Hello JackD1,
what year did going to need to do is make a slight configuration change in your nest thermostat to get the heat pump reversing valve working properly for your model of heat pump. All heat pumps are sold as either a primary cooling version or a primary heating version. What that means is if you are primarily a cooling version, the refrigerant reversing valve in the outdoor unit must be energized to switch it to a heating system.
you can only make this change at the thermostat itself. Go to your thermostat display tap it to wake it up. Go into settings, then go to equipment, there you will see a list of the wires that are currently detected by the nest thermostat. Your equipment will be specified as a heat pump and there is a field there for changing the reversing valve. Yours will say change valve for cooling, you need to change it, so it says change valve for heating.
I hope this information helps you get it changed,
The AC Cooling Wizard
NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.
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