Dometic AC shudder, no shake...

[fieldphoto]

Ok, I know there is lots of discussion on the Dometic (and others) AC units shaking/vibrating... Some violently!!
This is not one of those posts.

My AC works pretty darn well. You can hang meat from the ceiling after about 15 minutes, even in the Oklahoma heat. It makes a little noise, but it isn't too bad- what I would consider normal (with my vast body of knowledge of 1 unit lol)
So, here's my question... The AC cycles, as it should. It will kick on and run for a few minutes, then cycle off... Repeat. There is little to no vibration or shake as the unit runs, however there is a very discernable "shudder" as the unit kicks on and off. It has even been known to wake me up in the middle of the night... Just a quick nudge before it hums along keeping me cool

So, is this normal? As I have no other baseline to compare, I don't know if this is just to be expected, or if it can be improved upon.

Thanks!!

[rbryan]

It's pretty common to have it shudder or thump when the compressor kicks on or off. And it can be helped with a soft start kit, like the ones from Micro-Air.

[Darral T.]

Look at your 13' Scamp as one huge "kettle drum". It's small and absorbing the entire vibration of the unit. I have a Coleman A/C and it too will wake me the first few times the first night I'm camping. (I get use to it as time goes) The ONLY way to stop it is detach it from the shell....not gonna happen. I wouldnt be "concerned" about it as far as being a defect or problem. Just consider it a nuance of the small 13'er.

Originally Posted by fieldphoto

Ok, I know there is lots of discussion on the Dometic (and others) AC units shaking/vibrating... Some violently!!
This is not one of those posts.

My AC works pretty darn well. You can hang meat from the ceiling after about 15 minutes, even in the Oklahoma heat. It makes a little noise, but it isn't too bad- what I would consider normal (with my vast body of knowledge of 1 unit lol)
So, here's my question... The AC cycles, as it should. It will kick on and run for a few minutes, then cycle off... Repeat. There is little to no vibration or shake as the unit runs, however there is a very discernable "shudder" as the unit kicks on and off. It has even been known to wake me up in the middle of the night... Just a quick nudge before it hums along keeping me cool

So, is this normal? As I have no other baseline to compare, I don't know if this is just to be expected, or if it can be improved upon.

Thanks!!

[fieldphoto]

Thank you both for your replies!!

Rbryan- love the idea, dont love the $300! its not THAT big of a problem.

Darryl- Sounds like the same for me, I dont notice it after a while, but since I am getting ready to get on top of the camper for some cleaning, I figured I would ask, in case there was some maintenance that could be done!

[Wayne Collins]

Any rotating machine, such as a compressor motor or fan, as you have in the A/C has a "natural frequency" The slightest bit of unbalance can cause a vibration.
As long as the operating speed is well away from its natural frequency it will not shake enough to be noticeable. But, as the unit shuts down, the RPM slows and passes through the natural frequency at which point the vibration is amplified.
You car engine may do the same thing. Pay attention as you start and stop the engine. there may be a momentary shudder there too.

[fieldphoto]

Wayne, that makes complete and total sense, thank you. I don't like the answer, when I am shaken awake lol, but I appreciate the science.

[Joe Romas]

Originally Posted by fieldphoto

Thank you both for your replies!!

Rbryan- love the idea, dont love the $300! its not THAT big of a problem.

Well then get the circuit board only for about half the cost. ($158)
It may require some creativity on your part it but your $$'s ahead.

https://www.microair.net/collections...nt=29181710923

I started this thread hear last year with lots of information. suggest you read it all for the most information.

http://www.fiberglassrv.com/forums/f...tor-76833.html


I have no connection whatever to Micro Air other then a totally satisified customer

Joe