2
Power optionsWiring terminal designations

Shaded areas below apply only to TH5320U/TH5220D or as otherwise noted.

M29370

Keep wires in this

shaded area

Connect C for primary AC power

(optional if batteries are installed).

Insert batteries for primary

or backup power.

Remove factory-

installed jumper

only for two-

transformer

systems.

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.

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 only
G Fan relay
Aux/E Auxiliary/Emergency heat relay
L Sends output when set to Em. Heat
C 24VAC common
TH5110D Rc
Y
W
G
R
C

TH5220D

RcYWGW2Y2 RC

TH5320U

RcYWGW2Y2 RC
TH5110D Rc
Y
O/B
G
R
C
RcYG
LR
C

TH5220D

RcYGAux
E
Y2
LR
C
OB
/
OB
/

TH5320U

MCR29371A
Aux
E