Emerson Liebert iCOM Manual De Usuario

S168 Fan Back Draft Control—Enables or disables the Back Draft fan control. This feature allows 

EC fans (only) to operate at very low speeds to prevent airflow from cycling through the unit due to a 

higher under-floor static pressure than the above-floor static pressure. VFD’s cannot be used with 

this feature because motor and or bearing degradation may occur at the low fan speeds required.
S169 VSD Setpoint BACK DRAFT—The variable speed device setpoint is set as a voltage 

reference. The lower the voltage, the slower the fans will spin. This parameter is set based on the 

application. Higher under-floor static pressure may require a higher setting to prevent air flow 

through the unit. 
S171 Not Selectable Zone 1—The Not Selectable Zone 1 and 2 are zones that the EC fans cannot 

operate within due to vibration harmonics that the fans may introduce to the unit. These parameters 

will be set from the factory based on model type and should not need adjusted in the field. 
S172 Not Selectable Zone 2—The not selectable zone 1 and 2 are zones that the EC fans cannot 

operate within because of vibration harmonics the fans may apply to the unit’s frame. These 

parameters will be set at the factory based on model type and should not need adjusted in the field.
S173 Stop BDR when System is Off—The above is true when S173 Stop BDR when System is Off 

is set to Yes. If S173 is set to No, the BDR mode will not be interrupted, unless BDR is disabled or the 

unit is restarted.

Risk of electrical shock. Can cause injury and death.
Never use any of these functions—Display Off, BMS Off, LOC Off—in place of lockout/tagout 

procedures.
Some internal components of Liebert cooling units require and receive power even during the 

Unit Off mode of the Liebert iCOM.
The factory-supplied optional disconnect switch is inside the Liebert cooling unit. The line 

side of this switch contains live high voltage.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote 

disconnect switch. Refer to the unit electrical schematic.
Follow all local codes.