Furnace problems

[Jeep peeps]

Hi everyone,

The wife and I brought our 2015 Jayco GreyHawk 31 DS home. We bought it awhile ago but did not pick up till yesterday. Due to Covid we did not get a walk through. I was wondering if any of you would have any idea what might be wrong with the propane furnace. It will light but once the igniter stops it goes out. Does it and after three failed attempts I aborted. This is our first motorhome but not first camper. We did not get any manuals for it which we did not discover until we got looking this morning. Any help would be appreciated. I took the cover off the outside and there is no brand name I can find.

Thanks and have a great Easter.

[Route 66 Traveler]

You didn't mention the name of the furnace, but if it's a Dometic after three unsuccessful lighting attempts it will go into a lockout mode. If you remove the 12 volt power from it for a short time it will reset. There also might be a reset switch on the top cover you can try. Make sure there is propane available for the furnace...does your stove or water heater work on propane?
If you know the make and model you can search online for the owner's manual.

[Lake Huron]

Not trying to insult you or anything, but is the propane tanks on and are the bottles full? The dealer may have said they are, but you may want to look at the gauge if you have one and/or maybe take one or both out and make sure they feel (heavy) full.
If all that check out, light the burners on the stove to make sure you have good propane thru the lines. Then try to relight the furnace.
Also, does the hot water heater work on propane?
If all that checks out and it still doesn't work, one thing I've had happen in the past on 2 different trailers is a heat/flame sensor go bad. It's going to have 2 wires that plug into it. The sensor itself is round with 2 mounting screws holding it on. I've taken those wires off and shorted them together to complete the circuit. This way it thinks there is heat and it will keep running. That sensor is a safety feature so if there is no flame the furnace won't keep sending propane into the furnace creating a bad situation.
Try the propane issues first before having to tear into the furnace.

[Jeep peeps]

Thanks guys for the ideas. Yes there is propane. I will try the water heater and stove. I can't see the brand name on the furnace. I took the exterior access panel to see if I can get the brand and model but no luck.

[Nature Ist]

Originally Posted by Jeep peeps

Hi everyone,

The wife and I brought our 2015 Jayco GreyHawk 31 DS home. We bought it awhile ago but did not pick up till yesterday. Due to Covid we did not get a walk through. I was wondering if any of you would have any idea what might be wrong with the propane furnace. It will light but once the igniter stops it goes out. Does it and after three failed attempts I aborted. This is our first motorhome but not first camper. We did not get any manuals for it which we did not discover until we got looking this morning. Any help would be appreciated. I took the cover off the outside and there is no brand name I can find.

Thanks and have a great Easter.

We need you to clarify a few things: you stated "It will light but once the igniter stops it goes out." When you are calling for heat, the first step is the exhaust blower kicks on, there is a flow switch (sail switch) that detects the air movement through the exhaust, which then completes the electrical circuit allowing the propane solenoid to open and the igniter to activate. I assume you are getting to that point with all of these steps functioning properly. If it actually lights and you can hear the flame or detect heat through the exhaust you are getting propane and ignition. If it goes out after the igniter stops making a sound, then you probably have a bad thermocouple, which detects heat from the flame and keeps the propane solenoid open. If the thermocouple does not detect heat, it closes the propane solenoid to prevent a build-up of propane. It is also possible, though unlikely, your sail switch could be faulty. I say unlikely because you stated that it does light in the beginning.
You would likely have to access the heater from inside the coach to see the labels that identify your make, model, etc etc.
Once you get that information, you should be able to search online for manuals, and hopefully a service manual for it.

[pconroy]

Originally Posted by Jeep peeps

Thanks guys for the ideas. Yes there is propane. I will try the water heater and stove. I can't see the brand name on the furnace. I took the exterior access panel to see if I can get the brand and model but no luck.

We've got a 2016 so odds are close that we have the same make and model.
Ours is an Atwood but I can't find where I wrote the model number down.



Yeah - make sure the stove works. In fact I usually run the stove to purge the lines of any air. If the furnace still does it's thing - then there's a set of LEDs inside that'll blink a diagnostic code.


When ours started acting up, even though the codes suggested something else, our Mobile RV tech said "Humor me, let me replace the sail switch."


That was it.
We've been golden (and warm) ever since.


Start with those LEDs.

[mini4mw]

If the unit sits for a period of time air gets into the lines. Each time we get in I fire up the range, usually takes a few tries, let it burn for a bit and then the water heater (gas) and furnance will work. Sometimes, even after range works, it takes 3 -5 tries to get water heater to work. Turn on, faults, eventually kicks in. All related to sit in the lines.

[Jeep peeps]

Thanks for the info. The stove fires up no problem. I can't try the water heater as it is still winterized and too cold to fire up the water system yet. I will take some pieces off from inside the coach and try and get manufacturer etc. Thanks again.

[mini4mw]

Will the fridge fire up on propane?