Nest Thermostat Compatible With Trane HVAC System

[MHRABY]

Afternoon I'm trying to see if my Nest Thermostat (not the learning thermostat) is compatible and will work with my Trane HVAC unit.  I have attached a pic of the current configuration.  The orange, black, and brown wire are not connected.  Any help would be greatly appreciated.  Trane wiring 

[Jesterin]

I have a nearly identical old system and my heat will not turn on with the nest. If I install the old tstat everything works fine. Like your old baseplate I have an R wire connected and jumpered to the RC. the nest does not have RC only R.

[MHRABY]

Thank you for the info.  I wish there was a way to work around this issue.  

[Patrick_Caezza]

@MHRABY 

It looks like you have a conventional Heat/Cool system, and you should use the top labels.

Just match the labels from the original thermostat to the label on the Nest. The blue wire needs to go to the C terminal, and the jumper between the R and RC terminals can be ignored as the Nest will automatically make the connection internally if needed.

[MHRABY]

@Patrick_Caezza 

Thanks for the info.  Just to ensure that I am understanding you correctly, I am only going to use the green, yellow, blue, and white wires.  I will disregard the red wire and put the blue wire in the C terminal.   

[Patrick_Caezza]

@MHRABY 

You will still need the red wire, just ignore the silver jumper between the R and RC terminals. Yes on the blue wire.