Unoccupied Mode; Occupied Standby Mode; Occupied Bypass Mode - Trane Tracer Uc

Programmable bacnet controller for variable-air-volume (vav) units
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Unoccupied Mode

Unoccupied mode, known as night setback, is the normal operating mode for unoccupied spaces
or nighttime operation. Unoccupied setpoints enable or disable occupied space temperature
control.
When the controller is in the unoccupied mode, and configured for space temperature control, the
controller attempts to keep the space temperature between the active unoccupied heating setpoint
and the active unoccupied cooling setpoint. When the controller is in the unoccupied mode and
configured for ventilation flow control, it will not run in unoccupied mode. In addition, the air valve
is closed and local heat is disabled.
A flow tracking controller runs the same as when it is occupied. When the controller is in the
unoccupied mode and configured for flow tracking control, it runs the same as it does in occupied
mode.

Occupied Standby Mode

Occupied standby mode is used to reduce the heating and cooling demands during the occupied
hours when the space is unoccupied. As an example, it can be activated for a classroom currently
not in use.
The controller can be placed in the occupied standby mode when a communicated occupancy
mode request (from a communicated occupancy override, occupancy schedule, or occupancy
sensor) is combined with an occupancy request from the local (hard -wired) occupancy binary
input. Once in occupied standby mode, the controller uses the occupied standby cooling and
heating setpoints, which typically cover a wider range than the occupied setpoints. The wider range
reduces the demand for heating and cooling in the space.
When the communicated occupancy mode request is unoccupied, the occupancy binary input
signal (if present) does not affect the controller occupancy mode. When the communicated
occupancy mode request (communicated occupancy override not valid, communicated occupancy
schedule occupied, or communicated occupancy sensor not valid) is occupied, the controller uses
the local occupancy binary input to switch between the occupied and occupied standby modes.
When the controller is in the occupied standby mode, it uses occupied standby setpoints and is
controller by:

Occupied Bypass Mode

Occupied bypass mode is used for timed overrides. For example, if the controller is in unoccupied
mode or occupied standby mode, pressing the zone sensor ON button places the controller in
occupied bypass mode for 120 minutes (default configured occupied bypass time) or until
someone presses the zone sensor CANCEL button. The controller can be placed in occupied bypass
mode by either communicating an occupancy mode request of bypass mode (communicated
occupancy override) to the controller or by using the zone sensor timed override ON button. The
occupied setpoints are used when in occupied bypass mode.
When the controller is in the unoccupied mode, pressing the zone sensor ON button places the
controller in the occupied bypass mode for the duration of the configured occupied bypass time.
When the controller is in the occupied standby mode, pressing the zone sensor ON button places
the controller in the occupied bypass mode for the duration of the configured occupied bypass
time.
VAV-SVX07B-EN
Occupied temperature control
Ventilation flow control
Flow tracking control
Calibration, Operation Modes, and Control
47

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