Gas Furnace Will Not Light

lbyeary · 10-22-2018, 06:22 AM

The propane furnace in our 2018 Greyhawk Prestige 29MVP will not ignite. It was working when we went to bed last night and in the middle of the night we woke up cold. The blower will come on but shuts off after about a minute. I checked the stove and refrigerator and they are both working on propane. Tank is full at 3/4. I checked the fuse and it is fine. About a month ago I checked the wires that could come in contact with heater exhaust and they were fine but I pushed them a little further out of the way and added a wire tie to keep them back. Any thoughts on what the problem could be?

hboy · 10-22-2018, 08:29 AM

Can the igniter go out in those. Maybe.?

cabinetmaker · 10-22-2018, 08:38 AM

Quote:

Originally Posted by lbyeary

The propane furnace in our 2018 Greyhawk Prestige 29MVP will not ignite. It was working when we went to bed last night and in the middle of the night we woke up cold. The blower will come on but shuts off after about a minute. I checked the stove and refrigerator and they are both working on propane. Tank is full at 3/4. I checked the fuse and it is fine. About a month ago I checked the wires that could come in contact with heater exhaust and they were fine but I pushed them a little further out of the way and added a wire tie to keep them back. Any thoughts on what the problem could be?

Raining lately? Maybe the frig has leaked water down on the control board?

Open the outside cover and inspect the control board. If moisture gets under that board it will cause your problem. Some have used a hair dryer and gently dried the board and got things going gain.

If this works be sure to check your seal around the outside cover to help prevent water from entering.

Hope that helps!

lbyeary · 10-22-2018, 08:41 AM

I went out this morning and took the cover off the heater and everything looked fine, wires were still away from the exhaust. I did notice a reset switch, it was not off but I turned it off and back on. I then turned the furnace back on and it ignited. Fingers crossed see if it works tonight. Temps tonight are only going down to mid 40’s so will probably use heat pump but will definitely try the furnace to see.

LI-Camper · 10-23-2018, 02:01 PM

I carry a 1500 watt electric heater in my 29 MV. Sunday night the temps dipped to about 35 or so. I used the electric heat pump and the electric heater, too. The heat pump turned on less frequently with the electric heater turned on. My electric heater has four settings: fan only, 500 watts, 1000 watts, and 1500 watts. It is about 40 years old or more. My brother gave it to me to use in my pop-up camper I had in the early 90s. He used it in his pop-up in the late 70’s. It is good as a back-up when you have shore power.

lbyeary · 10-23-2018, 03:02 PM

We keep a My Buddy propane heater in the RV but that requires a couple of windows to be cracked open. The gas heater did not ignite last evening until I went out and took the cover off again and hit the reset switch. I am leaning toward an air flow issue and nothing to do with the reset switch. The blower kicks on and I assume that is to prove air flow over the burner. When the outside cover is off the thing will ignite but with the cover on it will not. The cover off provides plenty of air to the blower but I am thinking something may be restricting flow with it on. Took the grill off inside the RV but can’t see anywhere an air inlet may be. I called our local dealer and they can’t look at it until Dec 20 and a local Camping World can’t take it until November 23. Can’t understand the constant delay in getting RV service.

Dave55 · 10-24-2018, 08:00 AM

On the furnace circuit board near the back is a red led. With the blower on see if it flashing. Attached is the service manual. See page 7 for the diagnostics codes. Also, turn off the coach main power and then remove the circuit board by taking out the one screw in the front and check for any mositure. Even if dry use a hair dryer on low temp for several minutes.Water can get under the black circuit breaker on the board. Good luck and I hope this helps.Furnace Atwood AFM.PDF

Dave55 · 10-24-2018, 08:18 AM

The attachment did not work. Here a link:
https://www.google.com/url?sa=t&sour...uyzYiaQGHJZpbS

Sorry bout that.

lbyeary · 10-25-2018, 12:16 PM

We spent the last two days and 650 miles driving home and did not use the furnace. It did not rain at all during the trip home. I went out this morning and the propane furnace fired right up and has cycled off and on several times now. I am guessing the circuit board dried out during the drive. I am still going to follow your advice and check the LED, etc. I have a couple of questions regarding sealing the outer panels. It looks like the RTV should be applied between the exhaust vent cover and the main cover. The foil tape looks to be between the main cover and the bezel (attached to the motorhome). Is that correct? Does using the RTV make it hard to get the cover off next time?

