Confirming Nest Wire compatibility

[MikeInDc]

 i only have red, white and blue wires and the compatibility checker asked me to contact support to confirm compatibility.  Will the nest work with my system or do I need to install a constant power wire for it to work?

Thanks in advance.

[Houptee]

If the Blue goes to common on the heater then you are good to go you would have Rh is power  C is common  and W is heat 

[MikeInDc · Accepted solution]

Thanks for the response.  I used the support chat option to connect to a tech and was informed that my particular Trane system is not compatible with Nest.  Trane xc95m. Bummer.