Community Forums

scottandanna · 03-25-2016, 11:35 AM

I need to clean off the adhesive from the old gasket, and put new gasket on, and I know some refrigeration compressors get messed up if you flip them over, and let the oil drip to the top.

Is this true for our A/C on the trailer, a Coleman Mach unit?

I don't really want to work on it upside down, if I don't have to.

BFlinn181 · 03-25-2016, 06:30 PM

As long as you don't turn it on immediately after it's been upside down I think you'll be fine. The caution about turning a fridge upside down is more for absorption refrigerators, not compressor run ones.

LINADR · 03-25-2016, 07:58 PM

Should be fine, as long as you don't run it for 24 - 48 hours.

scottandanna · 03-26-2016, 12:35 AM

Awesome! It will make it MUCH easier to work on it!

MnTom · 03-26-2016, 08:39 AM

Quote:

Originally Posted by LINADR

Should be fine, as long as you don't run it for 24 - 48 hours.

Exactly. The problem lies with the oil in the compressor. It can seep into the compression chamber. Since oil does not compress you stand a chance of breaking valves and possibly bending or breaking the connecting rod. If either of those things happen you need to replace the compressor.

BFlinn181 · 03-26-2016, 10:01 AM

Quote:

Originally Posted by MnTom

Exactly. The problem lies with the oil in the compressor. It can seep into the compression chamber. Since oil does not compress you stand a chance of breaking valves and possibly bending or breaking the connecting rod. If either of those things happen you need to replace the compressor.

Your identification of the oil as being the only issue that can shift on turning the unit upside down is correct, but the damage the oil could do is not.

I've never seen an RV rooftop A/C unit with a piston compressor. They are all scroll compressors, which have no connecting rods or valves. In a rooftop A/C unit it would cost more to remove and replace the sealed system containing the compressor, evaporator, and condenser, than buy and install a new A/C unit.

24 hours is the usual 'rule of thumb' for waiting after inverting an A/C unit. Thie oil is pretty thin and if it should return to the 'bottom' way less than 24 hours. The wait time is just to be absolutely safe you're not 'pumping oil.'

scottandanna · 03-26-2016, 10:37 AM

I just did the job, and realized that I didn't need to invert it. I was able to swap out the gasket with my wife holding it not even 90 on its side, just long enough for me to slap on the new gasket, maybe 30 seconds.

And since it was hot and humid working on it, I was able to run the machine while I was torquing down the bolts and reassembling the inside parts.

I just didn't want to even take a chance of screwing up the A/C. Can't live without it down here.