Trane CNT-SVX07C-EN, N512, Zone Controller User Manual
Installation and
Operation
Tracer™ ZN521
Zone Controller
CNT-SVX07C-EN
Installation and
Operation
Tracer™ ZN521
Zone Controller
CNT-SVX07C-EN
April 2005
CNT-SVX07C-EN
Tracer ZN521 Zone Controller Installation and Operation
This guide and the information in it are the property of American Standard Inc. and may not be used or reproduced in whole or in part,
without the written permission of American Standard Inc. Trane, a business of American Standard, Inc., has a policy of continuous
product and product data improvement and reserves the right to change design and specification without notice.
Although Trane has tested the hardware and software described in this guide, no guarantee is offered that the hardware and software
are error free.
Trane reserves the right to revise this publication at any time and to make changes to its content without obligation to notify any person of such revision or change.
Trane may have patents or patent applications covering items in this publication. By providing this document, Trane does not imply
giving license to these patents.
The following are trademarks or registered trademarks of American Standard Inc.: Trane, Tracer, Rover.
®
™
The following are trademarks or registered trademarks of their respective companies or organizations: BACnet from
®
™
Printed in the U.S.A.
© 2005 American Standard Inc. All rights reserved
ASHRAE; Neuron, LonMark, LonTalk, and LonWorks from Echelon Corporation; National Electrical Code form the National
Fire Proctection Association, Inc.
CNT-SVX07C-EN
NOTICE:
Warnings and Cautions appear at appropriate sections throughout this manual. Read these carefully:
WARNING
Indicates a potentially hazardous situation, which, if not avoided, could result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation, which, if not avoided, may result in minor or moderate injury.
It may also be used to alert against unsafe practices.
CAUTION
Indicates a situation that may result in equipment damage or property damage.
The following format and symbol conventions appear at appropriate sections throughout this manual:
IMPORTANT
Alerts installer, servicer, or operator to potential actions that could cause the product or system to
operate improperly but will not likely result in potential for damage.
Note:
A note may be used to make the reader aware of useful information, to clarify a point, or to describe
options or alternatives.
◆ This symbol precedes a procedure that consists of only a single step.
CNT-SVX07C-EN
Contents
Chapter 1 Overview and specifications . . . . . . . . . . . . . . . . . . 1
Product description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Storage environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Agency listing/compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Additional components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Power transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Water, duct, and outdoor-air temperature sensors . . . . . . . . . . . . . . 4
Binary input switching devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Output devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Zone temperature sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Valve actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Damper actuators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Zone humidity sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
CO2 sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 2 General wiring information . . . . . . . . . . . . . . . . . . . 7
Input/output terminal wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
AC-power wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Communication-link wiring and addressing . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 3 Mounting the controller . . . . . . . . . . . . . . . . . . . . 11
Location recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Operating environment requirements . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Mounting recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 4 Input/output functions and wiring for typical
applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Binary inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
BI1: Low-coil-temperature detection . . . . . . . . . . . . . . . . . . . . . . . . 14
BI2: Condensate overflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
BI3: Occupancy or generic binary input . . . . . . . . . . . . . . . . . . . . . . 15
BI4: Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
CNT-SVX07C-EN i
Contents
Analog inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
GND: Ground terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
ZN: Zone temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
SET: Local setpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
FAN: Fan mode input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
AI1: Entering water temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
AI2: Discharge air temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
AI3: Outdoor air temperature or generic temperature . . . . . . . . . . 18
AI4: Universal 4–20 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Binary outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Generic binary output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Overriding binary outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Wiring requirements and options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Chapter 5 Sequence of operations . . . . . . . . . . . . . . . . . . . . 35
Power-up sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Random start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Occupancy modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Occupied mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Unoccupied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Occupied standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Occupied bypass mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Timed override control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Zone temperature control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Cascade zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Simplified zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Discharge air tempering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Morning warm-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Morning cool-down. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Heating or cooling mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Entering water temperature sampling function . . . . . . . . . . . . . . . . . . . 40
Fan operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Exhaust control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Valve operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Modulating valve operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Modulating valve calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Two-position valve operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Isolation-valve operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Two-pipe operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Four-pipe operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
ii CNT-SVX07C-EN
Contents
Modulating outdoor/return air dampers. . . . . . . . . . . . . . . . . . . . . . . . . 43
ASHRAE Cycle 1 conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
ASHRAE Cycle 2 conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Economizing (free cooling) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Two-position control of a modulating outdoor air damper . . . . . . . . . 46
Face-and-bypass damper operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Face-and-bypass, isolation-valve operation . . . . . . . . . . . . . . . . . . 46
DX cooling operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Electric heat operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Baseboard heat operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Dehumidification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Peer-to-peer communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Unit protection strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Smart reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Low-coil-temperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Condensate overflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Fan off delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Filter-maintenance timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Freeze avoidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Freeze protection (discharge air temperature low limit) . . . . . . . . 50
Chapter 6 Status indicators for operation and
communication. . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Test button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Manual output test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Service pin button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Interpreting LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Types of diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Manual (latching) diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Automatic (nonlatching) diagnostics . . . . . . . . . . . . . . . . . . . . . 58
Smart reset diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Informational diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Table of diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
CNT-SVX07C-EN iii
Contents
Chapter 7 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
iv CNT-SVX07C-EN
Chapter 1
Overview and specifications
This guide provides installation and configuration information for the
Tracer ZN521 zone controller, as well as a description of its operations.
