Install a damper with an AMT actuator in the duct supplying air
to the sleeping area and wire the terminals to the
corresponding terminals on the T21. Install a second damper
with an AMT actuator in the duct supplying air to the living area
and wire it to the T21. Each damper uses 2.4VA of power.
Green LED
Red LED
INSTALL DAMPERS
Ensure that damper installation does not cause obstruction
to the damper blade.
!
DAMPER WIRING
Warning!
!
Turn the power to the HVAC equipment off before wiring.
Use 3-conductor, 18 or 20 gage, thermostat cable to wire from
the T21 Thermostat to the sleeping and living area dampers.
There are separate terminals for the sleeping and living area
dampers.
Multiple dampers can be used to construct the sleeping or living
zones. Daisy chain terminals– COM to COM, OPN to OPN and
CLS to CLS.
Closes Damper
Opens Damper
Common
Function
Damper
Terminal
COM
CLS
OPN
Wire Color
White
Red
Green
T21
Terminal
COM
CLS
OPN
i
Ensure the damper for the sleeping area is wired to the
terminals labeled SLEEPING and the damper for the living
area is wired to the terminals labeled LIVING.
When two or more dampers are required to define the sleeping
or living area, the damper may be wired in parallel. LEDs on
the damper actuator indicate when the damper is fully open
(green) or fully closed (red). When properly installed, the
dampers will never fully close.
Gas/Electric, 2H/1C
Gas/Electric, 1H/2C
Use 6-conductor, 18 or 20 gage, thermostat cable.
Use 6-conductor, 18 or 20 gage, thermostat cable.
T21
Terminal
T21
Terminal
R
R
C
C
W/OB
W/OB
Y1
Y1
G
G
W2E/Y2
W2E/Y2
Wire Color
Wire Color
Red
Red
Blue
Blue
White
White
Yellow
Yellow
Green
Green
Brown
Brown
Equipment
Terminal
Equipment
Terminal
R, Rc, Rh
R, Rc, Rh
C
C
W, W1
W, W1
Y, Y1
Y, Y1
G
G
W2
Y2
Function
Function
24VAC Power
24VAC Power
Common
Common
Stg1 Heating
Stg1 Heating
Fan
Fan
Stg2 Heating
Stg2 Cooling
Cooling
Stg1 Cooling
Heat Pump, 1 Compressor
Heat Pump, 2-Compressor
Use 6-conductor, 18 or 20 gage, thermostat cable.
Use 6-conductor, 18 or 20 gage, thermostat cable.
T21
Terminal
T21
Terminal
R
R
C
C
WOB
WOB
Y1
Y1
G
G
W2E/Y2
W2E/Y2
Wire Color
Wire Color
Red
Red
Blue
Blue
White
White
Yellow
Yellow
Green
Green
Brown
Brown
Equipment
Terminal
Equipment
Terminal
R, Rc, Rh
R, Rc, Rh
C
C
O or B
O or B
Y, Y1
Y, Y1
G
G
W, W2 or E
Y2
Function
Function
24VAC Power
24VAC Power
Common
Common
Rev Valve
Rev Valve
Fan
Fan
Aux Heat
Stg2 Compressor
Compressor
Stg1 Compressor
WIRING
Warning!
!
Turn the power to the HVAC equipment off before wiring.
INSTALLER SECTION
page 8 of 16
P/N 780101703 3/18 Rev A
