User manual

Siemens Building Technologies, Inc. 6
2
Applications
Basic Operation
The BACnet VAV Actuator provides Direct Digital Control (DDC) for Variable Air Volume
(VAV) terminal box applications. Temperature control varies with the application. If present,
heating can be provided by hot water, up to three stages of electric reheat, or optional
baseboard radiation.
Sequencing Logic (optional)
This application has the additional capability to sequence the flow and mechanical heating
when heated supply air is available.
Control Temperature Setpoints
The controller maintains a specified temperature setpoint based on Day/Night mode, or the
heating/cooling mode, or the setpoint dial (if used).
Day/Night Mode
The controller maintains the specified day setpoint temperature during daytime hours and the
specified night setpoint at night.
Night Mode Override Switch
If the ROOM TEMPERATURE SENSOR has an override switch, it can be used to command
the controller into day mode for an adjustable period of time. This only affects a controller in
night mode.
Control Loops
Temperature Loop – Heating Loop – Cooling Loop – maintain temperature setpoint by
changing the flow setpoint or modulating the heat source (valve/electric heat).
Flow Loop – maintains flow setpoint by modulating the damper actuator.