The overview includes a product description, specifications, and descriptions of ancillary products that may be necessary.
Product description
The Tracer ZN521 is an application-specific controller that provides
direct-digital zone temperature control. The controller can operate as a
stand-alone device or as part of a building automation system (BAS).
Communication between the controller and a BAS occurs by means of a
LonTalk communication link, which complies with the LonTalk protocol.
The Tracer ZN521 supports the following equipment:
• Fan coils
• Unit ventilators
• Blower coils
The Tracer ZN521 can be configured to control:
• Tri-state modulating or two-position valves
• Tri-state modulating dampers:
outdoor/return air, and face-and-bypass
• DX cooling (single stage)
• Electric heat (two stages)
It is designed to be field-installed and is sent from the factory unconfigured. Use the PC-based Rover service tool to configure the controller for
specific applications
Note:
For information about using the Rover service tool, see the
Rover Installation/Operation/Programming guide (EMTXSVX01A-EN).
CNT-SVX07C-EN 1
Chapter 1 Overview and specifications
Storage environment
If a Tracer ZN521 zone controller is to be stored for a substantial amount
of time, store it in an indoor environment that meets the following
requirements:
• Temperature: –40° to 185°F (–40° to 85°C)
• Relative humidity: 5–95%, noncondensing
Dimensions
Plastic-cover model dimensions
For complete dimensional drawing, see Figure 1 on page 3.
• Height: 5.375 in. (137 mm)
• Width: 6.875 in. (175 mm)
• Depth: 2 in. (51 mm)
Metal-cover model dimensions
For complete dimensional drawing, see Figure 2 on page 3.
• Height: 9.0 in (25 mm)
• Width: 10.37in. (263 mm)
• Depth: 2.25 in. (58 mm)
Clearances
Plastic-cover model
(see Figure 1 on page 3)
• Front: 4.0 in. (102 mm)
• Each side: 1.0 in. (25 mm)
• Top and bottom: 4.0 in. (102 mm)
Metal-cover model
(see Figure 2 on page 3)
• Front: 24.0 in. (610 mm)
• Each side: 2.0 in. (51 mm)
• Top and bottom: 1.0 in. (25 mm)
2 CNT-SVX07C-EN
Figure 1. Plastic-cover model dimensions and clearances
1 in
(25 mm)
Clearances
4 in
(102 mm)
5.625 in.
(143 mm)
5.625 in (143 mm)
1 in
(25 mm)
6.31
(160 mm)
Figure 2. Metal-cover model dimensions and clearances
1 in.
(25 mm)
4 in.
(102 mm)
1.875 in.
(48 mm)
4 in
(102 mm)
6.5 in.
(165 mm)
6.875 in
(175 mm)
2 in. (51 mm)
0.28 in.
(7 mm)
9 in.
(229 mm)
7 in.
(178 mm)
2 in.
(51 mm)
24 in.
(610 mm)
Clearances
Dimensions
CNT-SVX07C-EN 3
10.37 in.
(263 mm)
width with cover
1 in.
(25 mm)
2 in.
(51 mm)
1 in.
(25 mm)
2.25in.
(58 mm)
10.25 in.
(260 mm)
width without cover
9 in.
