Wiring
Terminal Designations
Conventional Terminal Letters:
Y2
2nd stage compressor contactor.
W2 2nd stage heat relay.
K
Optional wirer save module.
S1
Optional outdoor or remote sensor.
S2
Optional outdoor or remote sensor.
Rc
Cooling power. Connect to secondary side
of cooling system transformer.
R
Heating power. Connect to secondary side
of heating system transformer.
W
1st stage heat relay.
Y
1st stage compressor contactor.
G
Fan relay.
C
Common wire from secondary side of
cooling transformer (if 2 transformers).
69-2733EFS—01
Y2
Y2
L
E/AUX
W2
K
K
S1
S1
S2
S2
HEAT PUMP
CONVENTIONAL
RC
Heat Pump Terminal Letters:
Y2
2nd stage compressor contactor.
L
Heat pump reset (powered continuously
when System is set to Em Heat; system
monitor when set to Heat, Cool or Off).
E/Aux Auxiliary/Emergency heat relay.
K
Optional wirer save module.
S1
Optional outdoor or remote sensor.
S2
Optional outdoor or remote sensor.
Rc
Cooling power. Connect to secondary side
of cooling system transformer.
R
Heating power. Connect to secondary side
of heating system transformer.
O/B Changeover valve for heat pumps.
Y
1st stage compressor contactor.
G
Fan relay.
C
Common wire from secondary side of
cooling system transformer.
2
RC
R
R
W
O/B
Y
Y
G
G
C
C
MCR34051