Atwood furnace won't ignite

I had the board tested at the dealer and checked out good.

I pulled out the burner assembly and there was a large chunk of buildup on the electrode and burner. It was hard but crumbled. I cleaned it out but it still isn't working properly.

I can hear it spark and no longer smell propane. The burner runs for about 15 seconds then the gas turns off. Is there a sensor fouled by the soot?

I think the problem was initially caused by recirculating carbon monoxide. The heater is near the wall of a deck. It gets airflow but probably not enough. I don't normally use my heater much but temps dropped into the 30s over Christmas & New Years.

I took pictures of the alien life form and will post when I get home. I don't get cellular service at my RV so I'm on the side of a road right now.

Thanks for the help.

93ToyTruck wrote:
I had the board tested at the dealer and checked out good.
Snip

ToyTruck:

I had my board tested as well and it showed good but in reality the board was defective.

If your problem continues you might want to take a harder look at the ignitor board.

Your problem sounds a lot like mine.

BoonHauler wrote:

93ToyTruck wrote:
I had the board tested at the dealer and checked out good.
Snip

ToyTruck:

I had my board tested as well and it showed good but in reality the board was defective.

If your problem continues you might want to take a harder look at the ignitor board.

Your problem sounds a lot like mine.

Board Testers are NOT reliable. The OP cannot smell LP now in ignition cycle. THAT points to a problem either with the orifice being clogged or the Gas Valve is not energized or is sticking closed. Which a new board will NOT fix. FYI, It is RARE to replace a Furnace or Water Heater Control board. They ARE that reliable. It is usually another control part or dirty appliance that is the cause of malfunction. Doug

I think you're right about the board.

These are the chunks that built up on the burner and electrode:

That's a wasps nest!

Wow, that is a wasp's nest.

What does the exhaust pipe and intake grill look like? .... Pic?

I've had to modify my exhaust pipe in order to get it to install properly. The exhaust pipe outlet now has screen in it just for that same reason. I'm going to install screen in the combustion air intake as well when I reinstall the furnace.

I had a long conversation with Atwood this morning regarding my issues. They've gone ahead and authorized me to return the entire unit for inspection/analysis so I'll keep you posted as to the out come.

The intake is 1/4" squares in steel. The exhaust is 1 1/2" pipe with a small piece of steel across the center of the opening. The could go in either way.

I've had the RV for 5 years and the nest must have been there when I bought it. I would know if there was wasps flying a few feet from the rv door.

I'm going to try replacing the electrode before the board. The troubleshooting guide says that the board senses the current draw to determine if it should go into lockout state. A new electrode is $7 on eBay so it's worth a shot. The nest was attached to the electrode.

Boy that does look like there has been a combustion issue, sooted up bigtime.

ToyTruck:

Any updates on your problem? Please let us know what the fix was.

Thanks

I'm going out this weekend to try a new electrode. I'll let you know what I figure out.