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Designing a Liebert XD Solution
24
Figure 24 Hydraulic diagram
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 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 dis-
abled 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 Figures 26 and 25 for piping details of the bypass flow controller.
Refer to Table 6 to determine the number of bypass flow controllers needed, based on the total nomi-
nal cooling capacity of the cooling modules in each Liebert XD system.
Table 6 Bypass flow controllers for Liebert XDC- or Liebert XDP-based systems
Cooling Modules -
Cumulative Model Size
Required Number of Bypass Flow Controllers
Liebert XDP Liebert XDC
32 to 63 3 N/A
64 to 95 2 2
96 to 127 1 1
128 to 160 0 0
Liebert XDC
or
Liebert XDP
XD Cooling
Module *
XD Cooling
Module *
XD Cooling
Module *
XD Cooling
Module *
Pumped
Refrigerant
Liebert XDC
or
Liebert XDP
Supply Lines
Return Lines
Pumped
Refrigerant
* XD CoolFrame,
XDH, XDO or XDV
A
B
A
B
C
D
C
D
C
D
C
D