Coleman Mach 10

[edlynnrich]

We picked up our new 21C on May 11 in Sumas and are slowly making our way home. We tested and used all the systems except the AC in the first four weeks of travel. We have now caught up with the heat wave that has spread across the mid-west. Using the AC for the first time and it is working great at 95* temps. However when the compressor kicks in there is an audible thump and we can feel the trailer shake. Is this normal for the Coleman Mach 10? This unit is supposedly the soft start model.
Ed

[uthorns]

We have the Coleman Mach 10 in our 2021 5.0 and use it all the time in Texas. It's not the soft start that I know of but haven't noticed any thumping or shaking when it starts. I do run the unit on cool low or high, not on auto cool so the fan runs all the time and doesn't cut on and off. It's not loud to us and like it running continuously.

[edlynnrich]

Addendum
The thump and shake seems more pronounced when the compressor shuts down.

[cpaharley2008]

Yes, it is normal.....

[sofmerc]

Originally Posted by cpaharley2008

Yes, it is normal.....

ugh... that doesn't seem normal to me.

[brroberts]

We have the Colman with soft start and use Auto Low when we use the A/C. It has never clunked. The last two RV’s had Dometic non soft start and they clunked hard. I wonder if you really got the soft start, or if it was accidentally omitted.

[sofmerc]

Glad I got the Houghton...

[Ooshkaboo]

Originally Posted by uthorns

We have the Coleman Mach 10 in our 2021 5.0 and use it all the time in Texas. It's not the soft start that I know of but haven't noticed any thumping or shaking when it starts. I do run the unit on cool low or high, not on auto cool so the fan runs all the time and doesn't cut on and off. It's not loud to us and like it running continuously.

Same here, I can hear the compressor kick on but its not way noticeable. But I like background noise when I sleep, also the heat strip works better than I expected.

[Rockhead]

Originally Posted by sofmerc

Glad I got the Houghton...

Same here on the houghton best $$$$ I’ve spent on our 21 super quite and cools it down better than the dometic did

[brroberts]

If it matters, our Coleman also has the heat strip, and we use it more than the A//C. I was skeptical the heat strip would work well, but it will over heat the 19 down to at least 15F.

[edlynnrich]

What should I look for to see if I have the correct capacitor that makes up the soft start.
We also have the heat strips and were impressed with how well they worked. We were initially skeptical. The furnace also works great now that we got the sail switch issue worked out, thanks to the most excellent advice from the fine folks on this forum. So far we have gone a max of six days without hookups and can easily go longer. We are happy campers!

[brroberts]

I wish I could help on the soft start. I’ve never looked at the Coleman. It has just worked.

I got it because it was much quieter than the Dometic, and I didn’t have to find a limited supply Houghton, nor self install it. I also avoided the Dometic digital thermostat I did not want. It’s a couple things on a long list I didn’t have to do myself.

The Dometic was simply so loud that at times I would sweat just to avoid the noise. We can have a normal conversation with the Coleman.

I do hope you find a solution to the clunk whether it’s no soft start, or something not secured correctly. I’d start with YouTube or the forum and open it up and look for obvious loose parts. I’d also verify your actual model number matches soft start on the manufacturer website.

[Crazypill]

Mine shakes the trailer a bit, kind of a shudder when the compressor kicks on or off

[BobG]

I have 2021 21NE with the Coleman Mach10 that has soft start. I run it on Low Auto Cool but do check the High Auto Cool once in a while. It is quiet and does not thump. I turned it on at bed time pretty much every day last March and April. I go to bed early. The fan starts first and then the compressor a second or 2 later. I leave it on at night and it has never woken me up.

[splitting_lanes]

We have the Coleman Mach AC with heat, and I can hear the compressor kick on and off. I thought I wouldn’t be able too with soft start, but it’s noticeable.

[BobG]

I should have been more forthcoming in my previous reply. I am hard of hearing and that may be why I am not bothered by the AC turning on and off at night. I do definitely hear the the fan turn on and then the compressor turn on even without hearing aids. Mine is not a thump like the Dometic AC.

[Vermilye]

Just a reminder - There are 2 kinds of "Soft Start". The least expensive is to add or increase the starting capacitor on the compressor. This is what Dometic does on their soft start versions of their Acs, and I suspect it is also what Coleman does.

The other type of soft start cost far more (a couple of hundred dollars) and consists of a microprocessor generated compressor starting current curve. Examples are Micro Air's Easy Start or Soft StartRV.

I doubt either Coleman or Dometic adds this type of product to their ACs, but a microprocessor controlled easy start device will eliminate the compressor starting thump and often allow 2K generators to power the AC.

[brroberts]

I’d also bet the Colman is a simple soft start, but my old (2002) Honda Eu2000i will run it at 1000’ elevation. I have not tried it higher yet.

[C-weed]

We have used our Coleman A/C extensively for the first time. Ours has a definite clunk on compressor start and stop. The clunk at compressor stop is louder than starting and shakes the trailer with a shudder. Clunk and jolt sounds like a broken compressor mount. Very annoying. I have compared model number and it is supposed to be a soft start. Starts up slow like I would suspect a soft start to do. I will have to remove the hood and watch it cycle. Maybe something is loose. But I would not think this is normal. I can sleep thru most things but this clunk/shake is very disturbing. Not a happy camper.

Picked up our trailer NOV 2022. Maybe this is a sign of covid era units...

[Rockhead]

Before I swapped out our dometic ac ( wind tunnel lol ) it did the same thing from day one. We installed a recpro houghton 9500. No more knocking and super quite