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deprived · 12-09-2021, 11:55 AM

I have a compressor that won't run on a 2007-era Coleman Mach 3.

Here's what I've tested:

1: The cap is relatively new, about 4 months and tests good. I added a "Big Kick" capacitor but that also didn't change anything.

2: Tested resistance at the run/common/start posts and that test teemed to be good with the resistance between common-start and common-run adding up to the resistance between start-run.

3: Thermal switch had no resistance, there fore I think it's good.

4: Checked for 12v at the wire coming from the thermostat to close the compressor relay. There was 12.9V and when I connected the wire back to the control unit, I could hear the compressor relay close.

5: I swapped out the entire control board with the one from our other Mach 3. Still nothing.

6: No evidence of lost refrigerant or leaks.

Is there any other thing I can test before I can conclude that the compressor has had it?

Old-Biscuit · 12-09-2021, 12:43 PM

120VAC to Compressor??

Does FAN Start/Run??

deprived · 12-09-2021, 02:48 PM

Quote:

Originally Posted by Old-Biscuit

120VAC to Compressor??

Does FAN Start/Run??

Yep - 120 to the comp and the fan runs like gangbusters.

This is a puzzler...

Old-Biscuit · 12-09-2021, 05:07 PM

All components test good.....bad compressor motor which means new A/C Unit

ernieh · 12-09-2021, 05:10 PM

Starting load before the breaker on the compressor kicks off? My locked up compressor would show around 52a before it tripped, but it never tripped the breaker on the panel.

rollinghills · 12-09-2021, 09:53 PM

Are you indicating the switch is open or closed when you say "no resistance"? An over-temp condition (or defective device) will open a compressor's normally-closed thermal switch to cut power.

That'll keep the compressor from running.

RH

deprived · 12-10-2021, 07:08 AM

Quote:

Originally Posted by rollinghills

Are you indicating the switch is open or closed when you say "no resistance"? An over-temp condition (or defective device) will open a compressor's normally-closed thermal switch to cut power.

That'll keep the compressor from running.

RH

You're right, I was unclear! The circuit is closed.

deprived · 12-10-2021, 07:21 AM

Okay - I am not 100% sure but I think there might be a bad crimp on one of the spade connectors going to the control board (or something like that) because last night I buttoned the whole thing back up, threw the breaker back on and went to PPL to look at A/C units (which are mostly out of stock right now).

When I came back the AC was blowing cold and has been working fine since. It could be a fluke or some other intermittent gremlin I have not found yet.

I'll get back up there on Sunday and see if I can find a goofy wire going to the control box.