Trane Tracer ZN517, Инструкция по установке и эксплуатации

Страница: 52 / 111

Chapter 6 Sequence of operations for the 4-cool configuration
40 CNT-SVX12C-EN
Occupied bypass mode
The controller is placed in occupied bypass mode when the controller is
operating in the unoccupied mode and either the timed override ON but-
ton on the Trane zone sensor is pressed or the controller receives a com-
municated occupied bypass signal from a BAS. In occupied bypass mode,
the controller maintains the zone 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
will remain in occupied bypass mode until either the CANCEL button is
pressed on the Trane zone sensor or the occupied bypass time (config-
urable using the Rover service tool or a BAS) expires. The temperature
setpoints can be local (hard-wired), communicated, or stored default val-
ues (configurable using the Rover service tool or a BAS).
Timed override control
If the zone sensor has a timed override option (ON/CANCEL buttons),
pushing the ON button momentarily shorts the zone temperature signal
to the controller. This short is interpreted as a timed override on request.
A timed override on request changes the occupancy mode from unoccu-
pied mode to occupied bypass mode. In occupied bypass mode, the control-
ler controls the zone temperature based on the occupied heating or
cooling setpoints. The occupied bypass time, which resides in the Tracer
ZN517 and defines the duration of the override, is configurable (using the
Rover service tool or a BAS) from 0 to 240 minutes (default value is 120
minutes). When the occupied bypass time expires, the unit changes from
occupied bypass mode to unoccupied mode. Pushing the CANCEL button
momentarily sends a fixed resistance of 1.5 k
Ω
to the ZN analog input of
the controller, which is interpreted as a timed override cancel request. A
timed override cancel request will end the timed override before the occu-
pied bypass time has expired and will transition the unit from occupied
bypass mode to unoccupied mode.
If the controller is in any mode other than unoccupied when the ON but-
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 CANCEL button is pressed on the Trane zone sensor or the
occupied bypass time expires.
Outdoor air damper operation
The Tracer ZN517 does not support a two-position outdoor air damper
actuator. However, a modulating, triac, 3-wire floating point actuator
with spring return can be used for two-position control. Two-position con-
trol can function only when an outdoor air temperature (either hard-
wired or communicated) does not exist, and by setting the damper mini-
mum position (using the Rover service tool) to the desired value. To con-