mycom i160S - Page 100

2203M4JE-MY-iS2-N_2017.04.
Chapter 6 Troubleshooting
Screw Compressor i-series
6-2
Symptom
Direct cause
Root cause
Action
02
Compressor
stops
immediately
after startup.
Motor overload
Motor overload that occurs just after startup is mostly
caused not by the refrigeration cycle but by the motor.
Refer to the instruction manual of the motor.
03
Abnormally
low pressure
(Low suction
pressure)
Refer to direct
cause, "Low
pressure protection
circuit activates", in
Item 02 above.
Same as left
Same as left
04
Low oil
pressure
(Low oil
supply
pressure)
Oil filter element is
clogged.
* Pressure
difference
between outlet
and inlet ports is
large.
Contamination of
lubricating oil
Remove clogging, and check oil
for contamination/replace oil.
Internal defects of
compressor
Check for oil contamination and
conduct vibration/noise diagnosis.
Overhaul compressor if
necessary.
Insufficient oil in oil
separator.
Oil heater is not
functioning,
refrigerant
dissolves
excessively when
the machine is
stopped, and oil
loss occurs at
startup.
Inspect oil heater alone, inspect
relays, etc. on related circuits, and
replace parts as necessary.
Insufficient oil
return due to
insufficient
refrigerant
circulation
Correct insufficient refrigerant
circulation, and return oil from
load-side heat exchanger.
* Supply lubricating oil temporarily.
Troubles such as
clogging in oil
return passage
Remove causes of the trouble,
and restore the system.
Extensive oil leak
Inspect machine room and around
the compressor, and take
necessary actions.
Check if there is oil floating in
cooling water system.
→If there is, check for oil leak
from heat transmission tube of
oil cooler and take necessary
actions.
If oil line piping is damaged due to
excessive vibration, take
measures to reduce vibration
(including measures for
resonance vibration).
Oil pressure
detection function is
defective.
Failure of oil
pressure protection
switch, pressure
sensor, relay, etc.
Identify defective device(s),
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.