Liebert® XDF Air-Cooled Product Application Guidelines
To ensure successful installation and proper operation of the Liebert® XDF air-cooled unit, please adhere to
the guidelines below. If questions remain after reviewing these guidelines, please contact Emerson Network
Power, at 1-800-222-5877 to speak with an application specialist.
Application
Question
Can the Liebert XDF
be installed in any
size room?
Requirements
The air-cooled, self-contained
XDF is intended to be used in an
open room. If no ducting is
used, a minimum room size of
1600 sq ft is required.
Comments
Additional air exchange to a large space (for
example, via an open door) is recommended
whenever possible.
How much heat will
the Liebert XDF
exhaust and how
should it be
removed?
The self-contained Liebert XDF
produces 2700 CFM of airflow
with up to 68,000 BTU of heat
load and an air temperature
increase of up to 25°F. This heat
must be removed by the building
system serving the room in
which the self-contained XDF is
installed.
Inadequate exchange of condenser air will cause
recirculation and will adversely affect
performance. Ducting or a water-cooled Liebert
XDF should be considered if adequate airflow
and heat removal aren’t available.
Should the exhaust
air be ducted?
In applications where the room
volume is small, the condenser
exhaust air should be ducted.
The Liebert XDF condenser fan
is optimized for open discharge,
not for ducting, so a booster fan
should be used in most
applications to ensure adequate
exhaust airflow.
Please consult a contractor to determine the
appropriate booster fan requirements given the
ducting that will be installed at your site. Ducted
condenser air can significantly increase back-up
ventilation time.
When ducting the exhaust, the condenser fan
power source should be modified to ensure the
condenser fan runs during back-up ventilation
mode. Please reference the Liebert XDF user
manual (SL-17010) available at
www.liebert.com for instructions.
How much make-up
air is required for
this unit?
If ducting is used, a make-up air
source must be provided. 2700
CFM of air, between 35°F and
104°F is required.
Insufficient make-up air will reduce condenser
airflow and will adversely affect performance.
If adequate make-up air is not available, the
water-cooled Liebert XDF should be used.
In what ambient
temperature can the
Liebert XDF operate
effectively?
Can the unit be
operated in a highhumidity
environment?
The ambient temperature should
be between 35°F and 104°F.
Ambient temperature will affect the capacity of
the Liebert XDF. Temperatures above 95°F
begin to reduce the XDF’s capacity.
The unit can be operated
anywhere from 20% RH to 80%
RH.
High humidity will impact the cooling capacity
of the Liebert XDF. Conditions with a dew
point above 60°F (31% RH at 95°F, or 60% RH
at 75°F) will begin to reduce the XDF’s sensible
cooling capacity.
Liebert XDF Air-Cooled
Product Application Guidelines
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SL-17007_Rev3_09/08
Liebert® XDF Air-Cooled Product Application Guidelines
Application
Question
How will condensate
be removed?
Requirements
Condensate created via the
cooling process should be fed
into a gravity drain or pumped
away with an optional, factoryinstalled condensate pump.
Comments
The condensate pump will increase the distance
the condensate can be run from the unit to
approximately 30 horizontal feet and/or 12
vertical feet.
Should cable
entrances be sealed?
Yes, cables entrances should
always be sealed.
What is the
minimum room size
in which the Liebert
XDF can be
operated?
The smallest acceptable room
dimensions based solely on 36”
service clearances on the side,
top, front and rear are:
• 10’D x 5’10”W x 9’10”H
• 574 cubic feet
If cables are not sealed, air infiltration will
adversely affect unit performance and allow
contaminants inside the cabinet.
Without ducting, the minimum room size the
XDF should be operated in is 1600 sq ft. If
ducting is used, the room size requirement is
minimal, but makeup air must be considered (per
the guidelines above).
The volume of the room will also impact the
back-up ventilation time. Refer to the table on
page 3 for more information.
In what type of
environment can the
Liebert XDF be
operated?
Environments containing caustic
or explosive vapors are not
acceptable for this product.
The backup ventilation mode of the XDF will
circulate room air through the cabinet.
What equipment
heat load can this
unit accommodate?
The equipment load should be
between 3 kW and 14 kW.
Equipment load will also impact back-up
ventilation time. Refer to the table on page 3 for
more information.
What is the power
requirement for this
unit?
Two power connections are
required:
• 120/208V 3-ph (NEMA
L21-30P), and
• 120V 1-ph (NEMA 5-15P)
Please ensure 3-ph power (4 wires + ground) is
available to the room in which the Liebert XDF
will be located.
How much sound
will the Liebert XDF
make?
The sound power of the Liebert
XDF air-cooled unit is 86 dBA
(slightly louder than a fully
configured IT rack).
The water-cooled Liebert XDF has a lower
sound level than the Liebert self-contained, aircooled XDF (79 dBA compared to 86 dBA) and
is recommended for applications in which
people are working full-time in the same area.
How will I be able to
control and monitor
my Liebert XDF?
Liebert XDF comes standard
with an iCOM monitor and
control module.
An optional webcard can be ordered for remote
viewing and control via SNMP.
What type of backup
power is
recommended to be
used with this unit?
A true on-line, doubleconversion UPS is
recommended.
It is recommended that the Liebert XDF 1-ph
power connection be plugged into UPS backup
power to ensure the backup ventilation system
allows ample time for safe automated shutdown
of IT equipment in the event of an outage.
Liebert XDF Air-Cooled
Product Application Guidelines
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SL-17007_Rev3_09/08
Liebert® XDF Air-Cooled Product Application Guidelines
Backup Ventilation System
The back-up ventilation system in the Liebert XDF circulates room air through the cabinet in case of a power
failure or interruption of cooling inside the XDF. The size of the room, the temperature of the room, and the
heat load inside the XDF all affect the amount of back-up ventilation time available.
The table below contains estimates of the time until the internal rack equipment reaches 95°F (with back-up
ventilation running and Liebert XDF cooling off).
Room Volume (Cubic Feet)
1,200
2,400
5,000
7,500
10,000
6 kW Load
2 minutes
4 minutes
8 minutes
12 minutes
15 minutes
10 kW Load
1 minute
2 minutes
5 minutes
7 minutes
9 minutes
14 kW Load
45 seconds
1.5 minutes
3 minutes
5 minutes
6 minutes
NOTE - The following assumptions apply:
• Liebert XDF controls and internal fans continue to run during back-up ventilation. This may require that
they be powered from a separate back-up power source. This back-up power source must have sufficient
run time.
• The temperature in the room is 75° F when back-up ventilation begins operating.
• No cooling is done by the building system during the back-up ventilation. If the building cooling system
continues to run during backup ventilation, the time to reach 95°F will be longer.
Additional Information
Additional information related to specifying, engineering, and installing a Liebert XDF cooling solution is
available in the following documents. The documents can be accessed at www.liebert.com by entering the
SL number listed below into the search bar:
• Liebert XDF User Manual, SL-17010
• Liebert XDF Guide Specification, SL-17015
Liebert XDF Air-Cooled
Product Application Guidelines
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SL-17007_Rev3_09/08