Last fall I replaced our old mercury thermostat with the Honeywell 7 day programmable thermostat. Turned the AC on this evening and it will only blow hot air. Temp. Set to 70, auto, cool and it continues to continuously blow hot air. The house is now 81 and I shut the system to off. When hooking up the thermostat I followed the wiring guide and for heat all was good. Please any help is greatly appreciated.

I'd call them at 1 (877) 841-2840, but it may just be the circuit board in the thermostat - should be under warranty still, no? I would get a replacement.

Let me know what wires you have hooked to what terminals at the stat and Ill see what I can come up with. Need a detailed explanation. Also, what wires are hooked to what terminals at the furnace.