ZPC overpressure valve. Back-draught butterfly damper prevents unwanted airflow.

• Spring loaded blades mechanism, non adjustable, blades are opened by air pressure and are closed with a spring
• Casing made out of galvanized steel sheet, damper blade made out of anodized aluminium
• In case of horizontal installation, damper axis must be in vertical position
• Install the backdraft damper into the ventilation system with respect to the air flow direction