Vertiv Liebert XD Series, System Design Manual

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For additional information about piping connections, see the unit’s user manual: Liebert XDP, 16647;
Liebert XDC, SL-16673; Liebert XDO, SL-16666; Liebert XDV, SL-16626; Liebert XDCF, SL-16678; Liebert
XDR SL-16935; and Liebert XDH SL-17210.
NOTE: To minimize the amount of refrigerant required, do NOT oversize the piping.
Figure 3.15 Generic piping layout
3.14 Liebert XD Piping Slope
The main supply and return lines to and from the XDP/XDC must be sloped downward toward the
XDP/XDC at a rate of 1-2" per 20 feet (25-51mm per 6m) of pipe run. Horizontal connector lines should also
be sloped downward from the cooling modules toward the main supply and return lines.
3.15 Bypass Flow Controllers
To ensure the Liebert XDP/XDC pumps operate within the optimum range, some installations require one
or more bypass flow controller(s). These devices are added to the field piping, and simulate the flow of
additional cooling modules.
Each bypass flow controller should be installed with one shutoff valve to allow the controller to be disabled
when cooling modules are added to a Liebert XD system.
If bypass flow controllers are required, they should be connected between the main supply and the main
return lines of the field piping. The connection points to the main supply and return lines should be in a
convenient and accessible location between the Liebert XDP/Liebert XDC and the first Liebert XD module
in the circuit. See Figure 3.17 on the facing page andFigure 3.16 on the facing page for piping details of
the bypass flow controller.
Refer to Table 3.8 on the facing page to determine the number of bypass flow controllers needed, based
on the total nominal cooling capacity of the cooling modules in each Liebert XD system.
Vertiv | Liebert® Xtreme Density™ System Design Manual | 40