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Site Preparation and Installation
19 Liebert
®
Mini-Mate2
™
Chilled Water Piping—On chilled water units install manual service shut-off valves at the supply
and return lines of each unit. These shut-off valves are used for routine service or emergency isolation
of the unit.
Chilled water supply and return lines must be insulated. Insulating them will prevent condensation
of the water supply and return lines to the unit.
The minimum recommended water temperature is 42°F (5.5°C). Connection sizes are 1-1/8" (28.6mm)
OD copper.
Water/Glycol Piping—Water- and glycol-cooled systems require coolant loop connections as
specified in the condensing unit installation instructions.
Refrigerant R-407C Piping—All split systems require two refrigerant lines (an insulated copper
suction line and a copper liquid line) between the evaporator and the condensing unit.
Two possible methods exist for installing the copper suction and liquid lines.
• Close coupling the units together using the quick connects. (See Figure 15).
• Using an optional sweat adapter kit and hard piping between the two units.
All refrigeration piping should be installed with high temperature brazed joints. Prevailing good
refrigeration practices should be employed for piping supports, leak testing, evacuation, dehydration
and charging of the refrigeration circuits. The refrigeration piping should be isolated from the
building by the use of vibration isolating supports. To prevent tube damage when sealing openings in
walls and to reduce vibration transmission, use a soft flexible material to pack around the tubes.
When installing remote condensing units above the evaporator, the suction gas line should be trapped
at the evaporator. This trap will retain refrigerant oil in the off cycle. When the unit starts, oil in the
trap is carried up the vertical riser and returns to the compressor.
!
WARNING
Risk of explosive discharge of high pressure refrigerant. Can cause serious injury.
Relieve refrigerant system pressure before working with piping/connections.
Table 8 Recommended refrigerant line sizes
Equivalent Pipe
Length, ft (m)
Liquid Suction
50 (15) 1/2" 1-1/8"
100 (30.5) 5/8" 1-1/8"
150 (45.7) 5/8" 1-3/8"
Suction line and liquid line sizing based on < 3 psi pressure drop in each and suction line refrigerant
velocities >1000FPM (5.1m/s) for proper oil return.
Table 9 Equivalent lengths for various pipe fittings, ft (m)
Copper Pipe
OD, in.
90 Degree
Elbow Copper
90 Degree
Elbow Cast
45 Degree
Elbow Tee
Gate
Valve
Globe
Valve
Angle
Valve
1/2 0.8 (0.24) 1.3 (0.39) 0.4 (0.12) 2.5 (0.76) 0.26 (0.07) 7.0 (2.13) 4.0 (1.21)
5/8 0.9 (0.27) 1.4 (0.42) 0.5 (0.15) 2.5 (0.76) 0.28 (0.08) 9.5 (2.89) 5.0 (1.52)
3/4 1.0 (0.3) 1.5 (0.45) 0.6 (0.18) 2.5 (0.76) 0.3 (0.09) 12.0 (3.65) 6.5 (1.98)
7/8 1.45 (0.44) 1.8 (0.54) 0.8 (0.24) 3.6 (1.09) 0.36 (0.1) 17.2 (5.24) 9.5 (2.89)
1-1/8 1.85 (0.56) 2.2 (0.67) 1.0 (0.3) 4.6 (1.4) 0.48 (0.14) 22.5 (6.85) 12.0 (3.65)
1-3/8 2.4 (0.73) 2.9 (0.88) 1.3 (0.39) 6.4 (1.95) 0.65 (0.19) 32.0 (9.75) 16.0 (4.87)
1-5/8 2.9 (0.88) 3.5 (1.06) 1.6 (0.48) 7.2 (2.19) 0.72 (0.21) 36.0 (10.97) 19.5 (5.94)
Refrigerant trap = Four times equivalent length of pipe per this table