4
BAS-PRC006-EN
The Tracer ZN511 zone controller
provides digital control of fan coils and
water-source heat pumps. The Tracer
ZN511 improves comfort control and
provides stand-alone or networked
building automation.
Inputs and outputs
Tracer ZN511 inputs and outputs include:
•
Analog inputs
: zone temperature,
entering or leaving water temperature,
discharge air temperature, zone tem-
perature setpoint, fan mode switch
•
Binary inputs
: occupancy, conden-
sate overflow, low water temperature,
low pressure protection, high pres-
sure protection
•
Outputs
: water-source heat pump:
compressor 1, compressor 2, two-
position outside air damper, reversing
valve, fan on/off
Fan coil: fan high, fan medium, fan
low, 1 cool, 1 heat, two-position
outside air damper
•
Generic points
for use with a Tracer
Summit building automation system:
binary input (shared with occupancy),
binary output (shared with outside air
damper)
The generic inputs pass information to
the building automation system. They do
not affect the operation of the unit. The
generic binary output is controlled by
the building automation system and its
state is not changed by unit operation,
even under a diagnostic shutdown.
Features
Easy installation
The controller can be installed in existing
Trane and competitive HVAC equipment
without major wiring changes, and
clearly labeled screw terminals ensure
that wires are connected quickly and
accurately. A compact enclosure design
simplifies installation in minimal space.
Entering water temperature sampling
A traditional system using a two-way
control valve on a fan coil might not
sense the correct entering water
temperature during long periods when
the control valve is closed. The Tracer
ZN511 solves this problem by opening
the valve for three minutes to allow the
water temperature to stabilize before
the temperature is taken. This feature
allows the use of two-way control valves
to provide accurate two-pipe system
changeover for 1heat/1 cool applications.
Automatic heat/cool mode
determination
The Tracer ZN511 automatically
determines whether heating or cooling
is needed to maintain comfort levels,
without the need to manually adjust unit
controls. The controller measures the
zone temperature and setpoint
temperature, then uses a proportional/
integral algorithm to maintain zone
temperature at the setpoint.
Occupied and unoccupied operation
The occupancy input works with a
motion (occupancy) sensor or time
clock. A communicated value from a
building automation system through the
LonTalk communication link can also be
used. The input allows the controllers to
use unoccupied (setback) temperature
setpoints.
Random start
This feature randomly staggers multiple-
unit start-up to reduce electrical demand
spikes.
Warm-up and cool-down
This feature is available with the
installation of an outside air damper. If
the room temperature drifts too far from
the setpoint, the controller temporarily
closes the damper to bring the
temperature to the desired setpoint as
quickly as possible.
Manual output test
Pressing the test button on the
controller exercises all binary outputs in
sequence. This feature is an invaluable
troubleshooting tool.
Peer-to-peer communication
Multiple controllers can share data if
they are bound together. Shared data
can include setpoint, zone temperature,
mode, and fan status. Applications
having more than one unit serving a
single large space can benefit from this
feature, which prevents multiple units
from simultaneously heating and
cooling.
Interoperability
The Tracer ZN511 conforms to the
LonMark
®
Space Comfort Controller
(SCC) profile and communicates via the
LonTalk protocol. This allows it to work
with other control systems that support
LonTalk and the SCC profile.
Continuous fan or fan-cycling
operation
Users can choose to have the fan run
continuously at a given speed, or cycle
on and off automatically by selecting the
AUTO
mode.
Equipment protection
The Tracer ZN511 includes inputs that
allow for the following equipment
protection:
• Refrigerant high- and low-pressure
protection to prevent the unit from
operating with high/low refrigeration
pressure levels (heat pump only)
• Compressor minimum on and off tim-
ers to extend compressor life by pre-
venting short cycling (heat pump only)
• A condensate overflow switch to pre-
vent water damage to the building
• Low-temperature detection to prevent
compressor operation during
abnormal conditions (heat pump) or
coil freeze-up (fan coil)
Timed override
The timed override function for after
hours operation allows users to request
unit operation by the touch of a button
on the unit zone sensor. Additionally,
users can press the
CANCEL
button at
any time to place the unit back into
unoccupied mode.
Fan status
The controller monitors the fan output
status as proof of airflow. This method is
cost effective and commonly used on
direct-drive fan applications.
Filter maintenance
Filter maintenance status is based on
the cumulative hours of operation of the
unit fan. The controller has timers that
can be reset, and when the time limit
expires, Tracer Summit software or the
Rover service tool indicates that unit
maintenance is recommended.
Tracer ZN511 zone controller
