Emerson Copeland 4MF-13X User Manual page 14

Pressure Safety Controls
High-pressure Control
A high-pressure control with a maximum cut-out setting of 28 bar(g) is required. The high-pressure cut-out should have a manual reset
feature for the highest level of system protection.
Low-Pressure Control
The normal minimum cut-out setting is 0.1 bar(g) for R404A. The low-pressure cut-out should have a manual reset feature for the highest
level of system protection.
Maximum Operating Pressures
Maximum operating pressures according to EN 12693 shown on the compressor nameplate are obligatory and must not be exceeded.
NOTE: The compressor operating range may be restricted for various reasons. Check the application range limitations in
Copeland brand products Selection Software on www.EmersonClimateAsia.com.
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High-pressure side (HP): 28.0 bar
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Low-pressure side (LP): 22.5 bar
Brazing Procedure
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 minimizes any
entry of contaminants and moisture.
Figure 8: Suction tube brazing
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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.
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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.
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As with any brazed joint, overheating may be detrimental to the final result.
To Disconnect:
Heat joint areas 2 and 3 slowly and uniformly until the braze material softens and the tube can be pulled out of the fitting.
To Reconnect:
Recommended brazing materials: Silfos with minimum 5% silver or silver braze used on other compressors.
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The copper-coated steel tubes on Stream compressors can be brazed
in approximately the same manner as any copper tube.
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Recommended brazing materials: any silfos material is recommended,
preferably with a minimum of 5% silver. However, 0% silver is
acceptable.
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Be sure tube fitting inner diameter and tube outer diameter are clean
prior to assembly.
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Using a double-tipped torch, apply heat in area 1.
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As the tube approaches brazing temperature, move the torch flame to
area 2.