Coleman mach AC issues.

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pam and bill

Jun 19, 2007
My wife and I bought a 2008 Itasca Latitude in February 2009 and have lived in it full time, in or near Phoenix since then. We had to have a Compressor replaced a few years ago on the Coleman-Mach basement AC. It was a sealed system, on a model which was no longer made. There were no replacement AC units made which could be used in our rv. I found a shop in Mesa that could replace the #2 Compressor. They did and it worked fine until recently. Now, it's over 105° every day. The ac comes on and blows cold (69°) for an hour or so and then blows warm(97°). If I turn up the thermostat, shutting of the unit and then turn it back on in 30 minutes, it blows cold again. The process repeats.
As you are aware, Phoenix is having record heat. These are Recreational Vehicles, you might consider giving the AC a break during extremes, maybe find a pool to hang around.
Terrible to time to have problems with the a/c. We have some members who have knowledge about those basement air conditioners. I'm sure some will be able to help you trouble shoot the problem. Best wishes.
Hi Bill,

On our previous Horizon I replaced the hallway vent with a roof air for a few extra BTUs in the summer so you might want to consider that in the future.

Anyway, I'm not an HVAC tech but I do have some experience with the units. I had to pull the basement air on our Horizon a few times for various issues.

I'm guessing there's a high pressure (or low pressure) switch on a compressor that is tripping. Have a look at your basement air wiring diagram to see if they are there. If you do have these switches they will be plumbed in the high pressure and low pressure lines on one or maybe both compressors.

When the shop replaced the #2 compressor did you watch them? They had to add a service fitting (or simply a valve) to recharge that part of the system. The main point here is they had to weigh in the refrigerant and not just guess. The tank of refrigerant had to sit on a scale while they charged the system and watched the scale readout (after they evacuated, i.e. ran a vacuum pump for a few minutes). If they charged it with too much refrigerant the high pressure side will trip or not enough the low pressure switch will trip.

That's my best guess at this point for high ambient air temperature related problem. Of course it could be something else but I suspect the problem is something beyond your capability to fix yourself based on your post.
First thing I would do is check the condensers... They can get "Clogged" and need cleaning (Same for Radiators on cars) this is a "no cost" repair.

Also check the evaporator for icing. That's a tad harder to fix.

Had that problem at work turns out the Condenser fans were fried.
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