Trane ZN.520, Tracer Unit Ventilator User Manual

1.38 Mb
Loading...

Installation

Owner

Diagnostics

Tracer® ZN.520 for Classroom

Unit Ventilator

UV-SVP01A-EN

Start-up Procedures

Installation of New Units

1.Follow all instruction for installation of classroom unit

ventilators as detailed in UV- IOM-1 (Installation Operation Maintenance manual).

2.Disconnect power or disable the circuit breaker to unit.

3.Run communication link wire when required. (See wiring diagram in the unit).

4.Install zone sensor when

required. (See wiring diagram in the unit and zone sensor submittals).

5.Reapply power.

6.Check for GREEN Status LED

operation to ensure power has been made to the TracerTM ZN.520 unit controller.

7.Check for YELLOW Comm LED

operation to help ensure communication has been made to the Tracer ZN.520 unit controller when required.

Peel IDENTIFICATION TAG from

unit and place in the Appendix of this document, or on building plans for future location use. The

actual room location on the tag may be hand written.

UV-SVP01A-EN

5

Start-up Procedures

Power Up Sequence

Manual output test can be initiated

at any time in the power up sequence or during normal operation.

When 24 VAC power is initially applied to the controller, the follow-

ing sequence occurs:

1.Green Status LED turns on.

2.All outputs are controlled Off.

3.The controller reads input values to determine initial values.

4.Standalone control is assumed unless occupancy data is communicated.

5.Random start timer expires (5 to 30 seconds, random).

6.Power-up control Wait feature is applied. When power up

control Wait is enabled, the controller waits 120 seconds to allow ample time for commu-

nicated control data to arrive. If, after 120 seconds, the controller does not receive a com-

municated occupancy request, the unit assumes standalone operation.

7.All modulating valves and

damper calibrate closed, face and bypass damper calibrate to bypass (when present).

8.Normal operation begins after

290 (potentially) seconds have passed.

Note: Manual output test can be initiated at any time.

6

UV-SVP01A-EN

General Information

Tracer® ZN.520

Overview

The Trane® Tracer® ZN.520 controller is a factory-installed and

commissioned, direct-digital controller (DDC) offering for classroom unit ventilator sys-

tems. (See Figure 1: “Tracer ZN.520 Control Board”) The Tracer ZN.520 can also be applied to

other Trane® interoperable HVAC equipment, including the fan coil and blower coil products. (For

more information see,Table 1: Tracer™ ZN.520 Unit Controller features and coil availability, on

page 8 for more information.) For more information regarding the application of the Tracer ZN.520

to other Trane products, contact the appropriate local Trane sales office.

Trane offers a complete solution to space comfort control with the

flexibility of Integrated Comfort System (ICS) and stand-alone control packages. The ICS control

package combines HVAC equipment and building management into one environmental comfort

system.

Integrating the Tracer ZN.520 on

classroom unit ventilators, and tying them to a Tracer Summit® system will provide a complete

building management system. The stand-alone control package offers the features and function-

ality of the direct digital control without a front-end building automation system, while providing

future considerations for ICS.

Equipment problems can often be

diagnosed on each unit without having to access the unit componets. These diagnostics can be re-

ceived remotely via a modem with a Tracer Summit building automation system, thus reducing the

number of actual on-site service calls; through the Rover® service tool connected to a communica-

tion jack located inside the Trace zone sensor; or connected to the unit.

Figure 1: Tracer ZN.520 Control Board

The Tracer ZN.520 is factorymounted, tested, wired, config-

ured and commissioned for the selected application.

The Tracer ZN.520 configuration has flexible point and product configurations. For example, with

point configuration, a specific binary point can be configured to accept input from either a time clock

or some type of generic device.

UV-SVP01A-EN

7

General Information

Table 1: Tracer™ ZN.520 Unit Controller features and coil availability

 

 

 

 

 

 

 

Auto

Face and

 

 

 

Entering

 

Multiple

Dehumid-

Valve

Economizer

Auxiliary

Water

Coil

Damper

Bypass

Fan Speeds

ification

Control

Damper

Heat2

Temperature

 

Adjust

Damper

 

 

 

 

 

 

Sampling

 

 

 

 

 

 

 

 

2-pipe changeover

X

 

X

X

X

X

X

X

2-pipe hot water

X

 

X

X

X

X

X

 

only

 

 

 

 

 

 

 

 

 

 

2-pipe steam only

X

 

X

X

 

X

X

 

2-pipe changeover/

X

X

X

 

X

X

X

X

electric heat

 

 

 

 

 

 

 

 

 

2-pipe cool only

X

 

X

 

X

X

 

 

2-pipe cool only/

X1

 

X1

 

X

X

X

 

electric heat

 

 

 

 

 

 

 

 

 

 

 

4-pipe hot water/

X

X

X

X3

X

X

X

 

chilled water

 

 

 

 

 

 

 

 

 

4-pipe changeover

X

X

X

X3

X

X

X

X

4-pipe steam/chilled

X

 

X

 

X

X

X

 

water

 

 

 

 

 

 

 

 

 

 

 

Electric heat only

 

 

 

 

 

X

X

 

DX/hot water

X1

 

X1

 

X

X

X

 

DX/steam

X1

 

X1

 

X

X

X

 

DX/electric heat

 

 

 

 

 

X

X

 

DX cooling only

 

 

 

 

 

X

 

 

1.Multiple fan speeds are available in hydronic units only.

2.Auxiliary heat is designed to bring on baseboard heat as the second stage of heating. The baseboard heat must be the same type as the

unit heating coil.

3. Units with face bypass dampers cannot actively dehumidify.

8

UV-SVP01A-EN

Controller Circuit Board

Features

Power

Generic

Auto Test Button

Status LED

Communications LED

Service Button and LED

Communications

Zone Sensor Connections

 

Figure 2: Tracer ZN.520 unit controller circuit board

UV-SVP01A-EN

9

Controller Features

Each Tracer ZN.520 unit controller circuit board is equipped with enhancements to help facilitate ser-

vice, testing, and diagnosis. Each board has

qManual test button,

qStatus LED,

qCommunication status LED,

qService button,

qQuick terminal connectors, and

qEasy to read screen printing.

(See Figure 1: “Tracer ZN.520 Control Board”).

Service

The Trane Tracer ZN.520 unit con-

troller is serviced using Rover®, the ICS software service too. Rover is designed to support the Tracer

ZN.520 unit controller on the classroom unit ventilator.

For “remote” access to the communicating units, the zone sensors offered with the Tracer ZN.520

have a telephone style (RJ-11) connector allowing field connection between Rover and the zone sen-

sor; however, the RJ-11 connector must be connected to the terminals TB2-5 and TB2-6 on the Tracer

ZN.520 unit controller.(See Figure 3: “Rover service tool connected to the RJ-11 communication jack in a

zone sensor”)

The zone sensor may also be used when trying to locate a unit. By pressing the ON button on the zone

sensor for 5 seconds or using the “wink” command in Rover, the circuit board receives the signal caus-

ing the Communication LED to “wink”. Winking allows visual identifier on the board for service

technicians.

The Tracer ZN.520 also includes

features such as a test output to manually test all of the end devices and color coded wires (i.e. red for

heating valves and blue for cooling valves) to aid in the troubleshooting process.(See “Manual Output

Test” on page 48, for more information.)

Figure 3: Rover service tool connected to the RJ-11 communication jack in a zone sensor

Typical Components

A typical classroom unit ventilator

system with a DDC package consists of the following physical components, in addition to the

mechanical equipment:

qTracer ZN.520—contains the

sensor input circuits, service adjustments, microprocessor control electronics, and communications hardware.

Power is supplied by a separately mounted 24 VAC\90 VA transformer.

qSensor Modules—a variety of analog sensors that provide

temperature and optional

humidity sensing and CO2 sensor; and an operator interface to the Tracer ZN.520 for operating modes, status, and temperature setpoints.

qStandard End Devices—a variety of devices that help to gather information, control

capacity, and provide ventilation are used by the Tracer ZN.520 in its control

algorithm to condition the space to the desired temperature and relative

humidity level. (See “Standard End Devices” on page13, for more information.)

10

UV-SVP01A-EN

Communication Configurations

Note: The Tracer ZN.520 is a

connect to a maximum of 120

configured controller. It will

Tracer ZN.520 controllers.

not operate without a valid

 

downloaded configuration

 

file.

 

The Tracer ZN.520 controller sup-

 

ports ICS and peer-to-peer com-

 

munications as well as stand-

 

alone operation. A number of con-

 

trol features may be configured at

 

the factory or by using the Rover

 

service tool. (See “Configuration”

 

on page32, for more information.)

 

Integrated Comfort

System

Note: The Tracer ZN.520

controller may only be used with Tracer Summit version 11.0 or greater with a Comm5

communications card.

Classroom unit ventilators can op-

erate as part of a large building automation system controlled by Tracer Summit. The Tracer ZN.520

is linked directly to the Tracer Summit via a twisted pair communication wire. Each Tracer Summit

building automation system can

Figure 4: Communications link wire

The ICS system allows for complete communication with the classroom unit ventilators via

Tracer ZN.520 unit controller. All points connected to the Tracer ZN.520 may be observed from the

Tracer Summit front-end controller. The Tracer Summit can also initiate an alarm on a loss of per-

formance or equipment malfunctions.

The ICS system also allows all of

the classroom unit ventilators to share information without the presence of hardwired sensors at

each unit. Some typical shared points include outside air temperature, entering water temperature,

and occupancy schedules.

Peer-to-Peer

Communications

On a peer-to-peer communication

system, multiple Tracer ZN.520 controllers may share data, via a twisted pair communication wire,

without the need for a Tracer Summit system. (See Figure 5: “Peer- to-peer communication connec-

tions”)

Peer-to-peer communications al-

lows features such as master/slave operation, in which multiple units operate off of a single zone sensor.

This is typically seen in large spaces requiring multiple units.

The Rover service tool is required to set up peer-to-peer communications.

Figure 5: Peer-to-peer communication connections

UV-SVP01A-EN

11

Communication Configurations

Stand-Alone

In a stand-alone configuration,

commands for operation are determined based on input from the zone sensor, humidity sensor, and

factoryor field-mounted timeclock.(See Figure 6: “Typical classroom unit ventilator installation”)

qThe timeclock is wired to the Tracer ZN.520 to index the unit

between occupied and unoccupied modes.

qA unit-mounted, analog, outside-air temperature sensor is used to initiate the dry bulb

economizer and freeze avoidance routines.

qOn changeover units, a unitmounted, analog, entering water temperature sensor is

used to automatically control the system in the heat/cool mode.

These sensors are required for proper system operation and are

provided as standard on standalone units.

Figure 6: Typical classroom unit ventilator installation

Communication Interface

Important! To help ensure

optimal performance of the Rover service tool, please use the latest version. To obtain

the latest version contact your local Trane sales representtative or service technician.

Note: Refer to the Tracer system manuals for more

information on communications.

The Tracer ZN.520 communicates via Comm5 (LonTalk) to a building management system, the Rover

service tool, and other unit controllers on the communications link. Each Tracer ZN.520 requires a

unique address for the system to operate properly. Every Tracer ZN.520 has this address (Neuron

ID) embedded in the microprocessor, which eliminates the need for field-addressing of the units. Each

unit also ships from the factory with a unit identification tag. (See “Location Identifier” on page38,

for more information.)

