Installation guide

Installation Guide
4
Wiring guide — conventional systems
[1] Power supply. Provide disconnect means and overload protection as required.
[2] Remove jumper
for 2-transformer systems.
[3] Optional 24VAC common connection.
[4] Common connection must come from cooling transformer.
See [notes] below
Wiring
Shaded areas below apply only to TH8320/TH8321
1H/1C System (2 transformers)
Rc Power (cooling transformer) [1, 2]
R Power (heating transformer) [1, 2]
W Heat relay
Y Compressor contactor
G Fan relay
C 24VAC common [3, 4]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
Heat Only System With Fan
Rc Power [1]
R [R+Rc joined by jumper]
W Heat relay
G Fan relay
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
Cool Only System
Rc Power [1]
R [R+Rc joined by jumper]
Y Compressor contactor
G Fan relay
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
2H/2C System (2 transformers)
Y2 Cool relay 2
W2 Heat relay 2
Rc Power (cooling transformer) [1, 2]
R Power (heating transformer) [1, 2]
W Heat relay 1
Y Cool relay 1
G Fan relay
C 24VAC common [3, 4]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
1H/1C System (1 transformer)
Rc Power [1]
R [R+Rc joined by jumper]
W Heat relay
Y Compressor contactor
G Fan relay
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
Heat Only System
Rc Power [1]
R [R+Rc joined by jumper]
W Heat relay
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
Heat Only System (Series 20)
Rc [R+Rc joined by jumper]
R Series 20 valve terminal “R” [1]
W Series 20 valve terminal “B”
Y Series 20 valve terminal “W”
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor
2H/2C System (1 transformer)
Y2 Cool relay 2
W2 Heat relay 2
Rc Power [1]
R [R+Rc joined by jumper]
W Heat relay 1
Y Cool relay 1
G Fan relay
C 24VAC common [3]
S1 Optional outdoor/remote sensor
S2 Optional outdoor/remote sensor