Pipe Length m (ft)
External diameter mm (in.) x Pipe Thickness mm (in.)
CRD 25 Gas pipe
CRD 25 Liquid Pipe
CRD 35 Gas Pipe
CRD 35 Liquid Pipe
0 to 20 (0 to 65.6)
18 (3/4) x 1.2 (0.05)
16 (5/8) x 1 (0.04)
22 (7/8) x 1.5 (0.06)
16 (5/8) x 1 (0.04)
20 to 50 (65.6 to 164)
22 (7/8) x 1.5 (0. 06)
18 (3/4) x 1 (0.04)
25 (1) x 1.5 (0.06)
18 (3/4) x 1.2 (0.05)
50 to 120 (164 to 393.7)
25 (1) x 1.5 (0.06)
22 (7/8) x 1.2 (0.05)
25 (1) x 1.5 (0.06)
22 (7/8) x 1.5 (0.06)
Table 5.2 External Diameter and Thickness of Pipelines
External Diameter of Liquid Pipe mm (in.)
Equivalent Length m (ft)
90° Bend
45° Bend
16 (5/8)
0.27 (0.886)
0.15 (0.492)
18 (3/4)
0.3 (0.984)
0.18 (0.591)
22 (7/8)
0.44 (1.443)
0.24 (0.787)
Table 5.3 Equivalent Length of Components
Installing Pipelines
To install pipelines:
1.
Release the pre-charged nitrogen. The evaporator and condenser have been pre-charged with 2 bar (29 psig)
nitrogen. Open all the Schrader valves in the system to release nitrogen.
2.
Cut the liquid pipe and gas pipe connectors on the evaporator and condenser.
3.
Lay the pipes between the evaporator and condenser.
4. Connect a nitrogen cylinder to the Schrader valve. Purge the pipe with nitrogen to flow through the pipe while
welding the pipe.
NOTE: A pure dry nitrogen flow of 0.5 - 1.5 l/s (1 - 3 ft
3
/min) inside the pipe during brazing is sufficient to displace the
air. Control the flow using a suitable measuring device.
NOTE: Nitrogen prevents the formation of copper oxide scale inside the piping. When copper is heated in the
presence of air, copper oxide forms. Lubricating oil will dissolve these oxides from inside the copper pipes and
deposit them throughout the system, clogging filter driers and affecting other system components.
NOTE: Before brazing connections, use wet rags to quench the heat and prevent damage to piping bushings or heat
sensitive refrigerant components.
NOTE: When brazing connections from the bottom, do not weld the liquid pipe and the gas pipe at the same time.
Weld one pipe and then another. The location of the liquid pipe and the gas pipe in the bottom is shown in the figure
below.
5 Piping and Refrigeration Connections
39
Vertiv™ Liebert® CRV CRD25 and CRD35 Row-Based Cooling System User Manual
