2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Compound 2-stage Screw Compressor 2016**C
6-5
Symptom
Direct cause
Root cause
Action
06 Unusually
high
pressure
(abnormal
discharge
pressure)
Discharge oil
pressure detection
function is
defective.
Failure of high
pressure protection
device, pressure
sensor, relay, etc.
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Liquid clogging, etc.
due to clogged
pressure pipe
Remove clogging, and check oil for
contamination/replace oil.
Outlet shut-off
valve of oil
separator is closed.
Operator forgot to
restore after shut
down operation.
Human error
Open the valve or perform
emergent stop.
Be sure to conduct tagout while
handling valves.
Be sure to check valves before
starting the compressor.
07 Discharge
temperature
is
abnormally
high.
Overheated during
operation
Insufficient
refrigerant flow
See the causes listed in item 02
above.
Heat load on load
side is higher than
design value.
Inspect the conditions on load side
(warehousing volume,
opening/closing of doors, etc.), and
take necessary measures.
Failure of low
pressure protection
device, pressure
sensor, relay, etc.
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Non-condensable
gases mixed into
the system
Leak on low
pressure side
Perform a leak check, and take
necessary measures.
Air-purge the heat exchanger.
Oil supply
temperature is
high.
Heat exchange
failure in oil cooler
For water-cooling system, see
"Heat exchange failure in heat
exchanger" in 06 above.
For liquid cooling system, check
liquid supply expansion valve,
temperature sensor and related
relays/wiring/terminals, and take
necessary actions.
Oil temperature rise
protection feature
does not function.
Check temperature protection
device, temperature sensor and
related relays/wiring/terminals, and
take necessary actions.
Defective discharge
temperature
detection/protection
feature.
Failure of
temperature
protection device,
temperature
sensor, relay, etc.
Identify defective devices,
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Insufficient oil
supply
See "Low oil
pressure" in Item 04
above.
Same as left
08
Leak from
mechanical
seal
Initial leak after
replacement until
sliding faces settle
In some cases,
immediately after
replacement, the
compressor-specific
operating conditions
and the pressure
receiving conditions
of machined sliding
surface is unstable.
In case of initial leak, although leak
amount might increase temporarily,
it will decrease gradually. Check
that leak does not increase
continuously.
Duration of initial leak depends on
design/operating conditions. It is
approximately 200 hours, as a
rough indication.