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Piping installation
Installer and user reference guide
89
LREN8~12A7 + LRNUN5A7
CO₂ ZEAS outdoor unit and capacity up unit
4P704142-1 – 2022.08
15.3.5 To braze the pipe end
General guidelines
▪
When brazing, blow through with nitrogen to prevent creation of large quantities
of oxidized film on the inside of the piping. This film adversely affects valves and
compressors in the refrigerating system and prevents proper operation.
▪
Set the nitrogen gauge pressure to 20 kPa (0.2 bar) (just enough so it can be felt
on the skin) with a pressure-reducing valve.
a
b
c
d
e
f
f
a
Refrigerant piping
b
Part to be brazed
c
Taping
d
Manual valve
e
Pressure-reducing valve
f
Nitrogen
▪
Do NOT use anti-oxidants when brazing pipe joints. Residue can clog pipes and
break equipment.
▪
Do NOT use flux when brazing copper-to-copper refrigerant piping. Use phosphor
copper brazing filler alloy (CuP279, CuP281, or CuP284:DIN EN ISO 17672), which
does not require flux.
Flux has an extremely harmful influence on refrigerant piping systems. E.g., if a
chlorine-based flux is used, it will cause pipe corrosion or, in particular, if the flux
contains fluorine, it will deteriorate the refrigerant oil.
▪
Always protect the surrounding surfaces (e.g. using insulation foam) against heat
when brazing.
Preheating the piping
a
b
c
