WIRING
5
C terminal
The
C
(common wire) terminal does not
have to be connected when the thermostat is
powered by batteries.
TopTech Tips:
Terminal Designations
Terminal
2 Heat 2 Cool
Conventional System
2 Heat 2 Cool
Heat Pump System
3 Heat 2 Cool
Heat Pump System
RC
RH
C
B
O
G
W/E
W2
Y
Y2
Transformer power (cooling)
Transformer power
(heating)
Transformer common
(For 2 transformer systems,
use RH common.)
Energized in heating
Energized in cooling
Fan relay
First stage of heat
Second stage of heat
First stage of cool
Second stage of cool
Transformer power
(cooling)
Transformer power
(heating)
Transformer common
Heat pump changeover valve
energized in heating
Heat pump changeover valve
energized in cooling
Fan relay
Emergency heat relay
Auxiliary heat relay,
second stage of heat
First stage of heat & cool
Second stage of cool
Transformer power
(cooling)
Transformer power
(heating)
Transformer common
Heat pump changeover valve
energized in heating
Heat pump changeover valve
energized in cooling
Fan relay
Emergency heat relay
Auxiliary heat relay,
third stage of heat
First stage of heat & cool
Second stage of cool
& second stage of heat
This thermostat is shipped from the factory to operate a conventional heating and cooling system. This thermostat will
also operate a heat pump system. See the “heat pump” configuration step on page 7 of this manual to configure the
thermostat for heat pump applications.
Warning:
All components of the control
system and the thermostat
installation must conform to
Class II circuits per the NEC Code.
Note:
In many systems with no emergency
heat relay a jumper can be installed
between E and W2.
Wiring
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.
Loosen the terminal block screws. Insert wires
then retighten terminal block screws.
Place nonflammable insulation into wall
opening to prevent drafts.
Push wire into the wall so the thermostat can
mount securely to the subbase.
1.
2.
3.
4.
Wire specifications
Use shielded or non-shielded
18 - 22 gauge thermostat wire.
