For automatic shut-off of the air ducts and prevention of back drafting when the fan off. Suitable for installation in various premises. Compatible with 400x200 up to 600x350 mm rectangular air ducts.
Fixing to rectangular ducts in upright position. Provide free gravity actuated movement of the blade. Install the backdraft damper into the ventilation system with respect to the air flow direction.
Galvanized steel case and rotary gravity-actuated blade. The damper blade is opened with air pressure and reset automatically when the fan is off and no air pressure is produced. Manual handle with a counterweight to regulate the damper opening-closing sensitivity.