Specifications

When using the manual air control timer mode: Door 1 (damper 1) is open, door

2 (damper 2) is closed and door 3 (damper 3) is open. When using the

automatic energy-save mode: If the system calls for central air conditioning and

the outside air meets conditions then door 1 (damper 1) is open, door 2 (damper

2) is closed and door 3 (damper 3) is open.

In the automatic fresh air mode: If the fresh air minimums have not been met:

door 1 (damper 1) is open, door 2 (damper 2) is closed and door 3 (damper 3) is

open. The central air AC air blower fan is turned on and door 4 (damper 4) is

opened to blend in controlled amounts of fresh air between air exchanges.

Fresh air mode involves the main control unit making a decision to introduce new

air into the building from outside. This has many advantages including removing

stagnant air that has been inside the building along with any pollutants it has

picked up while in the building. In typical HVAC systems, the air inside the

building is repeatedly cooled and redistributed in the building. This means the

only way to introduce fresh air into the building is to open windows. Opening and

closing windows is a hassle for the occupants of the building because they must

be closed when the building is unoccupied, and in larger buildings opening the

windows is not always an option. Figure 24 pictured below is an air duct with a

damper motor assembly. This particular duct was removed due to a defective

damper.

Approx. 4'

Figure 24 Air duct with damper motor assembly

Dampers can be operated by two different distinct modes either manual or

automatic. These electronic zone dampers are often referred to as a Volume

Control Damper (VCD). Automatic dampers are the type of dampers we are

going to use in our design, whereas manual dampers function by turning a