VC Pro VRF 50/60Hz
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Part 3 - System Design and Installation
5.3.5 Bending piping
Bending copper piping reduces the number of brazed joints required and can improve quality and save material.
5.4 Refrigerant Piping Supports
When the air conditioning is running, the refrigerant piping will deform
(shrink, expand, droop). To avoid damage to piping, hangers or
supports should be spaced as per the criteria in the Table 3-5.2. In
general, the gas and liquid pipes should be suspended in parallel and
the interval between support points should be selected according to
the diameter of the gas pipe.
Suitable insulation should be provided between the piping and the supports. If wooden dowels or blocks are to be used, use
wood that has undergone preservative treatment.
Changes in refrigerant flow direction and refrigerant temperature result in movement, expansion and shrinkage of the
refrigerant piping. Piping should therefore not be fixed too tightly, otherwise stress concentrations may occur in the piping,
with the potential for rupturing.
Table 3-5.2: Refrigerant piping support spacings
Interval between support points (m)
Piping bending methods
Hand bending is suitable for thin copper piping (Ф6. 35mm - Ф12. 7mm).
Mechanical bending (using a bending spring, manual bending machine or powered bending machine) is suitable
for a wide range of diameters (Ф6. 35mm - Ф54.0mm).
Caution
When using a spring bender, ensure that the bender is clean
before inserting it in the piping.
After bending a copper pipe, ensure that there are no wrinkles or
deformation on either side of the pipe.
Ensure that bend angles do not exceed 90°, otherwise wrinkles
may appear on the inner side of the pipe, and the pipe may buckle
or crack. Refer to Figure 3-5.3.
Do not use a pipe that has buckled during the bending process;
ensure that the cross section at the bend is greater than 2/3 of
the original area.
Figure 3-5.3: Pipe bending in excess of 90°
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