Surburban Sf-30f furnace

[Degman]

We have a 2006 Sprinter, Copper Canyon fifth wheel and owned it since new. Furnace has worked well until the start of last fall. Prior to the trip I always test everything before going and ran furnace for about 1-2 hours of time and ran fine. Arrived at campground aound lunch and at dinner time turned on heat and furnace would not come on. blower yes, ignitor yes,heat no. 3 times then lockout, tried again and put hand over intake and furnace actually turned on, ran through cycle and upon start of next heating it would not start again, smell gas out of exhaust so i know its getting gas. used second heat source for that weekend. came home and cleaned furnace and it ran fine. Just went on first trip of 2013 and same problem occured with furnce, worked when temperature was 50 to 60 outside but doesn't work when temperature drops below 45 degrees. I have spent hours reading posts and researching and think the control board is the issue. looking for help

[Degman]

After cleaning furnace, went on second trip this past weekend and furnace did work but camper lights were constantly dimming when blower on furnace came on, and also when furnace shut off I could hear humming from converter and lights would dim for a little bit and then would go to normal, I think the problem is the converter because when plugged into my house im giving converter a true 30 amp connection, this problem only happens at campground so I think there is sub par 30 amp connection, any suggestions would be great.

[woodworker59]

With pig tails added one would relate the regulator at the tanks. I guess not. Oh well.

[Degman]

I have removed furnace and tore everything apart and cleaned it, it all looked fine, ran furnace and that also worked. I took tank out that i was using for furncae and attached it to my backyard grill. after lighting grill i could not get a constant blue flame, I had a lazy yellow flame on all three burners, I assume I might have had some bad propane which was over a year old in the tank. I will burn this out of tank and get fresh and retry furnace.

[Jerry_B]

Is the burner tube rusty inside? Rust will flake off and cause the orifice to clog up. Choking helps momentarily.

[oldbeek]

The gas valve, solenoid, is actually a finish regulator. Output at the jet should be 10.5 inch water pressure. But I would look at the spark gap.

[TimnJo]

Check the gas regulator/switch over at the tank(s). Mine froze up once, frosted up, ran hot water over and it was fine.

[enblethen]

What regulator on furnace? Are you talking the gas valve solenoid?

[Degman]

regulator on furnace?

[woodworker59]

Pull it out and bench test. If it runs right it is your regulator and/or pigtails. I had a problem with mine when temp dropped below 45 degrees. Hope this helps. Dave

[Degman]

thanks for all the help. pulling out this weekend and hopefully find problem

[TakingThe5th]

Degman wrote:
i will check electrode for gap and clean furnace and try again.

Look the burner and orifice over carefully when you clean it. Something as small as a spider web could cause the problem. Watch the gasket when you remove the plate, the gasket is fragile but reusable. Take it off before vacuuming otherwise it will be sucked up immediately.

[enblethen]

Check the electrcial connections. Pay close attention to the one on the circuit board.

[Degman]

furnace runs fine all the time it seems to be 50 to 60 degrees, any temperature below it, the furnace does not light, smell gas, here clicking, blower running but know ignition. i will check electrode for gap and clean furnace and try again. It's a cold weather problem only right now, and that's when it's needed the most.

[TakingThe5th]

Check all the registers, make sure they are not blocked either. Registers cannot be closed off.