FAMCO Butterfly Damper BD4

The FAMCO BD4 is a 4 inch butterfly backdraft damper for inline installation in round duct.

Four inch duct serves the smallest exhaust duties: powder rooms, small bathrooms, compact utility spaces, and dedicated appliance vents. At this size the damper's blade is light, which means it opens readily under modest fan pressure, an advantage on the low powered fans often paired with small ducts.

The corresponding characteristic is that a light blade is more susceptible to flutter. Where wind pressure at the termination varies, a small damper blade can oscillate audibly, and the resulting intermittent tapping travels along the duct into the room. Where this occurs, a termination with its own integral damper, or a hood that reduces wind exposure, is generally the remedy.

The damper's purpose is to close the duct when the fan is off. An undamped exhaust duct is a permanent opening between the conditioned space and outdoors, through which wind driven cold air enters, conditioned air escapes, and insects and debris travel. In a bathroom it also allows odours held in the duct to return to the room.

Mount in the correct orientation relative to airflow direction and to vertical so the blade can fall closed under gravity, and confirm the damper opens fully with the fan running.

Applications include residential bathroom, powder room, and small utility exhaust systems.

Brand

FAMCO

SKU

BD4

Category

Dampers

Weight

0.45 lbs

Dimensions

4.00" x 4.00" x 5.00"

Price

$27.00

Availability

In stock

Rating

0 / 5.0