Constant Volume Dampers Type ‘EN’


Rectangular self-powered volume flow controllers for the control of supply air or extract air in constant air volume systems

  • Suitable for volume flow rates up to 12,096 m³/h or 3,360 l/s
  • Volume flow rate can be set using an external scale, no tools required
  • High control accuracy
  • No on-site test measurements required for commissioning
  • Suitable for airflow velocities of up to 8 m/s
  • Casing air leakage to EN 1751, up to class C

Optional equipment and accessories

  • Acoustic cladding for the reduction of case-radiated noise
  • Secondary silencer Type TX for the reduction of air-regenerated noise
  • Hot water heat exchanger of Type WT for reheating the airflow
  • Actuator for switching between setpoint values

Product Information


  • EN: Volume flow controller
  • EN-D: Volume flow controller with acoustic cladding
  • Units with acoustic cladding and/or secondary silencer Type TX for demanding acoustic requirements
  • Acoustic cladding cannot be retrofitted



  • Galvanised sheet steel
  • P1: Powder-coated, silver grey (RAL 7001)


Parts and characteristics

  • Ready-to-commission controller
  • Damper blade with low-friction bearings
  • Bellows that acts as an oscillation damper
  • Cam plate with leaf spring
  • Scale with pointer to set the volume flow rate setpoint
  • Aerodynamic function testing of each unit on a special test rig prior to shipping



  • Min/Max actuators: Actuators for switching between minimum and maximum volume flow rate setpoint values
  • Modulating actuators: Actuators for the stepless adjustment of volume flow rates or to switch between minimum and maximum volume flow rate setpoint values
  • Retrofit kits: Actuators and installation accessories
  • EN with actuator only up to H = 300 mm


Useful additions

  • Secondary silencer Type TX
  • Heat exchanger Type WT


Construction features

  • Rectangular casing
  • Flanges on both sides, suitable for duct connection
  • Volume flow controllers from H = 400 mm are fitted with two damper blades and two volume flow rate scales


Materials and surfaces

Galvanised sheet steel construction

  • Casing and damper blade made of galvanised sheet steel
  • Leaf spring made of stainless steel
  • Polyurethane bellows
  • Plain bearings with PTFE coating


Powder-coated construction (P1)

  • Casing and damper blade made of galvanised sheet steel, powder-coated


Variant with acoustic cladding (-D)

  • Acoustic cladding made of galvanised sheet steel
  • Rubber profile for the insulation of structure-borne noise
  • Lining is mineral wool


Mineral wool

  • To EN 13501, fire rating class A1, non-combustible
  • RAL quality mark RAL-GZ 388
  • Biosoluble and hence hygienically safe according to the German TRGS 905 (Technical Rules for Hazardous Substances) and EU directive 97/69/EC


Standards and guidelines

  • Casing air leakage to EN 1751, class C (B + H ≤400, class B)



  • Maintenance-free as construction and materials are not subject to wear

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