Emerson 3000/ITR User Manual

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 per-

centages. 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, con-

sult 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.

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).

Risk of electric shock. Can cause injury or death.
The Liebert iCOM microprocessor 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.