Atwood furnace with intermittent lockout and NO ACCESS DOOR!

Thanks for the quick reply.

I'm running on shore power. And I'm definitely under the impression that I'm getting less airflow than I did initially.

Now, how I understand it, if the sail ever fails to register air flow the furnace will shut off. Wouldn't you expect that sometimes the furnace would shut off mid cycle if that were the issue?

The model is 8520 IV.

Thanks for any help you can offer.