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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 Dia
1/2 inch
5/8 inch
7/8 inch
1 1/8 inch
1 3/8 inch
d. Refrigerant line insulation
- Insulate suction lines from the evaporators to the condensing unit with
minimum of 1" thickness closed-cell type 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.
e. Electrical
- All electrical work must be done in accordance with the National Electrical
Code and existing local codes.
- Power supply must be the same as specified on the unit's name plate.
- Voltage fluctuations in excess of 10 percent must be corrected.
- Before starting the unit, ensure that all protective devices are in place
and that all wiring is secure.
f. Brazing Recommendation
Maintain a flow of oxygen-free nitrogen through the system at a very low
pressure during brazing. Nitrogen displaces the air and prevents the forma-
tion 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.
Max distance between 2 clamp
supports
1.2 M
1.5 M
1.8M
2.1M
2.3M
17
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