Power options
Keep wires in this
shaded
area
Wiring terminal designations
Shaded areas below apply only to
Conventional Terminals:
Rc
24VAC power from cooling
transformer
R
24VAC power from heating
transformer
W
Heat relay (stage 1)
W2
Heat relay (stage 2)
Y
Compressor contactor (stage 1)
Y2
Compressor contactor (stage 2)
G
Fan relay
C
24VAC common. For 2 transformer
systems, use common wire from cooling
transformer.
TH6110D
G
W
C
Y
TH6220D
Y2
W2
G
W
TH6320U
Y2
W2
G
Remove factory-
installed jumper only
for two-transformer
systems.
TH6320U/TH6220D
R
Rc
C
Y
R
Rc
W
C
Y
R
Rc
MCR29437A
Insert batteries for primary
or backup power.
C
Connect
for primary AC power (optional
if batteries are installed).
or as otherwise noted.
Heat Pump Terminals:
Rc
24VAC power from cooling
transformer
R
24VAC power from heating
transformer
O/B
Changeover valve
Y
Compressor contactor
Y2
Compressor contactor (stage 2)
only
G
Fan relay
Aux/E
Auxiliary/Emergency heat relay
L
Sends output when set to Em. Heat
C
24VAC common
TH6110D
G
C
Y
TH6220D
L
G
Aux
E
TH6320U
L
Y2
Aux
G
E
2
MCR29436
-TH6320U
R
Rc
C
Y
R
Rc
C
Y
R
Rc
MCR29438A