Atwood rv furnace only ignites if exhaust port plugged

[minihoser]

Hello,

I have a 97 RV with an atwood furnace #8531. Had dang mud dauber in exhaust port. Cleaned with air compressor, a few chunks of dirt came out. Pounded on exhaust pipes.

Still will not ignite on own. I hear the whoosh and clicking a few times. I can smell gas.

Strange thing is if I block the exhaust port. It will ignite and stay working. Felt air warm up. A soon as I uncover the exhaust port the flame will die and air cool back off. I have to plug approx 80% of the exhaust air for it to stay running.

Any suggestions are appreciated.

[azrving]

Try some of these.

Videos

[minihoser]

Can it be cleaned without removing the whole unit?

Any instruction available.

Thanks for the help.

[Chris_Bryant]

The burner needs cleaning.