The straightforward use of the outdoor air damper is to shut close the intake in the air duct while the AHU is stopped or in recirculation mode.

Closing of the damper can be delayed while stopping the Supply air fan. This prevents under-pressure and possible damage to the ductwork created by the de-energized but still free-spinning fan.

Configuration of the outdoor air damper


Available options & Selection


Activate function

Configuration > Functions > Function activation >


| No |

| Outdoor air |

| Outdoor air + Exhaust air |

| Exhaust air |

Activate function of the Outdoor air damper

Allocating IOs

Configuration > I/O allocation settings > Digital outputs

Outdoor air damper

Any available I/O

Control signal to hardwired actuator.

The DO can stay unconfigured for the modbus type actuator.

Configuration of modbus actuator

Damper close delay

Data & Settings > Fan control > Supply air fan

Outdoor air damper stop delay

[0] s

Damper will remain open for the set time after stopping of the Supply air fan

Graphical representation

Flowchart > Outdoor damper

Indication: Open / Closed

The outdoor air damper can also be modulated to regulate intake of the fresh air. The modulated outdoor damper is controlled in combination with the mixing damper by the Air quality control function.