Furnace not working - shake down trip

[jjbaird27]

We are newbies in the RV world and on our shake down trip. We can't get the furnace to run more than 30 seconds.
Propane is on and we have a good blue flame on the stove burners.
We are on 30 amp service and everything else is running smoothly except the hot water heater which is turned off.
2015 Precept 31 UL
Atwood furnace
RV Comfort HC Coleman Mach thermostat

Any tips or suggestions

[Kevin Cooper]

It is most likely the sail switch (makes sure fan is blowing), or the flame sensor (makes sure the gas was ignited).
There are several videos on furnaces on the HillbillyRVRepair channel on YouTube.

[JimD]

See the attached documents for troubleshooting a furnace.

[jjbaird27]

Thanks. I'll go watch HillbillyRV on YouTube. I'm sure I'll end up bookmarking his page and watching him frequently

Thanks for the PDFs about electrical systems and the multimeter..

[Kevin Cooper]

He just put up a new video on one that was running 30 seconds and shutting off. It was the high temperature switch had failed.
https://youtu.be/Ow0irnPw3fE?si=xElD1S1SFZmjm9t3

[jjbaird27]

Thanks for the link. Yep, it that is what our furnace does. We're going to take it to a service place because 1) we don't have the time and knowledge to do it ourselves right now and 2) we purchased a service contract that should take care of it. I wonder what the RV repair place will say is the cause.

[Kevin Cooper]

Well, at least you are somewhat educated enough to know if what they say makes sense, right?

[jjbaird27]

Somewhat educated, yes. I'll admit though that I don't know what I don't know. This is our first RV and it is 9-10 years old. It will need repairs which is why I bought a service contract and the furnace should be covered.

[Okie Traveler]

When you turn the furnace on do you hear the igniter arcing making snapping sound?
If the arcing isn't happening could be control board.

[jjbaird27]

No, we don't hear that snapping.

[Okie Traveler]

Originally Posted by jjbaird27

No, we don't hear that snapping.

You might stand outside by the furnace and have someone turn it on. If you don't hear that clicking sound the igniter is not functioning. Chances are the control board is out. Dinosaur electronics makes a great replacement board. I'm not sure if yours has a time delay relay, but if it does that's something else to check.

[jjbaird27]

Thanks for the info.

[Michael Francois]

Had the same problem. Turned out to be a faulty regulator.


Post-script: Went down all these rabbit holes. The furnace requires the highest gas flow of all your appliances. Your stove (next highest) and refrigerator may still work, but if the regulator is not allowing sufficient gas pressure to sustain a constant burn, it will light up them flame out after a few seconds. I have forgotten the required pressure, but it's in the manual.

[Johnynorthland]

Sail switch, high temp cutoff, (blocked hose duct), or the boards bad!

[Springhook]

When I took ownership of my 2021 Freelander, both furnaces wouldn't work. Turns out, there is a power switch on each furnace. Unscrew and remove the grill. Look for a switch. Good luck.

[wducat]

These guys have excellent replacement parts and will help over the phone to diagnosis. https://www.dinosaurelectronics.com

for me, the major issues I have run into with my furnace include a wet circuit board, a bad circuit board, a bad switch, and a bad sail switch. often, the LED blinking pattern on the board will help direct you to what’s actually going on.

[CBCOCRBO]

Originally Posted by jjbaird27

We are newbies in the RV world and on our shake down trip. We can't get the furnace to run more than 30 seconds.
Propane is on and we have a good blue flame on the stove burners.
We are on 30 amp service and everything else is running smoothly except the hot water heater which is turned off.
2015 Precept 31 UL
Atwood furnace
RV Comfort HC Coleman Mach thermostat

Any tips or suggestions

Most likely the sail switch. A small amount of dust on the switch will prevent the small amount of current required to cause ignition. Problem is most often the furnace sail switch is difficult to get at. Ours has failed twice. Had a mobile tech do the work. Would be easy if the manufacturers would build so that the furnace could be accessed and removed from the outside as opposed to the usual hard to get at location.
Cheers and good luck
Rick
2020 Jayco 29RKS, soon to be replaced (April) by 2025 Grand Design Reflection 315RLTS

[TGoldsbury]

I had mud daubers building nest in mine, cleaned them out and everything worked fine. I then put screens over the intake on that and the water heater. Got them from Amazon.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[jjbaird27]

The service department determined it was a faulty control board and switch. I'm waiting for the paperwork to file a claim with Wholesale Warranties to see what the name of these faulty parts are.