AC Compressor Run Capacitor Question

[Leaky88]

Hi,

I have a Trane Heat Pump System. Today, we noticed the increased temperature, and I discovered
the Outside Compressor/Fan unit had stopped working. The Air Handlers were still pumping air
out of the vents - albeit hot.

I had this problem before and learned to keep spare Capacitors on hand.

So, I changed out the Run Capacitor and back comes the AC. All is good.

Just for GP I tested the Capacitor I removed with my Fluke and found the Farad readings to be within specs for both the Fan and Herm.
This surprised me, because the last time I replaced the Run Capacitor it DID NOT show good Farad readings.

What else, if anything, could have caused the Run Capacitor to be defective?

Granted, I am very thankful the AC is working again, just wondering why? Or is this just a case of PFM?

Thanks

Leaky

 

[bb29510]

pfm symplex, yes

 

[fitter30]

Wonder if there was a little corrosion between spade and terminal or wire connection at the spade either end.

 

[FredWanaker]

did you check the contactor and start cap too?

 

[American Locomotive]

There could have been corrosion between the terminals. Its also possible the fan motor was failing and turned off on thermal overload.