Installation Manual

5 69-2738EFS—03
W2
G W
YR RCK
Y2
C
MCR33878
HEAT PUMP
CONVENTIONAL
AUX/E
G O/B
YRRCK
Y2
C
Conventional Terminal Letters:
Y2 2nd stage compressor contactor.
W2 2nd stage heat relay.
K Optional wirer save module.
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).
Heat Pump Terminal Letters:
Y2 2nd stage compressor contactor.
Aux/E Auxiliary/Emergency heat relay.
K Optional wirer save module.
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.
Terminal Designations
Wiring