OPERATING INSTRUCTIONS
GRASSO SYSTEM CONTROL
FOR TWO STAGE CHILLER/ PACKAGES WITH SCREW
COMPRESSORS
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A switch on frequency limitation of the LP compressor drive motor is still active
Start to start LP
A capacity limitation is active (LP motor current too high), "reduce output" solenoid
valve is opened.
Imot Limitation LP
A capacity limitation as active (LP discharge pressure too high), "reduce output"
solenoid valve is opened
Pdis Limitation LP
A capacity limitation as active (HP suction pressure too low), "reduce output" solenoid
valve is opened
Psuc Limitation HP
Starting command issued, control slide moves into the minimum position (LP)
Slide to min LP
Compressor motor has been started, and the running feedback signal from the
starter panel has not yet been received (LP)
Starting LP
The compressor unit/ chiller has received a shutdown command, the capacity slide is
moved towards its minimum position (LP)
Stopping LP
Text display flashes
Italic lettering
Text appears as static text
Normal lettering
The overall status of the compressor unit is displayed with the LEDs in
and
.
Key
Colour
Status
Explanation
Green Flashing
The unit/ chiller has received a start request. The
compressor could start any moment now.
Green Continuous
light
The unit/ chiller has received a start request. The
compressor is running.
The unit/ chiller is malfunctioning. The compressor is
not running. The (red) indicator light
‘
Collective fault
’
flashes or is permanently lit.
None OFF
+
red Continuous
light
The unit/ chiller is switched off. The compressor is not
running.
Green Continuous
light
Display of the system deviation or the ext. actuating
pulses of the HP compressor (more output is required)
Green Continuous
light
Display of the system deviation or the ext. actuating
pulses of the LP compressor (more output is required)
Green Continuous
light
Display of the system deviation or the ext. actuating
pulses of the HP compressor (less output is required)
Green Continuous
light
Display of the system deviation or the ext. actuating
pulses of the LP compressor (less output is required)
