Short Cycle; Optional/Custom Alarms; Loss Of Water Flow; Smoke Detected - Liebert CHALLENGER 3000 Operation And Maintenance Manual

5.1.16 Short Cycle

On compressorized systems, if the compressor has exceeded 10 cooling starts in one hour or if the
compressor has cycled five times in 10 minutes on the low pressure switch during non-cooling, the
Short Cycle alarm will occur. This can be caused by low refrigerant level (but not low enough to acti-
vate Low Suction Pressure alarm) or room cooling load is small compared to capacity of the unit.
Check for leaks, crimped lines, and defective components. If room load is low, increase sensitivity to
reduce cycling (proportional control). On GLYCOOL units, dirty filters can cause the coil freeze stats
to cycle the compressor.
5.2

Optional/Custom Alarms

5.2.1

Loss of Water Flow

Available only with 3-way valves and occurs when no water flow is detected in the chilled water or
condenser water supply line. An optional flow switch is required for this alarm. Check for service
valves closed, pumps not working, etc.
5.2.2

Smoke Detected

Smoke is detected in the return air by an optional Liebert Smoke Detector. Check for source of smoke
or fire, and follow appropriate emergency procedures.
5.2.3

Standby GC Pump On

The primary pump has failed, and the standby pump is activated (glycol cooled and GLYCOOL units
only).
Check for problems with the primary pump (fuses blown, motor burnout, service valve shut, stuck
check valve, impeller damage, etc.).
5.2.4

Standby Unit On

The primary environmental control system has had an alarm condition, and the standby system is
activated.
5.2.5

Water Under Floor

Water is detected by an optional Liebert Water Detection System. Check under the raised floor for
water or other leaks.
NOTE
The alarms are specified by the customer at the time of order. All alarms will report to a
Liebert remote monitoring unit. Additional devices and wiring may be required at the factory
for some of the alarms.
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Alarm Descriptions