Furnace not firing

CLB

Member
When I turn on my furnace I hear it try to fire 3 time's then nothing. There is a orange wire loose in the AC unit I'm pretty sure is my problem can anyone tell me where it is supposed to go?
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ram22

Well-known member
AC? My furnace and AC are completely independent... I think. But I did have similar symptoms. Turned out to be a tool nick in one of the leads to the thermocouple. That lead eventually got close enough to some heat shield or something metal that it was shorting and an otherwise good thermocouple wasn't sending the right voltage to the circuit board so even though the pilot would light, the motherboard wasn't getting a signal that it was lit so system logic would close the gas valve. After 3 attempts, I'd have to shut off the heater switch to reset and then try again, with same results. Tool damage looked to be from manufacture, but took a dozen uses and just enough time for warranty to lapse before it started shorting. New thermocouple fixed it. Maybe a good way for you to troubleshoot would be to try a new thermocouple, if that made sense with your exact symptoms.


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danemayer

Well-known member
On some rigs, there is a control box at the A/C return, where the thermostat connects and operates relays to fire the furnace.

However, if your furnace blower runs and ignition is attempted 3 times, that's not where the problem is. Assuming that when there is an ignition attempt, there is a spark, then either your gas is not flowing, or the gas valve is not opening, or the igniter is out of position.

Start at the most likely. Close the propane tank valves and reopen verrrrrrrry slowly. There's an overflow protection device that will block propane flow if the valves are opened at 'normal' speed.

Light the burner on the range to make sure air is purged from the propane lines.

Check the hoses coming out of the dual regulator to make sure they aren't pinched anywhere.
 

Roller4tan

Well-known member
Check your paperwork that came with the trailer. There should be a booklet on your ac unit. In there you should find a schematic to help find where that wire goes. I agree if you fan comes on then that wire is for something else that won't work in the future.
 

CLB

Member
Check your paperwork that came with the trailer. There should be a booklet on your ac unit. In there you should find a schematic to help find where that wire goes. I agree if you fan comes on then that wire is for something else that won't work in the future.
Unfortunately I don't have a schematic and the orange wire goes into a brown insulation and then I don't know where not to the thermostat or furnace but going to check the gas now.

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CLB

Member
Unfortunately I don't have a schematic and the orange wire goes into a brown insulation and then I don't know where not to the thermostat or furnace but going to check the gas now.

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Well it came on for maybe a minute but just blew cold air and now it's back to 3 tries I'd love to find a older furnace and get rid of the complicated garbage. What was wrong with simple? I'm going to look for a different type of heater and trash this one there is absolutely no reason a heater needs a circuit board.

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