Hello All,

I am new to your forum. My first thread. Hope some of you guys can help me out on this problem.

Sorry for the long-winded message, but trying to bring you up-to-date on where I am on this.

I had a tech come out and check my AC, BTW, which he installed a new compressor a year ago. The compressor will not start now. It was kicking out the breaker (30 amp). He said I needed a new breaker (50 Amp)(that's all he checked). I installed a 40 amp as I thought maybe a 50 was to large for my 5 ton unit. It does not trip the breaker now but the compressor still will not start. It hums for 3-5 seconds and clicks off.

I have checked the capacitor and it checked OK, I replaced it anyway and got the same results, no start. BTW I have not called the tech back yet, he seems so sure there is no problem with the compresser motor (all that is still under warrenty).

I have checked the wiring connections and all seem normal except the 3-wire plug on the compressor and it shown signs of rust/corrision, which I clean up and checked with my meter and it appears to be OK.

The capacitor is a dual run type. One for the coil fan and one for the compressor. When I check the volts on each terminal of the cap, including the common, I have 120 volts on all 3 with nothing running. When I try to start, the fan shows 350 volts and the compresser cap terminal still shows 120 volts with no increase when compresser "hums" trying to start.

I checked for a short internally and "open" in the motor, but it seems to show none, at least to me. The ohm reading across all wires to the compresser show less than 2 except for one and it shows 2.4 ohms.

Is the "run" wire from the capacitor to the motor and fan supposed to show 120 volts when system is not in run position?

The contact switch, Red wire side from incoming power has direct path (metal strip) to compresser red wire side. The incoming Black wire has a contact point which engages when "run" is attempted, but when system is down, this black wire to the compresser has 120 volts constantly with contact points open, IS THIS NORMAL? The Black wire from the motor appears to be getting the 120 volts from the red wire's 120 volts into the motor. Is this normal?

If you need any more info or do more tests, I'll be glad to do my best.

Thanks and Have a Great Day,
jraquel