To Braze The Pipe End - Daikin RXYSQ4T8VB Series Installer And User Reference Manual

18 | Piping installation

18.2.6 To braze the pipe end

Installer and user reference guide
74
Flare tool for R410A
(clutch type)
A 0~0.5 mm
5 Check that the flaring is properly made.
a
a Flare's inner surface MUST be flawless.
b The pipe end MUST be evenly flared in a perfect circle.
c Make sure the flare nut is fitted.
NOTICE
Precautions when connecting field piping. Add brazing material as shown in the
figure.
≤Ø25.4
1
1
▪ 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 20 kPa (0.2 bar) (just enough so it can be felt on the
skin) with a pressure-reducing valve.
a b
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 (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.
Conventional flare tool
Clutch type
(Ridgid-type)
1.0~1.5 mm
b
c
c d e
f
Wing nut type
(Imperial-type)
1.5~2.0 mm
RXYSQ4~6T8V/YB
VRV IV-S system air conditioner
4P482277-1B – 2020.10