18 | Piping installation
Installer and user reference guide
86
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543427-1A – 2020.10
18.2.9 To braze the pipe end
NOTICE
Precautions when connecting field piping. Add brazing material as shown in the
figure.
▪ When brazing, blow through with nitrogen to prevent creation of large quantities
of oxidised 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 pressure to 20kPa (0.2bar) (just enough so it can be felt on the
skin) with a pressure-reducing valve.
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 (BCuP), which does not require flux.
Flux has an extremely harmful influence on refrigerant piping systems. For
instance, if 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. insulation foam) from heat when
brazing.
18.2.10 Using the stop valve and service port
To handle the stop valve
Take the following guidelines into account:
▪ Make sure to keep all stop valves open during operation.
▪ The gas and liquid stop valves are factory closed.
▪ The figures below show the name of each part required in handling the stop
valve.
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