Air Conditioning - condensor fan start capacitor?

Installed new Goodman a/c units about a year ago. On one of them (downstairs), condensor fan was found within a couple days not to be spinning. Replaced start capacitor and worked fine ever since. About 10 days ago, found fan not spinning on other unit (upstairs). Replaced capacitor and worked fine until now. Replacement capacitors have been exact same brand/model as came from factory. Gave fan a prod with a stick and spun right up. So, start capacitor seems bad again, but have not replaced it yet.

I'd hate to keep going through capacitors if there is another underlying problem. But maybe I got a bad batch/brand capacitor. Any input on how to diagnose/test? Or does anyone know the answer w/o having to diagnose/test? Thanks.

These are not likely "start" but "run" capacitors. If they are the dual type caps (3 sets of terminals), replace them with individual caps for the fan & compressor and your problem will dissapear. While you are at it, replace the wire going from the contactor to the capacitor with a heavier wire. Goodman is bad about this particular problem.

If I go to separate condensor and fan capacitors, how do they spec out? I think uF is the spec, right? Would there be different specs for the fan vs. the condensor?

The ratings should be marked on the capacitor. An example would be something like 35/5 uF, 370 volts. In this example the 35 would be for the compressor & the 5 for the fan motor.

I had to change a 4 month old capacitor under warranty yesterday. I don't know why but it seems we have more capacitors failing within the last few years. Not comparing them to the old pcb filled ones but to caps from the last 15 years or so.

Jeff, remember that the parts on a Goodman are warranted for either 5 or 6 years so it shouldn't cost.