The Nest Compatibility Checker cannot determine if your system is of the type to allow for battery charging using her Y or W wire. This charging ability depends on your forced air unit. If it uses a all digital control board it is not likely to allow for the W or Y power charging path. The best thing to check for is a spare or unused wire conductor in your thermostat cable that can be purposed for the Power Common.
AC Cooling Wizard
NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.
