Siemens BACNET 125-5037, Owner'S Manual, Page: 26 / 48

Applications
16 Siemens Building Technologies, Inc.
Application 2565 VAV Series Fan Powered with Hot
Water Reheat
Overview
In Application 2565, the controller modulates the supply air damper of the terminal box for
cooling and modulates a hot water valve 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 12.
Fan Operation
CAUTION:
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.
BACnet Actuator
Controller
Modulating
Damper
Actuator
TEC2565CDR1
Air
Velocity
Sensor
SAFETIES
BY
OTHERS
6
5
4
3
C
Wall Switch (Opt.)
"COMMON" Termination for all DOs
10K ohm Thermistor
or Spare DI
Hi/Lo Tubing
Connections
RTS
FLN
NO
Supply
Air Damper
Supply Air
Recirculated
Plenum Air
Recirculated
Air Damper
3 to 5 Straight Duct Diameters
required for proper sensor reading
Fan
Valve
Actuator
Spare DO
Figure 12. Application 2565 Control Drawing.