Why are both heating and cooling running at the same time with my Honeywell Thermostat?
- CCynthia MartinSep 7, 2025
If both the heating and cooling equipment are running simultaneously with your Honeywell Thermostat, it could be due to the System Type (ISU 0170) being incorrectly set to Heat Pump when the heating equipment is not a heat pump. Set the System Type (ISU 0170) to match the installed heating and/or cooling equipment. Another cause could be shorted heating and cooling wires; in this case, separate the shorted wires.