Building automation system

Trane offers a state-of the art frontend building automation system designed to coordinate and moni-

tor Trane equipment and controllers: Tracer Summit.

The Tracer Summit system allows the user to monitor and/or change Tracer ZN.520:

qstatus, parameters, sensor data, diagnostics, and internal variables; and

qsetpoints, operating modes, and outputs.

Service tool

Trane also offers a service tool to work in conjunction with the Tracer Summit system or with peer-to-

peer and stand-alone systems: the Rover service tool.

Communication to the Tracer ZN.520, or multiple controllers, can also be accomplished by using the

ICS software service tool.

A personal computer running Rover may be directly connected to a standalone Tracer ZN.520; con-

nected to the communications jack in the Trane zone sensor; or connected to a communicating unit’s

Tracer ZN.520 unit controller, to access all of the units on a communicating link.

Rover allows the user to interface with the Tracer ZN.520, but will not

allow any advanced control (e.g. equipment scheduling or trending). To purchase a copy of the ICS

software service tool, contact the BAS department at your local Trane dealer.

Interoperability

Trane has lead the industry with BACnet interoperability and Trane

is now expanding the realm of interoperable solutions by offering LonMark certified unit controllers.

The Tracer ZN.520 controller conforms to the LonMark Space Comfort Controller profile. (See

“Appendix—Data Lists” on page64, for more information.)

This allows the ZN.520 to be used

as a unit controller on other control systems that support LonTalk and the SCC profile. Now building own-

ers have more choices and design engineers have more flexibility to meet the challenges of building au-

tomation.

12

UV-SVP01A-EN

Standard End Devices

Table 2: End Device Specifications

Device

Fan Status Switch

Low Temperature Detection Switch (Freezestat)

OutsideAir Sensor/discharge AirSensor/Entering

Water Temperature Sensor/Unit Mounted, Zone

Return-air Temperature Sensor

Characteristic

Material

Operating Temperature Range

Contact Form

Preset

Trip Temperature:

Release Temperature

Rating—Auto Reset

Sensing Element

Description

Contact Blade—Pilot duty rated

-40°F/250°F (-40°C/120°C)

SPST-NO

Fan status - 0.07”

36°F ± 2°F (2°C + - 1.11°C)

44°F ± 3°F (6.67°C + - 1.67°C)

Pilot Duty

120

VAC

240

VAC

(24 VAC)

 

 

 

 

FLA

10.0

 

5.0

 

LRA

60.0

 

30.0

 

 

 

 

 

 

Thermistor 10 KOhms @ 77°F ± 1.8°F (25°C ±1°C)

UV-SVP01A-EN

13

Standard End Devices

Table 2: End Device Specifications

 

 

 

 

 

Device

Characteristic

Description

 

 

 

Outside Air Actuator

Description

Three-point floating with spring return

 

Ambient Temperature Rating

-25°F to 125°F

 

Power Consumption

5 VA

 

Torque

35 in-lbs.

Drive Time

90 seconds, 95 degree stroke

Face and Bypass Actuator

Description

Three-point floating

 

Ambient Temperature Rating

32°F to 122°F

 

Power Consumption

3 VA

 

Torque

35 in-lbs.

Drive Time

80-110 seconds, 95 degree stroke

2-way Control Valve

Description

Three-point modulating

 

Ambient Temperature Rating

140°F at 95% relative humidity

 

Drive Time

50 seconds

 

Max Pressure

400 psi water

 

Close Off

Varied by size and Cv

Temperature

Water 200°F maximum

14

UV-SVP01A-EN

Standard End Devices

Table 2: End Device Specifications

 

 

 

 

 

Device

Characteristic

Description

 

 

 

3-way Control Valve

Description

Three-point modulating

 

Ambient Temperature Rating

140°F at 95% relative humidity

 

Drive Time

50 seconds

 

Max Pressure

400 psi water

 

Close Off

Varied by size and Cv

Temperature

Water 200°F maximum

Time clock

Size

2.83'' x 4.0'' x 2.06''

 

Power Consumption

4.4 VA

 

Switch

SPDT dry contacts, silver cadmium oxide

 

Switch Rating

16A 250V resistive, 1000 Watts tungsten

 

Minimum Switching Current

100mA,230V

 

Shortest Switching Time

1 minute

 

Ambient Temperature Range

-14°F to 131°F

 

Wiring Connections

Screw terminals suitable for #10 to #24 AWG

 

Backup

Seven day capacitor backup

 

 

 

Zone sensor

 

 

Zone Sensor Wiring Size And

16-22 AWG: up to 200 feet

Maximum Lengths

 

UV-SVP01A-EN

15

Standard End Devices

Table 2: End Device Specifications

 

 

 

 

 

 

 

Device

Characteristic

Description

 

 

 

 

 

Humidity Sensor

Sensing Element

Polymer capacitive

 

 

Sensing Element

Accuracy: ± 5% over 20-95% RH @ 77ºF

 

 

Range

0 to 99% RH

 

 

Operating Temperature Range

0°F to 140ºF

 

 

Max Supply Voltage

24VDC

 

 

Output Characteristics

4 to 20 MA for 0-100% RH

 

 

Drift Rate

Less than 1% per year

 

CO 2 Sensor

Sensing Element

Accuracy: ± 100ppm full scale

 

 

Range

0-2000 ppm

 

 

Operating Temperature Range

59°F to 95ºF

 

 

Supply Voltage

24VAC

 

 

Output Characteristics

0-10 VDC for 0-2000 ppm

 

 

Power consumption

10 VA

 

 

Drift Rate

±5% full scale over four years

 

Fan Relay

 

20 amps at 120/240 vac

 

 

 

 

 

3/4 hp at 120 vac

 

 

Contact Rating

1 1/2 hp at 240 vac

 

 

 

20 amps @ 28 vdc

 

 

 

DPDT

 

 

Terminals

0.25 quick connect

 

 

Contact material

Silver-Cadium Oxide

 

 

Coil

24 vac 2.7 va

 

 

 

 

 

16

UV-SVP01A-EN

Standard End Devices

Table 2: End Device Specifications

 

 

 

 

 

Device

Characteristic

Description

 

 

 

 

Type

N.E.C. Class 2

 

Primary Voltage

120 vac

Control Transformer

 

24 vac at 90 va

 

 

 

Secondary voltage

Manual reset

 

 

4amp fuse in 24-volt circuit

 

 

 

UV-SVP01A-EN

17

Installation and Wiring

Specifications

Dimensions

Tracer ZN.520 board and mounting hardware:

Height: 5.25 inches (133 mm.)

Width: 5.50 inches (140 mm)

Depth: 2.25 inches (57 mm)

Power Requirements

18 to 32 VAC (24 VAC nominal)

50 or 60 Hz

570 mA AC

Operating Environment

32° to 140°F (0× to 60°C)

5% to 95% relative humidity, non-condensing

Storage Environment

-40° to 185°F (-40° to 85°C)

5% to 95% relative humidity, non-condensing

Agency Listings

UL and CUL 916 Energy Management System

Agency Compliance IEC 1000- 4-2 (ESD), IEC 1000-4-4(EFT), IEC 1000-4-5 (Surge)

Figure 7: Tracer ZN.520 circuit board schematic

18

UV-SVP01A-EN

Installation and Wiring

Binary Inputs

Each binary input associates an input signal of 0 VAC with open con-

tacts and 24 VAC with closed contacts.

Table 3: Binary inputs (typically 24 mA AC)

Description

Terminals

Terminal Function

Binary input 1

J2-1

24 VAC

(BI 1)

 

 

 

J2-2

Input

Binary input 2

J2-3

24 VAC

(BI 2)

 

 

 

J2-4

Input

Binary input 3

J2-5

24 VAC

(BI 3)

 

 

 

J2-6

Input

Binary input 4

J2-7

24 VAC

(BI 4)

 

 

 

J2-8

Input

UV-SVP01A-EN

19

Installation and Wiring

Binary Outputs

Outputs are load side switching tri-

acs. The triac acts as a switch, either making or breaking the circuit between the load (valve, damper,

contactor, relay) and ground.

Table 4: Binary outputs

Description

Fan high

Fan medium,

Exhaust fan

Fan low

No connection

Cool open, face bypass cool valve DX, 2-position cooling valve, BI 5

Cool close

Face/bypass damper open

Face/bypass damper close

Heat open

Face bypass isolation valve, 2-position heating valve Electric heat 1st stage

Heat close

Electric heat 2nd stage

Economizer damper open

Economizer damper close

Terminals

Output

Rating

 

J1-1

12 VA

J1-2

12 VA

J1-3

12 VA

J1-4 (Key)

J1-5

12 VA

J1-6

12 VA

J1-7

12 VA

J1-8

12 VA

J1-9

12 VA

J1-10

12 VA

J1-11

12 VA

J1-12

12 VA

Load Energized

Load De-energized

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

1 VAC RMS

24 VAC RMS

(typical)

(typical)

Generic/baseboard Heat Binary Output

Table 5: Generic binary outputs

 

 

 

 

Description

Terminals

Output

Load Energized

Load De-energized

 

 

Rating

 

 

Generic/ baseboard heat output

TB4-1

12 VA

1 VAC RMS

24 VAC RMS

 

 

 

(typical)

(typical)

24VAC

TB4-2

12 VA

NA

NA

20

UV-SVP01A-EN

Installation and Wiring

Analog Inputs

Table 6: Analog inputs

 

 

 

Description

Terminals

Function

Range

Zone

TB3-1

Space temperature input

5° to 122°F

 

 

 

(-15° to 50°C)

Ground

TB3-2

Analog ground

NA

Set

TB3-3

Setpoint input

40 ° to 115 °F

 

 

 

(4.4° to 46.1°C)

Fan

TB3-4

Fan switch input

4821 to 4919 Ω (Off)

 

 

 

2297 to 2342 Ω (Auto)

 

 

 

10593 to 10807 Ω (Low)

 

 

 

13177 to 13443 Ω (Medium)

 

 

 

15137 to 16463 Ω (High)

Ground

TB3-6

Analog ground

NA

Analog Input 1

J3-1

Entering water temperature

-40° to 212°F (-40° to 100° C)

 

J3-2

Analog ground

NA

Analog Input 2

J3-3

Discharge air temperature

-40° to 212°F (-40° to 100° C)

 

J3-4

Analog ground

NA

Analog Input 3

J3-5

Outdoor air temperature / Generic

-40° to 212°F (-40° to 100° C)

 

 

temperature

 

 

J3-6

Analog ground

NA

Analog Input 4

J3-7

Power port

4-20 mA

 

J3-8

Universal input

 

 

 

Generic 4-20ma

0 – 100%

 

 

Humidity

0 – 100%

 

 

CO2

0 – 2000ppm

 

J3-9

Analog ground

NA

UV-SVP01A-EN

21

Installation and Wiring

Mounting

The Tracer ZN.520 circuit board is

mounted in the left-hand end pocket for all classroom unit ventilator configurations. The sheet metal

mounting plate has raised embosses to accept the mounting feet on the circuit board. (See Figure 8:

“Classroom unit ventilator control box with close-up of horseshoe embosses and circuit board

mounting feet.”) This design allows the Tracer ZN.520 controller to be secured with a minimal num-

ber of sheet metal screws.

