Repair Section
56
(3) Cleaning brazing filler metal and piping
• When the refrigeration system has been opened up, exposure to the heat may have caused brazing
filler metal to stick to the inside and outside of the pipe. Brazing filler metal may also be compounded
with oxygen in the air to form the oxide film. Fat and oils may stick to the pipe from handling. All these
factors can reduce the effectiveness of brazing. It is necessary to eliminate excess brazing filler
metal using sand paper and by cleaning thoroughly with a solvent such as trichlene.
CAUTION
Do not use chlorine cleaner.
(4) Use of dry nitrogen gas
• During brazing, the inside of the pipe undergoes an oxidative reaction due to the brazing flame.
Introduce dry nitrogen gas 1 L/min; adjust with the flow regulator) through the pinch-off tube of
the refrigerant.
< NOTE >
Take care not to allow dirt, water, oil, etc. to enter into the pipe.
(5) Vertical joint
• Heat the whole brazed fitting to a proper
brazing temperature. Bring the brazing filler
metal into contact with the fitting so that the
brazing filler metal starts flowing by itself.
• Stop heating the fitting as soon as the brazing
filler metal has flown into the clearance. Since
the brazing filler metal flows easily into the
portion heated to a proper temperature, it is
essential to keep the whole fitting at a proper
brazing temperature.
I000564
Burner
45°
Tube
Brazing Filler Metal
Vertical Down Joint
I001725
Burner
45°
Tube
Brazing Filler Metal
Vertical Up Joint
