Engineering manual - UniSAB III 1.10.8
001930 en 2021.06
215/346
Set-up
Direct regulation of HLI cooling with a pulse modulated AKV valve and a solenoid valve. The HLI-AKV
cooling outlet is activated by rising discharge temperature. The solenoid valve is activated when oil cool-
ing is required and it remains active until the compressor stops. Within 6 seconds the AKV valve is pulse
modulated corresponding to the regulator output signal.
The set point for discharge temperature is adjusted in the parameter picture Control values/Discharge/
Temperature/Control Set point 1. In the same picture Neutral zone and Proportional band can be
adjusted.
HLI 4-20 mA
Liquid injection oil cooling (LIOC) by means of a 4-20 mA output signal from UniSAB III. Oil cooling out-
put is activated by rising discharge temperature. The regulator is a PID regulator. The set point for dis-
charge temperature is adjusted in the parameter picture Control values/Discharge/Temperature/Control
Set point 1. In the same picture Neutral zone and PID parameters can be adjusted.
Note: For SAB 193-233-283-355, HLI 2 output is activated when the volume slide is above 85%.
When the oil cooling parameter HLI 4-20mA is enabled, the Oil flow control parameter cannot be set.
See subsection 6.4.5 Oil system 2.2.44 Low discharge temperature difference alarm; 7: Oil flow control.
Example:
Set point 1 = 65°C
Neutral Zone = 4°C
Proportional Band = 30°C
Integral time = 10 sec.
Differential time = 0 sec.
The regulator keeps the discharge temperature between 63°C and 67°C.
Thermo pump internal
The Thermo pump function is activated when the compressor is running and the discharge temperature
is higher than 80° C. The set point for the thermo pump internal operation is set in Control/Discharge/
Temperature/Control/Set point 1. The Thermo pump function controls an output for filling an internal
compartment with liquid, which due to evaporation cools the top covers. The filling rate is controlled by
UniSAB III and it depends on the status of two level switches which indicate low and high level in the
compartment.
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