Liebert 8 Tons 5.1.3Humidity, 5.1.4Temperature, 5.1.5Humidifier Problem Alarm, 5.1.7Loss of Power

Alarms

5.1.3Humidity

The humidity 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 low humidity alarm setpoint. 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 READ- ING DISPLAY. Under these conditions, the control system deactivates both humidification and dehumidification. Check for a disconnected cable or failed sensor.

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?

5.1.4Temperature

The temperature level alarm may be activated under the following conditions:

•High: The 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.

5.1.5Humidifier 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 Fault

•1/2 second LED Flash = End of cylinder life, replace tank

5.1.6High-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.

5.1.7Loss 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 ON/OFF switch was pressed. A Lie- bert remote monitoring unit (optional) will immediately indicate loss of power.

5.1.8Short Cycle

A Short Cycle Alarm will occur if a compressor system has exceeded 10 cooling start attempts in a one-hour period. This can be caused by room cooling load is small compared to capacity of the unit. If room load is low, increase temperature sensitivity to reduce cycle.

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