Atwood A/C installation took 1 and 1/2 hours

[grubbyjeans]

Originally Posted by mmayville

.....Will upload pics this weekend. And it is soooooooooo quiet.

Pics or it didn't happen.

[SirDrake]

I just thought I would add some of my own observations when installing the Atwood Air Command A/C in my TrailManor.

I have a 2004 2720SL that had the infamous Coleman A/C that sounds like a hurricane.
It started leaking inside the TM last summer (looks like from condensation).
I attempted to clean the A/C unit on the roof and try and find the cause of the leak to no avail, so after reading through this forum and seeing the rave reviews of the Atwood, we decided to pull the trigger on the Atwood.

I used GrubbyJeans post as a guide (thank you!) and went to work on it the other night.
I spent 4 hours removing the old unit, cleaning the roof mount and putting the new unit in place (with the help of my nephew).
Then I spent another 4 hours last night getting the duct and plenum to fit on the inside!
Here is what I ran into...

The square hole that is pre-cut in the roof of my TM is "roughly" 14"x14".
I spent some time with my dremel and a carbide grinding bit shaving the edges to make the new Atwood duct fit (it is 14"x14").
Once I got that in, I measured and cut the duct extension to 2.25" (I later had to trim off a quarter inch after tightening the bolts down and it started to compress it).
I drilled the four corner holes for the hold down bolts (only had to drill through the thin plastic/fiberglass rooftop standoff piece as mentioned by others so I used a slow cordless drill, went through like butter).
Inserted the bolts and tightened everything down.
I have a torque wrench which I set to 5 ft lbs but I never got to that point as I tightened the bolts; it never triggered the torque wrench.
The Atwood instructions say to tighten the bolts to this spec OR until the bottom gasket is compressed to half it's size.
So I went with GrubbyJeans suggestion of tightening the bolts to the point where there was a quarter inch of space between the lip of the stand off and the A/C pan which achieves basically the same thing.

So I get everything mounted, wired up, and I install the plenum/control unit.
This is where I ran into an oddity...
The trim piece that is screwed to the ceiling that surrounds the A/C opening will not fit with the plenum installed!
It fits all the way around EXCEPT the side of the trim piece that faces the front of the TM has a "bump out" formed in it, I assume to direct air flow from the A/C.
Well this "bump" interferes with the plenum about a half inch!
So I pull the trim piece off to see if I can reposition it.
It looks like the factory cut the large opening that the trim covers a little cockeyed.
They cut more roof towards the rear and not enough in the front.
If they had cut it a half inch more on the front edge we would be good.

So I have two options:
Option 1: Cut a half inch off of the roof opening on the front edge and re-install the trim.
or
Option 2: Flip the trim around 180 degrees so the "bump" is at the rear of the A/C and re-install it.

I am thinking Option 2, thought not sure if switching the "bump" to the rear will adversely affect air flow. Probably not.
In either case, I have very limited room to attach the trim on the rear edge as moving it forward brings it closer to the opening (very narrow edge to sink the screw into).
I have some pics that I will post later.

Like I said, I thought I would share my experience in case others have run into this and have some advice or just to give a heads up for other future A/C DIYers.

~ John

[SirDrake]

Just a followup on my AC replacement...

I ended up flipping that trim ring around 180 degrees.
I had to reposition it on the ceiling and drill new screw holes but it works!
And no real difference in the air flow.

We used it for a couple of trips this summer as it was hot and humid.
And I have to say we are very pleased with it it so far.
It is quiet, cools the rig down pretty quick and maintains temperature (it will actually freeze you out if you set it low enough!).
We even used it in auto mode one weekend as it was hot during the day but got cool at night; the A/C kept it cool during the day and the heat pump kicked in over night and took the chill out!

I can't recommend this unit enough, and it was pretty easy to install (except for the trim ring issue, which worked out in the end without incident).
We definitely DO NOT miss the old Coleman hurricane machine, ha ha.

~ John

[simoesxp]

It is 2024 and I am in the market for a new AC - contacted Dometic because the Atwood model mentioned here is discontinued. Here is their response:
“
Thank you for contacting Dometic. We do not have decibel ratings on our units. The Air Command has been discontinued. The FreshJet is currently our quietest unit, however this is currently only offered as a cool only air conditioner. The Penguin would be the current recommended option if you wish to have a heat pump installed. “

Other TM owner installed the Coleman Mach 8 not sure how much quieter it is. The search continues …

[Bill]

If it is going to affect your choice of units, be sure you understand the difference between a "heat pump" and a "heat strip".

A "heat strip" is a simple electric heating element, the same thing you would buy at some place like Walmart for $20, but mounted inside the air conditioner enclosure. They generally consume about 1500 watts and provide about 5000 BTU of heat - a rather small amount. In the world of air conditioners, these are often called Chill Chasers, because they can't do any serious heating.

By contrast, a "heat pump" is a completely different animal. It is an integral part of the air conditioner's cooling mechanism. For the same electrical power consumption, it can produce a good deal more heat. It will also cost a good deal more, and limit your choices.

Still reading? Our TM air conditioner came with a Chill Chaser. We don't use it, and not only because of the small amount of heat produced. The other reason is that, being built into the air conditioner, it uses the air conditioner fan, which is noisy. A better solution for us was to buy one of those $20 portable electric heaters. It is small, sits on a countertop, has three fan speeds and an adjustable thermostat, is very quiet, and can be aimed in any direction. Perfect!

A couple notes if you go the portable heater route. First, for safety, the unit should have an overheat shutoff and a tip-over switch. I think they all do, but check it.

Second, for $20 each, we bought two of them, for times when more serious heat is needed. We run one of them on an extension cord which goes under a Velcro flap and out to the campground power post. That way, they don't use up any of the 30 amp capacity of the TM 30-amp main breaker.

Third - you can buy fancy versions of the portable electric heater. They can be tall and skinny, they can look like a fireplace or an apartment radiator, they can oscillate. They can use words like "oil", they can say "ceramic" or "quartz", and so forth. Lots of cool-sounding but meaningless words. All of them produce exactly the same amount of heat, so save your money.

Your choice, of course.

Bill

[Darrowman]

Do you have a model number for this unit? Where did you buy it? Is there much weight difference in the 2 units? And finally, you mention your website, but didn't list it. Can you share it please.
Thanks!

[Shane826]

I don’t think it’s available any longer in the ductless model but it was the Atwood Air Command 15kbtu. Rooftop unit p/n 15026 (black shroud, there was a different number for white) and ceiling control unit 15021. Dometic bought Atwood and said they weren’t going to discontinue the Air Command line but they did trim it down. I think they still make the 13.5k btu model but you lose the heat pump function.

I have this A/C and absolutely love it. It was way quieter than the original Coleman Mach 3, and then we added a Soft Start and it’s about as close to silent as you’re gonna get with a ductless A/C. Worthwhile to search for a new old stock unit somewhere. Maybe Bontrager’s RV Surplus in Michigan?