Thermostat upgrade from carrier to nest

[Tyrconnell1985]

I’m trying to see if my thermostat is able to be upgraded to a digital thermostat such as nest.   I currently have a carrier which has 7 wires (4 attached and 3 unattached).  The attached wires are white, yellow, green, and red and are fixed into the RS+, RS-, V+, and VG.   The unattached wires are orange, brown, and blue.   Are these wires compatible with next or any other newer model thermostats like the echo?   If not, what needs to be done to make it compatible?    Any help is greatly appreciated!

[Jarhead]

Hello Tyrconnell1985,
Basically you can say that the cables that are not connected to the old thermostat are not needed.
The colors of the cables that are connected may vary.
Not every installer works according to the code.

To help you, it is important for the community to know what the wiring looks like on the original thermostat.
Before you change anything on the thermostat, you should take a picture of what it looked like originally.
This will make it easier to correct any mistakes with a new thermostat.

[Tyrconnell1985]

[Jarhead]

I would be great to have some more information. Model on old thermostat and model on equipment.

Basically, it looks like the red W+ is your switching current (R).
Green (VG) could be the neutral conductor (G).
RS+ and RS- are normally the + and - of a remote sensor.

But these are only guesses.

[MelbaDT]

Hey folks, 

Appreciate your responses, Jarhead.

@Tyrconnell1985, I wanted to drop by to check if you still need help with this. If yes, let us know the information being asked above so we can check on it further. 

Best, 

Melba

[Longhairguy]

Hello, I have the same Bryant Zone Perfect  Plus stat controlling 4 zones (2003). The wiring is the same as the picture Tyrconnell shared above. I’m looking to see if Nest is compatible.  I would just add that the other side of that picture (board and pins) also shows 12V and ground that line up with V+ and VG respectively. Also, each zone controlled does have its own temperature sensor mounted on the wall.  I’ve seen the zoning board in the attic but I’ll have to make a trip up there to get specifics. It controls duct mounted dampers.