2205B0JE-DA-J-N_2014.05.
6 Troubleshooting
Screw Compressor J-series
6-5
Trouble
Direct causes
Factors
Actions
06 Abnormally
high
discharge
temperature
High supply oil
temperature
Heat exchange fault
in oil cooler
For water-cooling types, refer to
“Heat exchange failure at
condenser (heat exchanger)” in
item 05.
For liquid cooling type, inspect liquid
supply expansion valve,
temperature sensor, related relays,
wiring, terminals, etc., and take
measures.
Failure in oil
temperature
increase protection
feature
Inspect temperature protection
device, temperature sensor, related
relays, wiring, terminals, etc., and
take measures.
Defect in discharge
temperature
detection and
protection features
Malfunction in
temperature protec-
tion device,
temperature
sensor, relays, etc.
Identify malfunctioning devices,
examine their causes, and take
measures.
Then, replace malfunctioning
devices.
Insufficient supply
oil
Refer to item 04,
“Low hydraulic
pressure (low
oil-supply pres-
sure)”.
Same as on the left
07
Leak from
mechanical
seal
Initial leak after
replacement until
sliding surfaces fit
together
This happens
because of the
specific operating
conditions of the
compressor and
unsteadiness in
bearing pressure
condition of
processed sliding
surfaces following
replacement.
For initial leak, amount of leak might
increase temporarily. However, it
will gradually decrease, so check
that the amount of leak does not
increase continuously.
Period of initial leak might differ
according to design and operating
conditions. 200 hours can be a
rough guide.
Damaged sliding
surfaces due to
excessive heat of
sliding surfaces
Most cases are due
to excessive
repetition of
startup/stoppage.
* For a standard
device, more than
4 times per hour
is considered too
many.
If heat load is below the device’s
design conditions, re-examine
operating conditions. Set the control
settings to fewer startup/stoppage
times.
For capacity control malfunctions,
see item 10, “Capacity control
malfunction”.
A lot of refrigerant
mixed into the
lubricant, resulting
in decreased
viscosity.
For liquid backflow operation,
remove the causes.
For malfunction of oil heater and
other devices on control circuit,
replace them.
Overheat operation
Refer to Factor “Insufficient
refrigerant circulation volume” in
item 02.
High supply oil
temperature
Refer to the Direct cause “High
supply oil temperature” in item 06.
