Setting remote fan-speed control
NOTE: For more details about using a Liebert IntelliSlot® card for fan-speed control, refer to the
“Building Management Systems” section of the “Liebert
®
iCOM
®
User Manual” included with your
system documentation.
1. On the Service menu, touch S etp oin ts > Fan C on trol, set Fan Con trol T y p e to Manual, then
touch S av e.
2. On the Service menu, touch BMS & T eam work S etu p > BMS Setu p .
3. On BMS SETUP, touch C on trol Settin gs.
The CONTROL SETTINGS secondary panel displays:
• In Fan C on trol Sen sor, select Manual.
• Touch S av e.
BMS control of fan speed is set, and the BMS-set fan speed is displayed on the Fan Speed
slider.
NOTE: Set the fan speed via BMS by writing to the Fan Speed Maximum Set Point monitoring point. For
details, see SL-28170 IntelliSlot Reference Guide found at https :/ /w ww .vertivco .co m / en -u s/s u ppo rt/ .
NOTE: Local adjustments to fan speed are overridden when remote/BMS fan-speed control is set.
11.3.2 Automatic fan-speed control
Liebert iCOM on the CRV is factory-set for supply-air sensor control of fan speed and cooling capacity to
ensure that the CRV is delivering precise cooling to the cold aisle.
Remote rack sensors allows decoupling of fan speed and cooling capacity for the preferred operating
method of CRV(s) in a hot/cold-aisle configuration. Decoupling modulates cooling capacity based on
supply-sensor readings and relies on readings from the remote rack sensors for fan control to ensure that
cool air is delivered to the rack inlets on the cold aisle.
In the Setpoint screen, the controlling temperature sensor (S102) can be set to either Supply, Return or
Remote. As the selection is changed from one sensor to another, the setpoint is displayed next to the
corresponding sensor on the illustration, showing the sensors placement in relation to the LiebertCRV.
Temperature sensors can control fan-speed using one of three modes based on the type of sensor
selected as the fan-control sensor: supply, return, or remote, see Table 11.1 below. Control is based on the
selected sensor for both fan control and temperature control and their setpoints as follows:
• Coupled—the fan-control and temperature-control sensor selection is the same. When
coupled, fan speed is determined by the temperature setpoints.
• Decoupled—the fan-control and temperature-control sensor selection is different. When
decoupled, fan speed is determined by the fan setpoints.
TEMPERATURE CONTROL SENSOR SELECTED
SUPPLY SENSOR REMOTE SENSOR RETURN SENSOR
Fan Control Sensor selected
Supply Sensor Coupled N/A N/A
Remote Sensor Decoupled (Recommended) Coupled N/A
Return Sensor Decoupled Decoupled Coupled
Table 11.1 Fan-speed controlling sensor options
Vertiv | Liebert CRV Installer/User Guide | 122
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