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.
TH5110D
TH5220D
Y2
W2
G
W
TH5320U
Y2
W2
G
Remove factory-
installed jumper
only for two-
transformer
systems.
Rc
R
Y
C
W
G
C
Y
R
Rc
W
C
Y
R
Rc
Connect
(optional if batteries are installed).
TH5320U/TH5220D
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)
-TH5320U
G
Fan relay
Aux/E
Auxiliary/Emergency heat relay
L
Sends output when set to Em. Heat
C
24VAC common
TH5110D
TH5220D
L
TH5320U
L
2
Insert batteries for primary
or backup power.
for primary AC power
C
or as otherwise noted.
only
Rc
R
Y
C
O/B
G
O
Aux
G
C
Y
R
B /
E
O
Y2
Aux
G
C
Y
B /
E
MCR29371A
M29370
Rc
R
Rc