Emerson CW089, Design Manual

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115 Liebert
®
CW
™
System Design Manual
4.0 Miscellaneous Options
4.1 FLOW SWITCH—OPTIONAL
The flow switch shall activate the alarm system should the chilled water supply be interrupted. The switch
shall be factory mounted and wired.
4.2 VARIABLE SPEED DRIVE—OPTIONAL
A variable speed drive (VSD) is available for models CW106 and CW114 to reduce energy consumption.
The fan motor speed shall be varied from 100% to 60% of rated speed in response to room conditions.
This shall be controlled automatically by the Liebert iCOM
®
control. The variable-speed-drive option shall
be available with an infrared humidifier.
4.3 QUICK RESTART FUNCTION—OPTIONAL
Unit restart time shall be 15 seconds or less without additional power relays, capacitors or battery backup.
The quick start shall operate unit fan(s) and modulate the chilled water valve open to predefined points
while the Liebert iCOM is booting up. Liebert iCOM holds the chilled-water valve and fan at these
predefined points until the control has fully booted. Once the call for cooling and fan is established, the
valve and fan control are released to normal operation.
4.4 WIRED SUPPLY SENSOR(S)-OPTIONAL
Each Liebert iCOM shall have up to 10 optional supply-air sensors connected and used as controlling
sensors or for reference. This shall be in addition to the standard factory-supplied supply-air sensor. When
multiple sensors are applied for control purposes, the user shall be able to control based on a maximum or
average temperature reading.
4.5 WIRED REMOTE SENSOR(S)-OPTIONAL
Each Liebert iCOM shall have up to 10 2T sensors (20 sensor readings total) for control or reference. As
part of the U2U network, these sensors shall be shared and used to control the cooling units and provide
greater flexibility, visibility and control, using that to respond to changes in the conditioned space. When
the sensors are used for control, the user may set the control to be based on a maximum or average of a
selected highest temperature reading.
4.6 STATIC PRESSURE TRANSDUCER(S)—OPTIONAL
Each Liebert iCOM shall have up to 4 factory-installed and programmed static pressure transducer(s). The
transducer(s) may be used for control of fan speed or for reference of the supply plenum pressure. When
used for control, the Liebert iCOM shall be capable of:
• Sharing sensor data across multiple units in the U2U network to provide greater flexibility, visibility and
control. Only one transducer is required for a group of units. However, multiple transducers may be
applied per group and aggregated for redundancy.
• Offering the user with selections to control the fan on the average or the lowest pressure reading
collected in the U2U network.
4.7 AIRFLOW MONITORING—OPTIONAL
Liebert iCOM shall monitor evaporator fan airflow for monitoring purposes.
4.8 FLUID TEMPERATURE MONITORING—OPTIONAL
Up to 2 supply and 2 return chilled-water temperature sensors shall be provided to monitor entering and
leaving fluid temperatures at each unit. Fluid temperature shall be provided through the local display and
remote monitoring.