Having a problem with the electric heater and indoor fan remaining energized after the demand for heat is met (set point 72.... indoor temp shot up to 84) and even when the mode is switched to off and the fan set to auto. Only way to stop is kill the main power to air handler,when power is restored normal operation is resumed. This happened last year as well at the first cold snap, my apprentice attended that call and we concluded it was the stat. It was changed out and not a problem for the remainder of the heating season. Fast forward to this heating season, now a couple of months into it, no problem, first real cold night same issue has occurred again. heat pump off, tstat off,heaters energized /fan on and overheated home.
Anyone experience this sort of thing? will be attending in person to sort out