The Condenser - Important Damper Parts

Dampers are built from many components, but we usually focus on the blades and the frame. Let's look at three damper parts that deserve more attention.

The typical HVAC damper consists of a frame, blades, and linkage. There are dampers that stray from this design, like the curtain fire damper. Most dampers have these three parts. Here is a list of three common components found in dampers.

Axles: The core of every damper blade. Axles run the length of the blade and provide the means to rotate. When a damper opens or closes, all of its blades will rotate along axles.

• Axles are metal rods inside the damper blade.
• They are synchronized via linkage, so that all blades rotate on the same action.
• The axle attached to the actuator is the damper’s driving axle.
• Axles can be round, square, or pin-lock shaped.

Bearings: Support for rotating axles. Bearings allow each axle to rotate within the jamb of the damper’s frame. These components provide ease of motion for the blades and prevent damage from metal-on-metal friction.

• Bearings consist of two circular pieces that fit in holes in the damper’s jambs.
• The blade axle will fit inside of the bearing.
• Axles will rotate within the bearing for ease of motion.
• The shape of the bearing will match the shape of the axle.

Seals: Minimize leakage through the damper when it’s closed. Dampers can have blade seals and jamb seals to help close the gaps. Leakage can reduce air efficiency, which is why tight closure is important.

• Blade seals are made from soft, resilient materials like extruded silicone rubber. Jamb seals are made from thin pieces of steel.
• These components cover the gaps found between closed blades and between blades and the damper’s jambs.
• Jamb seals are flexible, so that damper’s blades are free to rotate.
• Blade seals on airfoil blades are set just behind the blade’s edge, so that they came together when the damper closes.

Every component is important. From the blades to the bearings, each part works to open and close your dampers. Manufacturers will list each component and their materials in the damper’s submittal.

Be sure to check the submittal when selecting dampers.

For more on dampers, check out these Newsstand article:

• Anatomy of a Damper
• Five Things to Know When Selecting Dampers
• The Condenser - Blade Design for Dampers
• Damper Showdown - Control Dampers vs. Backdraft Dampers