Emerson Liebert Challenger iCOM 3000 Operation & Maintenance Manual page 35

Circuit Board Adjustments
WARNING
!
Arc flash and electric shock hazard. Open all local and remote electric power supply
disconnect switches, verify with a voltmeter that power is Off and wear personal protective
clothing per NFPA 70E before working within the electric control enclosure. Failure to comply
can cause injury or death.
The Liebert iCOM does not isolate power from the unit, even in the "Unit Off" mode. The only
way to ensure that there is NO voltage inside the unit is to install and open a remote
disconnect switch. Refer to unit electrical schematic.
Only properly trained and qualified personnel should perform adjustment of the circuit board.
Hazardous voltages are present in the equipment throughout the procedure. Disconnect all
power from the unit before working within the cabinet.
Humidifier operation is governed by the humidifier control board. This board is located on the right
side of the humidifier compartment. There are three potentiometers mounted on the board. These
pots can be used to adjust for extreme water conductivity conditions and capacity.
The "%" pot controls the amperage at which the drain will energize. The pot is clearly marked in
percentages. This adjustment is factory set at 90%, which indicates that the unit will drain when the
amperage falls off to 90% of the capacity setpoint. Raising the value increases the frequency of drain
cycles. Lowering the value decreases the frequency of drain cycles. The frequency should be increased
for highly conductive water and decreased for less conductive water. If adjustment is necessary, and a
change of three to four percent in either direction does not permit normal operation of the unit,
consult your Liebert supplier.
The pot marked "SEC" controls the duration of the drain cycle. The pot is clearly marked in seconds.
This adjustment is factory set at 60 seconds and should not be readjusted without consulting your
Liebert supplier.
The pot marked "CAP ADJ" is factory set at 100%. The maximum capacity is determined by a fixed
resistor (R4) which is factory selected based on unit voltage.
Drain Tempering Feature
All units are equipped with a drain tempering feature which mixes cold fill water with hot drain
water to protect drain piping. This feature can lower drain water temperature to as low as 140°F
(60°C), depending on water pressure. To deactivate this feature, remove the diode from socket CR18
on the circuit board (lower left, above LED).
Component Operation and Maintenance
31
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Liebert ® Challenger 3000