Emerson Liebert iCOM Manual De Usuario

The Dehumidification Enable parameter (Service Menu, Options Setup) allows for enabling/disabling 

the dehumidification function.
A call for dehumidification is calculated in the same way as a cooling request. The components 

(valves, compressors) will follow this dehumidification request as soon as it is higher than the request 

for cooling.

Low Limit 1 and Low Limit 2 are used to avoid overcooling a room during dehumidification. When a 

low limit is reached, a compressor or the liquid cooling source that is used for dehumidification is dis-

abled. It is re-enabled when the return air temperature rises. The Low Limit 1 and 2 settings are in 

the Service menu under Setpoints.
Low Limit 1: Low Limit 1 will disable one of two compressors for dehumidification. If only one com-

pressor is set for dehumidification, or if the dehumidification source is chilled water, this limit will 

not be visible and will be inactive.
Low Limit 2: Low Limit 2 will disable both compressors for dehumidification. This limit will also 

stop dehumidification in single compressor units and in chilled water units.
The limits become active when the return air temperature drops below a temperature value equal to 

the sum of the temperature setpoint plus the value set on Low Limit 1 and 2 (the Low Limit settings 

are negative values).
A dehumidification source is deactivated if the return air temperature drops below the Deactivation 

Temperature, as in this example:

Under Factory Settings in the Advanced menu there is an item called Dehumidification With Comp. 

This item will be set to either 1, 2, 1 or 2, or BOTH. This setting determines which compressors are 

used for dehumidification. It also determines if Low Limit 1 will be available and impacts how the 

reheats will operate during dehumidification. The Dehumidification With Comp field is set when the 

cooling unit is built and should not be adjusted without consulting the factory first. Table 6 outlines 

which Low Limit settings will be available, based on the Dehumidification With Comp selection.

Low Limit 1 & 2 will be available only on cooling units with two compressors when Dehumidification 

With Comp is set to BOTH (see WARNING on page 30).

Temperature Setpoint:

70°F

Low Limit Value:

-7°F

Deactivation Temperature:

62°F

Low Limit 2 only

[blank] (units without compressors)

All Chilled Water Units

1 (Compressor 1 dehumidifies only)

Liebert Challenger 3000

™

, Liebert DS

™

, 

Liebert Deluxe System/3

™

2 (Compressor 2 dehumidifies only)

—

1 or 2 (Compressor 1 and 2 alternate)

—

Low Limit 1 & 2

Both (both compressors dehumidify)

—