FISCHER [CF] EASY User Manual page 77

3.3.2 Brazing recommendations
IMPORTANT
Blockage! Compressor breakdown! Maintain a flow of oxygen-free
nitrogen through the system at very low pressure during brazing. Nitrogen
displaces the air and prevents the formation of copper oxides in the system.
If allowed to form, the copper oxide material can later be swept through the
system and block screens such as those protecting capillary tubes, thermal
expansion valves, and accumulator oil return holes.
Contamination or moisture! Bearing failure! Do not remove the plugs until
the compressor is set into the unit. This minimises any entry of contaminants
and moisture.

Remove the discharge connection cap.

Remove the suction connection cap.

Open both valves mid-way. Care should be taken to avoid the holding charge releasing too
quickly.

Be sure tube fitting inner surface and tube outer surface are clean prior to assembly.

Both tubes are extended from the condensing unit housing, therefore we recommend to
isolate the housing by using a wet cloth on the copper tubing.

Recommended brazing materials: a copper/phosphorous or copper/phosphorous/silver
alloy rod should be used for joining copper to copper whereas to join dissimilar or ferric
metals a silver alloy rod either flux coated or with a separate flux would be used.

Use a double-tipped torch.
Figure 15: Brazing - Sectional view
3.3.3 Brazing procedure
For brazing of the tubes, please refer to Figure 16 and procedure hereunder:
Figure 16: Suction tube brazing

Then heat area 3. This will draw the brazing material down into the joint.
NOTE: The time spent heating area 3 should be minimal. As with any brazed joint,
overheating may be detrimental to the final result.
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
Fit the copper tube into the unit tube.

Heat area 1. As the tube approaches
brazing temperature,

Heat area 2 until braze temperature is
attained. It is necessary to heat the tube evenly. Move
the torch up and down and rotating around the tube.

Add braze material to the joint while moving
the torch around the joint to flow braze material
around the circumference.
C6.1.6/0513-0515/E