Suburban furnace momentarily lights then shuts off

jdamude · Nov 21, 2015

We have a new 20164010RD and the furnace lights and blows heat but the burner will not stay lit. The burner keeps cycling on and off and has fluttering sound when it is ignited. I would go back to the dealer but they are 4 hours away. Can anyone give me hints on what I should be looking for?

danemayer · Nov 21, 2015

Hi jmadude,

You're in luck. Gary Brinck just gave us permission to post a furnace troubleshooting document that he wrote a few years ago. It's in our Troubleshooting Documents Folder.

If the blower keeps running but the burner cycles on and off, you may have overheating in the flame chamer caused by restricted airflow. Make sure you don't have any blocked registers, and that the outside vents on the furnace don't have anything blocking airflow.

RoadJunkie · Nov 22, 2015

A tech once told me the largest cause of furnace failure was wasp nests in the exhaust. He called them something else, like mud daubers, or something like that.

Dean-Pam · Nov 22, 2015

I learned at a young age from my Dad to always use a screen on the furnace outlets to keep "dirt daubers" out of the furnace...it only took once not doing this to reinforce his teachings.

klindgren · Nov 23, 2015

Dean-Pam said:
I learned at a young age from my Dad to always use a screen on the furnace outlets to keep "dirt daubers" out of the furnace...it only took once not doing this to reinforce his teachings.

It's amazing how smart Dad's become as we grow older isn't it Dean. I always said my Dad went from really dumb to very smart the first 6 months I was in the Marine Corps.

olcoon · Nov 23, 2015

I've got a screen on ours, and haven't had any problems. However, the people who make the furnaces, and people like the Terry Cooper the "RV Professor" says NOT to use them as they restrict air flow. Terry recommends putting a pet flea collar inside the compartment to keep flying critters out.

cookie · Nov 23, 2015

olcoon said:
Terry recommends putting a pet flea collar inside the compartment to keep flying critters out.

Roy, my thoughts are that the flea collar will reduce the area inside the exhaust or intake thus restricting the air flow, and that probably would be no less than using a screen.
And what happens to the plastic flea collar when the heat turns on? I know that on some frosty morning when I want to get warm I would not remember to go out and remove the dang thing.
I would rather go with the screen.

Peace
Dave

RoadJunkie · Nov 23, 2015

Dave, I don't think that the flea collar is placed in the exhaust but rather just in the compartment, maybe just lying on the bottom. Personally, I use the screen and don't seem to have intake air flow problems.

cookie · Nov 23, 2015

Yeah, I guess I read that wrong, Roy did say to lay it in the compartment.
But, the problem is the daubers or any other insect will nest and cause problems in the intake or exhaust, and since it is a sealed combustion system what good would it do to lay it in the compartment?
I have always used the screen.

Peace
Dave

Bob&Patty · Nov 23, 2015

Off topic a little. "I was surprised how smart my father got was when I turned 21". Funny how that works. I have adult children that still call for advise.

pegmikef · Nov 23, 2015

Bob&Patty said:
Off topic a little. "I was surprised how smart my father got was when I turned 21". Funny how that works. I have adult children that still call for advise.

Still off topic, I think this was initially Mark Twain's observation.

Jeeper · Nov 23, 2015

I'm not that familiar with RV Furnaces, but when my home furnace does that (a Comfortmaker unit), it throws a 3-4 (34) code, which means to check the Flame Sensor unit. On the home furnace, it's a single electrode which protrudes into the flame chamber. It'll fire up, burn for a few seconds, then shut down, since it thinks it's feeding gas with no flame...

One screw, pull it out, clean off the oxidation with some emery paper, rough up the place where it screws to the furnace, reinstall the screw. Usually resolves the problem. Since your unit is new, I'd wonder if it's a defective sensor, bad ground, or a bad wire. Was it working before?

JanAndBill · Nov 23, 2015

jdamude said:
We have a new 20164010RD and the furnace lights and blows heat but the burner will not stay lit. The burner keeps cycling on and off and has fluttering sound when it is ignited. I would go back to the dealer but they are 4 hours away. Can anyone give me hints on what I should be looking for?

Just went through an aggravating experience with ours. While the furnaces are pretty simple, there is no room around it to do any diagnostics. About the only thing you can do with the furnace in place, is pull the control board and have it checked. In the end I found it was easier to just pull the furnace and bench test. All you need is a 12 power supply, tank, and regulator. Most any shop that works on rv's should be able to bench test it for you for less than the fuel to drive 4 hours and back. Pulling the furnace isn't hard.

Pizzaguy · Nov 23, 2015

I had this issue on my first Bighorn and it was a bad LP regulator. Sounds like low gas pressure. One thing you could try, is to close the valve to your tanks for a few minutes, then SLOWLY open them up again. The new tanks have an OPD valve that can partially close off flow if opened too quickly. If that doesn't help, I would suggest trying a different regulator.

Suburban furnace momentarily lights then shuts off

jdamude

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danemayer

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RoadJunkie

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Dean-Pam

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klindgren

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olcoon

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cookie

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RoadJunkie

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cookie

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Bob&Patty

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pegmikef

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Jeeper

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JanAndBill

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Pizzaguy

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