furnace not lighting

[revrusty]

Just got back from our annual vacation with our 1 month old Cougar 30 RKD. From Virginia to Idaho and back. On next to last night, ran out of gas during night. connected to full tank of gas but furnace will not ignite. Fan will run for 20 seconds or so as normal but no ignition. Read in book to bleed the line by lighting stove and did that. Also cooked breakfast so burned for long time. Still no furnace ignition. Even stopped at a camping world next day and was told to disconnect gas line and then reconnect and slowly turn on gas. No luck. Then told " Sorry, we don't have time to look at it."

Made it home with the electric fireplace but hoping for help to get furnace working. Thanks for any suggestions.

[Tbos]

Try running your fridge and water heater on gas too. It sounds like it may still need to be purged. If that still doesn’t work I’d set up an appointment with your dealer for a warranty claim.

[revrusty]

I have had the fridge on gas since each day of travel for 2 days and overnight last night till now. I did put the water heater on gas for 2 showers. Will try again this morning after we get done cleaning out the camper! Thanks for the advice.

[ChuckS]

After furnace failed to light off and fan was running did you turn the thermostat completely off to clear lock out mode?

If so does fan run and no sound outside of DSI making popping sound to ignite when listening near exhaust?

If fan runs but you hear nothing it could be bad sail switch, bad overtemp switch or bad furnace control module

If this is an Atwood furnace locate control module and observe LED light to obtain error code..If Suburban there is no LED

[revrusty]

I will have to look into that. I did cut the furnace off at the keypad. Several times. Didn't hear any popping sound but wasn't really listening for that. The fan sounded normal , there was just no sound of the furnace igniting. I will check the access panel and see what is behind it. Thanks for the suggestions.

[revrusty]

I removed the access panel located under the fridge. Nothing to see except a flat metal panel with several air ducts coming out. My owners manual says this is a dometic furnace. Is that still one of the 2 brands mentioned or a third one? Does it being Dometic spark any ideas? Thanks.

[GeekSquadOfUn]

I removed the access panel located under the fridge. Nothing to see except a flat metal panel with several air ducts coming out. My owners manual says this is a dometic furnace. Is that still one of the 2 brands mentioned or a third one? Does it being Dometic spark any ideas? Thanks.
Dometic bought Atwood a short while ago. They just re-branded it to Dometic.

Make sure your range works fine on gas firts to confirm you have gas.

When you put the thermostat ON, or call for heat using iN-Command's control panel, listen outside you should hear the fan start, this is to clear the flu and make it ready for gas coming in, 20 seconds later then click-click as it tries to light the flame. Can you hear that ?

[revrusty]

Yes. The fan runs for about 20seconds, furnace does not ignite. Then fan cuts off.

[JRTJH]

Yes. The fan runs for about 20seconds, furnace does not ignite. Then fan cuts off.

During that 20 seconds, near the end of the cycle, do you hear any "clicking" ?? The clicking is the "ignition cycle" which only occurs IF other conditions are met. The fan running is only one of those conditions. The sail switch must open (a check for the fan speed), the gas valve must open, and then the "clicking occurs". Once the propane is ignited, the flame sensor must detect a flame (check for successful ignition) and then the lockout allows the furnace to operate until the thermostat set temperature is satisfied....

There's much more than "the fan runs for about 20seconds, furnace does not ignite"...

Do you hear the clicking? If so, do you hear the propane "whoosh" as it ignites and feel the heat at the top vent outlet on the side of your trailer?

[revrusty]

I am only hearing the fan run. Sorry I didn't make that clear. I have listened for the clicking sound both inside and outside of the trailer and only hear the fan. Don't know about the switch mentioned or how I would check it. I have burned the range and turned the hot water heater on with gas. Both worked just fine. Thanks for all the suggestions so far and any further help will certainly be appreciated. I plan to call a dealership on Monday to set up a service appt. Hopefully they can see it before our planned trip in December.

[JRTJH]

Here's a link to a "Furnaces for Dummies" type of file. It isn't specifically geared to your furnace, but will give you an overall understanding of how they work, what the components look like and where they're located. Hopefully it will give you a better understanding of what happens when the thermostat calls for heat and possibly, what's "not happening" in your furnace.

https://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

[skids]

You might want to try turning off the gas from the tank, turn off the furnace, maybe turn on the propane valve very slowly. and turn on the stove, fridge. Then the furnace. From what I have heard, the propane valve has a safety mechanism that throttles way down if too much flow occurs all at once (and the furnace is a biggie).

[chuckster57]

You might want to try turning off the gas from the tank, turn off the furnace, maybe turn on the propane valve very slowly. and turn on the stove, fridge. Then the furnace. From what I have heard, the propane valve has a safety mechanism that throttles way down if too much flow occurs all at once (and the furnace is a biggie).



The safety device your thinking about will shut the flow of propane off before it reaches the regulator, so if the water heater and stove operate on LP, odds are the safety device isn’t the issue.

[jlonginav]

I had a similar issue when camping in cold weather. Fan would start but gas would not ignite. I accessed the furnace and pulled the two power wires leading to the control board. Waited 15 seconds and then reconnected. This basically forced the control board to re-boot. Put everything thing back and I was good.

[revrusty]

I wonder if turning the battery disconnect switch would affect it the same way. I am going right out to try that now. Thanks for the suggestion.

