Air Conditioning - Capacitor changed, still won't work

I had an A/C guy come out and diagnose my upstairs unit. He said that the capacitor was bad and that it would be $250.00 to replace it. I took out the old cap. and, sure enough, it was all puffed up on top like it had exploded internally. I bought a replacement, installed it and it still won't work. Neither the fan nor the compressor will come on (outside). The fan inside the house comes on but just blows warm air. I checked the breaker, it's OK. Any ideas?

$250 for a dual cap? Jeez, I'm going to come out of retirement, he he. You're 100% to 1000% sure you wired the new cap properly? Can hear any noise from the fan or compressor motors? Do you have 240 volts at the outdoor unit? How does the contactor look? Do the contact points look burned/overheated?

I'm sure I wired it right, not only did I photograph it with my cellphone before I disconnected the old one, I matched up the terminal names when reattaching the wires. I have 240 volts, not sure about hum (lower unit is right next to this one) and I'll check the contactor tonight.
Yeah! $250.00 to change a capacitor. Probably cost him $5.00 Not bad for 15 minutes work.

Did you check the disconect?

Yes I checked the disconnect. My first thought at your question was "do you think I'm stupid" and my second thought was "good question".

My next question is, did you kill power when you changed the stat?

I haven't changed the thermostat. What did you mean?

Thanks for your help. The thermostat was put in when the house was built 33 years ago. I'm going to get a new one this weekend.


Thought maybe you changed it already, at this point you are going to need a meter, need to chk for both line and low voltage at cond unit.

Are you comfortable doing that?

Oh, no, these are two different units. The (possible) thermostat problem is with my downstairs unit (Are you smarter than my A/C guy?). The capacitor problem is with my upstairs unit (Capacitor changed, still won't work)

OK, thought maybe you changed it and didn't kill powe first which many times results in a blown transformer.

So we are back to the do you have a meter?

If so chk incoming line voltage at the contactor should be 240v
also chk for 24v at the coil of the contactor

Need to make sure stat is on and calling for cooling:thumbup:

Thanks. I have a meter and I'll check it tonight. THanks for your help. On the other one, I will definitely throw the breaker before changing the thermostat. Thanks for help on that one too.