mycom 2016 C Series Instruction Manual page 114

Symptom
04 Low oil Insufficient oil in oil
pressure separator.
(low
lubrication
oil supply
pressure)
Oil pressure
detection function
is defective.
05 Intermediate High suction
pressure is pressure
unusually
high.
Liquid flow-back
from intermediate
liquid cooler.
There is problem in
compressor's
high-stage.
06 Unusually Heat exchange
high failure in condenser
pressure (heat exchanger)
Compound 2-stage Screw Compressor 2016**C
Direct cause
Extensive oil leak
Failure of oil
pressure protection
device, pressure
sensor, relay, etc.
Pressure pipe is
clogged.
Heat load on load
side is higher than
design value.
Malfunction of
suction pressure
adjusting
mechanism
Malfunction of
compressor's
capacity control
Failure or internal
leakage of
intermediate liquid
supply expansion
valve
Malfunction of
capacity control on
compressor's high-
stage
Excessive wear or
sliding damage of
the part(s) on
compressor's high-
stage
Heat transmission
tubes and/or fins
are contaminated or
blocked.
Root cause
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 piping is damaged due to
excessive vibration, take measures
to reduce vibration (including
measures for resonance vibration).
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Remove clogging, and check oil for
contamination/replace oil.
Inspect the conditions on load side
(warehousing volume,
opening/closing of doors, etc.), and
take necessary measures.
In case of pressure sensing failure,
replace the pressure sensor.
* In some cases, pressure pick-up
position is improper. → Change
the position.
If there is a problem in device(s) on
the control circuit, find the defective
device(s) and replace it.
If parameter (set value) on the
control circuit is improper, optimize
it.
In case of malfunction of pressure
adjustment valve, replace the valve
or remove the cause.
See Item No. 11 "Capacity control
malfunction".
Repair or replace.
See Item No. 11 "Capacity control
malfunction".
Overhaul compressor and replace
parts.
Replace the whole quantity of
lubricant.
Clean and wash.
Depending on the contamination
level, use chemical cleaning.
6-3
2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Action