[manonfire1978]

I had the exact same problem on my 2019 Fuzion. Everything worked (water heater, stove, fridge on propane, BBQ attached to quick connect) but the furnace wouldn't light. Just cycled the fan then cut out. Took in for warranty and they had to replace the Sail Switch. Tech said that they've had a lot of problems with a couple model years, said about 1 in 3 units were coming back with the problem but the new part has been upgraded or whatever so should be good for the long run now....we will see.

[JoeD]

I have a 2018 Cougar. On a round trip cross country trip from Oct 2018 to Feb 2019, my heater failed in Pennsylvania, on the way to Connecticut.
I also tried all those tips everybody mentioned, checked you tube and Google.
I called a service guy in Mystic Conn. He pulled the heater unit our from under the refrigerator, put in on the picnic table and tested it. Failed igniter board. He replaced it with a upgraded equivalent Dinosaur board. Put all back together, been working fine ever since (new board has 3 yr vs 1 yr warranty btw, cost me $144 for board and I hour labor). So when I got home, I put in an insurance claim through my RV insurance company and Dometic, I was able to recoup the cost of the furnace repair and hotel lodging on the road because I had to winterize my trailer from Penn to Connecticut. Hope this helps. Good luck.

[LHaven]

I had the exact same problem on my 2019 Fuzion. Everything worked (water heater, stove, fridge on propane, BBQ attached to quick connect) but the furnace wouldn't light. Just cycled the fan then cut out. Took in for warranty and they had to replace the Sail Switch. Tech said that they've had a lot of problems with a couple model years, said about 1 in 3 units were coming back with the problem but the new part has been upgraded or whatever so should be good for the long run now....we will see.

I've seen postings from multiple members over the past year (myself included) reporting this same syndrome in their brand-new Keystones. In every case, it was caused by Keystone's less-than-antiseptic construction practices leaving loose sawdust and styrofoam in the cavities that fouled the sail switch shortly after delivery. If the sail switch fouls, you won't hear the ignition clicking because the control board will never enable the gas feed and ignition to prevent a fire.

If this were my rig, I'd look for this first.

[revrusty]

Well I have an appointment at a dealer for service on Thursday of next week. I will certainly share all this info about the sail switch. The service manager must have a similar idea because they told me to wait for it to be ready. Will let y'all know how it works out.

[DocWMB]

I had problems getting my Water Heater to ignite. Took it into my Tech and he told me that they have had a big problem with the cheap igniter boards that are used in the Heater, Water heater and Fridge. He said that if they keep replacing with the same defective boards in warranty, they will continue to fail frequently. He recommended the Dinosaur Electronics igniter board and told me that he had never had to make a claim on their guarantee. They work. Great company right here on the coast of Oregon. https://www.dinosaurelectronics.com/

[JRTJH]

I had problems getting my Water Heater to ignite. Took it into my Tech and he told me that they have had a big problem with the cheap igniter boards that are used in the Heater, Water heater and Fridge. He said that if they keep replacing with the same defective boards in warranty, they will continue to fail frequently. He recommended the Dinosaur Electronics igniter board and told me that he had never had to make a claim on their guarantee. They work. Great company right here on the coast of Oregon. https://www.dinosaurelectronics.com/

Most of us with any "long time exposure" to RV propane appliance problems have used Dinosaur Electronics control boards for years. My first exposure to them was in the early 90's and I've been a fan since then...

That said, if the water heater, furnace or refrigerator is still in warranty, then the manufacturer will require (in every case I've seen) that OEM parts must be used. Once the warranty expires, using Dinosaur Electronics products should be, for most people, a "no brainer"... But during warranty, not allowed if a warranty claim is processed.

[flybouy]

Most of us with any "long time exposure" to RV propane appliance problems have used Dinosaur Electronics control boards for years. My first exposure to them was in the early 90's and I've been a fan since then...

That said, if the water heater, furnace or refrigerator is still in warranty, then the manufacturer will require (in every case I've seen) that OEM parts must be used. Once the warranty expires, using Dinosaur Electronics products should be, for most people, a "no brainer"... But during warranty, not allowed if a warranty claim is processed.

What John said. If it were me I'd by the dinosaur board and keep it on hand for when it DOES fail again. That way you can replace it and not have your trip interrupted, then have it replaced under warranty when you get back.

[donajohn]

The only problem I've ever had with my 12 year-old Suburban furnace is debris in the orifice. I've had it cleared 3 times. How it gets there, I don't know.
On one of the service calls when furnace didn't fire up, the guy replaced my board with a Dinosaur board. Still didn't work so then he found a grain of debris in the orifice. He cleared it and it fired up.
Meanwhile, the Dinosaur board did not consistently trigger my furnace. I had to manually run the thermostat lever up and down to get heater to fire up. Not convenient at 2am when furnace failed to start on its own.
A year later, I had the same tech replace the Dinosaur with a new Suburban board and haven't had a problem since. I assume he sent the Dinosaur board back.
In the meantime, I've had to have the orifice cleared 2 more times. Each time I've seen the evidence myself...a grain of something 1/2 the size of a pinhead.

That's always the first thing I look at when furnace doesn't start.

Good luck.

[jim1]

Check the sail with for construction debris from manufacture. There is a on/off switch on the furnace, I had to access mine from the outside panel. There should also be a light that blinks for different furnace codes and a code info sticker on the furnace outside. My 2019 315rls did the same thing and it was a mucked up sail switch. Good luck