4
1 HEAT / 1 COOL Single or Dual Transformer
Set Installer Switch to
CONV
Rh
24 Volt AC Power (heating transformer)
[note 2]
Rc
24 Volt AC Power (cooling transformer)
[note 2]
W1
Heat Relay (appears as
W1/E
on 2220NC)
Y1
Compressor Relay
G
Fan Relay
C
24 Volt AC Transformer Common
[note 1, 3]
Typical Wiring Configurations
NOTE:
The “Installer Switch” option will be configured in the next step.
Conventional Systems
24VAC Power
Terminal (C)
NOTES - Conventional Systems
[1]
If batteries are installed the 24 Volt AC common connection is optional
[2]
Remove factory installed jumper for dual transformer systems
[3]
In dual transformer systems, transformer common must come from
cooling transformer
[4]
If needed for system
Provide disconnect and overload protection as required.
2 HEAT / 1 COOL Single or Dual Transformer (2220NC Only)
Set System Type to
CONV
Rh
24 Volt AC Power (heating transformer)
[note 2]
Rc
24 Volt AC Power (cooling transformer)
[note 2]
W1
Heat Relay Stage 1
W2
Heat Relay Stage 2
Y1
Compressor Relay Stage 1
G
Fan Relay
C
24 Volt AC Transformer Common
[note 1, 3]
Heat Only or Millivolt
Set Installer Switch to
CONV
Rh
Power Connection
W
Heat Relay (appears as
W1/E
on 2220NC)
G
Fan Relay
[note 4]
C
24 Volt AC Transformer Common
[note 1]
