I am attempting to replace our Weathertron thermostat with a Honeywell RTH3100C. We have a Trane heatpump system. I am having trouble with the wiring. My wires don't match the 'less common wire designations' in the manual.
I have the following wires on the Weathertron:
R-red
T-brown
O-orange
G-green
Y-yellow
X2-black
B-blue
W-white

I'm not sure where the T wire should go or what to do with the grey wire.

Moved to HVAC.