Liebert Refrigerant Distribution Unit XDP - Manual (Page 20)

Piping
14
2.5 Piping Details—Shut-Off/Isolation Valves
To allow for maintenance of the Liebert XDP, isolation valves must be installed on the chilled water
circuit (see Figure 20).
Figure 20 General piping details
2.5.1 Piping Installation Method
All piping should be installed with high temperature brazed joints. Prevailing good refrigeration prac-
tices should be employed for piping supports, leak testing, dehydration and charging. Emerson Net-
work Power highly recommends venting the pressure relief of the Liebert XDP (located at the top of
the receiver) outside of the conditioned space where it is open to the atmosphere.
2.5.2 Piping Mains
All refrigeration piping mains, both supply and return, should be installed with a downward pitch
toward the Liebert XDP of 1-2" for every 20 feet (25.4-51mm per 6m) of pipe run.
Install a 20-40 mesh strainer on the chilled water supply to the Liebert XDP. The strainer is needed
to prevent particles in the chilled water from entering the heat exchanger of the Liebert XDP.
2.5.3 Evacuation and Leak Check
1. Open all service valves, including those located outside of the Liebert XDP.
2. Place 150 psig (1034kPa; 10.34 bars) of dry nitrogen with a tracer of R-134a in the system.
NOTICE
Risk of overpressurization. Can cause equipment damage.
Do not exceed 150 psig (1034 kPa; 10.34 bars) in the R-134a circuit.
3. Check the system for leaks with a suitable leak finder
4. After completion of the leak testing, release the test pressure (per local code) and connect to
vacuum pump(s) at the Schrader valves.
5. After four hours of pulling a deep vacuum, check the vacuum level and if it has not changed,
break the vacuum with dry nitrogen.
6. Pull a second vacuum to 250 microns or less. Recheck the vacuum level after 2 hours.
Liebert
XDP A
Liebert
XDP B
Return
Supply
Return
Supply
Floor
Building Chilled Water Supply
Building Chilled Water Return
Isolation
valves
Isolation
valves