Replacement Procedures; Compressor Replacement; Table 30 Dip Switch Settings For Humidifier Control Board - Liebert Mini-Mate2 MMD24E User Manual

POT2 controls the amperage at which the drain will energize and is clearly marked in percentages.
This adjustment is factory-set at 85%, which indicates that the unit will drain when the amperage
falls off to 85% of the capacity set point. 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 3 to 4 percent in either direction does not permit
normal operation of the unit, consult your Liebert supplier.
The POT1 controls the duration of the drain cycle. This adjustment is factory-set at 60 seconds and
should not be readjusted without consulting your Liebert supplier.
The DIP switch settings are used to set the capacity of the humidifier. If the humidifier is replaced in
the field, the DIP switches should be set to the required settings described below.
Table 30 DIP switch settings for humidifier control board (2- and 3-ton unit
Voltage SW1
208/230 Off
220/240 Off
277 On
380/415 Off
460 On
9.3

Replacement Procedures

9.3.1

Compressor Replacement

Infrequently, a fault in the motor insulation may result in a motor burnout (if system is properly
installed, motor burnout rarely occurs). Primarily this type of failure is due to mechanical or
lubrication problems, where the burnout is a secondary consequence.
Early detection can prevent a large percentage of the problems that can cause compressor failures.
Periodic maintenance inspections by alert service personnel (i.e., identification of abnormal
operation) can be a major factor in reducing maintenance costs. It is easier and more cost-effective to
implement the necessary preventative steps that ensure proper system operation; rather than ignore
a problem until it results in compressor failure and costly replacement. When troubleshooting a
compressor problem, check all electrical components for proper operation:
WARNING
!
Risk of contacting caustic substances. Can cause injury.
Avoid touching or contacting the gas and oils with exposed skin. Severe burns will result.
Wear protective clothing, safety goggles and long rubber gloves when handling contaminated
parts.
• Check all fuses and circuit breakers.
• Check pressure switch operation.
• If a compressor failure has occurred, determine whether its cause is an electrical or mechanical
problem.
WARNING
!
Risk of explosive discharge of high pressure refrigerant. Can cause serious injury.
This unit contains fluids and gasses under high pressure. Relieve pressure before working
with piping/connections.
Mechanical Failure: If a mechanical failure has occurred, the compressor must be replaced. If a
burnout occurs, correct the problem and clean the system. It is important to note that successive
burnouts OF THE SAME SYSTEM are usually caused by improper cleaning. If a severe burnout has
occurred, the oil will be black and acidic.
SW2 SW3 SW4 Amps
On Off On 6.4
On Off On 6.4
Off Off On 5.7
Off On Off 3.7
On Off Off 3.4
65
System Testing and Maintenance
®
Liebert Mini-Mate2
™