Sab 193, 233, 283 And 355 Without Oil Pump - Johnson Controls SABROE UniSAB III Engineering Manual

Compressor control and surveillance
Alarm surveillance
During start the following alarms are delayed:
Low oil pressure
High filter diff. pressure
Low superheat
High superheat
Low/high oil temperature
The delayed alarms are described in section 6.5 Timers.
Stopping sequence
When a SAB 193-233-283-355 compressor stops, UniSAB III will attempt to move the capacity slide be-
low 5% position. The solenoid valves for decreasing capacity and Vi position are activated for maximum
300 seconds. If the capacity slide is not below 5% within the 300 seconds a Capacity error shutdown will
be issued.
Balance piston for SAB 355
For SAB 355, the AUX output is dedicated for control of the balance piston. Choose the AUX output to
be activated At max. cap. in the menu Compressor control – user functions and set the Signal high limit
to 70% referring to slide capacity.
3.3.19

SAB 193, 233, 283 and 355 without oil pump

The compressors are equipped with capacity slide and automatic Vi-control.
If the compressor is equipped with a frequency converter (VSD) see subsection 6.4.1 Drive, 6: Rotatune
for additional set-up of UniSAB III.
The compressor has no oil pump.
Starting sequence
When the compressor has received starting permission, UniSAB III will check whether the capacity slide
is in minimum position. If the capacity slide is higher than 5% position, the solenoid valve for decreasing
capacity slide position will be activated for maximum 300 seconds. If the capacity slide is still higher than
5% position, a Capacity error shutdown will be issued and the compressor will not start. If the capacity
slide is lower than 5% position the compressor is allowed to start.
Before start-up UniSAB III will also check the oil level and temperature in the oil separator. If the oil level
is too low an oil system error alarm will be issued. No signal from the oil level switch during operation will
result in shutdown after a delay of 30 seconds. If the oil temperature is lower than the set limits a low oil
separator temp alarm or shutdown will be issued. The limits for oil separator temperature can be set in
the menu Control values/Oil/Separator temp/Limits.
If the oil level switch is active and the separator temperature is above the shutdown limit, the compressor
will start.
Engineering manual - UniSAB III 1.10.8
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