(229 mm)
Chapter 1 Overview and specifications
Agency listing/compliance
CE—Immunity: EN 50082-1:1997; EN 50082-2:1995
CE—Emissions: EN 50081-1:1992 (CISPR 22) Class B
UL and C-UL 916 listed: Energy management system
UL 94-5V (UL flammability rating for plenum use)
FCC Part 15, Class A
ASHRAE Cycle 1 & Cycle 2 control sequences
Additional components
The Tracer ZN521 zone controller requires the use of additional components for monitoring and proper control of the associated equipment. The
use of specific components depends on the application. These components
are not included with the Tracer ZN521 zone controller.
Power transformer
Use a UL-listed Class 2 power transformer supplying a nominal 24 Vac
(19–30 Vac) to power both the Tracer ZN521 zone controller (14 VA) and
its associated output devices, including relays and actuators, to a maximum of 12 VA per output utilized.
Water, duct, and outdoor-air temperature sensors
Temperature sensors must be Trane 10 kΩ (at 25°C) thermistors. Enter-
ing water and discharge air inputs may use a sealed temperature sensor
(part number 4190 1100).
Binary input switching devices
Occupancy, condensate overflow, low-coil-temperature, and fan status
inputs accept switching devices that may have normally open or normally
closed dry contacts.
Output devices
Output devices connected to the Tracer ZN521 binary outputs cannot
exceed 12 VA (0.5 A) current draw at 24 Vac.
Zone temperature sensors
Table 1 shows the Trane zone temperature sensors that are supported by
the Tracer ZN521 zone controller.
Valve actuators
Valve actuators cannot exceed 12 VA draw at 24 Vac. For two-position
valves, use actuators with on/off action, and with a spring action that
4 CNT-SVX07C-EN
Additional components
Table 1. Tracer zone temperature sensor options
Timed
Fan Zone
BAS
order
number
4190 1087 Any x
4190 1088 Any x x x x
4190 1090 Any x x x x x
4190 1094 Any x x x
4190 1095 Unit
4190 1115 Fan coil x x x x x x x x x x
4190 1116 Unit
4190 1117 Any x x x x x x x
Use
ventilator
ventilator
High Med Low Auto Off
xxxxxxxx
xxxxxxxxx
Setpoint
thumb-
wheel
Temperature
sensor
override
buttons
On Cancel
Comm
jack
returns the valve to normally open or closed (dependent on the desired
default position). For modulating valve control, use tri-state modulating
actuators with or without a spring return, as required by the application.
Damper actuators
Damper actuators cannot exceed 12 VA draw at 24 Vac. For control of outdoor/return air dampers, use tri-state modulating actuators that incorporate a spring return.
Zone humidity sensor
For measurement of relative humidity (RH), the Tracer ZN521 requires a
zone humidity sensor with a 4–20 mA output, where 4 mA is 0% RH and
20 mA is 100% RH. The controller provides 20 Vdc to power the zone
humidity sensor.
CO2 sensor
For CO2 measurement, the Tracer ZN521 requires a CO2 sensor with a 4–
20 mA output, where 4 mA = 0 ppm and 20 mA = 2000 ppm.
CNT-SVX07C-EN 5
Chapter 1 Overview and specifications
6 CNT-SVX07C-EN
Chapter 2
General wiring information
This chapter provides specifications and general information about wiring the Tracer ZN521 zone controller. The controller requires wiring for:
• Input/output terminals
• AC power to the controller
• Communication-link wiring, if the controller is to communicate with a
building automation system (BAS)
Input/output terminal wiring
All input/output terminal wiring for the Tracer ZN521 zone controller is
application specific and dependant on the configuration of the controller.
Input/output terminal wiring must meet the following requirements:
• All wiring must comply with the National Electrical Code and local
codes.
• Use only 18 AWG, twisted-pair wire with stranded, tinned-copper
conductors. (Shielded wire is recommended.)
• Binary input and output wiring must not exceed 1000 ft (300 m).
• Analog input wiring must not exceed 300 ft (100 m).
• Do not run input/output wires in the same wire bundle with any ac-
power wires.
For application-specific wiring information and diagrams, see Chapter 4,
“Input/output functions and wiring for typical applications”
AC-power wiring
WARNING
HAZARDOUS VOLTAGE!
Before making line voltage electrical connections, lock open the supplypower disconnect switch. Failure to do so may cause death or serious
injury.
CAUTION
Make sure that the 24 Vac transformer is properly grounded. Failure to
do so may result in damage to equipment and/or personal injury.
CNT-SVX07C-EN 7
Chapter 2 General wiring information
CAUTION
Complete input/output wiring before applying power to the Tracer
ZN521 zone controller. Failure to do so may cause damage to the controller or power transformer due to inadvertent connections to power
circuits.
