A/C tripping breaker - Think this was the problem?

[billybek]

You may have a weak breaker.
I was reading you put on a hard start kit. Was it one of the generic kits made to fit all compressors or the factory potential relay and capacitor? (some had current relays that do the same job)
For a residential application, you could install a delay on break timer.
This timer at the end of a call for cooling will not allow the compressor to restart for a settable amount of time.
What this does for you is allow the system pressures to equalize so that you do not start up against high head and draw more amperage.
Some new programmable T'stats have this feature built in.
Edit: Go to any HVAC supplier and they will have this type of timer. Very easy to install.
Edit again: Make sure that you check all the supply wiring to make sure the connections are tight. If there are pull boxes with wire nuts inside, check those too.

[LeeH]

I put in a new breaker last year when I was working on this.

The capacitor I added was a generic sort. There is a disconnect box next to the unit outside... I even replaced the disconnect as it showed some heat damage. It's cool to the touch now when the copressor is running.

My thermostat (Honeywell Chronotherm III) does have a built in delay, but I may replace it anyway as it's original to the house - about 15 years old.

The breaker doesn't necessarily trip on start up. Sometimes it's after the compressor has been running for a minute or so.

The only time my breaker trips is late in the afternoon when it's >102 outside. At that point, the sun is hitting the compressor, the disconnect, and the breaker box. Shouldn't think that would matter - especially since this only started happening last summer.

[billybek]

It is possible that you are in for a compressor replacement, but I would double check for voltage drop along the way.
If you are not comfortable with this, don't do it.
Check voltage at the panel. To do this you need to pull the panel cover off.
Check voltage with unit off. Check voltage with the unit on. Shouldn't be too much of a drop.
Check line to line and line to ground.
Do the same at the unit. Off, it should be the same as the panel. Running, you may experience a voltage drop. Again, line to line and line to ground.
If the voltage is good, it eliminates a supply problem.
It may be the start switch is not disengaging the start capacitor and you are pulling a little better than full load amps.
It is really hard to troubleshoot when you can't put your hands on it or hear it but it seems that it is doing hard starts for some reason.

[LeeH]

The compressor finally died Tuesday night at 9pm. Ya know... it's really hot this time of year in Phoenix without AC! I was lucky to find a guy who was able to get right on the replacement. The air handler has been a real pain, but we should have cool air shortly.

It's a tight squeeze to get the old condenser units in and out, so they prefer to do it by air.

[billybek]

Cool! (trade pun)
What manufacturer did you go with?
Air handler was tight to get in or difficult to adapt to the existing ductwork?

[LeeH]

New unit is a Carrier, as was the old one. The ductwork was an exact match to the old air handler, so that was easy. Getting it in place was the issue.

It's located above the master bedroom closet and the scuttle is tiny. Enlarging it wasn't an option, either. We ended up hacking a hole next to the air intake and sliding it through that way. Even so it was a very tight fit. Getting the air handler up on the shelf in the photo was downright frightening. I was sure it and the two guys lifting it were coming down more than once.