About 2 years ago, one of my 7 year old Trane heat pumps quit during AC season. Cap was bulged. Service guy replaced the dual section cap and all was well until today when the same one quit again. No fan or compressor running outside. Cap not bulged, but a little warm. I had bought two new caps, 35/5/440, after the previous failure. Installed one, outside fan runs, but even after a few minutes, the compressor is not running. So the other spare cap was installed. Running fine now. How often does one encounter a bad cap that has not been used before?
And if neither the fan or compressor is running, did the entire capacitor fail all at once? How frequently does that happen?