Hi all. This is my first post.
I am a refrigeration mechanic and am frustrated that I can't figure this problem out. It doesn't help that it's on my mother in laws heat pump.
Her system is a 3 year old R410a Heritage 15 American Standard electric variable speed air handler with 15 seer American Standard heat pump.
1) service call of lights flickering in house. When I arrive I notice that the start capacitor is very low (around 30 mfd). I replace and test the potential relay. Start windings drop out as they should. System runs great.
2) two weeks later they call me to say the lights are flickering again. I return to find the new start capacitor has literally blown up. Ohm out compressor windings and find 3.1, 2.2, 2.1. Suspect a Run to Start winding short. Replace compressor, potential relay, start capacitor, filter drier, and refrigerant. Start up and perform full system checklist. Everything is awesome.
3) today (about two weeks later) I go to their house to pick up my son and swing into the back yard to check things out with the heat pump. Rated compressor amp is 11.1. Actual is 8.9. I kill power to test the start capacitor and it measures 35-40 mfds. I restore power to the unit and it pulls LRA for about 2 seconds (56.7amps) before eventually starting up again.
What the heck is going on here? Any suggestions would be great.