I have an American Standard thermostat model acont800 hooked up to my American Standard furnace/heat pump and the fan is running way too much. The thermostat fan mode is set to auto, and the fan even continues to run while heat pump is in defrost mode which blows very cold air out of registers. It has done this since the time of installation, and after several HVAC men in the are and many dollars later, everyone agrees it's not right but nobody can seem to fix it. Does anyone know how to make an adjustment so fan will not run in defrost mode? Thanks in advance!