KGL Operating Manual – VS 3010 BS
2018-07-02
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Due to this process, all available Z2 compressors are loaded first during night operation. Z1 compressors
cannot be loaded until afterwards. The evaporation pressure regulator is not active during daytime operation
because a Z1 compressor is loaded due to the lower t0-Sollwert-Tag before the regulator can open. The
setpoint toggle can be carried out via an external signal or via the pack controller’s internal switching clock.
The suction gas bypass option can be entered using the parameter Sauggas-Bypass Y/N (menu 3-1):
Sauggas-Bypass = N The suction gas pressures of Z1 and Z2 are regulated independently of each
other.
Sauggas-Bypass = Y This option only influences the regulation during night operation.
Z1 compressors are only loaded if all Z2 capacity stages have been loaded. The switch-on times for the Z1
compressor do not start until the suction gas pressure of the Z1 compressor has increased to a value greater
than the setpoint plus half the Neutral Zone and all Z2 capacity stages have been loaded.
In the event of failure of all Z2 compressors (manual shutdown, motor protection etc.), the Z1 compressors are
loaded independently of the Z2 compressors. In the event of low-pressure fault of the Z2 compressors (t0 too
low or LP cutout), the function is maintained.
If running Z1 compressors are changed over from daytime to night operation, the function described above
does not become active until all Z1 compressors have been unloaded. The Sauggas-Bypass = Y input is only
possible if the Z2 compressors have pressure-controlled regulation. The parameter is not displayed if the Z2
compressors are directly controlled from a refrigeration point (parameter Booster/Sat. Reg. - menu 3-1
Consumers).
4.4.8 Setpoint shift
An optimally calculated setpoint for the operation can result in reduction of the energy costs. The determination
of the t0 setpoint (setpoint shift) for the low-pressure control can be performed using the following operations in
menu 3-2-1-2:
Room temperature sensor
Dependent on requirement from Z1 / Z2 consumer
Humidity sensor
to-Z1 setpoint shift with cascade regulation
