Another furnace issue

[GreG L.]

Hoping this is a common or known issue. Last trip I needed the furnace, it comes on and blows hot air for about 10 or so seconds then shuts off. I can switch it off and back on and it will do the same thing each time.
Any ideas?

[jsb5717]

Those symptoms could be a few different things. Ours has had those same symptoms a few times…each with a different fix.

The easiest thing to check is the thermal switch. That was our last fix.

Before that I pulled out the manifold and the diffuser was all rusted. Replaced it and it ran great.

Before that the issue was propane volume flow. Replaced the regulator and then it ran great.

[RMcNeal]

Sometimes spiders or mud dobbers will build a nest in the furnace tube where the propane and air mix causing a low gas flow situation as Jeff mentioned. You can easily check that from the outside and check that the exhaust port is not blocked either.

[Daryles]

Start with the 15A black self resetting fuse in the circuit breaker panel.
Swap it with a regular 15A blue fuse and try it again.

[raygreg]

I had a similar problem. Furnace would work and then not work etc.
I finally figured out the sail switch lever was hitting the surrounding fixed part and would not hit the switch every time.
I bent the lever with a needle nose pliers out and back (a sllght v) to clear the fixed object and trip the switch. It has been working for about 2 years now.
Sorry if this explanation is not very clear.

[plgavin]

I carry a multi-meter and alligator clip jumpers for trouble shooting things like this. Helps to sometimes narrow down the cause without as much disassembly. Cross connected the sail switch and tried again and then it worked, so looked at the switch and found junk on it.



Used these to figure why the gas side of the water heater wouldn't work by shorting the thermostat.

[ChuckS]

Since you have an outside access panel for the furnace remove the panel and see if there is an error code that flashes on the control board when you try to start it..

If its actually running only 10 seconds that sounds like an issue with the black self resetting fuse Atwood loves to use..

If however the blower run time is longer than 10 seconds then stand outside at the furnace and have helper turn furnace on..

you should hear blower , then a ticking sound along with a whiff of propane..

If the furnace fails to ignite after 3 tries it goes into lockout mode. TO clear this simply turn thermostat off and back on.

I would highly suspect issue with sail switch if your blower runs and no ignition or propane smell

There is also a toggle switch located on the shiny metal case of the furnace.. cycle that off and on a few times as well when making your checks

Again.. look at that control board and note the number of flashes from the LED on the board..

[badaxemi]

Originally Posted by Daryles

Start with the 15A black self resetting fuse in the circuit breaker panel.
Swap it with a regular 15A blue fuse and try it again.

This solved my same issue this year. I tore the furance apart hoping to find a noticeable problem and even ordered a new board and all it was that damn 15A black self resetting fuse. GRRRRRRR.

[Foldbak]

Originally Posted by Daryles

Start with the 15A black self resetting fuse in the circuit breaker panel.
Swap it with a regular 15A blue fuse and try it again.

Nailed it!

[Freedom@62]

Mine was doing the same thing and they fixed it at the rally. Burner was rusted and clogged. Replaced and all was good