Atwood Model 8940-III-DCLP L/D wont stay lit

[Jrmay]

I have a Atwood Model 8940-III-DCLP L/D in my 2014 Jayco that has always performed flawlessly until just recently. When I turn the thermostat on, the fan kicks on and blows for 20-30 seconds. I can then hear the ignitor and gas value kick on and the furnace lights for maybe 2 seconds and then you hear it kick back off.
I pulled the exhaust tube out thinking perhaps either wasps or something had made a next, but the tube is perfectly clear.
At this point I am thinking I may have a bad control board but wanted to see if anyone in here had any thoughts before I spend the money replacing something that is not the problem.

Thanks,
Gary

[OldWEB]

There is a LED on the control board, it should help you.

[Jrmay]

OldWEB

How long will these flash? The way my furnace is mounted, I will have to pull and spin it around in order to see the control board.

Thanks

[OldWEB]

Are you checking it from the outside?

[Old-Biscuit]

Spark Electrode provides high voltage for ignition of gas AND is also the return path for Flame Proving System
Dc Current is sened by circuit board....this milliamp current generated by the flame PROVES gas is ignitied

Your spark electrode is issue
*Dirty/soot-carbon ....stops the milliamp signal
*Bad high voltage wire connection or wire
*Ceramic Insulator cracked...milliamp goes to ground
*Spark Gap too wide/too narrow


Need to pull the burner assembly and check electrode

See pg 25 & 40
http://techsupport.pdxrvwholesale.co...anual-2007.pdf

[Jrmay]

OldWEB

The way mine is mounted in the trailer what is showing in your picture is flush to the outside wall. In order to see the side of the circuit board that has the LED, I have to pull the furnace and spin it around. I assume once it throws a code, the code stays until the furnace reset switch is flipped or power is lost>

Thank you.

[Jrmay]

Thank you Old-Biscuit. I will try taking a look at the spark electrode the next time I am there. It looked quite challenging to get to so I didn't explore that deep into it this past weekend.

[OldWEB]

Originally Posted by Jrmay

OldWEB

The way mine is mounted in the trailer what is showing in your picture is flush to the outside wall. In order to see the side of the circuit board that has the LED, I have to pull the furnace and spin it around. I assume once it throws a code, the code stays until the furnace reset switch is flipped or power is lost>

Thank you.

I am confused....
Can you not access that side from the outside?