My fan on my A/C compressor unit seems to start and even spins up to a reasonable speed, although not quite the speed at which it ought to spin, but then 5 seconds later slows down to a very low speed where you can almost see the individual blades. The run capacitor was clearly blown (the top had mushroomed) so I replaced it. However, that did not solve the problem at all. In fact, the pattern I just described did not change at all.
Should I replace the start capacitor as well? (I'm kind of doubting it since I would guess that a faulty start capacitor would prevent it from starting in the first place.) What else should I try before I call an expert?
Best Answer
Have you checked the actual voltages feeding the fan motor ?
You should use a volt meter , measure both at the contactor(both in & out sides) and the motor. I would like to know L1 to Neutral , L2 to Neutral and L1 to L2 as there is a slight possibility your actual Circuit Breaker is "broken" on one leg where you might get a reduced connection and thus not enough current passing.
Have you cycled your Circuit Breaker Off/On in your service panel ?
Also when you replaced the capacitor was it a dual fan/compressor type ?
Or Start/Run type ?
What this looks like is that your fan has a start capacitor and that gets it going but your run capacitor is not working.
Please post your Model number, I know it is a carrier - inside the panel there should also be a wiring diagram - post a good picture of that if you will.