Emerson Xtreme Density Manuel D’Utilisation

The free-standing Liebert XDH cooling unit is best placed among the equipment cabinets in a hot 

aisle-cold aisle arrangement (see Figure 18). The Liebert XDH draws in air from the hot aisle, cools 

it and discharges the cooled air into the cold aisle where it is drawn into the equipment cabinets. Reg-

ular spacing aids in optimizing cooling.
Liebert XDH units should be placed among the cabinets that generate the greatest amount of heat. If 

heat loads are dispersed evenly throughout the room, the Liebert XDH modules may be spread out 

accordingly.
If a Liebert XDH is installed at the end of a row, Liebert recommends using uni-directional air diffus-

ers on that Liebert XDH. The uni-directional diffusers can be used for left or right air discharge by 

removing them from the Liebert XDH, turning them 180 degrees, then reattaching them to the Lie-

bert XDH.
Liebert recommends using bi-directional air diffusers on Liebert XDH modules installed between 

racks.

The Liebert XDP/Liebert XDC may be placed in the critical space or in an adjacent equipment room. 

The allowable distance between the Liebert XDP/Liebert XDC and its connected cooling modules is 

determined by the piping design and by the amount of refrigerant required. Refer to 3.12 - Liebert XD 

Refrigerant and 3.13 - Liebert XD Piping System Design.
The maximum height of any of the main or connecting piping should be no more than 20 feet (6m) 

above the top of the Liebert XDP/Liebert XDC unit. Liebert XDV/Liebert XDO modules should be 

placed as close to the same level as possible. The differences in elevation between the highest and low-

est Liebert XDV or Liebert XDO module in a system should be no more than 6 feet (2m).

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