GE PTV15SAMR, Technician Service Manual

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Page 44
XI. SPECIAL EDITION ON MAINTENANCE OF ENVIRONMENTAL PROTECTION
REFRIGERATOR
11.2.3 Nitrogen being used in tube welding
During the welding of tubes, the oxidized
dirt in the tubes will cause the clogging
of capillary tube. So nitrogen must be
used to blow (nitrogen welding) the tubes
during the welding.
11.2.4 Vacuum degree (enhance the
accuracy of vacuum degree)
Operational sequence of below should
be based for the vacuum extraction and
freon-filling. The air in the freezing
system, especially in the case of
oxygen, will make ester become an oil-
base substance. Chemical reaction will
be developed by the oxidized oil and
metal in producing fluoride metal which
is one of the reasons of capillary tube
clogging. For this reason, higher degree
of vacuum is required.
11.3 SYNOPSIS OF MAINTENANCE
SEQUENCE FOR HFC-134A FREEZING
SYSTEM
11.3.1 Reactions for CFC -12
Upon repairing the freezing system,
connect the compound pressure gauge,
vacuum pump and filling tank as
indicated in the following figure. When
the repairs of HFC-134a system is
required, it is necessary to enhance the
vacuum degree and so, different tube
connections will be applied (as per figure
of below).
L H
Compound
Pressure Gauge
Freon filling tank
Vacuum pump