20
Refrigerant piping
Eliminate any residual moisture in the lines. Copper
plating, formation of acid sludge, freezing of the
laminating devices, formation of acids that corrode
metals and deteriorate the insulation of the electric motor
can occur in the case of non-compliant installation with
the presence of moisture. See paragraph “6.3 Vacuum
operation” page 40
Avoid weld undercutting that cannot be inspected; all the
piping must be accessible for inspection.
a
CAUTION
To prevent the refrigerant pipes from oxidising
during welding, charge with nitrogen.
In case of laying the lines before making the connection
to the units, keep the ends sealed until the time of
connection.
It is good practice to pinch the ends in case the lines are
laid a long time before the connection.
a
CAUTION
Use only nitrogen as a cleaning agent.
If residual moisture is found when cleaning with the
blowing of nitrogen, or if a long time has passed between
the laying of the lines and the connection, proceed with
the "triple vacuum".
This procedure consists in filling with nitrogen and
emptying twice before carrying out the final emptying
operation.
Make sure that the pressure does not rise during this
operation.
It is important that the joints are created to standard to
ensure a good seal.
For more information see paragraph “6.1 Flushing the
pipes” page 39 and “6.2 Gas leak test” page 39
l
WARNING
For connection of the lines, only “braze”
welding is allowed.
Brazing (1) consists in connecting metal pieces with the
help of a filler metal without melting the pieces to be
assembled. The filler metal penetrates by capillarity
between the pieces to be assembled.
The filler metal must be phosphorous copper or "rods of
silver alloy".
1
Fig. 23
Welding must be done in a neutral atmosphere (nitrogen).
An inert atmosphere (free of moisture and oxygen) must
be created inside the pipeline. In this way, no oxide
formations are created during welding
1
2
3
4
5
Fig. 24
1
Weld point
2
Rubber cap
3
Pressure reducer (operating pressure 0.2/0.5bar)
4
Pressure reducer on the cylinder
5
Cylinder of nitrogen
Connection method
Gas side Liquid side
Indoor unit
Welding or
flaring
Welding or
flaring
Outdoor unit Flaring Flaring
Branch pipe
Welding or
flaring
Welding or
flaring
If it is necessary to bend the piping, the risk of excessive
deformation must be avoided. The maximum deformation
allowed is 2/3rds of the diameter of the pipe itself.
2/3 Ø
Ø
Fig. 25
Pipes can be bent respecting the following bending radii:
Pipe diameter
(mm)
Radius (mm)
9.52
≥ 30
12.7
≥ 30
15.9
≥ 40
19.1
≥ 50
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