you have 2 problems

1. thermostat not wired up correctly is why it keeps running once it gets well below desired temp.

2. if it takes all night to get temp. back down to a comfortable level, then either your A/C system has a performance problem (low freon, high freon, clogged indoor or outdoor coil, etc.) OR your house has inadequate insulation. which problem #2 is, will be determined by the difference in temp. between the vent temp. and the temp at the return.


"Greg M" wrote in message ...
I've been having some trouble with the central AC in a house that I just recently moved into. The problem is, the AC works fine, but it won't keep a constant temperature. Basically, when I turn the thermostat to "cool" and "auto" it just runs and runs even after the desired temperature is met. I thought that it might be a bad thermostat, and since I wanted to upgrade to a programmable one anyway, I bought a new thermostat (Honeywell CT3500A1004) and installed it. The AC still does the same thing, I set the temperature at one day 75 when I left for work and when I got home it was down to 68 and the AC was still running. Now I haven't been running my AC during the day, but when I get home the temperature in the house is over 80, so it takes almost the entire night to get it back to a comfortable level. This is my last ditch effort before I have someone come out, any suggestions?



Greg M