SYSTEM NOTES:
Use standard 18 gauge thermostat wire.
Actuator requires a 24VAC 40VA transformer.
Option 2: Sensor can be relocated after the electric duct heater. RY1 relay coil can be wired to terminals
Option 1: RY1 can be used to bring on electric heat and drive damper open without relocating sensor. A 15K Ohm
PO
PC
W
R
C
DS
DS
Y
1
2
3
4
5
6
7
8
C
R
R
Y
W
1
2
3
4
5
ACTUATOR
BOARD
DAMPER OR
DIFFUSER
ACTUATOR
90 SECOND TIMING
90° STROKE
44 lb.-
in.
2
VA
DAMPER OPEN
(24VAC)
DAMPER CLOSED
(24VAC)
CALL FOR HEAT
(24VAC)
24VAC POWER
(HOT)
24VAC POWER
(COM.)
DUCT SENSOR
DUCT SENSOR
CALL FOR COOL
(24VAC)
DUCT SENSOR
(10K OHMS @77°)
OPEN
CLOSED
COM.
DS
DS
HEAT
COOL
WIRE TO
OPTIONAL
SLAVE
DAMPER
(UP TO 20 MAY BE WIRED
IN PARALLEL)
SC-Z20-T
AUTO CHANGEOVER
SPACE THERMOSTAT
FACTORY JUMPER
RED LED
INDICATES
A CALL FOR
HEATING
GREEN LED
INDICATES
A CALL FOR
COOLING
OPTION 1
resistor must be wired to the relay contacts so that when the relay is energized, the resistor will be in parallel with
the duct sensor. This will change the ohms value translating to a higher duct temperature which will drive the damper
open.
NC C NO
RY1
RELAY
24 V
COIL
15K Ohm Resistor
SC-Z20-T MODULATING OR TWO-POSITION
ZONE THERMOSTAT
WIRE TO SC-Z20
ZONE PANEL TERMINALS
3 and 5 on the actuator board. Relay contacts are wired in series with the duct heater coil.
OPTION 2
NC C NO
RY1
RELAY
24 V
COIL
WIRE TO DUCT HEATER COIL
5 3
WIRING DIAGRAM FOR ZONE HAVING AN ELECTRIC DUCT HEATER
COM
OPEN
CLOSE