Site Preparation and Installation
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.
Table 6 | Recommended refrigerant line sizes | |||
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Equivalent |
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| Suction | |
Feet |
| Circuit | Liquid Line | Line |
50 feet |
| 3/8" O.D. | 7/8" O.D. | |
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|
100 feet |
| 1/2" O.D. | 7/8" O.D | |
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|
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150 feet |
| 5/8" O.D. | ||
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|
50 feet |
| 1/2" O.D. | ||
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|
|
|
|
100 feet |
| 5/8" O.D. | ||
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150 feet |
| 5/8" O.D. | ||
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|
|
|
|
Consult your Liebert representative for longer line lengths.
NOTE
If field supplied refrigerant piping is installed, refrigerant
Figure 9 Refrigerant piping diagram
Evaporator
Suction Line Piping
Condensing Unit Below Evaporator
Evaporator
Pitch down 1/2" per 10 feet
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).
Condensing Unit
Condensing Unit
Suction Line Piping
Condensing Unit Above Evaporator
Traps recommended every 25 feet (7.6 m) of vertical rise.
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