Trane Tracer UC400 User Manual

40
BAS-SVX48H-EN
Unoccupied Mode
In unoccupied mode, the UC400 Controller attempts to maintain the space temperature based on
the unoccupied heating or cooling setpoint. The fan cycles between HIGH speed and OFF. In
addition, the outdoor air damper remains closed, unless economizing. The controller always
uses the stored default setpoint values (configured using the Tracer TU service tool), regardless
of the presence of a hard wired or communicated setpoint value.
Occupied Standby Mode
The UC400 Controller is placed in occupied standby mode only when a communicated occupied
request is combined with an unoccupied request from occupancy binary input BI1. In occupied
standby mode, the controller maintains the space temperature based on the occupied standby
heating or cooling setpoints. Because the occupied standby setpoints have a typical temperature
spread of 2°F (1.1°C) in either direction, and the outdoor air damper is closed, the occupied
standby mode reduces the demand for heating, and cooling the space. The fan continuously runs
as configured for occupied mode. The controller always uses the stored default setpoint values
(configured using the Tracer TU service tool), regardless of hard wired or communicated setpoint
values. In addition, the outdoor air damper uses the economizer occupied standby minimum
position setpoint to reduce the ventilation rate.
Occupied Bypass Mode
The UC400 Controller is placed in occupied bypass mode when:
• The controller is operating in the unoccupied mode.
• Either the timed override ON button on the Trane zone sensor is pressed or the controller
receives a communicated occupied bypass signal from a BAS.
In occupied bypass mode, the controller maintains the space temperature based on the occupied
heating or cooling setpoints. The fan runs as configured (continuous or cycling). The outdoor air
damper closes when the fan is OFF. The controller remains in occupied bypass mode until either
the CANCEL button is pressed on the Trane zone sensor or the occupied bypass time expires
(configured using the Tracer TU service tool). The temperature setpoints can be configured as
local (hard wired), communicated, or stored default values using the Tracer TU service tool.
Timed Override Control
If the UC400 Controller has a timed override option (ON/CANCEL buttons), pushing the ON
button initiates a timed override on request. A timed override upon request changes the
occupancy mode from unoccupied mode to occupied bypass mode. In occupied bypass mode,
the controller controls the space temperature based on the occupied heating or cooling
setpoints. The occupied bypass time, which defines the duration of the override and resides in
the controller, is configured from 0 to 240 minutes (default value of 120 minutes). When the
occupied bypass time expires, the controller transitions from occupied bypass mode to
unoccupied mode.
Pushing the CANCEL button cancels the timed override request. In addition, it ends the timed
override before the occupied bypass time has expired and transitions the unit from occupied
bypass mode to unoccupied mode. If the controller is in any mode other than unoccupied mode
when the ON button is pressed, it still starts the occupied bypass timer without changing to
occupied bypass mode. If the controller is placed in unoccupied mode before the occupied
bypass timer expires, it is placed into occupied bypass mode and remains in this mode until
either the CANCEL button is pressed on the Trane zone sensor or the occupied bypass time
expires.
Zone Temperature Control
The UC400 Controller has the following four (4) methods of zone temperature control:
• SSiinnggllee ZZoonnee VVAAVV CCoonnttrrooll:: varies the speed of the ECM fan motor as the zone cooling or
heating load changes. When the zone is at design cooling load, the UCU400 Controller
operates the fan at maximum speed and cooling capacity modulates or cycles to deliver the
air at the design discharge air temperature (DAT) setpoint for cooling. As the zone cooling
SSeeqquueennccee ooff OOppeerraattiioonn

Trane Tracer UC400 Specifications

General

Brand	Trane
Model	Tracer UC400
Category	Controller
Language	English