Mixing Dampers and Economizers

Front

What are mixing dampers?

Back

Mixing dampers are two sets of dampers: a return air damper (normally open) in the return air plenum and an outdoor air damper (normally closed) in the outdoor air intake duct, which controls the amount of outdoor air entering the air handling unit (AHU).

Front

How do mixing dampers function?

Back

The mixing dampers are positioned by the economizer motor to mix colder outdoor air with warm return air, producing the cool supply air that is supplied to the conditioned space.

Front

What happens as the fresh air and exhaust air dampers are driven from 0% open to 100% open?

Back

The mixing damper is driven from 100% open to 0% open, ensuring a constant volume of supply and return air.

Front

How do smaller packaged economizers operate?

Back

In smaller packaged economizers, the outdoor air damper and return air damper may operate together using a single actuator mechanically connected to one damper and a mechanical linkage connecting the two dampers.

Front

How do larger dampers operate?

Back

In larger dampers, it is common to have an actuator mounted on each damper.

Front

What types of control systems are used for dampers?

Back

The control system may be electromechanical, electronic, or pneumatic, operating the dampers together with a common control signal.