Compressor Connection; Vacuum Evacuation And Moisture Removal - Danfoss VRJ Application Manuallines

Application Guidelines

Compressor connection

Vacuum evacuation and
moisture removal
Installation
When brazing the compressor ttings, do not
overheat the compressor shell, which could
severely damage certain internal components
due to excessive heating. Use of a heat shield
and/or a heat-absorbent compound is highly
recommended. For brazing the suction and
discharge connections, the following procedure
is advised:
• Make sure that no electrical wiring is
connected to the compressor.
• Protect the terminal box and compressor
painted surfaces from torch heat damage
(see diagram).
• Use only clean refrigeration-grade copper
tubing and clean all connections.
• Purge nitrogen or CO2 through the
compressor in order to prevent against
oxidation and ammable conditions. The
compressor should not be exposed to the
open air for extended periods.
• Use of a double-tipped torch is
recommended.
• Apply heat evenly to area A until the brazing
temperature is reached. Move the torch
to area B and apply heat evenly until the
brazing temperature has been reached there
as well, and then begin adding the brazing
material. Move the torch evenly around
the joint, in applying only enough brazing
material to ow the full circumference of the
joint.
• Move the torch to area C only long enough
to draw the brazing material into the joint,
but not into the compressor.
• Remove all remaining ux once the joint has
been soldered with a wire brush or a wet
cloth. Remaining ux would cause corrosion
of the tubing.
Moisture obstructs the proper functioning
of both the compressor and the refrigeration
system.
Air and moisture reduce service life and
increase condensing pressure, which causes
abnormally high discharge temperatures that
are then capable of degrading the lubricating
properties of the oil. The risk of acid formation
is also increased by air and moisture, and this
condition can also lead to copper plating. All
these phenomena may cause both mechanical
Ensure that no ux is allowed to enter into the
tubing or compressor. Flux is acidic and can cause
substantial damage to the internal parts of the
system and compressor.
The PVE oil used in VRJ compressors is highly
hygroscopic and will rapidly absorb moisture
from the air. The compressor must therefore not
be left open to the atmosphere for a long period
of time. The compressor tting plugs shall be
removed just before brazing the compressor.
Before eventual unbrazing the compressor
or any system component, the refrigerant charge
must be removed from both the high and low
pressure sides. Failure to do so may result in
serious personal injury. Pressure gauges must be
used to ensure all pressures are at atmospheric
level.
For more detailed information on the appropriate
materials required for brazing or soldering, please
contact the product manufacturer or distributor.
For speci c applications not covered herein,
please contact Danfoss Commercial Compressors
for further information.
and electrical compressor failures. The typical
method for avoiding such problems is a vacuum
pump-down executed with a vacuum pump, thus
creating a minimum vacuum of 0.02 in Hg (500
µm Hg). Please refer to Bulletin "Vacuum pump
down and dehydration procedure".
Be sure to follow all government regulations
regarding refrigerant reclamation and storage.
AB141686422149en-US0401
Heat shield
C B A
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