Nest System Compatibility.

[DLauch]

I have a Trane heat pump with the following connected wires in my current thermostat. 
R, W1, W2, Y1, G, O, B 

Are Nest Thermostats Compatible with my system. 

[Patrick_Caezza]

@DLauch 

Only the Nest Learning Thermostat is 100% compatible with your current thermostat.

Trane labels its C wire as B.