Piping Works & Brazing Technique
• Do not use contaminated or damaged copper tubing.
If any pipings, evaporator or condenser had been
exposed or had been opened for 15 seconds or more,
then vacuum and purge with field supplied refrigerant.
Generally, do not remove plastic, rubber plugs and
brass nuts from the valves, fittings, tubings and coils
until it is ready to connect suction or liquid line into
valves or fittings.
• If any brazing work is required, ensure that the
nitrogen gas is passed through coil and joints while
the brazing work is being done. This will eliminate soot
formation on the inside walls of the copper tubings.
• Cut the pipe stage by stage, advancing the blade of
the pipe cutter slowly. Extra force and deep cut will
cause more distortion on the pipe and thus extra burr.
See figure.
• Remove burrs from cut edges of the pipes with
remover as shown in the figure. Hold the end of the
pipe downwards to prevent metal chips from entering
the pipe.
Piping Connection To The Units
• Align the center of the piping and tighten the flare nut
sufficiently with fingers.
• Finally, tighten the flare nut with the torque wrench
until the wrench clicks.
• When tightening the flare nut with the torque wrench,
ensure that the tightening direction follows the arrow
indicated on the wrench.
Pipe Size (mm/in}
Torque (Nm}
6.35 (1/4")
18
9.53 (3/8")
42
12.7 (1/2")
55
15.88 (5/8")
65
19.05 (3/4")
78
1/4t
10
Remove Burr
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Flare Joint
Flared Tube
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Flare Nut
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Torque Wrench
Spanner