Air Economizer Emergency Override
The Liebert® Air Economizer can be configured to override SA04 through SA07 in the event the facility gets too hot. This
override becomes active if the room temperature exceeds an adjustable high temperature high return temperature threshold
set on line SA10. The emergency override will open the outdoor air damper and close the indoor air damper. The override
function can be delayed after a fan start on line SA11, allowing airflow to pass over the room sensor to get an accurate reading
before any emergency modes are activated. When the economizer is operating in emergency mode, an Eco Emergency
Override event will be triggered.
3.5.3 Adjust the Restricted Airflow Switch on the Vertiv™ Liebert® Air Economizer
The restricted airflow switch inside the cooling unit must be adjusted for the Liebert® Air Economizer to operate properly and
efficiently. To adjust the switch:
1. Inspect all connections, restore power to operate the unit’s blower.
2. Go to the Service Menus, Diagnostic / Service Mode.
3. Enter the Service Menu password 5010.
4. Enable manual mode on line S313. The unit will shut Off.
5. Go to line S314 Motors and change the value displayed from No to Yes. This will allow the evaporator fan to run
with the outside air damper at minimum position.
6. Confirm the fan is running at minimum speed. This is shown on line S343 “Analog Out 3” of the Diagnostics /
Service Mode.
7. Confirm the outside air damper has moved to the minimum position by visually checking damper position.
8. Find the restricted airflow switch in the cooling unit (Figure 3.18 on page 45 shows the switch location in both the
Liebert® CW and Liebert® DS).
9. Turn the restricted airflow switch alarm setpoint knob clockwise until it trips. The cooling unit will also alarm.
a. Place a voltmeter on Terminal 56 and on the chassis ground.
b. Turn the airflow sensor counterclockwise until the voltmeter indicates 0VAC.
c. Turn the airflow sensor adjustment screw clockwise until the voltmeter indicates 24VAC.
d. When the voltmeter shows 24VAC, turn the screw counterclockwise one full turn.
Once the airflow switch has been calibrated, go to the Service Menus, Diagnostics / Service Mode. Using the Service Menus
password 5010, disable manual mode on line S313.
Cycle power Off to the unit using the I/O button, then turn the unit Off at the disconnect. Cycle power back On to the
disconnect, then press the I/O button once the control has finished booting up. Verify unit operation as the fan starts and
outside damper opens. If a 'Reduced Eco Airflow' alarm occurs during when the unit starts, the alarm time delay located in
Service, Set Alarms may need to be adjusted higher. The reduced airflow alarm is latched in the control for 90 minutes after
calibration. Acknowledge this alarm and allow it to clear by pressing the horn button on the control once. The alarm may also
be cleared by shutting Off power to the Vertiv™ Liebert® iCOM™ and cycling power to the cooling unit. The unit will now
resume normal operation.
3 Service Operation
80
Vertiv™ Liebert® iCOM™Installer/User Guide
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