Trane Tracer ZN.520 Installation Owner Diagnostics page 45

Power-Up
When 24 VAC is initially applied to
the controller, the following se-
quence of events occurs:
q Green status LED turns
q All outputs are controlled
q The controller reads input
values to determine initial
values.
q Random-start timer expires (5
to 30 seconds).
q When -
POW ER UP CONTROL W AIT
is enabled, the controller waits
0-120 seconds (depending on
configuration) to allow ample
time for communicated control
data to input. If the controller
does not receive communi-
cated information, standalone
control is assumed.
q All modulating valves and
dampers calibrate closed.
operation begins.
q
NORMAL
Occupancy
The valid occupancy modes for the
Tracer ZN.520 controller are:
q - Normal operating
OCC UPIED
mode for occupied spaces or
daytime operation.
- Normal
q
UNOCCUPIED
operating mode for
unoccupied spaces or
nighttime operation.
q
OCC UPIED STANDBY
used to reduce the heating and
cooling demands, while
providing ventilation, during
the occupied hours when the
space is vacant or unoccupied.
q -Used to
OCC UPIED BYPASS
temporarily place the unit into
the occupied operation.
The occupancy mode can be hard-
wired to the controller via the oc-
cupancy binary input or
communicated to the controller.
UV-SVP01A-EN
Unit Operation
OCC UPIED
When the controller is in the
mode, the unit attempts to
PIED
maintain the space temperature at
the active occupied heating or
.
ON
cooling setpoint.
.
OFF
OCC UPIED
mode of the Tracer ZN.520 control-
ler.
UNOCCUPIE D
When the controller is in the
OCC UPIED
to maintain space temperature at
the stored unoccupied heating or
cooling setpoint (i.e., config-
urable through Tracer Summit or
the Rover service tool) regardless
of the presence of a hardwired or
communicated setpoint. When
the space temperature exceeds
the stored unoccupied setpoint,
the controller brings on 100% of
the primary heating or cooling ca-
pacity.
The
UNOCC UPIED
tiated through a hardwired signal
to the occupancy binary input or
by a communicated request.
OCC UPIED STANDBY
The
OC CUPIED STANDBY
lows the unit to operate at a heat-
ing or cooling setpoint between
the occupied and unoccupied set-
points to help maintain the envi-
- Mode
ronment while decreasing energy
consumption.
This mode decreases the ventila-
tion for heating or cooling during
brief periods of vacancy in the
space. Unit operation in this mode
is similar to the occupied mode ex-
cept for the different heating and
cooling setpoints and a different
outside air damper position.
The
OC CUPIED STANDBY
initiated only when occupancy is
communicated to the Tracer
ZN.520 controller and the hard-
wired signal to the occupancy in-
put is calling for unoccupied
operation.
mode
OC CU
mode is the default
mode
-
UN
mode, the unit attempts
mode can be ini-
mode
mode al-
mode is
OCC UPIED BYPASS
- The
OCCUPIED BY PASS
used to transition the unit from the
mode to the
UNOCCUPIED
mode for a period of time
PIE D
from 0 to 4 hours (configurable
through Rover. Default=
controller can be placed in
mode by either com-
PIE D BYPASS
municating an occupancy request
of or by using the
BYPASS
(i.e., ) button on the
OVE RRIDE ON
Trane zone sensor.
and Buttons
ON CANCEL
Some Trane zone sensors have
and buttons for timed over-
CANCEL
ride operation. Pressing the
button on the zone sensor when
the unit is in the
UNOCC UPIED
mode initiates the
mode and initializes the by-
PASS
pass timer. The
CANCEL
used to send the unit back into
mode before the bypass
OCC UPIED
timer has expired.
The button may also be used
ON
for the unit identification or the
" " feature. (See "Winking"
WINK
on page38.for more information.)
When the Tracer ZN.520 controller
is connected to a Tracer Summit
system or the Rover service tool,
the button may be used in place
ON
of the service pin for easy unit
identification.
Heating And Cooling
Changeover Logic
The Tracer™ ZN.520 Unit Control-
ler can receive communicated re-
quests for heating or cooling
operation. The communicated
variable nviApplicMode is used to
communicate the requests for the
controller's operating mode based
on the following values:
0 = Auto (mode determined by
controller)
1 = Heat (uses heating
setpoints)
2 = Morning Warm-up
3 = Cool (uses cooling
setpoints)
mode
mode is
-
OCC U
). The
RUN
-
OC CU
TIM ED
ON
ON
-
OCC UPIED BY
button is
-
UN
39