Hi,
All of sudden we felt cold today as temperature dropped. My wife increased the temp from thermostat but we didn't feel any difference and no hot air blowing from the vent. I went outside and found my A/C unit still running. Can some one help me. Last winter my furnace was running fine. The unit in only 2-3 years old. My furnace switch is on and I can hear something running inside

Thanks
:confused:

First of all you need to find out why the outside unit is still running in the heat mode? You did not say what the brand,model number, or weather this is a heat pump,gas or oil furnace?

Thanks for the reply
I don't know why my AC is running in heat mode. I turned the system off from thermostat, AC was also stopped. If I turn On the Fan on from thermostat, Fan also works fine. I turned off my AC switch from main board and AC was stopped. So everything is working fine. Only When I put my thermostat on Heat Mode, it doesn't give me hot air and AC keeps running.


Furnace is Unitary products Group High Efficiency Gas-Fired Furnace Tubular Heat Exchanger Series
Model P*DH/G9T-DH/FG9-UP (Upflow) 40-140 MBH INPUT
Model P*DH/G9T-DH/FG9-UP (Downflow/Horizontal) 40-120 MBH INPUT

Thermostat is White Rodgers 1F88-270 through 279

Since the ac unit outside does not run when the thermostat is turned off it probably is a short in the low voltage control wiring from the thermostat to the furnace. In the furnace disconnect the Yellow wire on the terminal strip. This should turn off the ac outside. Then you can trouble shoot the wiring back to the thermostat. Has this unit been installed for a few years or is this a newer install? Have you changed the thermostat lately/