2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Compound 2-stage Screw Compressor 2016**C
6-8
Symptom
Direct cause
Root cause
Action
11 Capacity
control
malfunction
"Micro-switches
and micro-switch
cam" of the
indicator do not
sense "100%"
position and/or
"0%" position.
Micro-switch failure
Replace.
Loosening of
micro-switch or
micro-switch cam
screw due to
vibration.
Adjust the position of the cam and
switch, and tighten them.
Use thread locking agent when
necessary.
When compressor's vibration is
unusually high, see Item No. 12
"Compressor generates abnormal
vibration and/or sound".
Failure of capacity
control (4-way)
solenoid valve or
related relays
Mostly caused by
coil burnout.
If deteriorated over time, replace.
If the symptom is caused by water
leakage, etc., remove the cause(s)
and then replace defective part(s).
For details, refer to the instruction
manual of solenoid valve.
Internal leakage of
capacity control
(4-way) solenoid
valve
Liquid clogging, etc.
due to temperature
rise inside unloader
cylinder
If the symptom is caused by long
duration of low-load operation,
review and improve the operating
method.
Arrange inline check valve and oil
bypass route on the capacity control
oil supply line.
Defective capacity
control oil supply
line
Improper
adjustment of oil
flow control valve
Readjust.
Leak/clogging in
solenoid valve
gland or oil supply
piping
Remove cause, and check oil for
contamination/replace oil.
Unloader piston
does not move.
(Though this is one
of the causes of
"Defective capacity
control oil supply
line", it is listed
separately here.)
Damage on the cap
seal of the piston
Check oil for contamination/replace
oil.
Replace O-ring, cap seal, etc.
Cap seal is
pinched.
Replace O-ring, cap seal, etc.
Cap seal is worn.
Check oil for contamination/replace
oil.
Replace O-ring, cap seal, etc.
There is residual
refrigerant gas
inside unloader
cylinder.
Stop the compressor. By operating
the oil pump, repeat load/unload
operation to purge refrigerant gas
from unloader cylinder.
In case of liquid flow-back, remove
the cause(s).
If oil heater or devices on its control
circuit are defective, replace the
defective part.
12
Compressor
generates
abnormal
vibration
and/or
sound.
Shaft poorly
aligned with motor
If the shaft vibration
value of axial
direction is high, it
may be caused by
this.
Conduct shaft alignment again.
If this occurs frequently in
monocoque unit, perform hot
alignment (operate the compressor
at rated speed to raise the
temperature and make adjustment
before it cools down).