Summary of Contents for Specified Controls SC-Z20
- Page 1 Commercial Zone Control System Modulating or Two-position Installation Manual SC-Z20...
- Page 2 SC-Z20 MODULATING ZONE CONTROL SYSTEM System Features • Fully modulating zone dampers and diffusers • Up to 20 zones • Auto changeover • Works with single stage, multi-stage, or heat pump systems • No programming required • Auxiliary heat control option for each zone •...
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Page 3: Sequence Of Operation
MODULATING ZONE CONTROL SYSTEM OVERVIEW The SC-Z20 is a commercial zone control system that allows a single HVAC unit to have up to 20 individual zones. Each zone is controlled by its own space thermostat and a modulating damper. When a majority of zones are calling for cooling, the system operates in the cooling mode. The SC- Z20 controls up to two stages of cooling to maintain a cooling discharge air setpoint. - Page 4 SC-Z20 MODULATING ZONE CONTROL SYSTEM WIRING AND LAYOUT GUIDE SC-Z20 SC-Z20-NS NIGHT STAT...
- Page 5 SC-Z20 PANEL LAYOUT PC BOARD 4 AMP COOL NOT USED HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT COOL COOL HEAT HEAT STATUS HEAT COOL...
- Page 6 FAN RUN TIME AFTER CLOCK 5 MINUTES 20 SECONDS CONTACTS OPEN Speed Up Mode auto-resets after 15 minutes SC-Z20 SYSTEM STATUS LED DEFINITIONS AND FUNCTIONS Time Delay Speed - Up BLINKS when time delays are in speed up mode Discharge Air Sensor GREEN...
- Page 7 HEAT HEAT STATUS HEAT COOL COOL DAS ACTIVE HEAT OCCUPIED COOL PLACE JUMPER ACROSS ‘R’ AND ‘T’ TERMINALS HEAT SC-Z20 ‘E’ AND ‘E’ CONTACTS ECONO CLOSE IN OCCUPIED MODE COOL HEAT TIME DELAYS DIVIDED BY 15 COOL SPEED HEAT MODE...
- Page 8 SC-Z20-T MODULATING OR TWO-POSITION ZONE THERMOSTAT WITH AUTO CHANGEOVER KEY FUNCTIONS ON/OFF KEY - When the SC-Z20-T is not locked, this key allows the thermostat to be turned ON or OFF. When in the OFF position, the damper is also driven closed...
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Page 9: Operation Sequence
SC-Z20 panel that there is a heating call. When the room temperature is 1.5 degrees above the setpoint the thermostat will close the R to Y contacts on the actuator board and signal the SC-Z20 panel that there is a cooling call. DAMPER NOTES: To balance the HVAC system, unlock the thermostat by setting slide switch 1 to the OFF position. - Page 10 SC-Z20-T MODULATING OR TWO-POSITION ZONE THERMOSTAT WIRING DIAGRAM FOR ZONE HAVING AN ELECTRIC DUCT HEATER DAMPER OR DIFFUSER ACTUATOR ACTUATOR SC-Z20-T BOARD AUTO CHANGEOVER SPACE THERMOSTAT RED LED INDICATES A CALL FOR HEATING DAMPER OPEN (24VAC) DAMPER CLOSED (24VAC) HEAT...
- Page 11 Wiring the SC-Z20-NS to the SC-Z20 panel only requires 18 gauge thermostat wire. (See diagram) Wire the thermostat ‘C’ terminal to the Clock Power ‘C’ terminal on the SC-Z20 panel. Wire the thermostat ‘R’ terminal to the Clock Power ‘R’ terminal on the SC- Z20 panel.
- Page 12 HOW IT WORKS: The SC-Z20-NS does not control the HVAC equipment and only uses the ‘G’ fan relay to put the SC-Z20 panel in either the occupied or unoccupied mode. This is accomplished by using the Programmable Fan option so that the fan relay is energized during occupied mode (Always On) and de-energized during unoccupied mode (Automatic).
- Page 13 7. Tap Program again until the hour flashes and Night is displayed on the LCD. Use the DOWN arrow to set the hour start time. Note: PM hours are indicated by on the LCD. 8. Tap Program again until the minutes flash. Use the DOWN arrow to set the minutes.
- Page 14 DO NOT mount the SC-Z20 panel on or inside the rooftop unit. • Use a separate 24 VAC, rated at the proper VA transformer for the SC-Z20 panel. • All wiring should be 18 gauge standard or plenum rated thermostat wire.
- Page 15 GENERAL NOTES 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.
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Page 16: Warranty
APPLICATION: The model SC-Z20 is a commercial zone control system that allows a single heating and cooling unit to have up to 20 individual zones. Each zone is controlled by its own space thermostat and motorized damper. If a majority of zones are calling for heat, the system will operate in the heating mode. -
Page 17: Zone Dampers
1.01 ZONE CONTROL SYSTEMS Genera l. Provide a SC-Z20 zone control system manufactured by Specified Controls to meet the performance as specified in this section. Each zone control system shall meet the following requirements. The zone control system shall be composed of one logic panel, up to 20 zone dampers with actuators, zone thermostats, and bypass damper(s). -
Page 18: Bypass Dampers
. EDPM seal installed on inside of round damper shell. Leakage shall be less than 2% at 3 inches of static pressure. Dampers shall be Specified Controls ZD-XX, ZD-XXXX or approved equal. VAV Diffusers shall be Specified Controls VD-XX or approved equal. -
Page 19: Service And Guarantee
SC-Z20 SPECIFICATION SUGGESTIONS 1.05 WIRING Control Wiring All control wiring shall be 24 Volts or less. All control wiring shall be standard or plenum-rated thermostat wire. 18 gauge minimum. No shielded cable shall be required. Control wire and cable shall be installed in accordance with NEC.
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