Installation and Maintenance Manual

Startup
UV-SVN02C-EN 77
Zone Sensor (Tracer ZN520)
The Tracer ZN520 controller accepts the following zone
sensor module inputs:
• Space temperature measurement (10kΩ thermistor)
• Local setpoint (either internal or ex
ternal on the zone
sensor module)
• Fan switch
• Timed override (On) and Cancel timed override
• Communication jack
Space Temperature Measurement (Tracer
ZN520)
Trane zone sensors use a 10kΩ thermistor to measure the
space temperature. Typically, zone sensors are wall-
mounted in the room and include a space temperature
thermistor. As an option, the zone sensor can be unit-
mounted with a separate space temperature thermistor
located in the unit’s return air stream. If both a hard-wired
and communicated space temperature value exist, the
controller ignores the hard-wired space temperature input
and uses the communicated value.
External Setpoint Adjustment (Tracer ZN520)
Zone sensors with an external setpoint adjustment (1kΩ)
provide the Tracer ZN520 controller with a local setpoint
(50°F to 85°F or 10°C to 29.4°C). The external setpoint is
exposed on the zone sensor’s front cover.
When the hard-wired setpoint adjustment is used to
determine the setpoints, all unit setpoints are calculated
based on the hard-wired setpoint value, the configured
setpoints, and the active mode of the controller. The hard-
wired setpoint is used with the controller’s occupancy
mode (occupied, occupied standby, or unoccupied), the
heating or cooling mode, the temperature deadband
values, and the heating and cooling setpoints (high and
low limits) to determine the controller’s active setpoint.
When a building automation system or other controller
communicates a setpoint to the controller, the controller
ignores the hard-wired setpoint input and uses the
communicated value. The exception is the unoccupied
mode, when the controller always uses the stored default
unoccupied setpoints. After the controller completes all
setpoint calculations, based on the requested setpoint, the
occupancy mode, the heating and cooling mode, and
other factors, the calculated setpoint is validated against
the following setpoint limits:
• Heating setpoint high limit
• Heating setpoint low limit
• Cooling setpoint high limit
• Cooling setpoint low limit
These setpoint limits only apply to the occupied and
occu
pied standby heating and cooling setpoints. These
setpoint limits do not apply to the unoccupied heating and
cooling setpoints stored in the controller’s configuration.
When the controller is in unoccupied mode, it always uses
the stored unoccupied heating and cooling setpoints.The
unit can also be configured to enable or disable the local
(hard-wired) setpoint. This parameter provides additional
flexibility to allow you to apply communicated, hard-
wired, or default setpoints without making physical
changes to the unit.
Similar to hard-wired setpoints, the effective setpoint
value for a communicated setpoint is determined based
on the stored default setpoints (which determines the
occupied and occupied standby temperature deadbands)
and the controller’s occupancy mode.
Fan Switch (Tracer ZN520)
The zone sensor fan switch provides the controller with an
occupied (and occupied standby) fan request signal (Off,
Low, Medium, High, Auto). If the fan control request is
communicated to the controller, the controller ignores the
hard-wired fan switch input and uses the communicated
value. The zone sensor fan switch input can be enabled or
disabled through configuration using the Rover service
Table 25. Analog inputs (Tracer ZN520)
Descripti
on
Termina
ls Function Range
Zone TB3-1 Space temperature
input
5°F to 122°F
Ground TB3-2 Analog ground NA
Set TB3-3 Setpoint input 40°F to 115°F
Fan B3-4 Fan switch input 4821 to 4919 W (off)
2297 to 2342 W (auto)
10593 to 10807 W (low)
13177 to 13443 W
(medium)
15137 to 16463 W (high)
Ground TB3-6 Analog ground NA
Analog
input 1
J3-1 Entering water
temperature
-40°F to 212°F
J3-2 Analog ground NA
Analog
input 2
J3-3 Discharge air
temperature
-40°F to 212°F
J3-4 Analog ground NA
Analog
input 3
J3-5 Fresh air temp/generic
temp
-40°F to 212°F
J3-6 Analog ground NA
Analog
input 4
J3-7 Universal input 0% to 100%
Generic 4–20mA 0% to 100%
Humidity 0 to 2000 ppm
CO
2
J3-8 Analog ground NA
G r o u n d J 3 - 9 An a l o g g r o u n d N A
Notes:
1. The zone sensor, entering water temperature sensor, discharge air
sensor, and the outside air temperature sensor are 10KΩ thermistors.
2. Zone sensor: Wall-mounted sensors include a thermistor soldered to
the sensor’s circuit board. Unit mounted sensors include a return air
sensor in the units return air stream.
3. Changeover units include an entering water temperature sensor.
UV-SVN02_-EN.book Page 77 Thursday, January 24, 2013 4:48 PM