Installation Guide

4

69-2668—03
Wiring guide—conventional systems
Wiring

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

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

See [notes] below

[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.
Shaded areas below apply only to TH7220.