Need help with furnace.

[James3344]

Boondocking in Sedona and its been dropping to 25 degrees at night. Last night I woke up to the furnace not running. After taking the cover off outside and playing with the wires I got it up and running again.

The only problem is, I can only get it to ignite when I first turn the thermostat on. But after it automatically shuts itself off it won’t restart after the temp drops. It will run the fan for a bit and then just shuts off. Not sure where to go from here. Any help is appreciated because we probably won’t get much sleep tonight trying to keep this thing from freezing.

[James3344]

Oh and I forgot to add that it works fine if the thermostat is set up over the half way mark. Which makes it even more confusing. It’s one of the older non-digital thermostats

[azflycaster]

is there a blinking error code on the circuit board when it fails?

[Night owls]

Sounds strange. Are your batteries charged enough to run the furnace? Sometimes when low they will start the furnace but not run for much longer afterwards.

[GCinSC2]

James

Can you post model number of furnace please?

You giggled a wire and it ran? Mine (8535-IV) did that too. Culprit was the wire tap connection was failing. IIRC it had about three of these connectors. These are where they made a connection to a wire by clipping on to it thru the insulation.

All other gas appliances ok?

Thermostat only allows furnace to cycle on off. Furnace doesn’t sense temp that’s t stats job.

Gary

[banderabob]

Maybe no help, but the only time I have had a similar situation of the fan coming on and the furnace not igniting was when the propane tank was empty.

[James3344]

Thank you for the replies. There was no blinking light indications and I am sure we have propane.

I was able to get it to run all night last night. It seems that three or more of the spade connectors inside of the furnace were not clamped tight enough. Because after i went through and squeezed them with pliers it has been working. So hopefully it stays fixed!

[perryg114]

Good luck. Isolate the thermostat wires so you know where they are. I believe not matter what sort of thermostat or comfort control center that all the thermostat does it short those two wires. When the thermostat opens up it turns the furnace off after a cool down cycle. You can always hot wire it or put in a cheap bimetal thermostat as a temporary fix.



Perry

[GCinSC2]

James

When you can I suggest good idea to inspect crimps and terminal connections like you started. Just expand inspection in furnace wiring area and those inline taps too.

Gary

[Palik]

OP, I had a similar problem two days ago.

Solution: I removed sail switch and inspected it. Found a slight bit of fuzz. I removed it. Furnace works correctly.

Symptoms:
- furnace came on with interior temp at 60, set temp at 65
- furnace heated to 65 and shut off
- interior temp came to 60, furnace did not turn on
- fan would come on but the furnace would not ignite

Troubleshooting:
- regarded manual for steps to reset to include propane check
- power and propane were not the issue
- reset the switch by rocking from "off" to "reset" 3 times
- with the digital thermostat "off" the diagnosis LED was no on
- turned thermostat "on" with set temp below interior temp
- LED indicator had one flash
- removed sail switch screws, found the fuzz

Furnace model: Atwood AFMD 25141

Timothy