Dometic AC dissection for Noise reduction

[HABBERDABBER]

Originally Posted by cpaharley2008

My 2016 E19 and 2019 E21 have the same a/c and thermostat

So what is the model designation for the AC's?

[cpaharley2008]

I'm sorry I was giving you a starting point. Escape can give you the model Dometic 11,000 btu. I'll have to go out to find my paperwork but I'm under the weather right now,

[Bea]

Originally Posted by HABBERDABBER

So what is the model designation for the AC's?

Our 2019 21C came with a Dometic AC model # 640310CXX1C0 -Bea

[HABBERDABBER]

Originally Posted by Bea

Our 2019 21C came with a Dometic AC model # 640310CXX1C0 -Bea

Thank you for your efforts.

[rotorbudd]

Well I got the chance to take down the overhead and shoot a few pix.
I'll try to get up on the roof sometime tomorrow and get a few showing the rooftop unit.

I used a couple of different pieces. For most of the top side frame sections I used a foil backed heavy weight damper sheet. Just search Amazon for:::: Noico 80 mil 10 sqft car Sound deadening mat This is adhesive backed so just cut to size and apply.
I was trying to get the compressor vibs absorbed. It worked OK but I found a better solution that I'll explain with the top side pix.

For the interior I used the foil backed on the framing, and the rest of it is a lightweight sound absorbing sheet.::::::: 12 Pack Set Acoustic Absorption Panel, 12 X 12 X 0.4 Inches Grey Acoustic Soundproofing Insulation Panel This doesn't have a sticky back so I just used carpet tape.
This did a fairly good job of quieting the fan noise inside the trailer. It's not perfect, but It doesn't wake me up at night when the A/C kicks on like it used to. It also seems
low enough that it just becomes a background noise after a day or so.

There is still a rumble that is noticeable at both ends of the trailer when the compressor is running. Got a few ideas I'm going to try later to fix this.

This has done a great job on quieting the outside unit. It's almost unnoticeable if standing next to the trailer.

BTW I did something similar to my Honda generator and it seemed to work even better on it

[hrewer]

Thanks Rotorbudd.
Looking forward to hearing more.
We installed the Easy Start and that has helped a bit.

[Telescopist]

Originally Posted by Vermilye

I did add a Micro Air Easy Start to my 2017 21's Dometic AC even though it has the Dometic idea of soft start (separate fan & compressor starts). I don't have an amp meter capable of reading start up current, but it definitely has gone down. No more loud thump or temporary voltage drop when the compressor starts. It starts fine on my 2200 watt Sportsman generator (a 276' above sea level) running on propane, although it also started before the Easy Start addition.

I spit out some coffee which fortunately missed my keyboard when I saw the price of a Micro-Air EasyStart 364 Soft Starter ASY-364-X20-IP. $299 smackers?

Also there is some grumbling about performance issues I.e: Cool down time can be up to 2x longer?

[Ginger]

Originally Posted by tdf-texas

It wouldn't matter - the A/C Casita forum is working on is the Coleman Mach 8 which has different fan blades than the Dometic. If you wish to see it - here are some links:
Mach 8 hush kits
Mach 8 Hush Kit – The Handy Camper

BTW, the Dometic is much quieter than the Mach 8 - the Mach 8 sounds like a jet engine taking off.

Come on Tom, fix this noisy ac

[drjp]

Hi. I dimly remember, when this same question came up a few years ago, someone saying that we’re kinda stuck cause we’ve got a bunch of rotating parts in the AC turning on and off while basically floating on the surface of a big fiber glass drum (the roof). So unless you Really isolate all vibration, every buzz is going to be amplified a bunch. Make sense?

Made friends with ear plugs in the lower 48; it’s getting hotter by the year!
Jonathan

[dana mcdaniel]

Hi, We have a 2019 Escape 19. We noticed an old post of yours regarding quieting the ac unit. Our main concern is the vibrating hum caused by the compressor. Wondered if you found something to help with that problem. Thanks

[rotorbudd]

I was just up on the roof doing some fine tuning on the compressor isolation mounts. ( what a coincidence). This last experiment seems ti have gotten rid of the drumming I had when laying in the bed.
I'll take a few pix and post them this afternoon.

[dana mcdaniel]

Hi, Thanks and we are happy of the coincidence that you are presently working on this very issue. Any tips or direction would be greatly appreciated,

[rotorbudd]

Here's some pix of the rooftop unit.
The silver and gray pieces are for soundproofing. same as used on the interior.
The vibration asorbers are just stacked isolators made of softer silicone rubber that replaces the hard rubber. I just stacked them to the height shown. You will have to enlarge the hole in the original top rubber so the small tubular silicone rubber tube fits inside it.
One caution, make sure NOT to kink the copper lines to the compressor. Just lift it enough to remove and install the vibration asorbers.
The reason I was on the roof earlier today was to change out to softer absorbers. The ones I had on earlier still had some drumming. so I went to the next softer set. That got rid of the noise in the forward end.
BTW I also isolated the fan motor. Let me know if you're interested in that project.

[Chris R]

Originally Posted by rotorbudd

BTW I also isolated the fan motor. Let me know if you're interested in that project.

yes please, anything to quiet the jet engine.

[Craiger]

In my previous life I was a tooling engineer. When you create noise/vibration in a machining application. You have to start changing the tool, the set up, the machine type or the fixturing. This can be taken to any application where you have a problem with noise. Experimentation with various materials to change the frequency of the vibration. Is the goal. By changing the hard rubber to a softer material you will wind up changing the frequency of the vibration. you keep experimenting until you reach a level of noise/vibration you can live with. This is the short and sweet of a one hour class I used to give.

[rotorbudd]

Originally Posted by Chris R

yes please, anything to quiet the jet engine.

Adding soundproofing to the interior section of the A/C will get you the largest gain as far as fan noise goes. Just pull down the inner cover and start adding insulation like I showed in an earlier post.
Isolating the fan motor should be done second because it won't be noticed if you haven't already done the interior.
But I'll get some pix of the motor ASAP. It's just adding some silicone spacers under the mounts. Kind of hard to get to.

[dana mcdaniel]

Hi, Thanks again for the information. We’ll look into the Isolateit info and look for proper silicone stacked washers. We have not yet pulled the top off of the unit so the photos will make a lot more sense once we are more familiar with the construction of the ac.

[Gasguy]

I put similar sound proofing on the inside of the outside Maxfan shroud. It cut the ambient noise from the outside quite a bit when closed. Mainly needed at noisyRV parks,

[cpaharley2008]

I find as I age I have become hard of hearing, no noise reduction needed here..........

[dana mcdaniel]

Removed the ac cover this morning to compare our set up to the photos. So, if I understand you replaced the existing cushion washers with softer ones from Isolateit. I looked those up and found three levels of density 30,50,and 70 with 30 being the softest. So, I suppose softest might be quietest.

However the current cushion washers seem soft. These are approximately 1” tall and secured by a metal washer and cotter pin on top. No hard rubber anywhere I saw. Wondering if this system has been in use for a while or if this is a change Dometic has made in the last few years ( our trailer was completed 12/19) in order to try to quiet the compressor rumble. If these stock cushion washers are softer than those previously in use, swapping them out may have little effect. If rotobudds set up is as I have described on our ac I’ll give the washer replacement a try.

Hoping I don’t have to depend on long term hearing loss as the solution. Maybe we are just too sensitive to noise. A real possibility.