Figure 8: Classroom unit ventilator control box with close-up of horseshoe embosses and circuit board mounting feet.

22

UV-SVP01A-EN

Installation and Wiring

The mounting position on the ver-

tical classroom unit ventilator configuration allows complete access to the Tracer ZN.520 by re-

moving the front panel. (See Figure 9: “Vertical classroom unit ventilator end pocket”) The

mounting plate swings out of the way with the removal of a single screw to allow access to the com-

ponents behind the control board.

The mounting plate on the hori-

zontal classroom unit ventilator configuration is designed to slide out with the removal of a sin-

gle screw for complete access to the Tracer ZN.520. (See Figure 10: “Horizontal classroom unit venti-

lator end pocket”) The location of the control board on this unit configuration allows complete access

to the other components in the end pocket when the front panel is removed.

For additional convenience, quick

connects and modular wire harnesses are used on the control board and mounting plate. (See

Figure 11: “Quick connects to control board in the classroom unit ventilator”) These quick connects

help facilitate ease of wiring devices (e.g., zone sensor) to the control board, and helps add accessibility

to major components.

Figure 11: Quick connects to control board in the classroom unit ventilator

Figure 9: Vertical classroom unit ventilator end pocket

Figure 10: Horizontal classroom unit ventilator end pocket

UV-SVP01A-EN

23

Installation and Wiring

Wiring

! WARNING

Warning! Disconnect all electrical power before servicing unit to prevent injury or death due to electrical shock. Use copper conductors only. The use of aluminum or other incorrect types of wire may result in overheating and equipment damage.

! CAUTION

Caution: To prevent damage to the unit ventilator, refer to the diagram provided on the inside of the unit's access panel for specific wiring infor-

mation. All controls are wired at the factory. Single point power, zone sensor, and communication wiring is to be installed by the contractor.

Important! All wiring must comply with state, local, and federal guidelines. Contact the

appropriate local agency for furthur information.

Important! Wires for temperature sensors, communication lines, 24 VAC,

and contact closure sensing inputs should not be bundled with or run near high voltage

wiring.

qPower wiring must be

separated from the Tracer ZN.520 and all low voltage wires. External input wires

should be run in separate conduits from high voltage wires.

qWires connected to pin headers should be formed and routed

so as to cause minimum strain on the Tracer ZN.520 connector.

qA minimum of 1.5" clearance (from the pin centerline) for wires up to 16 AWG is

recommended for bending and forming wires.

qAll sensor and input circuits are at or near ground potential. Do not connect any sensor or input

circuit to an external ground connection.

qA close-coupled ground connection is required for the Tracer ZN.520. T

qTable 7: Tracer ZN.520 Wiring Requirements, shows Tracer ZN.520 wire types and lengths.

Table 7: Tracer ZN.520 Wiring

Requirements

Application

Wire Type

Length

 

 

 

Contact Closure

18 AWG

Up to

1000 ft.

 

 

24 VAC

16-22 AWG

Up to

1000 ft.

 

 

Thermostat

16-22 AWG

Up to

1000 ft.

 

 

Zone

16-22 AWG

Up to

Sensor

200 ft.

 

Communications

Belden 8760

Up to

 

or equivalent

5000 ft.

Power

The Tracer ZN.520 controller is

powered by 24 VAC. (See Table 7: “Tracer ZN.520 Wiring Requirements”)A total of two 1/4-inch

quick-connect terminals are provided for 24 VAC connection to the board.

Figure 12: Power connection to the Tracer ZN.520 unit controller

24

UV-SVP01A-EN

Installation and Wiring

Installing the WallMounted Zone Sensor (Optional)

Zone sensor location is an important element of effective room

control and comfort.

The best sensor location is typical-

ly on a wall, remote from the HVAC unit. Readings at this location assure that the desired set-

point is achieved across the space, not just near the unit itself.

Note: It may be necessary to

subdivide the zone with multiple units to ensure adequate control and comfort

throughout the space.

The following are typical areas

where the zone sensor should NOT be mounted:

qNear drafts or “dead spots” (e.g., behind doors or corners);

qNear hot or cold air ducts;

qNear radiant heat (e.g., heat

emitted from appliances or the sun);

qNear concealed pipes or chimneys;

qOn outside walls or other nonconditioned surfaces; or

qIn air flows from adjacent zones or other units.

Figure 13: Proper zone sensor placement

Note: All zone sensor wiring

will be done in the factory unless zone sensor options are selected to be wall mounted.

When a unit-mounted speed switch is selected with a wall-

mounted zone sensor, the contractor must disconnect the cooling setpoint on the unit mounted sen-

sor if the wall mounted cooling setpoint is used. The zone signal will be cut at the factory. The unit-

mounted speed switch cannot be used as a zone sensor.

THe communications link is not connected in the factory. Communications should be wired to the

wall-mounted sensor.

UV-SVP01A-EN

25

Installation and Wiring

Humidity and CO2 Sensors

Humidity and CO2 sensors should be mounted in a similar location as the zone sensor.

Figure 14: Relative humidity sensor

Figure 15: CO 2 Sensor

26

UV-SVP01A-EN

Typical Wiring Diagram—Wall

Mounted Zone Sensor

UV-SVP01A-EN

27

Typical Wiring Diagram—Unit

Mounted Zone Sensor

28

UV-SVP01A-EN

Typical Wiring Diagram—Unit

Mounted Switch, Wall Mounted Sensor

UV-SVP01A-EN

29

Input/Output Summary

Input/Output Summary

The following lists all possible bi-

nary and analog inputs and outputs available for the classroom unit ventilator applications. Some

of the points listed may be mutually exclusive and some are optional.

(See Table 8: Input and output summary)

Table 8: Input and output summary

Most binary inputs and outputs are wired from the factory based on unit configuration and options. If

the generic inputs and outputs are to be used, wiring connections are made at the 1/4” quick-connect ter-

minals provided.

Analog inputs from a wall-mount-

ed zone sensor, humidity sensor, CO2 sensor, or a generic device

Input

Description

 

Freezestat

Binary Inputs

Fan Status

 

Occupancy/Generic

 

J1-1 Fan High Speed

 

J1-3 Fan Low Speed

 

J1-2 Exhaust Fan

 

J1-5 Cooling Open

 

(Modulating valve/DX/

 

Isolation valve)

 

J1-6 Cooling Close

 

J1-7 Face and Bypass Damper

 

Open

 

J1-8 Face and Bypass Damper

 

Close

Binary Outputs

J1-9 Heat Open (Modulating

 

 

valve/Isolation valve) or 1 st

 

Stage Electric Heat

 

J1-10 Heat Close or 2 nd Stage

 

Electric Heat

 

J1-11 Economizer Damper

 

Open

 

J1-12 Economizer Damper

 

Close

 

TB4-1 Generic/Baseboard

 

Heat

 

TB4-2 24 VAC

 

 

must be wired to the 1/4” quickconnect terminals provided. Most other analog inputs will be wired

from the factory.

30

UV-SVP01A-EN

Input/Output Summary

Table 8: Input and output summary

Input

Description

Zone Temperature

Setpoint

Fan Speed

Entering Water Temperature

Analog Inputs

Discharge Air Temperature

Outdoor Air Temperature/

Generic

Generic/Humidity/CO2 (4-

20mA)

UV-SVP01A-EN

31

Configuration

Note: The Tracer Zn.520 unit controller only supports cascade control by controlling

the discharge air temperature. Therefore, the controller requires both a space

temperature input and a discharge air temperature input.

Table 9: Typical applications supported

Configuration

2-pipe cooling only

2-pipe heating only

2-pipe changeover

4-pipe

4-pipe changeover

2-pipe face bypass heating only

2-pipe face bypass changeover

4-pipe face bypass DX cooling only

DX cooling, 2-pipe heating

DX cooling, electric heating

Electric heat only (1 or 2 stage)

1. Isolation valves are 2-position only.

Trane configures the Tracer® ZN.520 Unit Controller at the factory per the selected unit configu-

ration. The controller is applied classroom unit ventilator configurations that support modulating

valves, 2-position valves, economizer damper (modulating only), direct expansion (DX) cooling, 1-

and 2 -stage electric heat, face- and-bypass damper, baseboard heat, dehumidification, and ge-

neric I/O. The controller also supports HIGH and LOW fan speeds with exhaust fan output on 1- and

2-speed fan applications.

Type of valve

 

 

Options

 

 

 

 

Electric Heat

 

Economizer

 

Baseboard

 

 

 

 

Modulating

2 position

(1 or 2 stage)

 

Damper

 

Heat

ü

ü

ü

 

ü

 

 

ü

ü

 

 

ü

 

ü

ü

ü

ü

 

ü

 

ü

ü

ü

 

 

ü

 

ü

ü

ü

 

 

ü

 

ü

 

ü1

 

 

ü

 

ü

 

ü1

 

 

ü

 

ü

 

ü1

 

 

ü

 

ü

NA

NA

 

 

ü

 

 

ü

ü

 

 

ü

 

ü

NA

NA

ü

 

ü

 

ü

NA

NA

ü

 

ü

 

ü

 

 

 

 

 

 

 

Configurable parameters

Rover service tool uses the unit type to determine and download

many other aspects of the unit configuration, such as the default analog input configuration, the default

binary input configuration, and the default binary output configuration.

Cooling source

qNone

qHydronic (main coil changeover)

qDedicated hydronic

qDX

Heating source

qNone

qHydronic

qDedicated hydronic

qSteam

qElectric heat

qHydronic (main coil changeover) + dedicated hydronic (auxiliary coil)

qHydronic (main coil changeover)

32

UV-SVP01A-EN

Configuration

Binary Outputs1

Table 10: Binary output summary

 

 

 

 

 

 

 

 

 

Binary output

Classroom unit ventilator

Valid range

 

 

 

 

 

 

 

J1-1

Fan high

 

 

NA

J1-2

Exhaust fan or none

 

 

NA

J1-3

Fan low

 

 

NA

J1-4

(Key)

 

 

NA

 

Cooling valve open

 

 

NA

J1-5

Face bypass cool isolation valve

Normally open or normally closed2

2-position cooling

 

Normally open or normally closed2

 

 

 

DX

 

 

NA

J1-6

Cooling valve close

 

 

NA

J1-7

Face bypass damper open

 

 

NA

J1-8

Face bypass damper close

 

 

NA

 

Heating valve open

 

 

NA

J1-9

Face bypass heat isolation valve

Normally open or normally closed2

Electric heat stage 1

 

 

NA

 

 

 

 

2-position heating

 

Normally open or normally closed 2

J1-10

Heating valve close

 

 

NA

Electric heat stage 2

 

 

NA

 

 

 

J1-11

Outdoor air damper open

 

 

NA

 

 

J1-12

Outdoor air camper close

 

 

NA

 

 

 

 

 

 

 

TB4-1/TB4-2

Terminals

 

Output Rating

Load Energized

 

Load De-energized

 

 

 

 

 

 

 

Generic/baseboard heat output

TB4-1

 

12 VA

1 VAC RMS (typical)

 

24 VAC RMS (typical)

24 VAC

TB4-2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.Trane’s Rover service tool uses the unit type to determine and download the proper default binary output configuration.

