2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Compound 2-stage Screw Compressor 2016**C
6-1
Chapter 6 Troubleshooting
Table 6-1 describes typical trouble symptoms of compressors, their causes and actions to be taken. For
information about troubleshooting for the unit or the whole refrigeration cycle, refer to the instruction
manual of the unit.
Table 6-1 Troubleshooting
Symptom
Direct cause
Root cause
Action
01 Compressor
does not
start up.
Power source is off. Mostly caused by
forgetting to turn on
after inspection.
Use a check sheet for
post-inspection actions and
implement finger pointing and call
check to prevent forgetting.
Main motor failure
Mostly caused by
activation of
overload protection
circuit.
Refer to the operation manual of the
motor for details including other
causes and actions.
"Micro-switch and
micro-switch cam"
of the indicator do
not sense capacity
control of 0%.
Micro-switch failure
Replace.
Loosening of
micro-switch or
micro-switch cam
set 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".
Defective capacity
control oil supply
line
Improper
adjustment of oil
flow control valve
(throttled
excessively).
Readjust.
Leak/clogging in
piping or solenoid
valve
Remove cause, and check oil for
contamination/replace oil.
Oil pressure not
detected
Failure of oil
pressure protection
device, pressure
sensor, relay, etc.
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Pressure pipe is
clogged.
Remove clogging, and check oil for
contamination/replace oil.
Cooling water
circulation is not
confirmed.
Failure of devices
such as cooling
water pump and
related circuits
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Circulation route is
clogged.
Remove the clogging.
Failure of magnet,
relay, etc. in
compressor startup
circuit
Aging degradation
Replace with new one.
Poor installation
environment
Replace ventilation fans, etc. if
defective.
Improve temperature, humidity and
ventilation at the installation site.
02
Compressor
stops
immediately
after
startup.
Low pressure
protection circuit
activates.
Insufficient
refrigerant flow
To correct insufficient refrigerant,
check leak, stop leak and then add
refrigerant.
* Also pay attention to moisture
entering into the system.