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Maintenance
Note: The service pumpdown algorithm expects the
liquid line service valve to be closed during service
pumpdown.The EXV will open, allowing the
refrigerant between the liquid line service valve
and EXV to be pumped out.
Service pump down is complete when:
•
Service pump down time expires (60 x (100/circuit
capacity %))
•
Saturated evaporator pressure falls below Low
Pressure Cutout x1.15 for one second
After pump down terminates, the MP automatically puts
circuit into lockout. Pump down can also be terminated by
"Abort Pump down" in service tool, an immediate
shutdown diagnostic occurs or a pressure transducer fails.
Oil Equalizer Line
CSHN Compressors
The oil equalizer line is equipped with a Rotolock fitting for
easy removal.Torque values for tightening these fitting is
100 ft.-lbs, plus or minus 10 ft. lbs.
Drain the oil to a level below the oil equalizer tube fitting
before removing the oil equalizer line.This must be done
on both compressors. Use the oil drain valve on the
Figure 105. Compressor location
Slant Unit
134
2B
1B
2A
1A
compressor. If the oil is drained below the level of the oil
level sight glass, it will be below the oil equalizer line level.
Pressurize the low side of the compressor using nitrogen
to help drain the oil. No more than 10 psig of pressure will
be needed.
CSHD Compressors
CSHD compressors do not have an oil drain valve.
Therefore, before removing the oil equalizer line, the
system refrigerant charge must be recovered before
draining the oil. Use a catch pan to catch the oil when the
compressor oil equalizer line is loosened to ensure that oil
does not spill out of the compressor when the equalizer
line is removed.The torque value for the Rotolock fitting
on CSHD compressors is 64 ft.-lbs., plus or minus 2 ft.-lbs.
Tandem Compressor Suction Restrictors
Since most tandem compressor sets use unequal size
compressors, these combinations require the use of a
restrictor in the suction line of one or more compressors
in order to provide correct oil level balance between
compressors when they are operating. See
p. 134
for compressor installation locations for various
unit configurations and
restrictor applications.
V Unit
1B
1A
Figure 105,
Table 75, p. 135
for correct
W Unit
2C
2B
2A
CG-SVX17E-EN
1C
1B
1A
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