Application 2564 VAV Series Fan Powered with
In Application 2564, the controller modulates the supply air damper of the terminal box for
cooling and controls stages of electric reheat for heating. When in heating, the terminal box
either maintains minimum airflow or modulates the supply air damper. The terminal box also
has a series fan for air circulation. In order for the terminal box to work properly, the central
air-handling unit must provide supply air. See Figure 11.
On series fan powered terminal boxes, the terminal box fan must be
controlled/interlocked to start either before or at the same time as the central air
handler. Failure to do so may cause the terminal box fan to rotate backwards and
cause consequent damage at start up.
In day mode, the fan is ON all the time. In night mode, the fan cycles on when heating or
cooling is required.
Siemens Building Technologies, Inc.
3 to 5 Straight Duct Diameters
required for proper sensor reading
Figure 11. Application 2564 Control Drawing.
Siemens BACnet VAV Actuator Owner's Manual
"COMMON" Termination for all DOs
Wall Switch (Opt.)