Atwood furnace

Glad to hear about a problem getting fixed and an education along the way.

I've had ants, birds, wasps and moles rob my wallet and fry my nerves many times.

49ford wrote:
I got the furnace working. After failing to take it completely out of the RV. I started taking every screw I could reach out of the furnace. On the right side of the furnace is a small spiral housing that eventually came off and out. It had the fan motor and squirrel cage fan and a small blower fan on it. On taking it out, I saw a mud dauber nest completely blocking the inlet. Cleaned it all out, checked the sail switch while I was in there. Put together and it worked.

Cautions. Don't try to pull the unit out from the inside by cutting around the exhaust flange. You will have stuff to fix.
Put a BUG SCREEN on the furnace outlet, not door screen, a slightly larger mesh screen for the RV furnace.

I hate mud daubers! But I know a heck of a lot more about furnaces than I did a month ago.

Thanks for letting us know that you found the problem.

I got the furnace working. After failing to take it completely out of the RV. I started taking every screw I could reach out of the furnace. On the right side of the furnace is a small spiral housing that eventually came off and out. It had the fan motor and squirrel cage fan and a small blower fan on it. On taking it out, I saw a mud dauber nest completely blocking the inlet. Cleaned it all out, checked the sail switch while I was in there. Put together and it worked.

Cautions. Don't try to pull the unit out from the inside by cutting around the exhaust flange. You will have stuff to fix.
Put a BUG SCREEN on the furnace outlet, not door screen, a slightly larger mesh screen for the RV furnace.

I hate mud daubers! But I know a heck of a lot more about furnaces than I did a month ago.

Is it the Solenoid. They get weak and kick off.

Still not lighting.
I ordered a manometer to check gas pressure. Got impatient and bought a gas regulator and installed. Nice fat blue stovetop flame but no furnace lighting.
I checked ignitor gap, 1/8 inch not 1/4, shined up probes. I even took a video of the thing arcing. If I can figure out how to get it off my phone.
Not recommended, but, with ignitor out I turned on furnace long enough to get my ear down by the unit and you could literally hear the gas going into the burner. I only ran it several seconds, not a full cycle, and then turned it off.

Could just be that its an Atwood

Did you ever get the problem fixed ?

I pulled burner out, cleaned out chamber area and round tube beside it of ladybugs. I checked burner, it was clean. I pulled orifice out of gas valve unit, it was clean. I applied 12 volts to solenoid and it snapped and let air go through. I had circuit board tested, it was ok. There were no visible cracks on igniter porcelain, it had a brown area on it.
Now what?

Ok. Monday and I got the ignitor out. Its gray not sooty. It has a gap about 1/4 inch between electrodes. Is that right? I messed up and lost part of white hi temp gasket so am dead in the water for now. Looking in the chamber I saw nothing. No mud wasps or critters. I really didn't want to but is it necessary to completely dismantle the gas chamber assembly to fix these things?

thanks for explanation. It'll be Mon afternoon before I can get to the rv to work on it.
thanks again