My 4 ton-unit AC compressor has been intermittently turning off. I replaced the old PTC hard start kit SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque with a new SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque. I also installed a new run capacitor 35+5 mf 440/370 Volts, thinking that the capacitor may be starting to fail. The air conditioner compressor kicked right on after the installation. I went upstairs to work on some things and noticed it getting hot upstairs, so I went outside and noticed the compressor was off again. Honestly I’m not sure if the compressor failed to start back up or if the compressor kicked off while it was still running when I was upstairs. I have attached a picture of the hard start kit I installed. Any tips or suggestions?

 

Is the compressor contactor still closed or is the compressor off on thermal?

 

The contactor is still closed to my understanding because the condenser fan is still running trying to cool the condenser. I know the condenserr is not on because hot air is blowing out of house vents, I can't hear it running and the thick line coming out of the AC unit into the house is not cold to the touch like it usually is. What do you mean when you say is the compressor off on thermal?

 

It means the compressor has overheated, and a thermal overload switch inside the compressor shell has opened.

 

How can this be fixed? What could be causing it that I can change, so it doesn't happen again?

 

First you need to verify that’s whats happening.
If so the cause will be electrical or a refrigerant issue causing the compressor to overheat.

 

How can I tell if it's overheating? What are the common electrical issues and refrigerant issues that could cause it to overheat?

 

Is there power to the peckerhead?
Wrong wiring, wrong start/run capacitors will do it.
Low refrigerant charge will also cause these problems.