2.The normally open/closed configuration item refers to the inactive state of the controlled end device (such as an 2-position cooling valve output).

UV-SVP01A-EN

33

Configuration

Binary Inputs1

Table 11: Binary input summary

Binary input

Configuration

Valid range

 

 

 

BI 1

Low coil temperature detection or not used

Normally open

Normally closed

 

 

BI 2

Not used

Normally open

Normally closed

 

 

BI 3

Occupancy, generic, or not used

Normally open

Normally closed

 

 

BI 4

Fan status or not used

Normally open

Normally closed

 

 

 

 

 

1. Trane Rover service tool uses the unit type to determine and download the proper default binary input configuration.

Analog Inputs1

Table 12: Analog input summary

Analog input

Configuration

 

 

Zone

Space temperature

Set

Setpoint (hardwired)

Fan

Fan switch

AI 1

Entering water temperature

AI 2

Discharge air temperature

AI 3

Outdoor air temperature or generic temperature input

(Note 2)

 

AI 4

Humidity, CO2 or generic

4-20mA input

 

 

 

Calibration range

+/- 10.0°F (0.1°F resolution)

+/- 10.0°F (0.1°F resolution)

NA

NA

NA

NA

NA

1.Trane Rover service tool uses the unit type to determine and download the proper default analog input configuration.

2.Analog input 3 (AI 3) configured as generic temperature input does not affect unit operation. When configured, the Tracer™ ZN .520 Unit

Controller communicates the generic temperature value to Rover or Tracer Summit and displays it as generic temperature.

34

UV-SVP01A-EN

Configuration

Fan Configuration

Table 13: Fan configuration ranges

 

 

 

Fan configuration

Default

 

 

Fan operation in heating

Continuous

Fan operation in cooling

Continuous

Number of fan speeds

Varies 2

Configurable fan speed heating

Varies 2

Configurable fan speed cooling

Varies 2

Zone sensor fan switch

Enable

 

 

Valid range

Continuous (during occupied) Cycling with capacity (unoccupied)

Continuous (during occupied) Cycling with capacity (unoccupied)

1, 2

Off, low, high, auto

Off, low, high, auto

Disable or enable

End Device Configurations

Table 14: End device ranges

Main, cooling/changeover valve stroke time Entering water sampling

Auxiliary, heating valve stroke time

Outdoor air damper stroke time

Occupied outdoor air damper minimum position

Occupied standby outside air damper minimum position

Alternate minimum outside air damper position for low fan speed

Economizer enable temperature

Exhaust fan enable setpoint1

Face-and-bypass damper stroke time

Default

Valid range

 

 

Varies2

30 - 360 seconds

Varies2

Disable or enable

Varies2

30 to 360 seconds

Varies2

30 to 360 seconds

15%

0 to 100%

15%

0 to 100%

40%

0 to 100%

55°F

30 to 70°F

9%

0 to 100%, 101% disables the

exhaust fan

 

65 seconds

30-360 seconds

 

 

1.The exhaust fan is energized when the outdoor air damper is equal to or greater than the exhaust fan enable point, and the exhaust fan is turned off when the outdoor air damper is 10% less than the exhaust fan enable point.

2.Varies with unit configuration.

UV-SVP01A-EN

35

Configuration

Setpoints

Table 15: Setpoint defaults

 

 

 

 

 

Setpoint

Default

Valid range

 

 

 

Occupied heating setpoint

71°F

40 to 115° F

Occupied cooling setpoint

74°F

40 to 115° F

Occupied standby heating setpoint

67 °F

40 to 115° F

Occupied standby cooling setpoint

78 °F

40 to 115° F

Unoccupied heating setpoint

60°F

40 to 115° F

Unoccupied cooling setpoint

85°F

40 to 115° F

Heating setpoint low limit1

40°F

40 to 115° F

Cooling setpoint low limit1

40°F

40 to 115° F

Heating setpoint high limit 1

105°F

40 to 115° F

Cooling setpoint high limit 1

110°F

40 to 115° F

Thumbwheel setpoint

Enable

Disable or enable

 

 

 

1. The heating and cooling setpoint high and low limits only apply to the occupied and occupied standby setpoints and are never applied to the unoccupied setpoints.

Discharge Air Limits

Table 16: Discharge air limit ranges

 

 

 

 

 

 

Default

Valid range

 

 

 

Low limit 1

38 °F

30 to 50°F

Control point high limit2

150 °F

38 to 150°F

Control point low limit2

45 °F

35 to 150°F

1.The low limit is the temperature at which the controller shuts down the unit to prevent the coil from freezing.

2.The control algorithm is limited to calculating this discharge air temperature based on capacity request.

Freeze Avoidance

Table 17: Freeze avoidance setpoint range

 

 

 

 

 

 

Default

Valid range

 

 

 

Freeze avoidance setpoint1

40 °F

20 to 60° F

The controller disables freeze avoidance when the outdoor air temperature rises 3 °F above the freeze avoidance setpoint.

36

UV-SVP01A-EN

Configuration

Occupied Bypass Timer

Table 18: Bypass timer range

 

 

Default

Valid range

 

 

 

 

Occupancy bypass timer1

 

120 Minutes

0 to 240 minutes

 

(1 minute resolution)

 

 

 

1. The occupied bypass timer is used for timed override applications.

 

 

Power-Up Control Wait

 

 

Table 19: Control wait timer

 

 

 

 

 

 

 

 

Default

Valid range

 

 

 

 

Power up control wait (2 minutes)

 

120 seconds

Disable or enable

Maintenance Timers

 

 

Table 20: Maintenance timer range

 

 

 

 

 

 

 

 

Default

Valid range

 

 

 

 

Maintenance timer

 

0

0 to 10,000 hours

 

 

 

 

UV-SVP01A-EN

37

Location Identifier

Unit Identification Tag

The unit identification tag is factory mounted and provided for easy

identification of an installed unit. It contains model number, tagging, and location information.

The top portion of the unit identification tag remains permanently af-

fixed to the unit for identification purposes. The bottom portion of the tag provides pertinent informa-

tion that is removable to be placed on building plans or in “Appen- dix—Location Identifier” on

page68. This provides identification history about the unit’s location for quick reference.

These tags provide information about

q unit serial number;

qNID (neuron identification number)—The NID is similar to the serial number of the unit

but is specific to the identification of the Tracer ZN.520 unit controller circuit board; and

qunit location—The location identification is a customer defined, clear English description, of the unit’s

physical location. This is a 27 character description, including spaces, of the location. For

example, if the location identification for a unit is “Conference Room 101”, the

ZN.520, Rover (the Trane Comm 5 service tool), and Tracer Summit, will recognize this clear English description.

If location identification is not de-

fined, it will default to the unit serial number. This unit identification tag provides some information so

the user has multiple references to the unit. The blank location is provided for field modification in case

the unit is moved from the initial location.

Note: Fold and tear carefully along dashed removable line.

Figure 16: Unit identification tag

Winking

Winking a device causes the green

status LED on the device selected to blink at a rate of twice per second for approximately 10 seconds.

This feature is useful when a discrepancy in device location exists. As part of the troubleshooting pro-

cess, one person can WINK the device while another can observe the blinking and verify the device’s

physical location.

Important! If the status LED on

the ZN.520 does not blink, the device may not be communicating or it may not

be the device you selected according to the stored address.

A Tracer ZN.520 unit controller may be set to wink by

qholding the ON button on the zone sensor for 5 seconds

qusing Rover, Trane’s communication service tool

38

UV-SVP01A-EN

Unit Operation

Power-Up

When 24 VAC is initially applied to the controller, the following se-

quence of events occurs:

qGreen status LED turns ON.

qAll outputs are controlled OFF.

qThe controller reads input values to determine initial values.

qRandom-start timer expires (5 to 30 seconds).

qWhen POWER-UP CONTROL WAIT

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 communicated information, standalone control is assumed.

qAll modulating valves and dampers calibrate closed.

qNORMAL operation begins.

Occupancy

The valid occupancy modes for the Tracer ZN.520 controller are:

q OCCUPIED - Normal operating mode for occupied spaces or

daytime operation.

q UNOCCUPIED - Normal

operating mode for unoccupied spaces or nighttime operation.

q OCCUPIED STANDBY - Mode

used to reduce the heating and

cooling demands, while providing ventilation, during the occupied hours when the

space is vacant or unoccupied.

q OCCUPIED BYPASS -Used to

temporarily place the unit into the occupied operation.

The occupancy mode can be hardwired to the controller via the occupancy binary input or

communicated to the controller.

OCCUPIED mode

When the controller is in the OCCU- PIED mode, the unit attempts to

maintain the space temperature at the active occupied heating or cooling setpoint.

OCCUPIED mode is the default mode of the Tracer ZN.520 control-

ler.

UNOCCUPIED mode

When the controller is in the UN-

OCCUPIED mode, the unit attempts to maintain space temperature at the stored unoccupied heating or

cooling setpoint (i.e., configurable 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 UNOCCUPIED mode can be ini-

tiated through a hardwired signal to the occupancy binary input or by a communicated request.

OCCUPIED STANDBY mode

The OCCUPIED STANDBY mode al-

lows the unit to operate at a heat-

ing or cooling setpoint between the occupied and unoccupied setpoints to help maintain the envi-

ronment while decreasing energy consumption.

This mode decreases the ventilation for heating or cooling during brief periods of vacancy in the

space. Unit operation in this mode is similar to the occupied mode except for the different heating and

cooling setpoints and a different outside air damper position.

The OCCUPIED STANDBY mode is

initiated only when occupancy is communicated to the Tracer

ZN.520 controller and the hardwired signal to the occupancy input is calling for unoccupied

operation.

OCCUPIED BYPASS mode

The OCCUPIED BYPASS mode is

used to transition the unit from the

UNOCCUPIED mode to the OCCU-

PIED mode for a period of time from 0 to 4 hours (configurable

through Rover. Default=RUN). The controller can be placed in OCCU- PIED BYPASS mode by either com-

municating an occupancy request of BYPASS or by using the TIMED OVERRIDE (i.e., ON) button on the

Trane zone sensor.

ON and CANCEL Buttons

Some Trane zone sensors have ON and CANCEL buttons for timed override operation. Pressing the ON

button on the zone sensor when the unit is in the UNOCCUPIED mode initiates the OCCUPIED BY-

PASS mode and initializes the bypass timer. The CANCEL button is used to send the unit back into UN-

OCCUPIED mode before the bypass timer has expired.

The ON button may also be used for the unit identification or the “WINK” feature. (See “Winking”

on page38.for more information.)

When the Tracer ZN.520 controller is connected to a Tracer Summit

system or the Rover service tool, the ON button may be used in place of the service pin for easy unit

identification.

Heating And Cooling Changeover Logic

The Tracer™ ZN.520 Unit Control-

ler can receive communicated requests 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)

UV-SVP01A-EN

39

Unit Operation

4 = Night Purge (air

changeover) not supported

5= Pre-cool (morning cool down)

6= Off (no unit operation allowed)

7= Test (special test mode)

8= Emergency Heat not supported

9 = Fan Only (no heating or cooling allowed)

All other enumerations will be interpreted as Auto.

