Refrigeration Piping Installation - Emerson Copeland Scroll User Manual

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 of time (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. All interconnecting pipes should be sized to satisfy the duty required.
Usually the suction line is insulated, but the liquid line is not. However the liquid line can pick up additional heat from the
ambient and adversely affect the sub-cooling desirable for the liquid refrigerant before it enters the expansion valve.
The pipe should be sized to ensure optimum performance and good oil return. The sizing must also take into account 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.
Tube Size
12.7mm (1/2 inch)
16.0mm (5/8 inch)
22.0mm (7/8 inch)
28.5mm (1 1/8 inch)
ZXL liquid line insulation
ZXL liquid line should be insulated with a 19 mm insulation thickness. Temperature could be as low as –15°C.
Brazing recommendations
Maintain a flow of oxygen-free nitrogen through the system at a very low pressure during brazing. Nitrogen displaces the air
and prevents the formation of copper oxides in the system. If copper oxidization is allowed to form, the copper oxide material
can later be swept through the system and block screens such as those protecting capillary tubes, thermal expansion valves,
and accumulator oil return holes. This minimizes any entry of contaminants and moisture.
• Remove the liquid line connection cap.
• Then remove the suction connection cap.
• Open both valves midway. Care should be taken to
avoid the holding charge from releasing too quickly.
• Be sure tube fitting inner diameter and tube outer
diameter are clean prior to assembly.
• Since both tubes are extended from the condensing
unit housing, we recommend insulating the housing
by using a wet cloth on the copper tubing.
• Recommended brazing materials: a copper /
phosphorous or copper / phosphorous / silver alloy
rod should be used for joining copper to copper
whereas to join dissimilar or ferric metals, use a
silver alloy rod, either flux coated or with a separate.
• Use a double tip torch.
Max distance between
2 clamp support
1.20 m
1.50 m
1.85 m
2.20 m
OUTSIDE
End of tube
During brazing
protect housing with
damp cloth
INSIDE UNIT
During brazing
pull back fire
insulation
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