Help with furnace

[tbax46]

Need to know if any of you might take a guess on my furnace. It comes on for about 30 seconds, then goes off like it threw a breaker or something. It has propane. Not sure
what to look for. The fuse is okay or it wouldn't come on in the first place.
All suggestions appreciated.

[TXiceman]

More than likely it is a voltage problem at the unit. Check for proper voltage at the furnace with the fan running. If the sail switch does not make, the ignitors and gas valve will not fire.

Ken

[0rion]

kjchipmunk wrote:
I had something similar to this when my batteries were below the required voltage to run the heater. It would try to start the heater, run the fans for a bit then shut off. New batteries fixed the problem.

yep...that's because the fans weren't running fast enough to close the sail switch.
It could be an ignitor but he would hear them firing and it would cycle longer trying to keep firing the ignitors. If that sail switch doesn't close you get no ignition.

[kjchipmunk]

I had something similar to this when my batteries were below the required voltage to run the heater. It would try to start the heater, run the fans for a bit then shut off. New batteries fixed the problem.

[WeBeFulltimers]

Could also be bad or misaligned ignitor.

[0rion]

have had this happen on 2 furnaces I've owned....both times it was the sail switch. Just replaced the sail switch on my current furnace this fall due to this. It's an easy job and part is about $10. The hi limit switch is right on the front of the furnace and again.....$10 part if you wanted to try that first but I'm betting sail switch.

[hilke40]

My Suburban furnace, had exactly same problem, was high limit switch, on front behind panel. $8.50 for part. RV repairman said to tap on it and sometimes they would work. Mine did. Two screws and two clips on wires to replace.

[kennethwooster]

Ours went out last year and required a new board.

[Dakota98]

This may help

Trouble shooting Furnace

[donn0128]

Propane regulator, hi temp limit switch would be my first two guesses.