Twinflow STDR

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Twinflow STDR Direct Drive Twin Centrifugal Fan
Elta Select Product

Quick Facts

  • 5 standard sizes from 200mm to 500mm.
  • Air volume flow rates up to 0.23 m³/s (AC) / 1.65 m³/s (EC).
  • Static pressures up to 500 Pa (AC) / 960 Pa (EC).
  • Suitable for operating temperatures up to +60°C.
  • Extensive range of stock available.
  • Available in AC and EC.


  • Available for next day delivery with Elta Select

Demand Control Ventilation

  • Fan & inverter packages available, please contact us for more information

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Features & Benefits

Material Strength

This robust and durable unit has a casing manufactured from natural finish Aluzinc, with a louvred air discharge which provides protection against ingress from the elements and is self draining.

Ease of installation

All models are designed for direct connection to standard diameter flexible or rigid circular ducting with long spigots with EPDM rubber U shaped seals for ease of connection.


High efficiency low tonal noise backward curved centrifugal impellers are directly driven by an AC or EC external rotor motor, designed to be non-overloading and provide high performance characteristics.

Quality Assurance

All units are designed and manufactured with procedures as defined in BS EN ISO 9001:2008.

Design Appeal

Ideal for external roof mounting applications where space is a premium.

Full Accessory Range

Speed controllers, fast clamps, silencers, flexible connectors and auto-changeover panels.


Each STDR has a 12 month warranty.


The unit casing shall be manufactured from 1.2mm thick natural finish Aluzinc. The casing shall be designed so as to minimise vibration and shall incorporate a louvered air discharge guarded against bird ingress. Drain points shall also be provided. Each casing provides an inlet spigot to suit standard circular ducting. EPDM (Ethylene Propylene) rubber U shaped seals (being ozone and UV stable) are used to ensure a good seal back to the duct that is to be attached. Top access panels shall be provided for ease of servicing.


The Twin range of units may have either an EC or AC external rotor motor fitted as standard. The motor contains sealed for life bearings. Thermal Class of motors to THCL 130 or 155 dependent on size. Manufactured by Ziehl-Abegg providing increased reliability. All motors are suitable for use in ambient air conditions up to +60°C.


High efficiency low tonal noise backward curved centrifugal impeller, dynamically balanced to ISO 14694 Grade G6.3 and directly driven by the motor to provide a smooth airflow through the unit.

Quality Management

All units in the Elta range are designed and manufactured to procedures as defined in BS EN ISO 9001:2008. They are also tested in accordance with BS848 Part 2 1985 (sound performance) and ISO 5801:2007 (airside performance).
  • ACO PanelACO Panel
  • Electronic ControllerElectronic Controller
  • Fast ClampsFast Clamps
  • Flexible ConnectionsFlexible Connections
  • SilencerSilencer
  • Transformer ControllerTransformer Controller