Ventilation control dampers — manual and automatic airflow control on duct branches

Control dampers are the elements that enable hydraulic balancing of the ventilation installation — correct distribution of airflow across each branch of the duct network so that every grille or diffuser receives exactly the design airflow. Without control dampers, air follows the path of least resistance, preferentially supplying the shortest or largest branches while leaving other zones under-ventilated. Manual dampers: manually adjustable blade(s) via a shaft with position indicator. Set once during system balancing and fixed permanently. Simple, economical solution for stable installations not requiring airflow changes after commissioning. Actuator dampers: the damper blade is driven by an electric actuator receiving a command signal from a thermostat, CO₂ sensor, BMS controller or timer. The basis of VAV (Variable Air Volume) systems in modern buildings. Available in circular (direct mounting on spiral duct) and rectangular (for sheet metal rectangular ducts) forms.