Pro1 T855i Installation manual - Manual (Page 6)

6
Replacement Thermostat Wiring
1.
2.
3.
If you are replacing a thermostat, make note
of the terminal connections on the thermo-
stat that is being replaced. In some cases the
wiring connections will not be color-coded.
For example, the green wire may not be
connected to the G terminal.
Loosen the terminal block screws. Insert
wires then retighten terminal block screws.
Place nonflammable insulation into wall
opening to prevent drafts.
This thermostat requires a 24V Common Wire
to the C terminal.
All components of the control
system and the thermostat
installation must conform to
Class II circuits per the NEC
Code.
Use shielded or non-shielded
18-22 gauge thermostat wire.
WIRING
Wire Specifications
Warning
EMHEAT EMHEAT
DO NOT OVER TIGHTEN TERMINAL
BLOCKS. CAN CAUSE DISTORTIONS
AND MALFUNCTIONS.
Warning
Note: Devices such as a float switch that mechanically break circuits should
be installed so that they break the control wire (Y) not the power (R).
Interrupting the power circuit will shut off power to the thermostat completely
and not allow it to operate.