I have a York heat pump that is 16 years old. I have a very intermittent problem with the indoor air handler blower. Every now and then the blower will remain on indefinitely even after the outside compressor has shut off. In normal operation, once the outside shuts off the indoor blower stays on for approx. 2 extra minutes then turns off. The only way I can get it to turn off is to raise the Honeywell thermostat a few degrees to get the outside unit to turn on. Once it reaches temp the indoor blower will then shut off. What could be the cause? The Yorkguard IV control board, a relay, the thermostat?
Any help would be greatly appreciated. Thank you!