MCDLG Newsstand

The Condenser - A Closer Look at Linkage

How do adjustable blades move at the same time? In this Condenser, we take a closer look at linkage.

All blades must rotate together to open and close a damper. Otherwise, you would be stuck with half-open dampers and bad airflow. Linkage are the assemblies that connect adjustable blades together. When one blade rotates, the linkage will translate that rotation to all connected blades. With linkage, you can operate all the blades with one actuator tied to a driving axle.

Linkage assemblies have several parts that work together. The crank arm is the primary driver of translating blade rotation. Each blade will also have a fastener and a bearing that ties the blade to the crank arm. The specific construction of the linkage will depend on its location: either concealed in the jamb of the damper or installed along the face of the damper.

For in-jamb linkage, the crank arm will sit inside trunnions connected to each blade axle. The connect trunnion will pivot as the driving blade rotates. From here, the crank arm will translate this rotation to the trunnions connected to the other blades. In this way, all blades will rotate when the driving blade rotates. On-face linkage consists of brackets and pivots that tie the crank arm directly to the face of each blade. The crank arm will be connected to each bracket with a pivot to help translate blade rotation. When the driving blade rotates, the connected bracket will drive the crank arm, which will move the other connected brackets.

A closer look at linkage, highlighting the individual parts

Linkage can be configured for parallel or opposed blade action, so that all blades rotate in the same direction or in opposite directions in relation to neighboring blades. Opposed linkage will have two sets of crank arms tied to different blades. If each blade is numbered, even-numbered blades will share crank arm while odd-numbered blades will have a separate crank arm. The crank arm for the odd-numbered blades will be installed upside down. This ensures that each set of blades rotates in separate directions. A series of smaller jumper linkages will be configured to both sets of blades to synchronize them to the same rotation action.

You don’t need an actuator for every blade axle. Linkage assemblies ensure that dampers can open and close with one action.

MCDLG & Continuing Education

Want to know more? MCDLG offers a free self-paced course on control dampers.  

"An Introduction to Air Control Dampers" covers the basics of control dampers: what they do, where they go in an HVAC system, the principles that dictate their performance, and guidelines for installing and maintaining your control dampers.  

Visit AEC Daily to browse our online courses

This course provides continuing education credits for a variety of institutions, including ASHRAE's PDUs. Learn the basics of control dampers and earn credit, at your own pace. Visit the MCDLG Campus Portal today!

Do you have a question about something we haven't covered here? Or do you need help from industry experts? MCDLG can help. Contact us by clicking on the button below.

Get printed materials from MCDLG with our PDQ Portal

Sign up to our PDQ Portal for printed materials from MCDLG brands.

Mestek Commercial Damper and Louver Group

MCDLG is a collective of top-tier HVAC brands.
  • Arrow United Industries
  • Air Balance
  • Cesco Products
  • Louvers & Dampers
  • Airline Louvers

We build every louver and damper from the ground up to meet your specifications. Our team works to ensure that you get the best solutions for your project's requirements.

Want to know more? Contact us online through the MCDLG Contact page. We are ready to help!

Click here to contact MCDLG 

Subscribe to Email Updates