As the controller automatically determines its heating or cooling mode, it changes from cool to heat

or from heat to cool, while the error (integrated over time between the active setpoint and the space tem-

perature) is (900°FhSec). Integration only begins once the heating and cooling capacity is equal to 0%

or the discharge air temperature is being limited by the discharge air temperature control limits.(See

Figure 17: “Heat/Cool Changeover logic”).

Figure 17: Heat/Cool Changeover logic

If the measured space temperature is 69 °F and the active cooling set-

point is 72 °F, the error between the space temperature and the setpoint is three degrees. If the same

error exists for one minute (60 seconds), the integration term is

(3 °Fh60 Sec) or (180 °Fh Sec).

The Tracer™ ZN.520 Unit Controller changes from heating to cool-

ing and cooling to heating when the integration term exceeds (900 °FhSec). Along with satisfy-

ing the integration for heating and cooling changeover, the measured space temperature must fall out-

side the setpoint range. This means the space temperature must be greater than the active

cooling setpoint or lower than the active heating setpoint.

Example: If the cooling setpoint is 75 °F and the heating setpoint

70 °F, any space temperature greater than 75 °F or less than 70 °F is outside the setpoint range.

Once the integration term is satisfied and the space temperature is

outside the setpoint range, the controller changes modes. However, before the unit's heating or

cooling capacity ramps up, the controller checks to make sure it is capable of heating or cooling.

For some units, heating and cooling capability exists with local re-

sources such as electric heat or

compressors. For these units, central heating or cooling plan opera-

tion is not required for heating or cooling because they are capable of providing their own local heat-

ing or cooling.

For 2-pipe changeover and 4-pipe

changeover units with hydronic capacity, heating and cooling is provided through hydronic. For those

hydronic, central heating or cooling plant operation is required for the unit to deliver heating or cool-

ing. To determine whether the central plant is providing the desired water temperature, an entering

water temperature sensor (either hardwired or communicated) must be present.

40

UV-SVP01A-EN

Unit Operation

The entering water must be five

degrees or more above the space temperature to allow hydronic heating, and five degrees or more

below the space temperature to allow hydronic cooling.

If the desired water temperature is available, the unit begins normal heating and cooling operation. If

the measured entering water temperature is not adequate for the desired heating or cooling, the

controller begins the entering water temperature sampling logic.

The Tracer™ ZN.520 Unit Controller operates the modulating valves and dampers based on a heating

or cooling capacity calculated by the control algorithm. The control algorithm calculates the heating or

cooling capacity based on the measured space temperature, the active setpoint and the discharge

air temperature. When the measured space temperature is within the active heating and cooling set-

points, the heating and cooling capacity approaches zero.

Cooling Operation

During the COOLING mode, the Tracer ZN.520 controller attempts

to maintain the space temperature at the active cooling setpoint. Based on the controller’s occupan-

cy mode, the active cooling setpoint is one of the following:

qOccupied cooling setpoint

qOccupied standby cooling setpoint

qUnoccupied cooling setpoint

The controller uses the measured space temperature, the active

cooling setpoint, and discharge air temperature along with the control algorithm to determine the re-

quested cooling capacity of the unit (0-100%). The outputs are controlled based on the unit configu-

ration and the requested cooling capacity.

Heating Operation

During the HEATING mode, the Tracer ZN.520 controller attempts

to maintain the space temperature at the active heating setpoint. Based on the controller’s occupan-

cy mode, the active heating setpoint is one of the following:

qOccupied heating setpoint

qOccupied standby heating setpoint

qUnoccupied heating setpoint

The controller uses the measured space temperature, the active

heating setpoint, and discharge air temperature along with the control algorithm to determine the re-

quested heating capacity of the unit (0-100%). The outputs are controlled based on the unit configu-

ration and the requested heating capacity.

Fan Operation

For multiple fan speed applications, the Tracer ZN.520 controller

allows separate default fan speeds to be configured for heating and cooling modes. When the fan

mode switch is in the AUTO position or no hardwired input exists, the fan operates at the configured

default fan speed (i.e, HIGH).

The Tracer ZN.520 controller also

allows the default fan speed to be configured as AUTO. When the fan speed switch is in the AUTO posi-

tion and the default fan speed is configured as AUTO, the unit may change fan speeds based on the

requested heating or cooling capacity. In this mode, the unit fan will operate at LOW speed until the

requested capacity requires HIGH fan speed operation to maintain space comfort.

The fan mode request can be either hardwired or communicated

to the Tracer ZN.520 controller. When both are present, the communicated request has priority

over the hardwired input. Additional flexibility in the controller al-

lows the fan speed switch to be

disabled. When this occurs, the unit will operate at the default fan speed unless a communicated re-

quest is present.

During OCCUPIED, OCCUPIED

STANDBY, and OCCUPIED BYPASS

modes, the fan will normally operate continuously at the appropri-

ate fan speed. The fan will only be OFF in these modes when the MAN- UAL OUTPUT TEST has been initiat-

ed, a latching diagnostic is present, or the communicated or hardwired fan speed is OFF. (See

“Manual Output Test” on page48.for more information.)

During the UNOCCUPIED mode, the unit fan is controlled OFF. When capacity is required to maintain the

unoccupied heating or cooling setpoint, the unit fan is controlled to high speed regardless of a hard-

wired or communicated fan speed.

Table 21: Absolute two-speed fan switch points

Fan Speed

Absolute

Change

Temperature Error

Low to High

2.00

°F

High to Low

1.25

°F

 

 

 

Fan Off Delay

When a heating output is controlled off, the Tracer™ ZN.520

Unit Controller automatically holds the fan on for an additional 30 seconds. This 30-second delay

gives the fan time to blow off any residual heat from the heating source, such as a steam coil. When

the unit is heating, the fan off delay is normally applied to control the fan; otherwise, the fan off de-

lay does not apply.

Fan Start On High Speed

On a transition from off to any oth-

er fan speed, the Tracer™ ZN.520 Unit Controller automatically starts the fan on high speed and

runs the fan at high speed for 0.5

UV-SVP01A-EN

41

Unit Operation

seconds. This provides the ample torque required to start all fan motors from the off position.

Exhaust fan/damper operation

This binary point is a shared point with medium fan speed. For this

point to be used for exhaust control, the controller must be configured for a 1- or 2-speed fan. The

exhaust fan/damper is coordinated with the unit fan and outdoor damper operation. The exhaust

output is energized only when the unit fan is operating and the outdoor damper position is greater

than or equal to the configurable exhaust enable point. The exhaust fan output is disabled when the

outdoor air damper position drops 10% below the exhaust enable point. If the enable point is less

than 10%, the unit turns on at the enable point and off at 0.

Valve Operation

Modulating Valves

The Tracer ZN.520 controller supports one or two modulating valves for hydronic heating and

cooling operation. The main valve/ coil is used for cooling only, heat/ cool changeover (2-pipe applica-

tions), or cooling (4-pipe applications). The auxiliary valve/coil provides heating in 4-pipe and

heating only applications.

At power-up, the Tracer ZN.520

controller drives the modulating valves to the closed position. The controller calibrates to the full

closed position by overdriving the actuator 135%. Whenever the controller requests a valve position of

zero or 100%, the controller overdrives the actuator 135% regardless of the current valve position.

Face-and-Bypass

Isolation Valves

Face-and-bypass units may use

isolation valves to prevent unwanted water flow in the coil. This eliminates problems such as radiant

heat or excessive condensate in 2- pipe systems.

In 4-pipe applications, the isolation valves are used to prevent conflicting capacities within the unit.

Face-and-Bypass

Damper Operation

Note: The Face-and-bypass actuator is located in the right-

hand end pocket of the classroom unit ventilator.

The Tracer ZN.520 controller actuates a face-and- bypass damper to modulate a percentage of air to the

face of the coil to maintain space comfort. When a requested capacity is present, the unit modulates

the damper to allow more air to the face of the coil. An averaging sensor is used on the discharge air to

provide accurate capacity control.

Figure 18: Horizontal unit with face-and-bypass damper option.

42

UV-SVP01A-EN

Unit Operation

Figure 19: Vertical unit with face-and- bypass damper operations

Upon power-up, the controller cal-

ibrates the face-and-bypass damper to the full bypass position by overdriving the damper actuator.

During normal operation, whenever the Tracer ZN.520 controller generates a face-and-bypass

damper position request of zero or 100%, the unit calibrates the actuator by overdriving the damper ac-

tuator 135%.

Entering Water

Temperature Sampling

Units with 4-pipe changeover and 2-pipe changeover require an en-

tering water temperature to determine if the appropriate water temperature is present for the re-

quested mode (heating or cooling). This temperature may be communicated in an ICS system or

hardwired to the Tracer ZN.520

controller for standalone applications.

When a unit uses 2-way modulat-

ing valves, it is possible for the water near the entering water temperature sensor to migrate to-

wards ambient temperature. The Tracer ZN.520 controller has a water sampling feature for these ap-

plications. When the sensed water temperature is not sufficient for the requested heat/cool mode

(5°F above the zone temperature for heating or 5°F below the zone temperature for cooling), the con-

troller drives the valve fully open. The controller then monitors the water temperature until the appro-

priate temperature is sensed or until the three minute time limit expires. If the water temperature is

acceptable for the requested capacity, the unit continues normal operation. If the three minute tim-

er expires and the water temperature is still unsuitable, the unit closes the valve and waits one

hour before invoking the sampling feature again.

Table 22: Water assumption chart

Unit Configuration

Temperature

Assumed1

 

2-pipe Heating valve

Hot

2-pipe cooling valve

Cold

2-pipe H/C valve with

auto changeover enabled Hot

2-pipe H/C valve with

auto changeover Cold disabled

1. Assumption based on absence of a valid entering water temperature

Modulating Outdoor Air Operation

The Tracer ZN.520 controller oper-

ates a modulating (3-wire floating) outdoor air damper actuator according to the effective occupan-

cy, outdoor air temperature, space temperature, effective setpoint, discharge air temperature, and

discharge air temperature set-

point. Default minimum damper

positions are provided and can be changed for occupied and occupied standby modes, or for low

speed operation. The controller can also receive a communicated outdoor air damper minimum po-

sition from Tracer Summit. A communicated minimum position from Tracer Summit has priority

over all configured setpoints.

During the OCCUPIED mode the

outdoor air damper will always be controlled to the effective minimum position unless ASHRAE Cy-

cle I, ASHRAE Cycle II, or economizing modes are active.

Figure 20: OA/RA actuator mounting for the vertical unit ventilator

Figure 21: Figure 2: OA/RA actuator mounting for the horizontal unit ventilator

UV-SVP01A-EN

43

Unit Operation

Automatic Outdoor Air

Damper Adjustment

The Tracer ZN.520 controller is ca-

pable of using different minimum outdoor air damper positions for high and low fan speeds, which are

configurable. This allows the ventilation rate to be maintained when switching between fan speeds.

Note: The typical reduction in airflow between high and low

fan speeds is 25%, however, if precise control is desired, an air balancer should be

consulted.

Economizer

Operation

Note: When there is a request

for 0% or 100% actuator position, the actuator will overdrive the actuator 135% to

help maintain calibration.

With a valid outdoor air tempera-

ture (hardwired or communicated), Tracer ZN.520 uses the modulating economizer damper as the highest

priority source of cooling.

