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Site Preparation and Installation
14
Refrigerant (R-22) Piping
All split systems require two sets of refrigerant lines (two insulated copper suction lines and two cop-
per liquid lines) 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.
• 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 refrig-
eration 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.
Figure 9 Refrigerant piping diagram
Table 6 Recommended refrigerant line sizes
Equivalent
Feet Circuit Liquid Line
Suction
Line
50 feet 3-ton 3/8" O.D. 7/8" O.D.
100 feet 3-ton 1/2" O.D. 7/8" O.D
150 feet 3-ton 5/8" O.D. 1-1/8" O.D
50 feet 5-ton 1/2" O.D. 1-1/8" O.D
100 feet 5-ton 5/8" O.D. 1-1/8" O.D
150 feet 5-ton 5/8" O.D. 1-3/8" O.D
Consult your Liebert representative for longer line lengths.
NOTE
If field supplied refrigerant piping is installed, refrigerant (R-22) must be
added to the system.
Suction Line Piping
Condensing Unit Below Evaporator
Suction Line Piping
Condensing Unit Above Evaporator
Traps recommended every 25 feet (7.6 m) of vertical rise.
Condensing Unit
Evaporator
NOTE: When installing remote condensing
units below the evaporator, the suction gas
line should be trapped with an inverted trap
to the height of the evaporator. This
prevents refrigerant migration to the
compressors during off cycles. Maximum
recommended vertical drop to condensing
unit is 20 feet (6.1 m).
Pitch down 1/2" per 10 feet
Evaporator
Condensing Unit