Dometic A/C unit bouncing!

[SMLJeep]

We have a 2017 FC 27" unit with the ducted air and we just arrived at a campground with the temp in the low 90's and when we turned on the A/C the unit was vibrating so bad you could see the inside ceiling below the A/C unit moving up and down. I immediately tuned it off and started to troubleshoot. First checked power, everything was OK. Then turned on just te unit in fan mode, vibration was the same so not the compressor. Took down one of the return vents to see if something was loose in the return, nothing. When to look at the unit outside it is vibrating up and down like it's on springs.

I'm thinking the fan has somehow gone out of balance. I don't have a way of getting on the roof to remove the shroud until I get home. Unfortunately I don't have a 30 amp service at home so other than making sure everything is bolted down I can't run the unit to see what is going on.

Anyone ever come across this issue?

Looks like I'll be going to the dealer (2.5 hour away) before we head to the international rally next month!

[CRH]

I do not have a 30 amp outlet at home. I run my AC on a wall outlet out of my garage. When I run it, I don't have anything else running in the circuit.

[DKB_SATX]

The first thing I'd check for a sudden onset of vibration like that (assuming it was working smoothly before, and had been sitting unused for a while) would be something like "mud daubers" building a nest on the exterior fan, especially since the vibration is the same in fan-only mode as it is with the compressor running.

[AWCHIEF]

Have you checked the mounting bolts for proper tightness? That was the culprit for vibration on my Bambi II.

[wulfraat]

If it's vibrating when just the fan is running then you can run it on 15 amps.

When you get home, plug in the trailer to 15amp. Get up on the roof and remove the shroud. Visually inspect the fan - perhaps it lost a blade? If it looks ok then head back down and turn on the fan only. (Fan mode, not AC or Heat pump). Head back up top and inspect while fan is running.

I'm guessing you'll be able to spot the problem without even having to run the fan.

Let us know what you find out....

[overlander63]

I had to remove a mud dauber's nest as big as my fist from the fan blades on a brand new unit last week. The entire air conditioner was jumping up and down, and so noisy it could be heard all the way across the lot.

[Taroni]

Take the cover off. Check for Dirt dabbed nest on fan blade

[Taroni]

Originally Posted by Taroni

Take the cover off. Check for Dirt dabbed nest on fan blade

Check for Dirt Dobber nest on fan blade

[Gneiss Guy]

Look around the campground for someone with a ladder. Knock on their door and look pitiful, while you tell them your story and then ask if you can borrow their ladder for an hour or two.

[SMLJeep]

We come home today and I found a mud dauber nest in the squirrel cage blower the size of 2 golf balls. Thanks everyone for the information, saved me some time and money.