Furnace will not light

Tankfab · 10-31-2018, 12:09 PM

I have a 2018 330rsts with a dometic DF series furnace. After working fine for a couple months, this morning the furnace failed to light. The blower comes on, but I do not hear the igniter and the furnace does not light. The blower runs for a short while and then shuts off. Switched to a full propane tank and stovetop burner works. I'm on shore power and the battery is only a couple months old and reads 13 volts. I've reset the unit several time turning the thermostat to off and also checked 12 volt fuse. I had noticed in the past when the furnace igniter flashed, some of the 12v ceiling lights also flashed. I don't know if this is normal or a symptom of something going wrong. I guess I'm thinking there is either a board issue or something wrong with the igniter.

I'm in northern Wyoming (need heat) and currently do not have a tow vehicle to take the trailer for warranty service, even if someone was available to look at it.

Help!

Thanks, Mike

Marine1 · 11-01-2018, 01:33 PM

There is a reset toggle switch on the heater itself. You will most likely have to feel around to find it but it's there. Turn off for a minute or so then back on. The other issue you may have is the fuse in the thermostat check it... if none of the above work you may also have a spider web or some other small critter in your propane line use a an air hose and blow it out,,, Good Luck

Tankfab · 11-01-2018, 02:16 PM

Thanks for the response Marine, I tried the toggle switch and checked the thermostat fuse with no luck. I need to get a compressor to check the propane line, but I’m doubtful as I’ve had the oven and all three burners going for 15-20 min. with no apparent lessening of flame size.

I guess my next decision is whether to try to remove the furnace and take it somewhere or try to find a mobile service duty.

RVJayhawk · 11-01-2018, 05:20 PM

I recently had a similar experience. Our furnace became intermittent as far as starting and staying on. I finally figured out it was either the sail switch or the high temp switch so I ordered new parts. As soon as they arrived I attempted first to replace the high temp switch. On my furnace it is a bit difficult to reach it, but I have long skinny arms and finally reached the two push-on terminals on the switch. To my surprise as soon as I touched one of the terminals it fell off completely. I was able to properly attach the lead and did not replace either part. The furnace is working perfectly now. I suspect the terminal was never properly connected at the Jayco factory.

Duke4857 · 11-01-2018, 06:37 PM

Our 2016 24RKS had the same thing happen to it. The dealer removed the heater and adjusted the sailswitch. The dealer said the switch was bent out of alignment, it was covered under warranty at the time.

Tankfab · 11-01-2018, 06:48 PM

That’s a good idea. I’ll see if I can get the control compartment open and just look inside with a mirror. This furnace had come on and ran for probably 15 min and then shut off when the temperature had come up. Then 20 min later it kicked back on like it alway does, but didn’t light after the blower came on. Hasn’t worked since.

Seann45 · 11-02-2018, 03:13 PM

If you dont hear the sparker that means a fail in that circuit. Could be a bad gap on it or something else.

GrumpyDad · 11-02-2018, 05:12 PM

Quote:

Originally Posted by RVJayhawk

I recently had a similar experience. Our furnace became intermittent as far as starting and staying on. I finally figured out it was either the sail switch or the high temp switch so I ordered new parts. As soon as they arrived I attempted first to replace the high temp switch. On my furnace it is a bit difficult to reach it, but I have long skinny arms and finally reached the two push-on terminals on the switch. To my surprise as soon as I touched one of the terminals it fell off completely. I was able to properly attach the lead and did not replace either part. The furnace is working perfectly now. I suspect the terminal was never properly connected at the Jayco factory.

Loose connection is easy (ish) to check and worthwhile since it requires no parts to fix. Listening for the ignitor click and/or attempting to light with BBQ lighter can help you diagnose.

Tankfab · 11-02-2018, 05:29 PM

I assume the igniter is where the wires go into the top of the furnace. If I am able to remove the igniter (There is only o few inches of clearance above the furnace), should I just stick the Bbq lighter in the hole where the igniter is?

Tankfab · 11-07-2018, 01:40 PM

To close the books on this one, it ended up being a regulator that went bad on a two month old rv. Apparently the bad regulator allowed enough pressure for the other appliances, but not the furnace. After installing the new regulator, it still took 5 or 6 attempts before the furnace lit...I assume for the gas to migrate down the empty supply line.

Just in time too, 12 deg. tonight.

Janice bookie · 01-15-2019, 06:57 PM

Mike, I have the same Eagle model that you have and I’m having the same problem with my furnace. I don’t currently have a tow vehicle to take my rig to the dealer. Have you found a solution to your furnace problems?

The living area lights also flash when the furnace turns on. Unfortunately since my furnace isn’t working the lights haven’t been flashing.

Thanks
Janice

Tankfab · 01-15-2019, 07:40 PM

Janice,

The issue was the sail switch. It can be replaced by a mobile repair service or the furnace removed and taken to a rv dealer for repair.

I had the same issue of no tow vehicle and couldn’t get a repair service to come to me, so I removed the furnace and took it to them

Hope this helps.

Atlee · 01-16-2019, 04:45 AM

Tankfab, which of these problems was the reason your furnace didn't work?

"To close the books on this one, it ended up being a regulator that went bad on a two month old rv."

"The issue was the sail switch. It can be replaced by a mobile repair service or the furnace removed and taken to a rv dealer for repair."

Janice bookie · 01-16-2019, 05:21 AM

Mike, thanks for your quick reply! Could it void your warranty to remove the furnace yourself rather than having repair person do It?

Thanks
Janice

Tankfab · 01-16-2019, 07:51 AM

I initially thought the regulator, was the problem, but then the furnace quit again after working for a couple weeks. Now that the sail switch was replaced, it has worked for about 6 weeks with no problems running 24/7.

Tankfab · 01-16-2019, 08:20 AM

Janice, I’m not sure. I had talked to Jayco and they were willing to pay for the mobile repair service to fix the furnace, but the repair service I found wasn’t willing to travel to my location. The mobile service did, however, tell me how to remove the furnace and once I brought it to him, he fixed it under the Dometic warranty.

I’d suggest you call Jayco and discuss your situation. They were good to work with.

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