Erratic furnace ignition

[beerrun'r]

I have a 2006 19' Bambi and I have a furnace that is erratic with ignition.

Sometimes it'll "time itself out" without ever igniting. Next time it may ignite on the first or second attempt. Etc.

Any ideas??

[TBRich]

We had this problem in our 06 19' Bambi...in cooler weather it would not work at all (usually in the middle of a cold night)...didn't so anything but freak out the dogs with its incessant clicking to try to start....then failing. We ended up replacing the gas regulator and that fixed it...it was not getting enough gas flow in cooler temps...but that is not the only potential reason...could be caused by low voltage to the igniter or by a stuck sail switch...among other things... It can be tricky to diagnose... Here's at least one thread about furnace malfunctions and quirks...and there are more in the subforms dealing with furnace issues... http://www.airforums.com/forums/f427...air-37962.html Good luck and be persistent...you will eventually find the solution, but it may mean some trail and error.

[B4WEDI]

I had the same problem and it drove me nutz.

I bumped into Airstream techs at a rally I attended in FLA. Upon inspection, they noted that my regulator needed to be adjusted to provide more gas to the appliance.

A little tweak was all that was needed and all is well !

[beerrun'r]

Originally Posted by TBRich

We had this problem in our 06 19' Bambi...in cooler weather it would not work at all (usually in the middle of a cold night)...didn't so anything but freak out the dogs with its incessant clicking to try to start....then failing. We ended up replacing the gas regulator and that fixed it...it was not getting enough gas flow in cooler temps...but that is not the only potential reason...could be caused by low voltage to the igniter or by a stuck sail switch...among other things... It can be tricky to diagnose... Here's at least one thread about furnace malfunctions and quirks...and there are more in the subforms dealing with furnace issues... http://www.airforums.com/forums/f427...air-37962.html Good luck and be persistent...you will eventually find the solution, but it may mean some trail and error.

Thanx.

I ran across this on the 'net:

"Answer
The most likely problem is gas pressure. Do a quick check by simply lighting stove burners one at a time and watching carefully for a change in flame size in the other burners as additional burners are lit (if they get smaller each time, your pressure is too low). The valve can usually be diagnosed by simply listening or touching it - there should be an audible click. The fact that it does spark eliminates the limit switch. Check these items, let me know what you find... "

I checked the cook-top burners, as the answer recommends, and found them to all three stay the same size as far as I could tell. But I did wonder just how touchy the thing is on gas pressure and I think I'll have my gas man come out and check it and go from there. I do hear the click and I can see in my TV when it sparks.

[Mike Leary]

Is that a Suburban furnace?

[dogpound]

In addition to the regulator you might check the gas lines that go to the main line for the trailer. We had some problems with our 1998 unit by not having enough pressure and it turned out whoever filled the propane tanks prior to us had overfilled the tanks and the lines were filled with an oil which blocked the gas from getting to the appliance.

Good luck.

Bob

[Tim A.]

TBRich already gave you the link (http://www.airforums.com/forums/f427/furnace-blowing-cold-air-37962.html ) where I wrote about the furnace in our 2002 19' Bambi. From the sound of your problem (intermittent lighting), if the gas pressure is not the problem, the sail switch could easily be the culprit. After yanking out the furnace several times and replacing the sail switch, I have found that banging on the side of the furnace at the approximate location of the sail switch unsticks it and is as effective as replacing the thing. We happen to have an LP detector in a cutout just to the right of the furnace. That cutout is large enough for my hand and a screwdriver. The screwdriver's handle is just the right size and weight for the banging process.

We have not had to unstick the thing for about one year, but we are just now in West Yellowstone where overnight temperatures get low enough that the switch surely knows it can give us a hard time.

[HiHoAgRV]

If all else fails or checking the gas pressure is gonna be tough, check the voltage at the heater during the initial startup. My miss-fire problems were traced to a large voltage drop on the 12V and ground wires. The heater was only seeing around 11.8 volts and sometimes the gas solenoids wouldn't open, resulting in a misfire.

[Mike Leary]

Our furnace problems have been solved by first checking what all have posted, then
cleaning/replacing the ignitor then the board. With the Suburban, the boards last about
5 minutes.Dinosaur Electronics Home. High quality circuit boards for RV appliances.

[beerrun'r]

Gas pressure was low. 8.25" W.C. rather than 11". New LP regulator on the way!

[TBRich]

Originally Posted by beerrun'r

Gas pressure was low. 8.25" W.C. rather than 11". New LP regulator on the way!

Yea! Ain't it grand when you can figure out what the problem is! Another mystery solved. Now you can stay real warm on those cold winter camping nights...

Happy trails!

[beerrun'r]

Originally Posted by TBRich

Yea! Ain't it grand when you can figure out what the problem is! Another mystery solved. Now you can stay real warm on those cold winter camping nights...

Happy trails!

Thanx.

Indeed! We could only get pressure up to 10" with old regulator, but the furnace fires on the first try now.

Nowadays, when troubleshooting literally anything, the I'net is a real good first stop! "Somebody", "somewhere" has already 'been there'.