The controller initiates the econo-

mizer function if the outdoor air temperature is cold enough to be used for free cooling capacity. If

the outdoor air temperature is less than the economizer enable setpoint (absolute dry bulb), the con-

troller modulates the outdoor air damper between the minimum position and 100% to control the

amount of cooling capacity. When the outdoor air temperature rises 5°F above the economizer enable

setpoint, the outdoor air damper returns to its minimum position and mechanical cooling is initiated.

ASHRAE Cycle I

ASHRAE Cycle I admits 100% outdoor air except during the warm up

cycle or the unoccupied mode. To set up the Tracer ZN.520 controller for ASHRAE Cycle I conformance,

set the occupied outdoor air damper minimum position to 100%.

ASHRAE Cycle II

The Tracer ZN.520 controller con-

forms to ASHRAE Cycle II by allowing the modulating outdoor air damper to maintain a minimum

position during the occupied mode unless economizing is enabled or the space temperature falls more

than 3°F below the effective setpoint.

If the space temperature falls more than 2°F below the setpoint, the outdoor air damper will begin to

close. When the space temperature hits 3°F below the setpoint, the outdoor air damper is completely

closed.

Figure 22: ASHRAE cycle 2

DX Operation

Tracer ZN.520 supports direct expansion (DX) compressor operation for cooling only.

The controller does not allow both the DX compressor and economiz-

er to operate at the same time. This prevents problems where the entering air temperature is too low

for the evaporator coil to operate as designed.

Tracer ZN.520 also includes a fixed minimum on/off time of 3 minutes for compressor operation to pre-

vent short cycling of the compressor.

Electric Heat Operation

The Tracer ZN.520 controller supports 1 or 2 stages of electric heat

control.

To control space temperature,

electric heat is cycled to control the discharge air temperature. The rate of cycling is dependent on the load

in the space and the temperature of the incoming fresh air.

Baseboard Heat Operation

The Tracer ZN.520 controller can be configured to support one stage of baseboard heat. A 2 position

valve or an electric heat contactor will be energized at 2.5°F below the effective heating setpoint. The

baseboard heat is de-energized at 1°F below the effective heating setpoint.

The unit will provide heating capacity as required regardless of the

presence of baseboard heat. If the unit can not maintain the space temperature, the baseboard heat

will come on as a secondary stage.

If baseboard heat is to be used as

the primary source of heating, the discharge air high limit should be set to a moderate temperature.

This will allow the ventilation air to be tempered and avoid a “drafty” feeling. The baseboard heat will

then operate as the heating capacity for the space.

In the UNOCCUPIED mode, the baseboard heat and unit heating capacity are brought on simulta-

neously as needed to maintain the unoccupied setpoint.

Exhaust Fan

Operation

The exhaust fan is coordinated with the unit fan and outdoor air damper operation. The exhaust fan

output is energized only when the unit fan is operating and the outdoor air damper position is greater

44

UV-SVP01A-EN

Unit Operation

than or equal to the configurable

exhaust enable setpoint. This is useful for exhaust fans designed to offset the added economizer

ventilation.

The exhaust fan is disabled when

the outdoor air damper position drops 10% below the exhaust enable point. If the exhaust fan en-

able setpoint is less than 10%, the Tracer ZN.520 controller energizes the exhaust fan at the enable point

and disables it when the outdoor air damper closes.

Output Overrides

Manual Output Test

Manual output test allows the bi-

nary outputs to be energized in a predefined sequence.(For more information see, Manual Output

Test, on page 48 for more information.)

Water Valve Override

To enable quicker water balancing, the controller allows a user to specify the desired state of all wa-

ter valves. The values supported are:

qOpen all valves

qClose all valves

The valves in the system will remain open for two hours or until

normal operation is resumed.

The Tracer Summit or the Rover

service tool is required to access this feature.

Fan Status

There are two ways to do fan status monitoring:

1.The status of the fan is

reported based on the state of the binary output(s) dedicated to fan control. The fan status

is reported as HIGH or LOW whenever the corresponding binary output is directed ON.

The fan status is reported as

OFF when none of the fan outputs are directed ON.

2.The Tracer ZN.520 controller has a binary input available

for a fan status device (current sensing relay or differential pressure switch) which can

provide feedback of fan operation. If the device does not indicate fan operation after 1

minute, a unit shutdown is initiated, and the unit is latched

OFF.

Filter Status/ Maintenance Timer

The unit filter status\maintenance timer is based on the cumulative

run hours of the unit fan. The controller compares the fan run time against an adjustable fan run hour

limit and recommends unit maintenance as required.

The Rover service tool is used to edit the maintenance required setpoint time. Once the setpoint limit

is exceeded, the controller gener-

ates a MAINTENANCE REQUIRED infor-

mational diagnostic. When the

maintenance required setpoint time is set to zero, the controller disables this feature.

You can use the Trace Summit or the Rover service tool to clear the

MAINTENANCE REQUIRED informa-

tional diagnostic. Once the diagnostic is cleared, the controller

resets the fan run time to zero and begins accumulating fan run hours again.

Note: If at any time the unit loses power, the timer is reset

to zero.

Other Modes

DEHUMIDIFICATION

Note: If the unit is in the unoccupied mode, the

dehumidification routine will not operate

Dehumidification is possible when

mechanical cooling is available; the heating capacity is in the reheat position; and the space rela-

tive humidity setpoint is valid.

The controller starts dehumidify-

ing the space when the space humidity exceeds the humidity setpoint. The controller continues

to dehumidify until the sensed humidity falls below the setpoint minus the relative humidity offset.

The controller uses the cooling and reheat coils simultaneously to

dehumidify the space. When dehumidifying, the discharge air temperature is controlled to main-

tain the space temperature at the current setpoint.

Economizing is disabled during the dehumidification mode.

Note: While in the dehumidification mode, if there is a call for capacity by

the unit, the zone temperature setpoint will take priority over the relative humidity

setpoints.

DEFROST

For defrost operation, a sensor is

wired in series with the DX cooling relay. When a defrost condition is detected, the condensing unit is

disabled, and the unit is placed in the DEFROST mode.

During DEFROST the condensing unit is OFF the outside air damper is set to the minimum positions,

and the fan will continue to operate as continuous. The unit will remain in the DEFROST mode until

the senor resets at 48°F. The unit will return to NORMAL operation after the mode is discontinued.

FREEZE AVOIDANCE

FREEZE AVOIDANCE is used as low

ambient temperature protection,

and is only invoked when the fan is OFF. This includes the UNOCCUPIED mode when there is no call for ca-

pacity, or any other time the fan is

UV-SVP01A-EN

45

Unit Operation

OFF due to a safety or command. The controller enters the FREEZE AVOIDANCE mode when an out-

door air temperature is present (communicated or hardwired) and it is below the freeze avoidance set-

point (configurable). The controller disables freeze avoidance when the outdoor air temperature rises

3°F above the freeze avoidance setpoint.

When the controller is in the freeze avoidance mode:

qAll water valves are driven open to allow water flow through the coil

qFan is OFF

qFace-and-bypass damper (when present) is in full BYPASS

qDX and electric heat are OFF

MORNING WARM-UP

The Tracer ZN.520 controller keeps

the modulating outdoor air damper closed anytime during the OCCU- PIED mode when the space

temperature is 3°F or more below the heating setpoint.

Figure 23: Simple data sharing application

The damper remains closed indefinitely during morning warm-up until the space temperature is with-

in 2°F of the effective heating setpoint. The unit runs at full capacity until setpoint is met.

COOL-DOWN

The Tracer ZN.520 controller keeps the modulating outdoor air damp-

er closed for up to one hour at every transition from UNOCCUPIED to OCCUPIED mode when the space

temperature is 3°F or more above the cooling setpoint.

The damper remains closed during cool-down until the space temperature is within 2°F of the effective

cooling setpoint. The unit runs at full capacity until setpoint is met.

Data Sharing—LonWorks

Tracer ZN.520 allows peer-to-peer data communication through the use of LonWork’s technology. Data

such as space temperature setpoint, occupancy, etc. can be shared from a master controller to

a peer controller over a twisted pair of communication wire with or without the presence of a front end

building management system.

(See Figure 23: “Simple data sharing application”) This ability al-

lows units to operate with the same data to prevent conflicting control.

Data sharing is established through the use of “bindings”.

Bindings are set up through the Rover service tool.

The Tracer ZN.520 controller includes a network variable for master/slave operation. This variable

includes all of the information required for the slave units to operate with master controller. (See

Figure 24: “More complex data sharing application”)

For more information on establishing bindings, see the Rover service tool manual. For a complete listing

on shared points see “Appendix— Data Lists” on page64.

46

UV-SVP01A-EN

Unit Operation

Figure 24: More complex data sharing application

UV-SVP01A-EN

47

Unit Operation

Power-Up

When 24 VAC is initially applied to the controller, the following se-

quence of events occurs:

qGreen status LED turns ON.

qAll outputs are controlled OFF.

qThe controller reads input values to determine initial values.

qRandom-start timer expires (5 to 30 seconds).

qWhen POWER-UP CONTROL WAIT

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 communicated information, standalone control is assumed.

qAll modulating valves and dampers calibrate closed.

qNORMAL operation begins.

Occupancy

The valid occupancy modes for the Tracer ZN.520 controller are:

q OCCUPIED - Normal operating mode for occupied spaces or

daytime operation.

q UNOCCUPIED - Normal

operating mode for unoccupied spaces or nighttime operation.

q OCCUPIED STANDBY - Mode

used to reduce the heating and

cooling demands, while providing ventilation, during the occupied hours when the

space is vacant or unoccupied.

q OCCUPIED BYPASS -Used to

temporarily place the unit into the occupied operation.

The occupancy mode can be hardwired to the controller via the occupancy binary input or

communicated to the controller.

OCCUPIED mode

When the controller is in the OCCU- PIED mode, the unit attempts to

maintain the space temperature at the active occupied heating or cooling setpoint.

OCCUPIED mode is the default mode of the Tracer ZN.520 control-

ler.

UNOCCUPIED mode

When the controller is in the UN-

OCCUPIED mode, the unit attempts to maintain space temperature at the stored unoccupied heating or

cooling setpoint (i.e., configurable 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 UNOCCUPIED mode can be ini-

tiated through a hardwired signal to the occupancy binary input or by a communicated request.

OCCUPIED STANDBY mode

The OCCUPIED STANDBY mode al-

lows the unit to operate at a heat-

ing or cooling setpoint between the occupied and unoccupied setpoints to help maintain the envi-

ronment while decreasing energy consumption.

This mode decreases the ventilation for heating or cooling during brief periods of vacancy in the

space. Unit operation in this mode is similar to the occupied mode except for the different heating and

cooling setpoints and a different outside air damper position.

The OCCUPIED STANDBY mode is

initiated only when occupancy is communicated to the Tracer

ZN.520 controller and the hardwired signal to the occupancy input is calling for unoccupied

operation.

OCCUPIED BYPASS mode

The OCCUPIED BYPASS mode is

used to transition the unit from the

UNOCCUPIED mode to the OCCU-

PIED mode for a period of time from 0 to 4 hours (configurable

through Rover. Default=RUN). The controller can be placed in OCCU- PIED BYPASS mode by either com-

municating an occupancy request of BYPASS or by using the TIMED OVERRIDE (i.e., ON) button on the

Trane zone sensor.

