14
4.4
Tube adaptors
4.5
Filler metal
4.6
Brazing
Instead of expanding the connectors or reducing the diameter of the connection tube, copper adapter tubes
can be used for service.
A 6/6.5 mm adapter tube can be used when a compressor with millimeter connectors (6.2 mm) is to be con-
nected to a refrigerating system with 1⁄4” (6.35 mm) tubes.
A 5/6.5 mm adapter tube can be used when a compressor with a 5 mm discharge connector is to be con-
nected to a 1⁄4” (6.35 mm) tube.
For brazing, the connectors and copper tubes filler metals with a silver content as low as 2% can be used.
This means that the so-called phosphor filler metals can also be used when the connecting tube is made
of copper.
If the connecting tube is made of steel, a filler metal with high silver content, which does not contain phos-
phor and which has a liquidus temperature below 740 °C / 1364 °F, is required. A flux is also needed for this
purpose.
The following are guidelines for brazing steel connectors whis is different to brazing copper connectors.
During heating, the temperature should be kept as close to the melting point of the filler metal as possible.
Overheating will lead to surface damage, so decreasing the chances of good brazing.
Use the “soft” heat in the torch flame when heating
the joint. Distribute the flame so at least 90 % of
the heat concentrates around the connector and
approx. 10 % around the connecting tube
When the connector is cherry-red (approx. 600 °C /
1112 °F) apply the flame to the connecting tube for
a few seconds.
Continue heating the joint with the “soft” flame and
apply filler metal.
Draw the filler metal down into the gap by slowly
moving the flame towards the compressor; then
completely remove the flame.
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