Figure 23 Single And Dual Digital Scroll Compressor Activation Points - Emerson Liebert iCOM Manual

On single and dual digital scroll compressor systems, the first compressor is started at 25% calculated
output from the temperature proportional band and stopped at 10%. On dual digital scroll compressor
systems, the second compressor is started at 35% and stopped at 20%, see Figure 23. When a
compressor is started, the solenoid is energized longer than it is de-energized to match the call for
cooling. When the call for cooling increases to 100%, the solenoid is de-energized for the entire 15
second cycle.

Figure 23 Single and dual digital scroll compressor activation points

Temp Setpoint : 70°F
Proportional Band : 8°F
Comp 2 On Partially
Deadband : 2°F
Comp 1 On Partially
Loaded
½ Dead-
band
70 71 72
0%
Comp 1
Cooling
Off
Comp 2
Off
½ Proportional Band
Comp 1 & 2 On
Fully Loaded
Loaded
73 74 75
+ 100 %
Cooling
Increasing Temperature
29
Operation
® ®
Liebert iCOM for Liebert DSE
™