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Old 06-02-2021, 03:36 PM   #1
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My A/C quit cooling/drawing half amps

My 3 yr. old Coleman Mach 3 Plus ultra low profile ac suddenly quit cooling. And yes, I checked all breakers, including my power source, which are all good.

The inside and outside fans are working, but seems too quiet for the compressor to be running. My initial thought was bad capacitor, yet - it still draws 6-7 amps rather than the usual 11-12 amps.

When the compressor is not running, the fan-only mode is still the typical 1 amp draw. If the compressor is somehow locked, it should be pulling really high amps. If it lost freon, would that cause the compressor to run more easily and result in reduced amp draw?

But the roughly 1/2 normal draw is baffling. What should this be telling me?
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Old 06-02-2021, 04:32 PM   #2
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Sounds to me like you have lost your refrigerant. The compressor is not working against a load, so draws less current. I agree, though, that half the amp draw feels unexpectedly low. But, just to be sure, you need to confirm that the compressor is actually "running." This may require taking off the shroud and putting a hand on the compressor, since you aren't hearing the compressor sound that you are used to.

good luck!
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Old 06-02-2021, 05:03 PM   #3
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Originally Posted by Belegedhel View Post
Sounds to me like you have lost your refrigerant. The compressor is not working against a load, so draws less current. I agree, though, that half the amp draw feels unexpectedly low. But, just to be sure, you need to confirm that the compressor is actually "running." This may require taking off the shroud and putting a hand on the compressor, since you aren't hearing the compressor sound that you are used to.

good luck!

Oh man, that's what I'm afraid of. And the system has no service ports for adding refrigerant (just the crimped/soldered lines I saw during install). Should have sprung for the extra 3 yr. warranty, but didn't think it was worth the extra $89 at the time.


But now in hindsight . . .
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Old 06-02-2021, 05:35 PM   #4
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I would confirm that the compressor is/is not running before you assume you've lost your charge.



If you've lost the charge, it can be recharged it's just a matter of cutting the crimped copper end and brazing in a service port, any competent hvac tech can do it. Then replacing the filter dryer (if there is one), pulling a vacuum and weighing in the correct refrigerant charge.


If you go that route, get a quote before you do it. Depending on #hrs labor they quote the job will take and parts you may be bouncing on the price of a new one anyway.
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Old 06-03-2021, 10:35 AM   #5
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It would be very easy to rule out your capacitors and compressor with a simple multimeter check.
https://youtube.com/playlist?list=PL...-xzIIGXDm7i4pL
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Old 06-03-2021, 10:40 AM   #6
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Originally Posted by 88Limited View Post
I would confirm that the compressor is/is not running before you assume you've lost your charge.



If you've lost the charge, it can be recharged it's just a matter of cutting the crimped copper end and brazing in a service port, any competent hvac tech can do it. Then replacing the filter dryer (if there is one), pulling a vacuum and weighing in the correct refrigerant charge.


If you go that route, get a quote before you do it. Depending on #hrs labor they quote the job will take and parts you may be bouncing on the price of a new one anyway.
Plus , you need to repair a leak. Doesn't sound good.
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Old 06-03-2021, 10:44 AM   #7
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We had a similar condition with our AC in our 2013 Airstream Interstate. I was afraid of a catastrophic failure of the AC system. But somewhere on the forum a saw a suggestion to reset the wall mounted thermostat. So I pulled out the manual followed the directions to the letter and It worked. We now have our AC back. Try it. cheaper than a new AC unit.
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Old 06-03-2021, 11:06 AM   #8
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Ac

A refrigerant leak usually will leave a trace of oil residue where the leak is.
A bad valve could cause low amps.
Hopefully you can reset something.
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Old 06-03-2021, 01:04 PM   #9
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Quote:
Originally Posted by Buckless View Post
A refrigerant leak usually will leave a trace of oil residue where the leak is.
A bad valve could cause low amps.
Hopefully you can reset something.
A bad valve,hmm. Is this a heat-pump or AC only, no heat?
If heat-pump try on heat.
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Old 06-03-2021, 05:31 PM   #10
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Quote:
Originally Posted by 88Limited View Post
I would confirm that the compressor is/is not running before you assume you've lost your charge.
I had my wife start the ac from the inside while I stood on the outside. I confirmed the compressor was starting, but I also heard a noise I hadn't heard before. Kind of a low, quick clack-clack-clack-clack-clack just for a second or two as the compressor spooled up.

If you've lost the charge, it can be recharged it's just a matter of cutting the crimped copper end and brazing in a service port, any competent hvac tech can do it. Then replacing the filter dryer (if there is one), pulling a vacuum and weighing in the correct refrigerant charge.


I got a call back from my home ac guy who confirmed that low refrigerant could lower the compressor work load and draw less amps than usual.

If you go that route, get a quote before you do it. Depending on #hrs labor they quote the job will take and parts you may be bouncing on the price of a new one anyway.


I agree. Probably pricey, a month wait to get anyone to look at it, and then no guarantee how long it would work.
Quote:
Originally Posted by BigTexRex View Post
It would be very easy to rule out your capacitors and compressor with a simple multimeter check.
https://youtube.com/playlist?list=PL...-xzIIGXDm7i4pL

I watched two videos of this guy (one for my Mach 8 model but slightly older unit). He does a thorough explanation of his work. But in both cases he ended up replacing the units.


Quote:
Originally Posted by RON NICKELS View Post
Plus , you need to repair a leak. Doesn't sound good.
Yeah. Even the guy in the above video decided the unit he was working on lost refrigerant, yet he found no signs of oily residue which he said is usually present.


Quote:
Originally Posted by BoatNutG2 View Post
We had a similar condition with our AC in our 2013 Airstream Interstate. I was afraid of a catastrophic failure of the AC system. But somewhere on the forum a saw a suggestion to reset the wall mounted thermostat. So I pulled out the manual followed the directions to the letter and It worked. We now have our AC back. Try it. cheaper than a new AC unit.

Mine's an analog unit with no reset that I'm aware of. Is yours digital?


Quote:
Originally Posted by Buckless View Post
A refrigerant leak usually will leave a trace of oil residue where the leak is.
A bad valve could cause low amps.
Hopefully you can reset something.
See my reply to Ron Nickels & Boatnut above.


Quote:
Originally Posted by Wazbro View Post
A bad valve,hmm. Is this a heat-pump or AC only, no heat?
If heat-pump try on heat.


Mine is an ac-only unit.

Thanks to all who responded, see bold above.


PPLmotorhomes had a very few Coleman Mach 8 Plus low profile units in stock when practically everyone else's sites showed "out of stock".

I bit the bullet and ordered their last 13.5K for $950. Ouch for the second time in 3 years.
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Old 06-13-2021, 08:57 AM   #11
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Installed the new ac yesterday and all is well.


I removed the cover on the old unit for a quick autopsy and found only a small (an I mean 50cent sized) area of light oil on the compressor. Would have expected more signs of freon leak, but like the youtube rv mechanic's video, he found little sign of refrigerant leakage on a unit he diagnosed as losing its' freon.
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