Dayton 53DR11 20 in Backdraft Damper 22-1/2 in x 22-1/2 in

Application fit

This 20 in backdraft damper is designed for wall-mounted ventilation systems that require automatic airflow control. It suits installers and facility managers who need a gravity-operated shutter that opens when a fan runs and closes when it stops. The unit fits a 20 in fan diameter and mounts vertically in a 22-1/2 in by 22-1/2 in rough opening.

Pre-installation checks

Verify that the wall opening measures 22-1/2 in by 22-1/2 in and that the mounting surface can accept 9/64 in fasteners. Confirm the fan diameter is 20 in so the shutter blades can operate without interference. Ensure the installation allows a vertical mounting position and that the 5 3/4 in open depth clears any interior obstructions.

Build integration

The G-90 galvanized steel frame with tie rods provides structural rigidity while the mill-finish aluminum blades deliver a 2.519 sq ft free area at velocities up to 2500 FPM. The 1 1/2 in flange width simplifies sealing against the wall, and the 2 1/2 in frame depth keeps the profile shallow. This damper requires no external power or control wiring, freeing up electrical capacity for other components.