ON and CANCEL Buttons

Some Trane zone sensors have ON and CANCEL buttons for timed override operation. Pressing the ON

button on the zone sensor when the unit is in the UNOCCUPIED mode initiates the OCCUPIED BY-

PASS mode and initializes the bypass timer. The CANCEL button is used to send the unit back into UN-

OCCUPIED mode before the bypass timer has expired.

The ON button may also be used for the unit identification or the “WINK” feature. (See “Winking”

on page38.for more information.)

When the Tracer ZN.520 controller is connected to a Tracer Summit

system or the Rover service tool, the ON button may be used in place of the service pin for easy unit

identification.

Heating And Cooling Changeover Logic

The Tracer™ ZN.520 Unit Control-

ler can receive communicated requests 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)

UV-SVP01A-EN

39

Unit Operation

4 = Night Purge (air

changeover) not supported

5= Pre-cool (morning cool down)

6= Off (no unit operation allowed)

7= Test (special test mode)

8= Emergency Heat not supported

9 = Fan Only (no heating or cooling allowed)

All other enumerations will be interpreted as Auto.

As the controller automatically determines its heating or cooling mode, it changes from cool to heat

or from heat to cool, while the error (integrated over time between the active setpoint and the space tem-

perature) is (900°FhSec). Integration only begins once the heating and cooling capacity is equal to 0%

or the discharge air temperature is being limited by the discharge air temperature control limits.(See

Figure 17: “Heat/Cool Changeover logic”).

Figure 17: Heat/Cool Changeover logic

If the measured space temperature is 69 °F and the active cooling set-

point is 72 °F, the error between the space temperature and the setpoint is three degrees. If the same

error exists for one minute (60 seconds), the integration term is

(3 °Fh60 Sec) or (180 °Fh Sec).

The Tracer™ ZN.520 Unit Controller changes from heating to cool-

ing and cooling to heating when the integration term exceeds (900 °FhSec). Along with satisfy-

ing the integration for heating and cooling changeover, the measured space temperature must fall out-

side the setpoint range. This means the space temperature must be greater than the active

cooling setpoint or lower than the active heating setpoint.

Example: If the cooling setpoint is 75 °F and the heating setpoint

70 °F, any space temperature greater than 75 °F or less than 70 °F is outside the setpoint range.

Once the integration term is satisfied and the space temperature is

outside the setpoint range, the controller changes modes. However, before the unit's heating or

cooling capacity ramps up, the controller checks to make sure it is capable of heating or cooling.

For some units, heating and cooling capability exists with local re-

sources such as electric heat or

compressors. For these units, central heating or cooling plan opera-

tion is not required for heating or cooling because they are capable of providing their own local heat-

ing or cooling.

For 2-pipe changeover and 4-pipe

changeover units with hydronic capacity, heating and cooling is provided through hydronic. For those

hydronic, central heating or cooling plant operation is required for the unit to deliver heating or cool-

ing. To determine whether the central plant is providing the desired water temperature, an entering

water temperature sensor (either hardwired or communicated) must be present.

40

UV-SVP01A-EN

Unit Operation

The entering water must be five

degrees or more above the space temperature to allow hydronic heating, and five degrees or more

below the space temperature to allow hydronic cooling.

If the desired water temperature is available, the unit begins normal heating and cooling operation. If

the measured entering water temperature is not adequate for the desired heating or cooling, the

controller begins the entering water temperature sampling logic.

The Tracer™ ZN.520 Unit Controller operates the modulating valves and dampers based on a heating

or cooling capacity calculated by the control algorithm. The control algorithm calculates the heating or

cooling capacity based on the measured space temperature, the active setpoint and the discharge

air temperature. When the measured space temperature is within the active heating and cooling set-

points, the heating and cooling capacity approaches zero.

Cooling Operation

During the COOLING mode, the Tracer ZN.520 controller attempts

to maintain the space temperature at the active cooling setpoint. Based on the controller’s occupan-

cy mode, the active cooling setpoint is one of the following:

qOccupied cooling setpoint

qOccupied standby cooling setpoint

qUnoccupied cooling setpoint

The controller uses the measured space temperature, the active

cooling setpoint, and discharge air temperature along with the control algorithm to determine the re-

quested cooling capacity of the unit (0-100%). The outputs are controlled based on the unit configu-

ration and the requested cooling capacity.

Heating Operation

During the HEATING mode, the Tracer ZN.520 controller attempts

to maintain the space temperature at the active heating setpoint. Based on the controller’s occupan-

cy mode, the active heating setpoint is one of the following:

qOccupied heating setpoint

qOccupied standby heating setpoint

qUnoccupied heating setpoint

The controller uses the measured space temperature, the active

heating setpoint, and discharge air temperature along with the control algorithm to determine the re-

quested heating capacity of the unit (0-100%). The outputs are controlled based on the unit configu-

ration and the requested heating capacity.

Fan Operation

For multiple fan speed applications, the Tracer ZN.520 controller

allows separate default fan speeds to be configured for heating and cooling modes. When the fan

mode switch is in the AUTO position or no hardwired input exists, the fan operates at the configured

default fan speed (i.e, HIGH).

The Tracer ZN.520 controller also

allows the default fan speed to be configured as AUTO. When the fan speed switch is in the AUTO posi-

tion and the default fan speed is configured as AUTO, the unit may change fan speeds based on the

requested heating or cooling capacity. In this mode, the unit fan will operate at LOW speed until the

requested capacity requires HIGH fan speed operation to maintain space comfort.

The fan mode request can be either hardwired or communicated

to the Tracer ZN.520 controller. When both are present, the communicated request has priority

over the hardwired input. Additional flexibility in the controller al-

lows the fan speed switch to be

disabled. When this occurs, the unit will operate at the default fan speed unless a communicated re-

quest is present.

During OCCUPIED, OCCUPIED

STANDBY, and OCCUPIED BYPASS

modes, the fan will normally operate continuously at the appropri-

ate fan speed. The fan will only be OFF in these modes when the MAN- UAL OUTPUT TEST has been initiat-

ed, a latching diagnostic is present, or the communicated or hardwired fan speed is OFF. (See

“Manual Output Test” on page48.for more information.)

During the UNOCCUPIED mode, the unit fan is controlled OFF. When capacity is required to maintain the

unoccupied heating or cooling setpoint, the unit fan is controlled to high speed regardless of a hard-

wired or communicated fan speed.

Table 21: Absolute two-speed fan switch points

Fan Speed

Absolute

Change

Temperature Error

Low to High

2.00

°F

High to Low

1.25

°F

 

 

 

Fan Off Delay

When a heating output is controlled off, the Tracer™ ZN.520

Unit Controller automatically holds the fan on for an additional 30 seconds. This 30-second delay

gives the fan time to blow off any residual heat from the heating source, such as a steam coil. When

the unit is heating, the fan off delay is normally applied to control the fan; otherwise, the fan off de-

lay does not apply.

Fan Start On High Speed

On a transition from off to any oth-

er fan speed, the Tracer™ ZN.520 Unit Controller automatically starts the fan on high speed and

runs the fan at high speed for 0.5

UV-SVP01A-EN

41

Unit Operation

seconds. This provides the ample torque required to start all fan motors from the off position.

Exhaust fan/damper operation

This binary point is a shared point with medium fan speed. For this

point to be used for exhaust control, the controller must be configured for a 1- or 2-speed fan. The

exhaust fan/damper is coordinated with the unit fan and outdoor damper operation. The exhaust

output is energized only when the unit fan is operating and the outdoor damper position is greater

than or equal to the configurable exhaust enable point. The exhaust fan output is disabled when the

outdoor air damper position drops 10% below the exhaust enable point. If the enable point is less

than 10%, the unit turns on at the enable point and off at 0.

Valve Operation

Modulating Valves

The Tracer ZN.520 controller supports one or two modulating valves for hydronic heating and

cooling operation. The main valve/ coil is used for cooling only, heat/ cool changeover (2-pipe applica-

tions), or cooling (4-pipe applications). The auxiliary valve/coil provides heating in 4-pipe and

heating only applications.

At power-up, the Tracer ZN.520

controller drives the modulating valves to the closed position. The controller calibrates to the full

closed position by overdriving the actuator 135%. Whenever the controller requests a valve position of

zero or 100%, the controller overdrives the actuator 135% regardless of the current valve position.

Face-and-Bypass

Isolation Valves

Face-and-bypass units may use

isolation valves to prevent unwanted water flow in the coil. This eliminates problems such as radiant

heat or excessive condensate in 2- pipe systems.

In 4-pipe applications, the isolation valves are used to prevent conflicting capacities within the unit.

Face-and-Bypass

Damper Operation

Note: The Face-and-bypass actuator is located in the right-

hand end pocket of the classroom unit ventilator.

The Tracer ZN.520 controller actuates a face-and- bypass damper to modulate a percentage of air to the

face of the coil to maintain space comfort. When a requested capacity is present, the unit modulates

the damper to allow more air to the face of the coil. An averaging sensor is used on the discharge air to

provide accurate capacity control.

Figure 18: Horizontal unit with face-and-bypass damper option.

42

UV-SVP01A-EN

Unit Operation

Figure 19: Vertical unit with face-and- bypass damper operations

Upon power-up, the controller cal-

ibrates the face-and-bypass damper to the full bypass position by overdriving the damper actuator.

During normal operation, whenever the Tracer ZN.520 controller generates a face-and-bypass

damper position request of zero or 100%, the unit calibrates the actuator by overdriving the damper ac-

tuator 135%.

Entering Water

Temperature Sampling

Units with 4-pipe changeover and 2-pipe changeover require an en-

tering water temperature to determine if the appropriate water temperature is present for the re-

quested mode (heating or cooling). This temperature may be communicated in an ICS system or

hardwired to the Tracer ZN.520

controller for standalone applications.

When a unit uses 2-way modulat-

ing valves, it is possible for the water near the entering water temperature sensor to migrate to-

wards ambient temperature. The Tracer ZN.520 controller has a water sampling feature for these ap-

plications. When the sensed water temperature is not sufficient for the requested heat/cool mode

(5°F above the zone temperature for heating or 5°F below the zone temperature for cooling), the con-

troller drives the valve fully open. The controller then monitors the water temperature until the appro-

priate temperature is sensed or until the three minute time limit expires. If the water temperature is

acceptable for the requested capacity, the unit continues normal operation. If the three minute tim-

er expires and the water temperature is still unsuitable, the unit closes the valve and waits one

hour before invoking the sampling feature again.

Table 22: Water assumption chart

Unit Configuration

Temperature

Assumed1

 

2-pipe Heating valve

Hot

2-pipe cooling valve

Cold

2-pipe H/C valve with

auto changeover enabled Hot

2-pipe H/C valve with

auto changeover Cold disabled

1. Assumption based on absence of a valid entering water temperature

Modulating Outdoor Air Operation

The Tracer ZN.520 controller oper-

ates a modulating (3-wire floating) outdoor air damper actuator according to the effective occupan-

cy, outdoor air temperature, space temperature, effective setpoint, discharge air temperature, and

discharge air temperature set-

point. Default minimum damper

positions are provided and can be changed for occupied and occupied standby modes, or for low

speed operation. The controller can also receive a communicated outdoor air damper minimum po-

sition from Tracer Summit. A communicated minimum position from Tracer Summit has priority

over all configured setpoints.