IMPORTANT
Do not share 24 Vac between controllers.
All wiring must comply with National Electrical Code and local codes.
The ac-power connections are in the top left corner of the Tracer ZN521
zone controller (see Figure 3).
Figure 3. Connecting ac-power wires to the controller
24 Vac
transformer
The Tracer ZN521 may be powered by an existing transformer integral to
the controlled equipment, provided the transformer has adequate power
available and proper grounding is observed. If you are providing a new
transformer for power, use a UL-listed Class 2 power transformer supplying a nominal 24 Vac (19–30 Vac). The transformer must be sized to provide adequate power to both the Tracer ZN521 zone controller (14 VA)
and its associated output devices, including relays and actuators, to a
maximum of 12 VA per output utilized.
H
N
8 CNT-SVX07C-EN
Communication-link wiring and addressing
Communication-link wiring and
addressing
The Tracer ZN521 zone controller communicates with the BAS and with
other LonTalk controllers by means of a LonTalk communication link.
IMPORTANT
For important instructions on network wiring, refer to the Tr a ce r S u m -
mit Hardware and Software Installation guide (BMTX-SVN01A-EN).
Wiring for the communication link must meet the following requirements:
• All wiring must comply with the National Electrical Code and local
codes.
• 22 AWG Level 4 unshielded communications wire recommended for
most Comm5 installations.
• Termination resistors are required for wiring LonTalk devices com-
municating on a network. For specific information about using termination resistors for LonTalk applications, refer to the Tracer Summit
Hardware and Software Installation guide (BMTX-SVN01A-EN).
Each Tracer ZN521 zone controller has a unique 12-character alphanumeric device address for communicating on a BAS network. This address,
referred to as a Neuron ID, is assigned in the factory before the product is
shipped and cannot be changed. Each controller can be identified by viewing its unique Neuron ID, which is on a printed label attached to the circuit board of the controller. Additional adhesive-backed, peel-off Neuron
ID labels are tethered to the controller for placing on mechanical prints or
unit location worksheets. The Neuron ID will appear when communication is established with the Rover service tool or a BAS. An example Neuron ID is 00-01-64-1C-2B-00.
CNT-SVX07C-EN 9
Chapter 2 General wiring information
10 CNT-SVX07C-EN
Chapter 3
Mounting the controller
This chapter gives recommendations and requirements for mounting a
Tracer ZN521 zone controller.
Location recommendations
Trane recommends locating the Tracer ZN521 zone controller:
• Near the controlled piece of equipment to reduce wiring costs
• Where it is easily accessible for service personnel
• Where public access is restricted to minimize the possibility of tam-
pering or vandalism
The controller can often be mounted inside the wiring enclosure of the
associated mechanical equipment.
Operating environment requirements
Operate a Tracer ZN521 zone controller in an indoor environment that
meets the following requirements:
• Temperature: from 32°F to 140°F (from 0°C to 60°C)
• Relative humidity: 5–95%, noncondensing
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Chapter 3 Mounting the controller
Mounting recommendations
Mounting recommendations are as follows:
CAUTION
Mount the Tracer ZN521 zone controller with the cover on to avoid the
possibility of damaging the circuit board during installation.
• Mount the controller in any position, other than with the front of the
cover facing downward.
• Mount using the two
(see Figure 4). Mounting fasteners are not included.
• Attach the controller securely so it can withstand vibrations of associ-
ated HVAC equipment.
• When the controller is mounted in a small enclosed compartment,
complete all wiring connections before securing the controller in the
compartment.
Figure 4. Mounting the Tracer ZN521 zone controller
3
/16in. (4.8 mm) radius mounting holes provided
12 CNT-SVX07C-EN
Chapter 4
Input/output functions and wiring for typical applications
This chapter provides information about the function of inputs and outputs and examples of wiring for typical applications. Applications supported by the Tracer ZN521 zone controller are shown in Table 2.
Table 2. Typical applications for the Tracer ZN521 zone controller
Application
Multiple fan speed
2-pipe hydronic cooling only x x x x x x
2-pipe hydronic heating only x x x x x x
2-pipe changeover xxxxxxxx
2-pipe steam only x x x x x x
4-pipe hydronic heating and cooling x x x x x x x
4-pipe changeover x x x x x x x
4-pipe steam/chilled water x x x x x
Electric heat only (single- and two-stage) x x ×
DX/hydronic heating x x x x x
DX/steam heating x x x x x
DX cooling only xxx
Figures 7 through 17 (pages 23 through 33) show typical wiring diagrams
that include all required and all optional components for typical applications.
