User manual

Operation
45 Liebert
®
iCOM
®
Liebert Air Economizer Variable Speed Fan Operation (VFD and EC Fan)
Upon startup after a loss of power to the Liebert iCOM control board, the main fan will operate at
100% for the first 5 minutes of operation. After running at 100% for 5 minutes, the standard fan
control will be able to modulate the fan. For other control modes, refer to Variable Speed Fans—EC
or Variable Frequency Drives on page 18.
3.4.4 Disable the Liebert Air Economizer
™
The Liebert Air Economizer can be disabled through a deactivation switch field-installed and wired to
Terminals 24 and 51 in place of the factory-supplied jumper. Removing a factory-installed jumper will
deactivate the unit’s function (see Figure 40). Deactivating the Liebert Air Economizer will transfer
all cooling to the primary cooling unit.
Figure 40 Deactivation switch
3.5 Temperature Control—Reheat
If the room air temperature becomes too cold, the control will call for heating. Heating mode is
controlled by the Temperature Proportional Band, explained in 3.2.1 - Temperature Proportional
Band.
NOTE
Electric Reheat is not allowed during dehumidification. Staged Reheat is used when normal
reheat control is selected, the reheats are turned On at the normal control points of 33%, 66%
and 100% without influence if or how the compressors are in operation.
Delayed Reheat is permitted only when one compressor is it operation. As soon as both
compressors are working, the electric reheats are turned Off.
24 51
Liebert Air Economizer
Deactivation Switch
Terminals 24 and 51
Factory-Installed Jumper
Customer must remove jumper
and connect normally closed
contact to Terminals 24 and 51.
Open the contact to deactivate
the Liebert Air Economizer
functionality.
Main unit will continue to run without
the Liebert Air Economizer feature.
DPN001449
Pg. 6, Rev. 2