821A-FS: Rectangular – Face Operated FlexShaft

Submittal Form
SKU: 821A-FS Category:


Young 821A dampers are standard, manual, opposed blade volume control dampers, which can be used to regulate airflow in square or rectangular duct systems. The 821A is controlled in the air stream from the face of the damper. When the distance from the air outlet to the damper is unreachable, couple a flexible steel shaft to the operating screw of the damper. Flexible shafting is a direct, mechanical method for transmitting rotary motion between two points. The opposite end of the flex shaft cable is terminated to the PLBR just inside the grille to operate an inaccessible opposed blade damper from the face of the grille. Features and benefits of the 821A damper include:

• Fast, simple installation
• Rugged, heavy-duty construction of aluminum extrusions and stainless steel hardware for long, corrosion-resistant life & stand-alone quality.
• Opposed blade damper distributes air evenly over face of grille.
• Individual blade bushings for smoother and quieter operation, minimizing rattling.
• Gear rack converts rotational motion into linear motion when the spur gear is run against it.
• Gear that turns to move the rack that is fastened to the stainless steel slide mechanism is held in place with a Nylock nut that maintains pressure and resistance to prevent the blades from moving in higher velocities or pressures.

Tested up to 4” W.C.

Additional information


.050 Aluminum Extrusion with Reinforcing Channels


.050 Aluminum Extrusion with Reinforcing Channels


Stainless Steel

Blade Bushing

Individual Synthetic

Low Leak Seals

Not Available

Max Pressure

4" W.C.

Frame Width

2 1/8" Wide

Blade Width

1.438" – Contained Within Frame

Max Size

24" x 24" Side Controlled, 36" x 24" Bottom Controlled

Min Size

3" x 3"


Stainless Steel Construction, Tamper Proof, Hex Head or Star Head Adjustment Screw

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