Brazing Procedure; Filter Screens - Emerson Copeland 4MF-13X Application Manuallines

3.3

Brazing procedure

WARNING
Air/flammable refrigerant mixture! Creation of a potentially flammable
atmosphere! Fire hazard! Remove all refrigerant before opening the system.
When working on a refrigerant-filled system, make sure to follow the safety
and working instructions given in Chapter 6 "Maintenance & repair".
WARNING
High temperature! Burning! Proceed with caution when brazing system
components. Do not touch the compressor until it has cooled down. Ensure
that other materials in the area of the compressor do not come into contact
with it.
CAUTION
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 orifices.
Contamination or moisture! Bearing failure! Do not remove the connection
plugs until the compressor is set into the unit. This minimises any entry of
contaminants and moisture.
Refer to Figure 15 and procedure below for the brazing of the suction and discharge lines:
Figure 15: Brazing areas
connections where dissimilar or ferric metals are joined a silver alloy rod with a minimum silver
content of 30 % shall be used being either flux-coated or with a separate flux.
▪ Be sure tube fitting inner diameter and tube outer diameter are clean prior to assembly.
▪ Using a double-tipped torch, apply heat in area 1.
▪ As the tube approaches brazing temperature, move the torch flame to area 2.
▪ Heat area 2 until braze temperature is attained, moving the torch up and down and rotating around
the tube as necessary to heat the tube evenly. Add braze material to the joint while moving the
torch around the joint to flow braze material around the circumference.
▪ After the braze material flows around the joint, move the torch to heat area 3. This will draw the
braze material down into the joint. The time spent heating area 3 should be minimal.
▪ As with any brazed joint, overheating may be detrimental to the final result.
3.4

Filter screens

CAUTION
Screen blocking! Compressor breakdown! Use screens with at least
0.6 mm openings.
The use of screens finer than 30 x 30 meshes (0.6 mm openings) anywhere in the system should be
avoided with these compressors. Field experience has shown that finer mesh screens used to protect
thermal expansion valves, capillary tubes or accumulators can become temporarily or permanently
plugged with normal system debris and block the flow of either oil or refrigerant to the compressor.
Such blockage can result in compressor failure.
14
▪
Flushing oxygen-free nitrogen through the piping
during the brazing process is recommended for
applications with A1 refrigerants and mandatory for
applications with flammable A2L refrigerants.
▪
The copper-coated
compressors can be brazed in approximately the same
manner as any copper tube.
▪
Recommended brazing
material is recommended, preferably with a minimum of
5% silver. However, 0% silver is acceptable. For brazing
AGL_Stream_ST_A2L_A1_4M_6M_EN_Rev00
steel tubes on Stream
material: any Silfos