User manual

Operation
Liebert
®
iCOM
®
for Liebert DSE
™
40
Dehumidification Operation
• Dehumidification with four compressors operates until there is a call for the first stage reheat.
• Dehumidification with three compressors operates until there is a call for the second stage reheat
or LL1 is reached
• Dehumidification with two compressors is allowed to operate with full reheats until the LL2
threshold is met
• Digital compressors will operate when the unit is in 2 compressor dehum operation.
• This allows the outer coil to precool the air which makes the inner coil more effective for
dehumidification.
• If there are compressor alarms, the unit will adjust the compressor dehumidification operation
until three of the four compressors are unavailable.
• Compressors C1A, C1B, C2A, and C2B must be ON.
• The C1A Digital Compressor must be loaded at 100% at all times.
• The C2A Digital Compressor will adjust its loading based on whether the call for
dehumidification (CFD) is greater than the call for cooling (CFC): If the call for
dehumidification (CFD) is greater than or equal to the CFC, C2A must use the ramp on line DH05
(“C2A CFC @ 0% / 100% Dehum Ramp”), with the CFD value used to determine ramp %. If the
CFD is less than the CFC, then C2A must use the ramp on line DH06 (“C2A CFC @ 0% / 100%
Cooling Ramp”), with the call for cooling value used to determine ramp %.
• If a reheat stage greater than or equal to the stage on the left-hand side of line DH07 becomes
active, the C1B compressor must be turned Off. Once this happens, control operation moves to DH
Stage 2.
• If the Low Limit Sensor (Line S132) temperature becomes less than or equal to the Low Limit 1
border (lines S132 & S133, the C2B and C1B compressors must be turned Off. Once this happens,
control operation moves to DH Stage 1.
Dehumidification with Three Compressors (DH Stage 2)
• Compressors C1A, C2A, and C2B must be On, and C1B must be Off.
• The C1A Digital Compressor must be loaded at 100% at all times.
• The C2A Digital Compressor will adjust its loading based on whether the Call for
Dehumidification (CFD) is greater than the Call for Cooling (CFC): If the CFD is greater than or
equal to the CFC, C2A must use the ramp on line DH05 (“C2A CFC @ 0% / 100% Dehum Ramp”),
with the CFD value used to determine ramp %. If the CFD is less than the CFC, then C2A must
use the ramp on line DH06 (“C2A CFC @ 0% / 100% Cooling Ramp”), with the call for cooling
value used to determine ramp %.
• If the reheat stage indicated on the right-hand side of line DH07 becomes active, the C2B
compressor must be turned OFF. Once this happens, control operation moves to DH Stage 1.
• If the Low Limit Sensor (line S132) temperature becomes less than or equal to the Low Limit 1
border (lines S132 & S133), the C2B compressor must be turned OFF. Once this happens, control
operation moves to DH Stage 1.
• If a reheat greater than or equal to the stage indicated on the left-hand side of line DH07 is
inactive, and the Low Limit sensor (line S132) temperature is above the Low Limit 1 reset border,
then Compressor C1B can start (or restart) if the CFC becomes greater than or equal to the value
on line DH02 (“C1B Start @ CFC”). Operation then moves to DH Stage 3.