Timed Override Control; Morning Warm-Up; Space Temperature Control: Morning Warm-Up - Trane Tracer AH540 Setup And Operation

CNT-SVX05B-EN

Timed override control

This sequence applies to both space temperature control and discharge
air temperature control, with differences as noted.
If the zone sensor has a timed override option (
ing the button initiates a timed override request. A timed override
ON
request changes the occupancy mode from unoccupied mode to occupied
bypass mode. In occupied bypass mode, the controller controls the zone
temperature based on the occupied heating or cooling setpoints. The occu-
pied bypass time, which resides in the Tracer AH540/541 and defines the
duration of the override, is configurable from 0 to 240 minutes. The
default value is 120 minutes for space temperature control; the default
value is 0 minutes (disabled) for discharge air temperature control. When
the occupied bypass time expires, the unit transitions from occupied
bypass mode to unoccupied mode. Pushing the
timed override request. A timed override cancel request will end the
timed override before the occupied bypass time has expired and will tran-
sition the unit from occupied bypass mode to unoccupied mode.
If the controller is in any mode other than unoccupied when the
ton is pressed, the controller still starts the occupied bypass timer with-
out changing the mode to occupied bypass. If the controller is placed in
unoccupied mode before the occupied bypass timer expires, the controller
will be placed in occupied bypass mode and remain in that mode until
either the button is pressed on the Trane zone sensor or the occu-
CANCEL
pied bypass time expires.

Morning warm-up

The morning warm-up function initiates a special heating sequence to
raise space temperature to occupied conditions. This sequence is espe-
cially useful for a building occupancy transition from unoccupied to occu-
pied.
The Tracer AH540/541 controller operates this sequence according to the
configured control mode.

Space temperature control: Morning warm-up

The controller keeps the outdoor air damper closed (when a mixing box is
present) anytime during a occupied, occupied bypass, or occupied standby
mode when the space temperature is 3ºF or more below the heating set-
point. The damper remains closed indefinitely (no time limit). As the
space temperature increases above this threshold, the outdoor damper
progressively opens toward the minimum position setpoint. When the
space temperature is within 2ºF of the effective heating setpoint, the out-
door air damper will be at the minimum position setpoint.
The outdoor air damper normally is open to a minimum position during
the occupied mode when the controller turns On the supply fan. The
damper normally is closed during:
Timed override control
/ buttons), push-
ON CANCEL
button cancels the
CANCEL
but-
ON
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