Emerson CW089, Design Manual, Page: 105 / 132

Customer-supplied Equipment and Ductwork
95 Liebert
®
CW
™
System Design Manual
Appendix B: Optional Liebert Air Economizer™
for Liebert CW
The Liebert Air Economizer is an option for Liebert CW chilled water downflow units, Liebert DS™
downflow units and Liebert PDX/PCW downflow units. The Liebert Air Economizer uses cool outdoor air in
mild climates to condition indoor spaces. It is functional only on cooling units with Liebert iCOM
®
controls
that have been factory-wired and configured to accommodate the Liebert Air Economizer.
The Liebert Air Economizer is supplied with electrical wiring for connection to the cooling unit, outdoor air
sensors, return air sensors and a temperature-and-humidity-sensing unit (see
Figures B-4 through B-8 ).
Special firmware is loaded into the primary cooling unit at the factory to permit the primary cooling unit to
control the Liebert Air Economizer.
B.1 Customer-supplied Equipment and Ductwork
Installation and operation requires outside-air entry ductwork with louvers, screening and filtration to
prevent intrusion of precipitation, particulates, vermin and unauthorized entry (see
Figure B-1 ).
Proper installation also requires a customer-provided powered relief-air discharge to rid the structure of the
outside air drawn in for cooling. The relief-air discharge must be equivalent to the airflow of the total of all
cooling systems equipped with the Liebert Air Economizer.
A flange is provided to attach the Liebert Air Economizer to the outdoor air duct (see Figures B-2
and B-3 ).
See the Liebert Air Economizer manual, SL-18845 on the Liebert Web site, www.liebert.com , for more
details.
NOTE
When upgrading the firmware for the primary cooling unit, either a Liebert DS downflow unit or
Liebert CW downflow unit, ensure that the new firmware includes the Liebert Air Economizer
controls. If in doubt, contact your sales representative.