varmints in the squirrel cage?

[nolatodfw]

I have a 2015 27' FB International Serenity. I was using it full-time from May to October 2017 and the heater furnace was working fine. I put the trailer in storage from mid-October 2017 until now (Jan 2018). Upon turning the heat on there was a noise, much like a card in bicycle spokes. It also sounds like a binding in the squirrel cage. I think varmints have set up house in my furnace. I cannot see inside the furnace but does this sound reasonable? Is it easy to remove the furnace and fix this or should I leave it to the dealer. My local dealer can only support me one month from now. Is this typical of an Airstream dealer? Can any RV repair shop fix this or should a trust only the Airstream dealer?

[twobikes]

Mud dauber wasps maybe? Do you have a screen over the exhaust? No, it ain’t easy to pull a furnace but most any qualified RV tech can do it.
I belatedly installed the little screen and periodically remove the random chunks of red clay that rattle out...

[garry]

X2 on the mud daubers.
You may not want to get involved with removing and reinstalling gas lines and voltage connections. Not a major repair just depends on your skill level.
Yes, any dealer can repair.