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5.4.2 Brazing Preparations
After the holding charge has been vented, a torch can be used to remove the caps over the ends of the
supply and return lines.
The assembly and connection means used for piping in the Liebert XD system are similar to those
used for conventional refrigeration systems. All piping should be installed with high-temperature
brazed joints. Soft soldering is not recommended.
During brazing, the lines must be filled with flowing dry nitrogen to prevent excessive oxidation and
scale formation inside the piping. Prevailing good refrigeration practices must be employed for piping
supports, leak testing, dehydration and charging. Failure to use good system practices may result in
damage to the system. Refer to the ASHRAE refrigeration handbook for general good-practice refrig-
eration.
5.5 Connection Methods for Hard Pipe
The assembly and connection means used for piping in the Liebert XD system are the same as those
used in conventional refrigeration systems. Observe all standard practices during installation and
startup to prevent damage and contamination.
5.6 Recommended Piping Size
Connect the main pipes between the Liebert XDH branch piping and the Liebert XDP or Liebert XDC
according to Table 2. Elbows and restrictions must be minimized to ensure good fluid flow.
Please see Table 2 below for recommended pipe sizes and Figure 3 for piping segment locations.
5.6.1 Connecting Methods—One-Shot Connections
The assembly and connection means used for piping in the Liebert XD system are the same as those
used in conventional refrigeration systems. Observe all standard practices during installation and
startup to prevent damage and contamination.
Both supply and return fittings may be supplied with optional, one-shot connections. These fittings
contain pressurized R-134a refrigerant inside the Liebert XDH.
Table 2 Branch piping sizes for pumped refrigerant loop
Pipe Function Size / Equivalent Pipe Length
From Liebert XDH supply to supply line of
Liebert XDP/Liebert XDC
1/2" OD (0.430" ID) for lengths up to 10 feet (3m)
7/8" OD(0.545" ID) for lengths over 10 feet but less than 25 feet (3-7.6m)
From Liebert XDH return to return line of
Liebert XDP/Liebert XDC
7/8" OD(0.545" ID) for lengths up to 10 feet (3m)
1-1/8" OD(1.025" ID) for lengths over 10 but less than 25 feet (3-7.6m)
NOTE
To minimize the amount of pumped refrigerant required, do NOT oversize the piping.
!
CAUTION
Risk of sudden refrigerant discharge. Can cause loss of charge and minor injury.
If the optional precharged option is chosen, the Liebert XDH is shipped with a full charge of
R-134a refrigerant under pressure. Do not remove the pipe caps or plugs before the unit is
ready for connection to Liebert XD Piping.
Supply and return fittings on the precharged Liebert XDH units are one-shot connections. Do
not disconnect one-shot connections after they have been connected. Disconnection will
release pressurized R-134a refrigerant from the Liebert XDH.