Emerson Liebert Challenger 3000 User Manual page 19

Autorestart
When there is a loss of power to the cooling unit and power comes back, the unit will return to its pre-
vious operating status—on if it was on before the power off, off if it was off.
When power returns, the autorestart time—time-selectable: Single Unit Auto Restart (Service Menu,
Options Setup)—controls the start of the unit. If the units are on the same network, the autorestart
time runs in a loop, starting each unit in sequence, starting with Unit # 1.
Loss of Power Alarm
A Loss of Power Alarm is activated when power is restored after an interruption. If acknowledged, the
alarm resets automatically after 30 minutes. This alarm can be set to different event types (Message,
Alarm or Warning) and can be disabled under menu item Loss of Power (Service Menu, Set Alarms).
NOTE
Loss of Power alarm will be activated only on units that had the fan switched On before power
was lost.
Fan Alarm / Fan Protection Settings
The fan operation is protected by two digital devices: motor protection (optional) and a differential
pressure switch. The motor protection monitors for main fan overload (Main Fan Overload alarm) and
the differential pressure switch ensures that the blower(s) are moving air (Loss of Airflow alarm). If
either protection device is actuated after an adjustable time delay, an audible alarm occurs, an alarm
relay ativates and an event is recorded in the event log (Main Fan Overload and Loss of Airflow in
Service Menu, Set Alarms).
The fan delay at the unit start is always five seconds shorter than the control delay (to avoid short-
cycling components when the fan is not working).
There are two selection possibilities for both, Loss of Airflow and Main Fan Overload:
• Shutdown—stops the unit (intended for DX models).
• Disable—stops the humidifier, electrical heaters and dehumidification; allows cooling and
free-cooling only (intended for chilled water models / external cooling).
NOTE
When the Main Fan Overload alarm is active, the Loss of Airflow alarm is masked out.
13
Operation