Power options
For 24VAC primary power, connect common
side of transformer to "C" terminal.
Wiring
Remove factory-installed jumper
only for two-transformer systems.
Terminal Designations
Conventional Terminal Letters:
R
Heating power. Connect to secondary
side of heating system transformer.
Rc
Cooling power. Connect to secondary
side of cooling system transformer.
C
Common wire from secondary side of
cooling transformer (if 2 transformers).
W
1st stage heat relay.
W2 2nd stage heat relay.
Y
1st stage compressor contactor.
Y2
2nd stage compressor contactor.
G
Fan relay.
S1
Optional outdoor or remote sensor.
S2
Optional outdoor or remote sensor.
Push excess wire back into the wall opening. Plug
wall opening with non-flammable insulation.
Shaded areas below apply only to TH8320/TH8321.
Heat Pump Terminal Letters:
R
Heating power. Connect to secondary
side of heating system transformer.
Rc
Cooling power. Connect to secondary
side of cooling system transformer.
C
Common wire from secondary side of
cooling system transformer.
Y
1st stage compressor contactor.
Y2
2nd stage compressor contactor.
Aux Auxiliary heat relay.
G
Fan relay.
E
Emergency heat relay.
L
Heat pump reset (powered continuously
when System is set to Em Heat; system
monitor when set to Heat, Cool or Off).
O/B Changeover valve for heat pumps.
S1
Optional outdoor or remote sensor.
S2
Optional outdoor or remote sensor.
VisionPRO
Insert supplied batteries for
primary or backup power.
TH8000 Series
TM