I have a York Diamond 80 and blow motor continues to run even when the thermostat is in a off position. When you turn the thermostat to the on poisition and set to temp for heat the blower will turn off and the heat will kick in and will run fine. Once the house reaches it's temp. The heat will kick off but the blower will continue to run until the heat is ready to kick back in again. What could be causing the blower to continue to run?

Is it on auto or manual