Alarm Descriptions and Solutions
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6.0 ALARM DESCRIPTIONS AND SOLUTIONS

6.1 Alarm Descriptions

•LOSS OF FLOW P1 – Activated when pump 1 is commanded to run and the differential pres-
sure switch does not sense differential pressure (set at 6 psi; 41 kPa; 0.41 bars). After attempting
to start pump 1 for a period of 120 seconds (including time delays), the Liebert XDC will automat-
ically switch to the other pump to establish flow.
•LOSS OF FLOW P2 – Activated when pump 2 is commanded to run and the differential pres-
sure switch does not sense differential pressure (set at 6 psi; 41 kPa; 0.41 bars). After attempting
to start pump 2 for a period of 120 seconds (including time delays), the Liebert XDC will automat-
ically switch to the other pump to establish flow.
•PUMP SHORT CYCLE – Activated when the Liebert XDC is trying to establish flow (differen-
tial pressure) and it is unable to do it. The Liebert XDC will attempt to establish flow (differential
pressure) for 4 minutes on each pump, for a total of 8 minutes. If this cycling occurs within 30
minutes (can be adjusted from 10 to 60 minutes) and the Liebert XDC still does not establish flow,
a SHORT CYCLE alarm will be present. This alarm will shut down the Liebert XDC, main power
(disconnect switch) must be turned OFF then back ON to clear this alarm.
•CUSTOMER ALARM – Activated when 24VAC signal is applied to the customer alarm input on
the control board. Alarm will reset when the 24VAC signal is taken away.
•CONDENSATION – Activated when water is detected at the Liebert XD cooling module (24VAC
is applied to the condensation input on the control). When this alarm is active, the control will
raise its refrigerant control point by 4 degrees Fahrenheit. Alarm will reset when the 24VAC sig-
nal is taken away or main power removed.
•FAN FAILURE ALARM – Not currently being used.
•HIGH REMOTE TEMP & HIGH LOCAL TEMP – Activated when the remote or local temper-
ature exceeds the user specified setpoint. See 5.3.2 - SETPOINTS. Alarm will reset itself when
the room temperature drops below the setpoint.
•LOW REMOTE TEMP & LOW LOCAL TEMP – Activated when the remote or local tempera-
ture is below the user specified setpoint. See 5.3.2 - SETPOINTS. Alarm will reset itself when
the room temperature raises above the setpoint.
•REMOTE SENS PROB – Activated when no signal is present from the remote temperature or
humidity sensors. Alarm will reset when the temperature and humidity signals are re-estab-
lished.
•LOCAL SENS PROB – Activated when no signal is present from the local temperature or
humidity sensors or communications is lost from the display. Alarm will reset when the tempera-
ture and humidity signals are re-established.
•HIGH DEWPOINT – Activated when the room dew point exceeds the user specified setpoint. See
5.3.2 - SETPOINTS. Alarm will reset itself when the room temperature drops below the setpoint.
•HIGH HEAD PRESSURE C1A – Activated when a high head pressure signal is sensed from
compressor 1A by the control.
•HIGH HEAD PRESSURE C1B – Activated when a high head pressure signal is sensed from
compressor 1B by the control.
•HIGH HEAD PRESSURE C2A – Activated when a high head pressure signal is sensed from
compressor 2A by the control.
•HIGH HEAD PRESSURE C2B – Activated when a high head pressure signal is sensed from
compressor 2B by the control.
•LOW PRESSURE CKT 1 – Activated when the low-pressure switch for compressor circuit #1
doesn’t send the proper signal during normal operation, or during pump-down.
•LOW PRESSURE CKT 2 – Activated when the low-pressure switch for compressor circuit #2
doesn’t send the proper signal during normal operation, or during pump-down.
NOTE
Alarms must be acknowledged before they can be reset. To acknowledge or silence an alarm,
press the ALARM SILENCE / ? key.