Be sure to perform a nitrogen blow when brazing.
Brazing without performing nitrogen replacement or
releasing nitrogen into the piping will create large quan-
tities of oxidized film on the inside of the pipes, adversely
affecting valves and compressors in the refrigerating
system and preventing normal operation.
Do not use a flux when brazing the refrigerant pipe
Use phosphor copper brazing (B-Cu93P-710/795: ISO
3677) which does not require flux.
Flux has an extremely negative effect on refrigerant pip-
ing systems. For instance, if chlorine based flux is used,
it will cause pipe corrosion. If the flux contains fluorine, it
will damage the refrigerant oil.
Use of oxygen could cause an explosion resulting in se-
vere injury or death. Only use nitrogen gas.
Refrigerant gas may produce toxic gas if it comes in con-
tact with fire such as from a fan heater, stove or cooking
device. Exposure to this gas could cause severe injury or
The pressure regulator for the nitrogen released when
doing the brazing should be set to 2.9 psi or less.
Refer to figure 9.
Location to be brazed
5. Protection against contamination when installing pipes:
Take measures to prevent foreign materials like mois-
ture and contamination from mixing into the system.
More than a month
Less than a month
Regardless of the period
Great caution is needed when passing copper tubes
Precautions when selecting branch piping.
If the piping between the outdoor unit and the first refriger-
ant branching kit is 295 ft. or longer, be sure to enlarge the
main pipe in the liquid-side piping.
Do not enlarge the main pipe in the discharge-side and
Depending on the length of the refrigerant piping, the
power may drop but you still may enlarge the main pipe.
Refer to figure.
The first refrigerant branching kit.
Pinch the pipe
Pinch or tape the pipe
Installation of Outdoor Units