Daikin VRV II Series Design, Installation & Testing Instructions page 24

Installation
Method for
If brazing work is carried out without passing nitrogen gas through the pipes which are being brazed then
this allows the formation of oxidation bubbles on the inside surface of the pipes. These oxidation bubbles
Replacing
are then carried along inside the pipes to cause damage to various members of the system such as valves
Nitrogen
or compressors and the system ceases to function properly.
(Brazing)
In order to avoid this problem nitrogen is passed through the pipes while the soldering work is being
carried out. This operation is known as nitrogen replacement. (Air is replaced by nitrogen)
This is standard work practice for all brazing work.
Important points:
1. The gas used must be nitrogen (oxygen, carbon dioxide and flon should not be used.)
2. A pressure regulator must be used.
18
Si39-303
General Information