Liebert TM-10098 service manual iCOM Controls Training and Service Manual

iCOM Controls Training and Service Manual

The humidity controller activates the first stage of dehumidification operation when the return air humidity level increases to 50% of the humidity proportional band. The second stage of dehumidification is activated when the return air humidity level increases to 100% of the humidity proportional band.

The humidity controller deactivates the second stage of dehumidification operation when the return air humidity level decreases to 50% of the humidity proportional control band value. The first stage of dehumidification is deactivated when the return air humidity level decreases to the humidity set point of 50% or 0% of the humidity proportional band.

If the compressors have unloading capability (4-stage cooling), then the compressors are activated in the fully loaded condition for each stage of dehumidification.

2 Stage Compressorized Dehumidification – No Dead Band

Humidity Set Point + (1/2 Proportional Band)
Humid Set Point: 50%
Proportional Band: 8%		Dehumid		Dehumid
		Stage 1 On		Stage 2 On
50	51	52	53	54	55
Dehumid		Dehumid
Stage 1 Off		Stage 2 Off
				Increasing Humidity

Note: in the above example that the control band begins at the 50% humidity set point and has a length of 4%, which is ½ of the programmed humidity proportional band value.

As the return air humidity level increases, first stage dehumidification operation is activated at 52%RH or 50% of the dehumidification control band. If the return air humidity level continues to increase the second dehumidification stage actives at 54%RH, which 100% of the dehumidification control band.

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