Why would ac unit not work after brand new capacitor placed in unit?

Question

I had my unit servced and the technician replaced the capacitor but said the unit was overcharging. Tech did not see any other problems. About a week later the unit quits and the same tech comes over and tells me it is a bad breaker. I have an electrician friend come over and he take the breaker out and puts it back in at which time the unit starts back up and runs for a week then the compressor stops and only the fan runs. My electrician friend comes back over and replaces the breaker with a new one and we watch the unit attempt to trip the breaker. I am still not getting any cool air but the fan keeps running. Does anyone know what is wrong since the capacitor is new?

Answer 1

Overcharging means the high side pressure is too high. The link below lists possible causes.

The capacitor on the compressor is power factor correction (makes it easier to start and restart in hot weather).

If the capacitor is the wrong size or fails, the compressor may not start, or you will trip breakers, but that has nothing to do with overcharging.

You need to hire someone who knows what they are doing. Overcharging will destroy the compressor.

Answer 2

Not enough information ie.How old is the unit?Did the electricion put his amprobe on the unit to see how much it was drawing?Worst case you are looking at a bad compressor start winding(I am assumeing it was the compressor start cap that was replaced.I'd trust the electricion  a long time before I'd trust a HVAC "tech".I put them in the same group as tow truck drivers and lawyers.

Answer 3

Some of the air conditioners, in addition to a starting capacitor, have a starting relay (so that once the compressor is running, the start winding is disconnected) possibly yours is wearing out and intermittently sticking in the "off" state ?

If this is the problem, when it tries to turn on, you will hear the compressor hum for a few moments and trip the thermal breaker (usually located on the compressor).

Also, some units have a relay (which is activated by the thermostat) which fires up the unit, but I would think the fan would not run either if this were bad.

Answer 4

The tech new that something was still wrong after replacing the capacitor .

I don't know if he replaced the capacitor with the proper size or which capacitor but it could have faulty compressor windings and cant be corrected without replacing the compressor itself.

You needed a better tech to diagnose and not put you through this.

Answer 5

Check and make sure all the wires on the capasitor are tight. For Gods sake pull the relay on the wall mounted power supply. That capasitor can and will knock you on your ***.