Access 4.x

Exhaust damper (Open/Closed)

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

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

The exhaust air damper can be changed for or backed-up with the damper on the extract side of the AHU. The placement of the damper in the flowchart can be altered accordingly.

Configuration of the Exhaust\Extract air damper


Available options & Selection


Activate function

Configuration > Functions > Function activation >


| No |

| Outdoor air |

| Outdoor air + Exhaust air |

| Exhaust air |

Activate function of the Exhaust air damper

Allocating IOs

Configuration > I/O allocation settings > Digital outputs

Exhaust 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 > Extract air fan

Exhaust air damper stop delay

[0] s

Damper will remain open for the set time after the extract air fan has stopped

Flowchart setup

Configuration > Functions > Flowchart setup >

Exhaust air damper placement

| Exhaust air |

| Extract air |

| Exhaust air + Extract air |

Damper display options in the flowchart

Graphical representation

Flowchart > Exhaust air damper

Indication: Open / Closed

Flowchart > Extract air damper

Indication: Open / Closed