Emerson PFH020A-L, User Manual

Page: 61 / 117

Alarms
Liebert
®
Mini-Mate2
™
54
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 setpoint. Is the unit set
up for dehumidification? Check DIP switch.
Low: The room return air humidity decreases to the high-humidity alarm setpoint. Is the unit setup
for humidification? Check DIP switch.
High and Low Simultaneously: 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: Room return air temperature increases to the high-temperature alarm setpoint. Check for
proper setpoint 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 setpoint. Check for
proper setpoint 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.
8.1.6 High-Water Alarm
A float switch in the evaporator pan will shut down the evaporator on a high water level. Clear the
drain and reset power to the unit in order to clear the alarm.
8.1.7 Loss of Power
The Loss of Power Alarm will activate (after power is restored to the unit) if the unit has lost power or
the disconnect switch was incorrectly turned off before the unit’s On switch was pressed. A Liebert
remote monitoring unit (optional) will immediately indicate loss of power.
8.1.8 Short Cycle
A Short Cycle Alarm will occur if the compressor system has exceeded 10 cooling start attempts in a
one-hour period. This can happen if the refrigerant level is low or if the cooling load is small compared
to the unit’s capacity. Check for leaks, crimped lines and defective components. If the cooling load is
low, increase sensitivity to reduce cycle.
8.2 Optional/Custom Alarms
8.2.1 Loss of Water Flow
The Loss of Water Flow Alarm will occur if no water flow is detected in the chilled water or condenser
water supply line. An external flow switch is required for this alarm. Determine whether service
valves are closed, pumps are not working, etc.
8.2.2 Smoke Detected
This alarm is triggered when smoke is detected in the return air by an optional Liebert Smoke
Detector. The evaporator unit will automatically shut down upon smoke detection. Locate the source
of the smoke and follow appropriate emergency procedures.
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?