Vertiv Liebert iCOM - Page 42

Figure 3.7 Digital Scroll Compressor Operation to Provide 66% Cooling Capacity
No. Description
1 Solenoid de-energized.
2 Solenoid energized.
3 Percent loaded.
4 15 second capacity modulation cycle.
One Digital Scroll Compressor
In a single digital scroll system:
• The compressor starts when the cooling demand is at least 25% (calculated from temperature proportional
band) and operates at 50% capacity (valve open 7.5seconds/closed 7.5seconds) for an initial period set in
Winter Start Delay (see Setting Low Pressure Time Delay on page59 ), after which it operates per cooling
demand.
• As cooling demand increases, the length of time the valve is closed increases/capacity increases.
• At 100% cooling requirement, the valve remains closed for the entire 15 second interval and the compressor is
operating loaded at 100% capacity.
• The compressor stops when cooling demand decreases to 10%.
Figure 3.8 on the facing page illustrates digital scroll compressor operation with the following setpoint parameters:
• 70° setpoint
• 8° proportional band
• 2° deadband
3 Service Operation
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Vertiv™ Liebert® iCOM™Installer/User Guide