Wiring; Terminal Designations - Pro1 IAQ T925 Installation Manual

Caution: Electrical Hazard
Failure to disconnect the power
before beginning to install this
product can cause electrical
shock or equipment damage.

Wiring

1.
If you are replacing a thermostat, make
note of the terminal connections on the
thermostat 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.
2.
Loosen the terminal block screws. Insert
wires then retighten terminal block screws.
3.
Keep wires in shaded image as shown by
pushing wires into wall opening.
4. Place nonflammable insulation into wall
opening to prevent drafts.

Terminal Designations

Auxiliary heat relay
W2
Compressor relay, Stage 1
Y1
Compressor relay, Stage 2
Y2
G Fan relay
O Heat pump changeover valve
energized in cooling
PRO1 Tips:
C terminal
The C (common wire) terminal does
not have to be connected when the
thermostat is powered by batteries.
Warning:
All components of the control
system and the thermostat
installation must conform to
Class II circuits per the NEC Code.
C
O
B
E
W2
Transformer power
R
Heat pump changeover valve
B
energized in heating
Common wire from secondary side
C
of cooling system transformer or for
heat only system transformer
Emergency heat relay
E
Wire specifications
Use shielded or non-shielded
18 - 22 gauge thermostat wire.
WIRING
R
G
Y1
Y2
5