Nest thermostat is not recognizing “ G, OB, &Y” wire. I jumped out the thermostat, bad Nest thermostat. Homeowner’s prefer a basic thermostat that is easy to use. I also recommend a surge protector. I verified the refrigerant pressure & capacitor. A humming contactor was detected & I recommend replacing the humming contactor before failure. Thank you for choosing Total Air…. Basic thermostat