2205B0JE-DA-J-N_2014.05.
6 Troubleshooting
Screw Compressor J-series
6-2
Trouble
Direct causes
Factors
Actions
02 Compressor
stops imme-
diately after
startup.
Low pressure
protection circuit
activated
Insufficient refriger-
ant circulation
volume
If any heat exchange failures as
typified by poor defrost
performance, investigate the cause
and take measures.
For malfunction in pressure
adjustment valve operation, replace
pressure adjustment valve, or
remove the cause.
Malfunction of low
pressure protection
device, pressure
sensor, relays, etc.
Identify malfunctioning devices,
examine their causes, and take
measures.
Then, replace malfunctioning
devices.
Motor overload
In many cases, motor overload that occurs just after startup is
caused by the motor, not by the refrigeration cycle.
Refer to
the motor instruction manual.
03 Abnormally
low
pressure
(low suction
pressure)
Refer to the direct
causes “Low
pressure protection
circuit activated” in
item 2.
Same as on the left
Same as on the left
04
Low
oil-supply
pressure
Clogging in oil filter
element
* Big difference in
outlet/inlet
pressures
Contamination of
lubricant
Remove clogging. Check oil
contamination level and change
lubricant as necessary.
Defect inside
compressor
Check oil contamination level. After
vibration noise diagnosis, overhaul
compressor as necessary.
Insufficient oil
amount in oil
separator
Malfunctioning oil
heater, excessive
refrigerant dissolu-
tion during
stoppage, and oil
carried away during
startup.
Inspect oil heater.
Inspect relays, etc., on related
circuits.
Replace parts as necessary.
Insufficient oil
return caused by
insufficient
refrigerant
circulation
Resolve insufficient refrigerant
circulation, and then return oil from
load side heat exchanger.
* Replenish lubricant temporarily.
Troubles such as
clogging in oil
return circuit
Remove any causes of trouble to
restore.
Extensive oil leak
Inspect machine room and around
compressor and take measures.
Inspect for presence of oil floating in
cooling water system.
If there is any oil floating, check for
oil leak in oil cooler heat
transmission tube, and take
measures.
For damage in pipes, etc., caused
by excessive vibration, take
vibration reduction measures
(including sympathetic vibration
measures).