Brazing of refrigerant piping :
The following precaution should be taken.
1. Do not use flux when brazing copper to copper
refrigerant piping.
(Particularly for the HFC refrigerant piping)
Therefore, use the phosphor copper brazing filler
metal (BCuP) which does not require flux.
(Flux has extremely harmful influence on refrigerant
piping systems. For instance, if the chlorine based
flux is used, it will cause pipe corrosion or, in particu-
lar, if the flux contains fluorine, it will damage the
refrigerant oil.)
CAUTION
Pipe bending
Annealed copper pipe with small diameter (Ø6.35(1/4)
mm(inch) or Ø9.52(3/8) mm(inch)) can be easily bent
manually. In this case, secure large R (radius) for the
bend section and gradually bend pipe. If annealed
copper pipe is large in diameter (Ø15.88(5/8)
mm(inch) or over), bend pipe with bender. Use bender
appropriate for the pipe diameter.
CAUTION
Nitrogen Brazing
a. This procedure is designed to prevent formation of
oxidation film by filling piping with inert gas. Note
that excessive gas pressure will generate pinholes
at brazed points. (Nitrogen gas: Supply pressure
0.05~0.1kg/cm
2
G(0.71~1.42psi))
b. When supplying inert gas, be sure to open one end
of piping.
CAUTION
Brazing section
Taping
Copper pipe 1/4
Pressure regulator
Pressure
regulator
Nitrogen cylinder
Nitrogen cylinder
High
pressure hose
Hose
Pipe
Outdoor unit
Packless
valve
Packless
valve
1. Niorogen flushing method (During brazing)
If brazing work is carried out without passing nitrogen gas
through the pipes then it allows the formation of
oxidation bubbles on the inside surface of the pipes.
These oxidation bubbles are then carried along inside the
pipes to cause damage to various members of the system
such as valve or compressors and the system ceases to
function properly.
In order to avoid this problem nitrogen is passed through
the pipe while the soldering work is being carried out.
This operation work is known as nitrogen
replacement.(Air is replaced by nitrogen)
This is standard work during all brazing works.
Water enters
Plaster enters
N
2
(Direction of Nitrogen gas.)
Nitrogen Brazing
Make sure to keep the connecting piping dry (away
from water) , clean (away from dust) , and air tight
(avoid refrigerant leakage)
CAUTION
2.2.4 Brazing work
2. Guideline for each installation process
Heat pump 60Hz/R410A
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11
Installation of
Outdoor Units
SINGLE ZONE
