User manual

Operation
13
Autorestart
When input power returns after a power failure, the unit will return to its previous operating status:
On if it was On before the power failure, Off if it was Off.
When power returns, the autorestart time—time-selectable: Single Unit Auto Restart (Service Menu,
Options Setup)—will determine how quickly the unit restarts. If the units are on the same network,
the autorestart time runs in a loop, starting each unit in sequence, beginning 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).
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) or
EC fan fault and the differential pressure switch detects a loss of airflow. If either protection device is
activated after an adjustable time delay, an audible alarm occurs, an alarm relay activates 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—disables humidifying, heating and dehumidifying outputs; allows cooling and
free-cooling only (intended for chilled water models / external cooling).
NOTE
Loss of Power alarm will be activated only on units that had the fan switched On before power
was lost.
NOTE
When the Main Fan Overload alarm is active, the Loss of Airflow alarm is masked out.