Wiring Nest 1st gen Thermostat from a Trane TAYSTAT 540

[Kipsing]

My old thermostat controls a heat pump, AC, emergency heat. Wires feeding to ports G, B, R, Y, W, X2 and O. Nest doesn’t ever give me an X2 option & I don’t know what it is. 

[zoeuvre]

Hi Kipsing, 

Thanks for posting here in the Community forum and for showing interest in our Nest Thermostats. Fortunately, your thermostat wires are compatible with our Nest Learning Thermostat 3rd generation and should be wired to the Nest Learning Thermostat base as follows:

• G wire to G
• B wire to C
• R wire to RC/RH
• Y wire to Y1
• W wire to W1
• X2 wire to *
• O wire to OB

Also, here's a guide for the installation and setup of a Nest Learning Thermostat. 

Let us know if that helps.

Best,

Zoe