Starting sequence
Once the compressor has received starting permission, check that the capacity slide is in min-
imum position. The oil pump is started and oil will be pumped into the compressor lubrication
system. To avoid shutdown the oil flow switch must be activated within 45 seconds.
When the oil flow switch is activated, the compressor will start.
The pump will operate for a minimum of 60 seconds and 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.
3.3.13 GSV/RWF with oil pump
The pump is used for prelubrication and to maintain a minimum oil pressure level during op-
eration. The pump is started and stopped in accordance with the compressor differential pres-
sure (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.
Set point 1 is the pump start pressure and Set point 2 is the pump stop pressure. Conse-
quently, Set point 1 must be set for the lowest pressure level.
Normal setting for GSV/RWF:
Set point 1 = 2.5 bar.
Set point 2 = 4.0 bar.
If the compressor differential pressure is below Set point 1 during operation, the pump will
start immediately.
When the compressor differential pressure has been higher than Set point 2 for 60 seconds,
the pump will stop.
Starting sequence
When the compressor has received starting permission, it must be checked if the capacity
slide is still in minimum position. If the compressor stops, make sure that the capacity slide is
in minimum position.
Before start-up the oil level switch in the oil separator must be active. If not, a shutdown for
oil system error will be issued.
No signal from the oil level switch will result in shutdown after a delay of 60 seconds from
compressor start or during operation.
If the oil level switch is active, the prelubrication period will begin and oil will be pumped into
the compressor lubrication system. When the time period has expired, the compressor will
start and the pump will run for min. 60 seconds. The pump stops if the differential pressure is
higher than Set point 2.
Compressor control and surveillance
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Engineering manual - Unisab III 1.10
001930 en 2014.09
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