Fujitsu AIRSTAGE J-IIIL Design & Technical Manual page 558

CAUTION
• Brazing:
– If nitrogen gas is not blown through the pipes while they are being brazed, an oxidized layer
may form on the inside of the pipes. If this occurs, the cooling efficiency may decrease and it
will be caused to damage for compressor and clog the strainer and electronic expansion
valve.
Example: Inside state of brazing pipe section
Nitrogen gas used
– When brazing the pipes, do not use flux. If the flux is chlorine-based, the pipes will corrode
and when the flux contains fluorine, the refrigerant oil will deteriorate, etc. Using the flux has
an adverse affect on the refrigerant piping system.
– For brazing materials, use phosphor copper solder that does not require flux.
Nitrogen gas used but not sufficient
(Oxigen gas still inside the pipe)
- (06-36) -
Nitrogen gas does not used
3. Piping connection