Liebert iCOM Microprocessor TM-10098 - Manual (Page 25)

iCOM
Controls Training and Service Manual
Humidity Control
Humidification and/ or Dehumidification Required, in
Percent (%)
The humidity control programs for the
iCOM microprocessor is based on a
calculated percent (%RH) requirement for humidification and/ or dehumidification.
This percent (%RH) requirement is determined by the control type (algorithm)
selected by the user.
The two (2) user selectable humidity control programs are:
• Absolute Humidity, grains of moisture in the air
• Relative Humidity (%RH)
Humidity Control Program Types
Absolute (predictive) Humidity Control – Factory Default Setting
Absolute (predictive) humidity control is based on the moisture content in the
return air. The
iCOM microprocessor control automatically adjusts the humidity
control as the return air temperature deviates from the programmed temperature
set point. This calculation converts the return temperature and humidity values to
a moisture content value defined as either grains per cubic foot or grains per
pound. This recalculated content value is compared to the content control band
that is determined by the:
• Programmed temperature set point
• Programmed humidity set point in %RH
• Programmed
humidity proportional band in %RH
This automatic adjustment results in a predictive humidity control response. With
absolute humidity control, the humidity control program is automatically adjusted
approximately 2% RH for each degree difference between the return air
temperature and the temperature set point. Note the following example:
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