Dometic Air Conditioner Vibration
We've had our 2016 23D Flying Cloud for 2 weeks shy of a year, and have managed to exceed our goal of using it at least one long weekend per month, which is the Good News.
The Bad News is that last weekend we developed a MASSIVE vibration in the Dometic A/C unit. Couldn't carry-on a normal conversation inside. Outside, the unit was visibly vibrating and making 5-10 decibels more noise than usual. YIKES. We made an appointment with a Dometic dealer, and suffered through a four day weekend with the A/C sounding like a freight train.
Consulted various fora, including (GASP!) SOBs, where the opinion centered-on mud dauber wasp nests on the condenser squirrel-cage fan blades, which sounded WACKY.
Sent a note to our dealer up in Stephenville, TX, who also suggested the wacky Mud Dauber nest diagnosis.
Back at home, I dragged out the ladder, propped it on the zipdee, and removed the white A/C cover (4 Phillips-head fender-type screws). It took a minute to find it, but lo-and-behold there it was: a two-cell mud dauber nest near the outer end of the condenser squirrel cage, the single worst place to add an eccentric weight in the entire apparatus (as it adds a bending moment component to the mix)
Whole operation took about 15 minutes, a tiny fraction of the time I spent fretting about it up-front.
From what I can gather, and as weird as it sounds, this is indeed a relatively common problem along the Gulf Coast.
Hopefully I can save somebody from a bunch of panic, or worse, having to drag their Airstream into a dealer for such a simple fix.
One odd thing is that the fan motor shaft (a double extended shaft with squirrel cages each end, one for air handling and one for condenser) has a LOT of end-play in it, say 1/8" (about 3mm). I'm sending a note to Dometic to see if that's normal.