Occupied Mode; Unoccupied Mode; Occupied Standby Mode - Trane Tracer UC400 Installation, Operation And Maintenance Manual

S S e e q q u u e e n n c c e e o o f f O O p p e e r r a a t t i i o o n n
Table 10. Occupancy modes
Occupancy Request
(MV/6)
Occupied
Occupied Bypass
Unoccupied
Occupied Standby
Auto
Out of Service = True
(a)

Occupied Mode

In Occupied Mode, the UC400 Controller maintains the space temperature based on the occupied
space temperature setpoint ± occupied offset. When occupied, the fan can be configured to
operate continuously (default) or cycle ON/OFF with demand, based on BV/1 (Supply Fan
Configuration Command). The controller uses the occupied mode as a default mode when other
forms of occupancy requests are not present. The outdoor air damper, if present, closes when
the fan is OFF. The temperature setpoints can be local (hard wired), communicated, or stored
default values (configured using the Tracer TU service tool).

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 space
temperature setpoint, +/- the occupied standby offset (default 7.5°F). Because the occupied
standby setpoints have a wider spread than the standard occupied setpoints and the outdoor air
damper is closed, the occupied standby mode reduces the demand for heating and cooling the
space. The fan runs as configured for occupied mode.
36
Occupancy
Input (B/1)
Occupied
Unoccupied
Occupied
Unoccupied
X
X
Occupied
Unoccupied
Occupied
Unoccupied
Not recognized by the point as important.
Resultant Occupancy–
Occupancy Status (MV/
TOV
7)
Initiated
X (a) Occupied
Occupied Standby
Yes
Bypass
No
Occupied
X
Occupied Standby
No
Occupied Bypass
Yes
Unoccupied
No
Occupied Bypass
Yes
Occupied Standby
No
Occupied Bypass
Yes
Occupied
X
No Unoccupied
Occupied Bypass
Yes
Occupied
X
Unoccupied
No
Occupied Bypass
Yes
BAS-SVX065E-EN