5.4.5 Connecting VRF piping assembly
CAUTION
Incorrect installation will cause the unit to
malfunction
The branch joints should be as level as possible, and the
angular error must not exceed 10°.
U type branch joint
A-direction view
Error
Level
The branch joints come in different pipe diameters, which
can be easily matched with different pipe diameters.
When connecting pipes, select the pipe section with the
appropriate pipe diameter, cut it in the middle with a pipe
cutter and remove burrs, as shown in the figure below.
Middle of the pipe section
Use a special pipe cutter
The length of the straight pipe section between the
contiguous branch pipes shall be no less than 500mm.
The straight pipe section behind the branch pipe end
shall be no less than 500mm. The length of straight pipe
between two right angle bends shall be no less than
500mm.
≥500mm
≥500mm
≥500mm
≥500mm
A
Correct
10°
10°
Figure 5.18
Figure 5.19
Figure 5.20
33
When there are multiple outdoor units, the branch joints
must not be higher than the refrigerant piping as shown
below:
5.4.6 Brazing
During brazing, use nitrogen as protection to prevent
the formation of a large amount of oxide film in the
pipes. This oxide film will have adverse effects on the
valves and compressors in the cooling system, and
may hamper normal operations.
Use the reducing valve to set the nitrogen pressure
to 0.02-0.03 MPa (a pressure that can be felt by the
skin).
Copper pipe,
Brazing part
1/4"
Oxygen
Nitrogen
Copper pipe,
fittings
Copper pipe
Do not use antioxidants when brazing the pipe joints.
Use copper-phosphorus alloys (BCuP) when brazing
copper and copper, and no flux is required. When
brazing copper and other alloys, flux is required.
Flux produces an extremely harmful effect on the
refrigerant piping system. For example, using a
chlorine-based flux is used may corrode the pipes,
and when the flux contains fluorine, it will degrade
the frozen oil.
During brazing, protect the valve mounting plate and
wires from burning
5.4.7 Connecting stop valves
Stop valves
The following figure shows the names of all parts
required for the installation of the stop valves.
Stop valves are closed when unit is shipped from the
factory.
Figure 5.21
Packless valve
Pipe interface
High pressure
fittings for
hose for nitrogen
nitrogen filling
filling
Figure 5.22
V.1