Kim Gass · 10-25-2018, 01:01 PM

when boondocking ( you didn't specify if you were or not) our furnace will not heat when the battery gets low.

The furnace takes a lot of power. You no doubt recharged your battery on the ride home

Dave55 · 10-25-2018, 01:16 PM

Ibyeary,
On page 5, use the instructions for Standard Door Installation. The foil tape or RTV is applied on the lower right hand side sealing the furnace casing & the bezel (See drawing and picture). When I removed the door panel, I first took out the 4 screws for the ASM vent and pulled it straight out of the door, then removed the door. I do not believe there was any RTV. I will check again once I get the coach back out of storage in a couple of weeks.

lbyeary · 10-25-2018, 01:34 PM

Unfortunately we were not boondocking. We were connected to power the entire time.

pconroy · 10-25-2018, 10:31 PM

I had a similar issue on our 2016. It would work, then not, then work, then not. Usually worked when we didn't need it and not work when we did.

I called the local, mobile RV tech.
Of course it worked when he was there, but he did say he felt it was worth taking a shot at replacing the Sail Switch.

We did, or he did.
And it's been working fine for a year after that.

I don't recall the exact code, but our Flashing LED on the control board, wasn't much help.

lbyeary · 11-05-2018, 10:01 AM

Just got off the phone with Atwood rep and they have a relocation kit to move the circuit board. Unfortunately it has to be done by a service tech so it looks like that is the fix needed. The rep was well aware of the issue and since ours is still under warranty then I have to go with it.

Forelyndogs · 11-10-2018, 01:57 PM

You've got a lot of good advice so I'll only add a couple of comments. We had a similar problem with our furnace while on a trip. Got a mobile RV mechanic to come out and he replaced a circuit board. He suggested this was a common problem with RV furnaces. I made sure I got a surge protector for my rig and have had no troubles since then. Hard to know if one is connected to the other. Low battery can cause frustrating problems with slides, jacks, even propane and CO2 detectors. So keep it charged. Turns out even plugged in a low battery can haunt you.

lbyeary · 11-10-2018, 02:00 PM

Since it is still under warranty I am going to let them change out and relocate the board. Hopefully that fixes the problem.

112hCIC · 11-10-2018, 02:13 PM

It could be your mother board or your thermostat or a loose connection>
Mine was replacing thermostat. unless you licensed suggest tech do it at a dealer

Dave55 · 11-10-2018, 04:43 PM

It would be nice know exactly where they will relocate the circuit board. Post a picture if you get one.

Sam · 11-10-2018, 05:27 PM

Had the identical situation last December. It was the sale switch. Cost $18 and it took me less the 1/2 hour to change. My Seneca was out of warranty. The SW measures the volume of air going past the burner, if there is insufficient volume of air or the switch fails the burner will not ignite and the blower will shut down after 30 seconds or so. Hope this helps. Sam

Morttt · 11-10-2018, 05:46 PM

FWIW, we had the same problem on our 17XFD this summer in grand teton

Long story short, they replaced the control board, it failed again in Ft. Bragg, and they replaced it *again*. Then i went to pick it up and it was still broken...that time the wire to the ignitor was "loose" on the subsequent inspection..

But yea, basically the only things it can be are the board, the ignitor/wire the sail switch, or the thermostat/cutoff switch. Possibly the (dual) solenoid, but that is not likely.

If its under warranty, go that route. For anyone that its not, i'd suggest testing the sail switch/cutoff with a ohmmeter and then replacing the circuit board. I found ours for $80 on amazon. certainly cheaper than the trip to the dealer.

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