c. Refrigeration Piping Installation
All interconnecting pipes should be of refrigeration grade, clean, dehydrated and
must remain capped at both ends until installation. Even during installation, if the
system is left for any reasonable period (say two hours), pipes should be re- capped
to prevent moisture and contaminants from entering the system.
Do not assume that the service connection sizes on the unit (at the service valves)
are the correct size to run your interconnecting refrigeration pipes. The service
valve sizes have been selected for convenience of installation and in some cases
(larger units) these may be considered too small. However, for the very short pipe
run within our units, these service connection sizes are adequate.
The pipe should be sized to ensure optimum performance and proper oil return.
The sizing must also consider the full capacity range through which this particular
unit will need to operate.
Pipe runs should be kept as short as possible, using the minimum number of
directional changes. Use large radius bends and avoid trapping of oil and
refrigerant. This is particularly important for the suction line. The suction line
should ideally slope gently towards the unit. Recommendation slope is
1/200~1/250. P traps, double risers and reduced pipe diameters may be required
for suction lines where long vertical risers cannot be avoided. All pipes should be
adequately supported to prevent sagging which can create oil traps.
The recommended pipe clamp support distance is shown in the table.
d. Refrigerant line insulation
-
Insulate suction lines from the evaporators to the condensing unit with
minimum 1” thickness closed-cell type insulation on low temperature
circuits.
-
Liquid lines of Dual temperature systems to be insulated with minimum of ¾”
insulation.
-
Long liquid lines run in areas exposed to high temperatures should be fully
insulated with minimum 1/2” insulation.
-
Suction and liquid lines should never be taped or soldered together.
15
Tube Dia
Max distance between 2 clamp support
1/2 inch
1.2 M
5/8 inch
1.5 M
7/8 inch
1.8M
1
1/8 inch
2.1M
1-5/8
2.3
