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Alarms
53 Liebert
®
Mini-Mate2
™
Air-Cooled Systems
Check for power shut Off to the condensing unit, condenser fans not working, defective head pressure
control valves, closed service valves, dirty condenser coils and crimped lines. Also, make sure that
when the compressor contactor is energized, the side switch on the contactor closes to energize the
control circuit on the condensing unit.
Water/Glycol/ Systems
Check water regulating valves. Verify water/glycol flow (i.e., pumps operating and service valves
open). Is water tower or drycooler operating? Is the coolant temperature entering the condenser at or
below design conditions? Is AUX relay (terminals 70 & 71) operating during cooling to turn on the
drycooler?
8.1.3 Humidity Level
The humidity level alarm may be activated under the following conditions:
• High: The room return air humidity exceeds the pre-set high humidity alarm set point. Is the
unit set up for dehumidification? Check DIP switch.
• Low: The room return air humidity decreases to the low humidity alarm set point. Is the unit
setup for humidification? Check DIP switch.
• High and Low Humidity (simultaneously): The simultaneous display of two alarms results in
loss of the humidity input signal. DASHES WILL BE DISPLAYED IN THE HUMIDITY
READING DISPLAY. Under these conditions, the control system deactivates both humidification
and dehumidification. Check for a disconnected cable or failed sensor.
8.1.4 Temperature
The temperature level alarm may be activated under the following conditions:
• High: The room return air temperature increases to the high temperature alarm set point. Check
for proper set point value. Is the room load more than the unit can handle (i.e., capacity too
small)? Make sure cooling components are operating (compressor or valves).
• Low: The room return air temperature decreases to the low temperature alarm set point. Check
for proper set point value. Make sure all heating components are operating (e.g., contactors,
reheats, etc.). Are reheats drawing the proper current (refer to amp rating on nameplate).
• High and Low (simultaneously): The simultaneous display of these two alarms results in loss
of the temperature input signal (or the humidity is out of sensor range-15 to 85% RH). Dashes will
be displayed for the temperature reading. The control system will initiate 100% cooling. Check for
a disconnected cable or a failed sensor.
8.1.5 Humidifier Problem Alarm
The Humidifier Problem Alarm will sound and display a message if any of the following humidifier
conditions occur: overcurrent detection; fill system fault or end of cylinder life.
Check fault indicator LED on humidifier control board:
• Constant LED on = Overcurrent
• 1 second LED Flash = Fill System
• 1/2 second LED Flash = Replace Tank
8.1.6 High Water Alarm
A float switch in the evaporator pan will shutdown the evaporator on a high water level. Clear the
drain and reset power to the unit in order to clear the alarm.
NOTE
Check for proper setpoints. Does the room have a vapor barrier to seal it from outdoor
humidity? Are doors or windows open to outside air?