2205B0JE-DA-J-N_2014.05.
6 Troubleshooting
Screw Compressor J-series
6-8
Trouble
Direct causes
Factors
Actions
10 Capacity
control
malfunction
Capacity control
hydraulic line defect
Maladjustment of oil
controller valve
Readjust it.
Leak and clogging
in solenoid valve
gland and oil pipes
Remove factors. Check oil
contamination level and replace oil
as necessary.
Unloader piston not
moving (This is one
factor of a defect of
the capacity control
hydraulic line, but
described
separately.)
Damaged cap seal
for unloader piston
Check oil contamination level and
replace oil as necessary.
Replace O-ring, cap seal, etc.
Pinched cap seal
Replace O-ring, cap seal, etc.
Worn cap seal
Check oil contamination level and
replace oil as necessary.
Replace O-ring, cap seal, etc.
Refrigerant gas
retention in
unloader cylinder
Stop compressor. Operate oil pump
and repeat loading and unloading to
purge refrigerant gas from cylinder.
For liquid backflow operation,
remove the causes.
For malfunction of oil heater and
other devices on control circuit,
replace them.
11
Abnormal
vibration
and/or
noise of
compressor
Insufficient axis
adjustment with
motor side
If vibration value is
higher in the axial
direction, this might
be the cause.
Readjust the shaft-center.
If abnormal vibration and noise fre-
quently occur in monocock unit, hot
alignment (perform rated operation
of compressor once to increase its
temperature and readjust before the
temperature decreases) is recom-
mended.
Large runout in
Male rotor axis
Uneven tightening
for thrust bearing
glands
If loose locknuts exist and no other
fault is found in parts such as thrust
bearing, tighten locknuts evenly.
Loose thrust
bearing
Forgetting to bend lock washer claw
or wear of thrust bearing rolling
element (ball) can be considered.
→
Check for any defects in thrust
bearings. If there are any defects,
replace it. Then perform end
clearance adjustment as well as
axis contact check, and
reassemble it.
Imprecision in
dynamic balance of
rotors
Inspection only at site is impossible.
However, if no other causes for
abnormal vibration are found, and if
on-site overhaul has been
repeatedly performed, this might be
the factor.
Overhaul compressor at an
institution such at MAYEKAWA
Moriya Factory with dynamic
balance measurement/ adjustment
equipment.
