Non Return Damper
Non return dampers — also called backdraught shutters or gravity shutters — stop air flowing the wrong way through your ductwork. The galvanised steel butterfly blades are pushed open by the airflow when the fan runs, then simply fall shut under gravity when the fan stops, preventing backdraughts and reverse airflow through the system.
They are an inexpensive addition to kitchen and bathroom extract runs, commercial extract systems and any fan-driven ventilation where you want to stop outside air blowing back in when the fan is off.
We stock nine circular sizes from 100mm to 400mm: 100, 125, 150, 160, 200, 250, 315, 355 and 400mm — sized to suit standard spiral and circular ducting.
Fitting a plastic domestic system instead? See our plastic in-line back draught shutters (100–200mm). For airflow balancing rather than backflow prevention, browse single blade dampers or the full damper range. Order by 3pm for next-day delivery on stocked sizes.
Showing all 9 results
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Non Return Damper – 100mm
£6.40 + VAT Add to basket -
Non Return Damper – 125mm
£7.22 + VAT Add to basket -
Non Return Damper – 150mm
£7.96 + VAT Add to basket -
Non Return Damper – 160mm
£8.02 + VAT Add to basket -
Non Return Damper – 200mm
£10.60 + VAT Add to basket -
Non Return Damper – 250mm
£12.40 + VAT Add to basket -
Non Return Damper – 315mm
£16.90 + VAT Add to basket -
Non Return Damper – 355mm
£19.86 + VAT Add to basket -
Non Return Damper – 400mm
£23.64 + VAT Add to basket