Unit installation

Liebert iCOM Control

5.4 Liebert iCOM Control Setup

The Liebert iCOM on the Liebert CRV leaves the factory with the fan speed and cooling capacity con-

trolled by the supply air sensor. This control mode is extremely robust and will ensure that you are

delivering precise cooling to the cold aisle. To unlock the full capability of the Liebert CRV, the remote

rack sensors should be installed, which will allow the fan speed and the cooling capacity to be “de-cou-

pled.” This means that the fan speed can now be controlled independently of the cooling capacity. In

this advanced configuration, the Liebert CRV can control the discharge temperature of the unit by

modulating cooling capacity based on the supply sensor and use the remote rack sensors to ensure

that the cool air is being delivered to the inlet of the racks. Using the supply and remote rack sensors

in this de-coupled mode is the preferred method for controlling the Liebert CRV in a hot / cold aisle

configuration. In addition to this configuration Emerson has provided additional flexibility for other

applications shown in Table 7.

Figure 24 Setpoint screen

In Figure 24, the controlling sensor can be selected for the different types of sensor control modes. As

the selection is changed from one sensor to another, the setpoint value moves to the appropriate sen-

sor position, giving a visual indication of the sensor placement in relationship to the Liebert CRV.

Table 7 shows the flexibility of the Liebert CRV and how the different sensor configurations can be

used to control the Liebert CRV fan speed and cooling capacity. The table shows the different coupled

and decoupled modes available for the Liebert CRV.

Table 7 Controlling sensor settings

Cooling Control

S103Cool / S125 Fan Supply Remote Sensor Return

Fan Control

Supply

Factory Default

(Coupled)

N/A N/A

Remote Sensor

Recommended

(Decoupled)

(Coupled)

N/A

Return

(Decoupled)

(Coupled)