2202L5JE-DA-C5-N_2015.05.
6 Troubleshooting
Compound 2-stage Screw Compressor 1612LSC Speed Increaser Type
6-2
02: Compressor stops immediately after startup (continued)
Direct cause
Root cause
Action
Low pressure protection
circuit activates.
Insufficient refrigerant flow
Insufficient liquid supply
To correct insufficient liquid supply,
inspect expansion valve and liquid
supply strainer. Take necessary
actions.
In addition, inspect devices and
parameters (set values) of the
expansion valve aperture adjusting
mechanism, and take necessary
actions.
Heat exchange failure in heat
exchanger
If there are any problem (insufficiency)
in heat exchange, such as
malfunction of defrosting, investigate
the cause and take necessary
actions.
In case of malfunction of pressure
control valve, replace the valve or
remove the cause.
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).
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: Unusually low pressure (decrease of suction pressure)
Direct cause
Root cause
Action
Refer to direct cause,
"Low pressure protection
circuit activates", in Item
02 above.
Same as left
Same as left
04: Low oil pressure (low lubricating oil supply pressure)
Direct cause
Root cause
Action
Oil filter element is
clogged.
* Pressure difference
between the outlet port
and inlet port 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.
