We have a new Goodman furnace,an older Fedders central air unit, and a Honeywell thermostat. Our air conditioning unit--both compressor and fan will not stop running once the thermostat reaches the desired temperature. We usually keep the t'stat set on 72. The fan is set to Auto. This morning when I got up the room temperature was 62. The unit had run nonstop all night. The only way we can get the unit to stop is to turn the switch to Off on the t'stat. Any ideas?