This week I had an electrician come and upgrade my electrical box from 100amp to 200amp. After he was finished we believed everything was fine. About 1/2 hour later my wife said the A/C wasn't working. Electrician came back and thought the transformer was bad. He went to Grainger and replaced it for us. No Luck! I called a local A/C repair shop and they came out. They believe it's the circuit board and gave me an estimate of approx. $420.00 ($57. Svc. Call, $240. For the circuit board, $75. To pick up the part, and about $50. Labor). Please don't laugh, I don't have any experience with these things. The A/C repairman also said that we wouldn't know if there were other problems until the board was replaced. My unit is about 8 yrs. Old.

As I began looking for info. Online I read about others with circuit board problems. Some said they were able to bypass the board to see if the unit was running. The A/C tech didn't do anything like that. Like I said, everything is completely dead right now. Outside A/C unit, air handler (which is where the circuit board is), and thermostat inside house.

I just want to be sure I don't get taken for a ride. Does this sound like they are being fair and honest with me or should I get another opinion? I've had this A/C company work on my business A/C and they did a good job at a fair price. Any help would be appreciated.

Now, come on. "Thought" he transformer was bad. It either is or isn't. The test is so easy. This does not fall into a grey area.

Define "AC isn't working" Inside unit, outside unit, both?

It does make sense to do the following, Turn off both breakers (inside and outside) for about 5 minutes and turn them back on again.

If it fixes, then your done. Remember it takes about 5 minues for the AC to turn on after a power fail.

If your thermostat is electronic and the above didn't work: Then remove the batteries and do the steps again.

Check the installer settings in the thermostat. Nt likely that they changed. Sometimes there is a test mode.

Surges/loose connectiion at the panel can easily blow PC boards, so yes it's "possible" that the upgrade caused the problem. With the furnace boards being so expensive, you should consider a wired in surge supressor at the furnace.

I wasn't concerned about the transformer issue since the electrician replaced it at his expense. When the A/C guy came he was the one who concluded that the circuit board was bad. We've done all the other things: turned off and on breakers, checked thermostat. Unfortunately I live in Florida and it's 90 degrees inside and out. My wife and daughter are getting a little short on patience. I may have to go ahead with the A/C repair and hope for the best. Thanks for your response. I just wish I had better knowledge on the subject.