Discharge Temperature Is Abnormally High - mycom i125S Instruction Manual

Symptom
05 Abnormally
high
pressure
(Abnormal
discharge
pressure)
06 Discharge
temperature
is abnormally
high.
Screw Compressor i-series
Direct cause
Refrigerant is In some cases,
excessive. insufficient cooling
is judged as
caused by
insufficient
refrigerant and, as
a result, refrigerant
is charged
repeatedly.
Capacity of heat
changer is
insufficient.
Discharge oil Failure of high
pressure detection pressure protection
function is defective. switch, pressure
sensor, relay, etc.
Clogging of
pressure pipe
Outlet shut-off valve Operator forgot to
of oil separator is restore after shut
closed. down operation.
Human error
Overheated during Insufficient
operation refrigerant flow
Heat load on load
side is higher than
design value.
Failure of low
pressure protection
switch, pressure
sensor, relay, etc.
Non-condensable Leak on low
gases mixed into pressure side
the system
Oil supply Heat exchange
temperature is high. failure in oil cooler
Oil temperature
rise protection
feature does not
function.
Root cause
Properly adjust the refrigerant
charge.
If the symptom is caused by
change in operating conditions,
re-examine the conditions for
improvement.
If improvement is difficult, add
heat exchangers or increase their
sizes.
Identify defective device(s),
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Remove clogging, and check oil
for contamination/replace oil.
Open the valve or perform
emergent stop.
Be sure to conduct tagout while
handling valves.
Be sure to check valves before
starting the compressor.
See the causes listed in item 02
above.
Inspect the conditions on load
side (warehousing volume,
opening/closing of doors, etc.),
and take necessary measures.
Identify defective device(s),
investigate causes of failure and
take necessary actions.
Then, replace failed device(s).
Perform a leak check, and take
necessary measures.
Air-purge the heat exchanger.
For water-cooling system, see
"Heat exchange failure in heat
exchanger" in item 05 above.
For liquid cooling system, check
liquid supply expansion valve,
temperature sensor and related
relays/wiring/terminals, and take
necessary actions.
Check temperature protection
switch, temperature sensor and
related relays/wiring/terminals,
and take necessary actions.
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2203M4JE-MY-iS2-N_2017.04.
Chapter 6 Troubleshooting
Action