Dehumidification
Auto minimum damper adjust
Face and bypass damper
Val ve c ontro l
Economizing
Auxiliary (baseboard) heat
Electric heat
CNT-SVX07C-EN 13
Chapter 4 Input/output functions and wiring for typical applications
Binary inputs
The Tracer ZN521 controller includes four binary inputs. Each binary
input associates an input signal of 0 Vac with open contacts and 24 Vac
with closed contacts. You can use the Rover service tool to configure each
of the inputs as normally open or normally closed. If an application does
not warrant the use of a particular input, configure the input as Not
Used. This will disable the generation of diagnostics for this function.
Table 3 gives the function of each binary input.
Table 3. Binary inputs
Binary input
terminal label
BI1 Low-coil-temperature detection
BI2 Condensate overflow
BI3 Occupancy or generic binary input
BI4 Fan status
Each function is explained in the following paragraphs. For an explanation of the diagnostics generated by each binary input, see “Diagnostics”
on page 58. For more information about how the controller operates, see
Chapter 5, “Sequence of operations”
Function
BI1: Low-coil-temperature detection
Note:
BI1 applies to hydronic/steam coils only.
The function of low-coil-temperature detection is to protect the coil from
freezing. If BI1 is wired to a binary low-coil-temperature detection device
(freeze-protection switch) and a low-coil-temperature condition exists, the
Tracer ZN521 will detect the condition and generate a Low Coil Temp
Detection diagnostic.
BI2: Condensate overflow
The function of condensate overflow is to prevent the condensate drain
pan from overflowing and causing water damage to the building. If BI2 is
wired to a condensate overflow switch and the level of condensate reaches
the trip point, the Tracer ZN521 will detect the condition and generate a
Condensate Overflow diagnostic.
14 CNT-SVX07C-EN
Binary inputs
BI3: Occupancy or generic binary input
The BI3 binary input can function as either:
• The occupancy input
• A generic binary input
The function of occupancy is to save energy by spreading zone setpoints
when the zone is unoccupied. As the occupancy input, BI3 can be used for
two related functions. For stand-alone controllers, BI3 can be hard-wired
to a binary switch or timeclock to determine the occupancy mode—either
occupied or unoccupied. For controllers receiving a BAS-communicated
occupancy request, the function of BI3 is to change the mode from occupied to occupied standby. (For more information on occupancy-related
functions, see “Occupancy modes” on page 36.)
BI3 is the only binary input that can be configured as generic. If configured as a generic binary input, it can be monitored by a BAS and has no
direct effect on Tracer ZN521 operation.
BI4: Fan status
The fan status input provides feedback to the controller regarding the
fan’s operating status. If BI4 is wired to a fan status switch and the input
indicates that the fan is not operating when the controller has the fan
controlled to on, the controller will generate a Low AirFlow—Fan Failure
diagnostic. (For more information, see “Fan status” on page 49.)
CNT-SVX07C-EN 15
Chapter 4 Input/output functions and wiring for typical applications
Analog inputs
The Tracer ZN521 controller includes seven analog inputs. Table 4
describes their functions. Each function is explained in the following
paragraphs. For an explanation of the diagnostics generated by each analog input, see “Diagnostics” on page 58. For more information about how
the controller operates, see Chapter 5, “Sequence of operations”
Table 4. Analog inputs
Analog input
terminal label
ZN Zone temperature
GND Zone sensor common ground
SET Local setpoint
FAN Fan mode input
GND Auxiliary ground
AI1 Entering water temperature
AI2 Discharge air temperature
AI3 Outdoor air temperature or generic temperature
AI4 Universal 4–20 mA
Function
GND: Ground terminals
Use a GND terminal as the common ground for all zone sensor analog
inputs.
ZN: Zone temperature
The ZN analog input functions as the local (hard-wired) zone temperature
input. The controller receives the temperature as a resistance signal from
a 10 kΩ thermistor in a standard Trane zone sensor wired to analog input
ZN. A zone temperature value communicated by means of a LonTalk link
can also be used for controllers operating on a BAS. When both a hardwired and communicated zone temperature value is present, the controller uses the communicated value. If neither a hard-wired nor a communicated zone temperature value is present, the controller generates a Zone
Temp Failure diagnostic.
The ZN analog input is also used to communicate timed override requests
and cancel requests to the controller for applications using a Trane zone
sensor with
16 CNT-SVX07C-EN
ON and CANCEL buttons.
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