3.3.11 FV 24/26 with oil pump
The compressors FV 24 and FV 26 are small frequency regulated screw compressors, i.e. the
mounted slide is only used during start and stop.
The electrical oil pump is used for prelubrication and to maintain a minimum oil pressure dur-
ing operation. The pump is started and stopped in accordance with the compressor differential
pressure (discharge pressure - suction pressure) during operation.
The difference is set in the picture Oil/Pressure/Control whereupon Set point 1 and Set point 2
will appear.
Normal setting for FV 24/26:
Set point 1 = 2.5 bar
Set point 2 = 4.0 bar
Adjust set points as described in subsection 3.3.5.
Starting sequence
Once the compressor has received permission to start, the oil pump will start pumping oil into
the compressor lubrication system.
The oil flow switch must be activated within 45 seconds to avoid shutdown.
When the oil flow switch is activated, the solenoid valve (capacity slide down) will be open for
15 seconds and the electrical fan will start. The frequency converter will then receive a signal
to start. Speed is increased to 1000 rpm in 10 seconds.
The pump will operate for a minimum of 60 seconds and will stop if the differential pressure is
higher than Set point 2 as described above.
Alarm surveillance
During start the following alarms are delayed:
Low oil pressure 45 sec.
High filter diff. pressure 300 sec.
Low superheat 300 sec.
High superheat 300 sec.
Low/high oil temperature 300 sec.
See also section 6.5. Timers.
3.3.12 SV 24/26 with oil pump
The compressors SV 24 and SV 26 are small slide regulated screw compressors.
The electrical oil pump is used for prelubrication and to maintain a minimum oil pressure dur-
ing operation.
The pump is started and stopped in accordance with the compressor differential pressure (dis-
charge pressure - suction pressure) during operation.
The difference is set in the picture Oil/Pressure/Control whereupon Set point 1 and Set point 2
will appear.
Normal setting for SV24/26:
Set point 1 = 2.5 bar
Set point 2 = 4.0 bar
Adjust set points as described in subsection 3.3.5.
Compressor control and surveillance
Engineering manual - Unisab III 1.10
001930 en 2014.09
101/319
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