SC-Z20
WIRING DETAILS
GENERAL NOTES
I
nstall the SC-Z20 control panel on a flat surface near the HVAC equipment. The panel should be installed in a dry, clean
location approximately 60 inches from the floor. Do not install the control panel on or inside a rooftop unit.
24 VOLT POWER
The control panel requires a 24 Volt transformer with a proper VA rating. Do not power the control panel from the
transformer in the HVAC equipment. Connect 24 Volts to the terminals labeled
on the interface
24 VAC INPUT POWER
board. 18-2 thermostat wire is recommended.
DISCHARGE AIR TEMPERATURE SENSOR
The control panel requires a discharge air temperature sensor. Mount the sensor 26 inches from the HVAC equipment in
the supply duct. Connect the sensor to the terminals labeled
on the interface board. 18-2 thermostat wire is
DAS
recommended.
HVAC UNIT
The control panel is wired to the HVAC equipment in the same way as a standard 2-stage heat / 2-stage cool thermostat.
Connect the HVAC equipment to the terminals labeled
on the interface board. 18-8 thermostat wire is
HVAC SYSTEM
recommended.
R, C, Y, AND W ZONE DAMPER TERMINALS
The control panel requires a heating and cooling contact closure from each zone damper. Connect terminals
,
, , and
R C Y
W
R C, Y
W
from each zone damper to the terminals labeled
,
, and
on the interface board. 18-4 thermostat wire is
recommended.
SC-Z20-NS PROGRAMMABLE NIGHT STAT (OPTIONAL)
The control panel has an optional input for a SC-Z20-NS programmable night stat. To install the thermostat, remove the
factory installed jumper between the two terminals labeled
and
and wire the jumper across terminals
and . Refer to
T
T
R
T
the SC-Z20-NS wiring and programming instructions in this manual.
MINIMUM CALLS SELECTION SWITCHES
The control panel is equipped with two
selector switches located on the interface board. When both
Minimum Calls
switches are in the OFF position, any zone calling can bring on the equipment. When the
switch is in the ON
2 ZONES
position, at least two zones have to call to bring on the equipment. When the
switch is in the ON position, at least
3 ZONES
three zones have to call to bring on the equipment. If both
and
switches are in the ON position, the
2 ZONES
3 ZONES
default is three.
TIME DELAY SPEED UP BUTTON
The control panel is equipped with a time delay speed up button. When the speed up button is engaged the time delays
between stages and between modes of operation are divided by 15. The time delay speed up mode will reset after fifteen
minutes. Time delay speed up should only be used for start up and service.