Swirl Diffuser Type ‘VDL’


Circular ceiling swirl diffusers, with manual or motorised adjustment of the air pattern to ensure draught-free ventilation of the occupied zone both in heating and cooling modes

  • Nominal sizes 315, 400, 630, 800
  • Volume flow rate range 65 – 1080 l/s or 234 – 3888 m³/h
  • Diffuser face made of galvanised, powder-coated sheet steel and of aluminium
  • For supply air
  • For variable and constant volume flows
  • High induction results in a rapid reduction of the temperature difference and airflow velocity
  • Discharge direction can be adjusted manually or with an actuator
  • Diffuser face with aerodynamically optimised contours
  • Ideal for high rooms

Optional equipment and accessories

  • Exposed diffuser face available in RAL CLASSIC colours
  • Horizontal or vertical duct connection
  • An extended border improves the horizontal air discharge in cooling mode
  • Protective cage for use in gymnasiums
  • Actuators for adjusting the air discharge direction
  • Diffuser face can be removed from the room side

Product Information


  • A: Diffuser face without flange
  • B: Diffuser face with flange



  • F: Diffuser face only
  • H: Horizontal duct connection, with plenum box
  • V: Vertical duct connection, with plenum box


Diffuser face

  • N: Non-removable diffuser face
  • D: Removable diffuser face, only in variant with plenum box


Parts and characteristics

  • Circular diffuser face
  • Removable or non-removable diffuser face
  • Radially arranged fixed or adjustable blades for air discharge from horizontal (0°) to vertical (90°)
  • Diffuser face with or without flange
  • Adjustment mechanism covered by decorative cap



  • Lip seal
  • Electric actuators for adjusting the air discharge direction
  • Extended border and protective cage


Useful additions

  • TDC temperature difference control module


Construction features

  • Spigot suitable for circular ducts to EN 1506 or EN 13180
  • Spigot with groove for lip seal (if accessory lip seal has been ordered)


Materials and surfaces

  • Blades, casing, duct collar, extended border, plenum box and cross bar made of galvanised sheet steel
  • Diffuser face and decorative cap made of aluminium
  • Protective cage made of steel mesh
  • Blades, duct collar, extended border, plenum box, diffuser face and decorative cap powder-coated RAL 9010, pure white
  • P1: Powder-coated, RAL CLASSIC colour


Standards and guidelines

  • Sound power level of the air-regenerated noise measured according to EN ISO 5135



  • Maintenance-free as construction and materials are not subject to wear
  • Inspection and cleaning to VDI 6022

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