Emerson Liebert iCOM User Manual download pdf (Page 25)

Operation

The Temperature Proportional Band and Temperature Deadband parameters are in the Service

menu under the Setpoints submenu. The Temperature Setpoint parameter is in both the User Menu

and Service Menu under Setpoints.

There is a parameter AutoSet Enable (Service Menu, Setpoints), which automatically sets the

proportional bands for temperature and humidity, and both the integration time factors according to

the type of unit (chilled water, single or dual compressor).

3.2.2 Compressor Control

Depending on its type, a Liebert Precision Cooling unit may have one or two compressors with or

without unloaders or variable capacity.

Compressor Proportional Bands

One Single-Step Compressor Without Unloaders—One-Step

One single-step compressor, Cool 1, is started at 100% call for cooling from the temperature

proportional band and stopped at 0% (see Figure 13).

Figure 13 One single-step compressor without unloaders

NOTE

Before the proportional or integral setpoints can be changed, the Auto Set Enable must be

changed to NO.

Temp Setpoint: 70°F

Proportional Band: 8°F

Deadband: 2°F

½ Proportional Band

Cooling

+ 100 %

Cooling

71 72 73 7470

½ Dead-

band

Cool 1

Off

Cool 1

Increasing Temperature

1 2 ... 20 21 22 23 24 25 26 27 28 29 30 ... 107 108

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Emerson Liebert iCOM User Manual Page 25