What is the Orange wire for on the thermostat? I am converting from a Carrier to a Honeywell. The Carrier consists of two termanls:

One has the orange wire going to the O/W2
The other terminal has a red wire going to R, Yellow going to Y/T2, Green to G, Black to C, and White to W.

Hoever, the new Honeywell only has one terminal consisting of Rh, Rc W, Y, and G. How would this be wired?

THe only thing I can think of is that the orange wire is the power for the thermostat. The Honeywell is battery operated, but the old carrier is not.

Thanks!!

Sounds like you have a heat pump and the new thermostat won't work. Much of the info you need is in the sticky at the top of the forum.

Agrees with Labman, he's right on target!!