermostat to replace the analog one you now have. Uses the same wire colors.

Makes the swap easy.
2016 F-250 Crewcab 6.2L 4x4
2012 Palomino Sabre 32' Travel Trailer

Old-Biscuit
Explorer III
Explorer III
'WHITE' wire is for Furnace

Thermostat circuit board shorted-----sending DC to furnace and A/C
Is it time for your medication or mine?


2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31

Mikesr
Explorer
Explorer
2oldman wrote:
Sorry, I can't answer these questions. Someone will come along.

Many of us have replaced with digital units. You maybe could put that in the projects bin.

I agree and replacement is on the short list now.
Thanks
Mike and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH

2oldman
Explorer II
Explorer II
Sorry, I can't answer these questions. Someone will come along.

Many of us have replaced with digital units. You maybe could put that in the projects bin.
"If I'm wearing long pants, I'm too far north" - 2oldman

Mikesr
Explorer
Explorer
2oldman wrote:
A google search of that thermo should give you the manual and the wiring. If your internet connection isn't good I can do that for you.

I'm assuming you've not done that already or you wouldn't be asking us. But it seems like every time I say this, the poster comes back and says he did that.


Thanks
Google turned up its the white wire for the furnace
What could be causing this ?
Bad thermostat ?
Furnace problems ?
After turning thermostat off and on and pulling fuse the original problem has stopped.
I did give the thermostat a light tap or two can that help or hurt ?
Was this caused by the thermostat running on AUTO and not on normal ON position ?
Thanks
Mike and Donna
2016 Chevy 2500HD
2020 Open Range Light 312BH

Mandalay_Parr
Explorer
Explorer
Might be easier to disconnect the wire within the furnace cavity.
Jerry Parr
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