Q15 Temp Actual
Current value of the sensor selected as the Q15 Output Sensor.
Q15 Temp Output Threshold
Temperature threshold above or below which Q15 output activates.
3.3.12 Temperature Control: Setting Loss of Cooling Operation
Loss of cooling is defined as a state where the Liebert® unit can no longer support cooling operation. During a loss of cooling
situation, airflow output is still provided. This feature is supported on direct expansion (DX), chilled water (CW), and free
cooling (FC) applications. The following scenarios represent the operational situations where a given unit may experience a
loss of cooling:
1. Unit is OFF (excluding Standby operation, see A105.1 'Loss of cooling - Fan Operation')
2. Unit is ON but in Manual Mode
3. For Direct Expansion (DX) unit when one or more of the following are considered true:
a. DX unit is ON with Free Cooling unavailable and all refrigerant circuits are either:
• Low Pressure Phase 9 (LP w/ 90 min delay)
• Low Pressure Phase 6 (freeze protection 10 minute delay)
b. DX unit is ON with Free Cooling unavailable and compressors unavailable due to:
• Pump down failure
• High pressure lockout
• High discharge
• GC remote shutdown
• Compressor overload
• Various EEV alarm(s) preventing EEV operation
• Unit is ON, all cooling operations are unavailable due to customer alarm input (Comp Lockout, FC
Lockout, Flow AL LC, etc).
c. Free Cooling unavailable due to one of the following reasons:
• Unit not within mixed mode/pump mode
• Free Cooling status is continuously off for 130 seconds with a call for cooling because
• U305.2 'FC Status' is not "ON".
• Current call for cooling is less than 1%.
3 Service Operation
69
Vertiv™ Liebert® iCOM™Installer/User Guide
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