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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a central air conditioning unit with a Copeland

Customer Question

Hi, I have a central air conditioning unit with a Copeland CR42K6-PFV-130 unit that was working this morning! When I came home after running some errands I noticed the air wasn't as fresh and the humidity and temperature above the set points. I have a Nest thermostat, and was able to be outside when I lowered the thermostat... the fan comes on, but the compressor doesn't engage. I was wondering how I can troubleshoot to determine if the capacitor needs to be replaced or if there is additional issues. I would appreciate some assistance. Thank you. Dom
Submitted: 2 years ago.
Category: HVAC
Expert:  Phil replied 2 years ago.
Hello,If you heard the compressor try to start, with a heavy humm, then quit humming after 2 or 3 seconds, then the run capacitor might indeed be bad. If you heard on humming then it is not a capacitor problem. You will need a clamp around type amp meter to do the necessary testing. $25 at Harbor Freight, and $59 or so at Home Depot or Lowes.. this will have the needed multi meter functions on it as well. Next take a photo of the outside unit with the cover off over the controls section, and a photo of the wiring diagram glued to the inside of that service panel, well focused, close up, and straight on...use the paper clip icon at the top right. I can mark those photo's up with trouble shooting instructions and coach you from there. .
Customer: replied 2 years ago.
Hi Phil,
Appreciate you getting back to me. I do not hear the compressor attempt to start when calling for cooling. The fan spins up but compressor is silent.
I opened up the panel and snapped a picture of the wiring but there is no wiring diagram. There was a parts chart on the panel and There is a document rolled up but couldn't access it at the moment. Getting a thunder storm right now.I was able to snap a quick picture of the wiring as well as the model labels on the system before it started lightening but not very useful.
Awaiting further instructions.
Expert:  Phil replied 2 years ago.
Thanks,From the look of the wiring on the run capacitor, the unit is pretty old, next step is to visually inspect the 3 wires attached onto the compressor itself, under a plastic cover or metal box... inspect those for signs of over heating or having burnt off.Do that with the power OFF to the unit, use the disconnect on the wall, verify the power is off with a volt meter. To go further you will need a multi meter... or better a clamp around type amp meter Take the picture of the control panel wiring from about 4 feet away so that I can see all of it please.the rest of the wiring should be in the same compartment as the run capacitor you send the picture of. I will be in for another 5 hours this evening, then back all day tomorrow from 7 am to 10 pm on and off. We can go from there.