Hello Everyone. I just bought my new thermostat and installed it. Using my old thermostat, an old mercury White-Rodgers, I wiring the Honeywell to what I thought was a "conventional" system. I have gas heat and electric A/C. Outside I have the fan unit which blows air into the compressor and for heat, heated by the gas, and for A/C, the compressor cools it.

When I fired up the A/C with my new thermostat everything seemed to work well. The cool air come on and went to my programmed temperature. However, when it reaches the temp (slowly I might add), it doesn't shut off. I've noticed the air will shut off for 5 or 10 minutes and then come right back on.

Is this a wiring problem or simply a bad internal thermometer?

Any help is GREATLY appreciated!

See if your new stat offers settings to change the "starts per hour" , you may need to experiment to find the best to cool the area and keep cool, try 3 starts per hour and go from there.