During the OCCUPIED mode the

outdoor air damper will always be controlled to the effective minimum position unless ASHRAE Cy-

cle I, ASHRAE Cycle II, or economizing modes are active.

Figure 20: OA/RA actuator mounting for the vertical unit ventilator

Figure 21: Figure 2: OA/RA actuator mounting for the horizontal unit ventilator

UV-SVP01A-EN

43

Unit Operation

Automatic Outdoor Air

Damper Adjustment

The Tracer ZN.520 controller is ca-

pable of using different minimum outdoor air damper positions for high and low fan speeds, which are

configurable. This allows the ventilation rate to be maintained when switching between fan speeds.

Note: The typical reduction in airflow between high and low

fan speeds is 25%, however, if precise control is desired, an air balancer should be

consulted.

Economizer

Operation

Note: When there is a request

for 0% or 100% actuator position, the actuator will overdrive the actuator 135% to

help maintain calibration.

With a valid outdoor air tempera-

ture (hardwired or communicated), Tracer ZN.520 uses the modulating economizer damper as the highest

priority source of cooling.

The controller initiates the econo-

mizer function if the outdoor air temperature is cold enough to be used for free cooling capacity. If

the outdoor air temperature is less than the economizer enable setpoint (absolute dry bulb), the con-

troller modulates the outdoor air damper between the minimum position and 100% to control the

amount of cooling capacity. When the outdoor air temperature rises 5°F above the economizer enable

setpoint, the outdoor air damper returns to its minimum position and mechanical cooling is initiated.

ASHRAE Cycle I

ASHRAE Cycle I admits 100% outdoor air except during the warm up

cycle or the unoccupied mode. To set up the Tracer ZN.520 controller for ASHRAE Cycle I conformance,

set the occupied outdoor air damper minimum position to 100%.

ASHRAE Cycle II

The Tracer ZN.520 controller con-

forms to ASHRAE Cycle II by allowing the modulating outdoor air damper to maintain a minimum

position during the occupied mode unless economizing is enabled or the space temperature falls more

than 3°F below the effective setpoint.

If the space temperature falls more than 2°F below the setpoint, the outdoor air damper will begin to

close. When the space temperature hits 3°F below the setpoint, the outdoor air damper is completely

closed.

Figure 22: ASHRAE cycle 2

DX Operation

Tracer ZN.520 supports direct expansion (DX) compressor operation for cooling only.

The controller does not allow both the DX compressor and economiz-

er to operate at the same time. This prevents problems where the entering air temperature is too low

for the evaporator coil to operate as designed.

Tracer ZN.520 also includes a fixed minimum on/off time of 3 minutes for compressor operation to pre-

vent short cycling of the compressor.

Electric Heat Operation

The Tracer ZN.520 controller supports 1 or 2 stages of electric heat

control.

To control space temperature,

electric heat is cycled to control the discharge air temperature. The rate of cycling is dependent on the load

in the space and the temperature of the incoming fresh air.

Baseboard Heat Operation

The Tracer ZN.520 controller can be configured to support one stage of baseboard heat. A 2 position

valve or an electric heat contactor will be energized at 2.5°F below the effective heating setpoint. The

baseboard heat is de-energized at 1°F below the effective heating setpoint.

The unit will provide heating capacity as required regardless of the

presence of baseboard heat. If the unit can not maintain the space temperature, the baseboard heat

will come on as a secondary stage.

If baseboard heat is to be used as

the primary source of heating, the discharge air high limit should be set to a moderate temperature.

This will allow the ventilation air to be tempered and avoid a “drafty” feeling. The baseboard heat will

then operate as the heating capacity for the space.

In the UNOCCUPIED mode, the baseboard heat and unit heating capacity are brought on simulta-

neously as needed to maintain the unoccupied setpoint.

Exhaust Fan

Operation

The exhaust fan is coordinated with the unit fan and outdoor air damper operation. The exhaust fan

output is energized only when the unit fan is operating and the outdoor air damper position is greater

44

UV-SVP01A-EN

Unit Operation

than or equal to the configurable

exhaust enable setpoint. This is useful for exhaust fans designed to offset the added economizer

ventilation.

The exhaust fan is disabled when

the outdoor air damper position drops 10% below the exhaust enable point. If the exhaust fan en-

able setpoint is less than 10%, the Tracer ZN.520 controller energizes the exhaust fan at the enable point

and disables it when the outdoor air damper closes.

Output Overrides

Manual Output Test

Manual output test allows the bi-

nary outputs to be energized in a predefined sequence.(For more information see, Manual Output

Test, on page 48 for more information.)

Water Valve Override

To enable quicker water balancing, the controller allows a user to specify the desired state of all wa-

ter valves. The values supported are:

qOpen all valves

qClose all valves

The valves in the system will remain open for two hours or until

normal operation is resumed.

The Tracer Summit or the Rover

service tool is required to access this feature.

Fan Status

There are two ways to do fan status monitoring:

1.The status of the fan is

reported based on the state of the binary output(s) dedicated to fan control. The fan status

is reported as HIGH or LOW whenever the corresponding binary output is directed ON.

The fan status is reported as

OFF when none of the fan outputs are directed ON.

2.The Tracer ZN.520 controller has a binary input available

for a fan status device (current sensing relay or differential pressure switch) which can

provide feedback of fan operation. If the device does not indicate fan operation after 1

minute, a unit shutdown is initiated, and the unit is latched

OFF.

Filter Status/ Maintenance Timer

The unit filter status\maintenance timer is based on the cumulative

run hours of the unit fan. The controller compares the fan run time against an adjustable fan run hour

limit and recommends unit maintenance as required.

The Rover service tool is used to edit the maintenance required setpoint time. Once the setpoint limit

is exceeded, the controller gener-

ates a MAINTENANCE REQUIRED infor-

mational diagnostic. When the

maintenance required setpoint time is set to zero, the controller disables this feature.

You can use the Trace Summit or the Rover service tool to clear the

MAINTENANCE REQUIRED informa-

tional diagnostic. Once the diagnostic is cleared, the controller

resets the fan run time to zero and begins accumulating fan run hours again.

Note: If at any time the unit loses power, the timer is reset

to zero.

Other Modes

DEHUMIDIFICATION

Note: If the unit is in the unoccupied mode, the

dehumidification routine will not operate

Dehumidification is possible when

mechanical cooling is available; the heating capacity is in the reheat position; and the space rela-

tive humidity setpoint is valid.

The controller starts dehumidify-

ing the space when the space humidity exceeds the humidity setpoint. The controller continues

to dehumidify until the sensed humidity falls below the setpoint minus the relative humidity offset.

The controller uses the cooling and reheat coils simultaneously to

dehumidify the space. When dehumidifying, the discharge air temperature is controlled to main-

tain the space temperature at the current setpoint.

Economizing is disabled during the dehumidification mode.

Note: While in the dehumidification mode, if there is a call for capacity by

the unit, the zone temperature setpoint will take priority over the relative humidity

setpoints.

DEFROST

For defrost operation, a sensor is

wired in series with the DX cooling relay. When a defrost condition is detected, the condensing unit is

disabled, and the unit is placed in the DEFROST mode.

During DEFROST the condensing unit is OFF the outside air damper is set to the minimum positions,

and the fan will continue to operate as continuous. The unit will remain in the DEFROST mode until

the senor resets at 48°F. The unit will return to NORMAL operation after the mode is discontinued.

FREEZE AVOIDANCE

FREEZE AVOIDANCE is used as low

ambient temperature protection,

and is only invoked when the fan is OFF. This includes the UNOCCUPIED mode when there is no call for ca-

pacity, or any other time the fan is

UV-SVP01A-EN

45

Unit Operation

OFF due to a safety or command. The controller enters the FREEZE AVOIDANCE mode when an out-

door air temperature is present (communicated or hardwired) and it is below the freeze avoidance set-

point (configurable). The controller disables freeze avoidance when the outdoor air temperature rises

3°F above the freeze avoidance setpoint.

When the controller is in the freeze avoidance mode:

qAll water valves are driven open to allow water flow through the coil

qFan is OFF

qFace-and-bypass damper (when present) is in full BYPASS

qDX and electric heat are OFF

MORNING WARM-UP

The Tracer ZN.520 controller keeps

the modulating outdoor air damper closed anytime during the OCCU- PIED mode when the space

temperature is 3°F or more below the heating setpoint.

Figure 23: Simple data sharing application

The damper remains closed indefinitely during morning warm-up until the space temperature is with-

in 2°F of the effective heating setpoint. The unit runs at full capacity until setpoint is met.

COOL-DOWN

The Tracer ZN.520 controller keeps the modulating outdoor air damp-

er closed for up to one hour at every transition from UNOCCUPIED to OCCUPIED mode when the space

temperature is 3°F or more above the cooling setpoint.

The damper remains closed during cool-down until the space temperature is within 2°F of the effective

cooling setpoint. The unit runs at full capacity until setpoint is met.

Data Sharing—LonWorks

Tracer ZN.520 allows peer-to-peer data communication through the use of LonWork’s technology. Data

such as space temperature setpoint, occupancy, etc. can be shared from a master controller to

a peer controller over a twisted pair of communication wire with or without the presence of a front end

building management system.

(See Figure 23: “Simple data sharing application”) This ability al-

lows units to operate with the same data to prevent conflicting control.

Data sharing is established through the use of “bindings”.

Bindings are set up through the Rover service tool.

The Tracer ZN.520 controller includes a network variable for master/slave operation. This variable

includes all of the information required for the slave units to operate with master controller. (See

Figure 24: “More complex data sharing application”)

For more information on establishing bindings, see the Rover service tool manual. For a complete listing

on shared points see “Appendix— Data Lists” on page64.

46

UV-SVP01A-EN

Unit Operation

Figure 24: More complex data sharing application

UV-SVP01A-EN

47

Troubleshooting

Important! When viewing the Tracer ZN.520 through the Rover service tool, it is important that the version be up-to-date. To help ensure that your version is the most recent, contact you local Trane sales representative or service center.

The Service push button, located at the bottom center of the controller, can be used to install the Tracer™ ZN.520 Unit Controller in a communication network. Refer to the Rover and Tracer Summit product literature for more information.

Led Operation

Red Service LED

Table 23: Red service LED activity

Red LED

Description

activity

LED is OFF continuously

after power is Normal operation. applied to the

controller.

LED is ON

continuously,

Someone is pressing the

even when

Service push button or

power is first

the controller has failed.

applied to the controller.

Un-install (normal controller mode). Use

Rover service tool to

LED flashes

restore the unit to

about once

normal operation. Refer

every second.

to the Rover product literature for more information.

Black Service Push

Button

Note: If the Service push button is held down for more than 15 seconds, the Tracer™ ZN.520 Unit Controller will uninstall itself from the ICS communication network and shut down all unit operation. This mode is indicated by the red Service LED flashing once every second. See the Red Service LED section. Use Rover service tool to restore the unit to normal operation.

Figure 25: Black service button

Green Status LED

The green LED normally indicates whether or not the controller is powered on (24 VAC).

Table 24: Green status LED activity

Green LED

Description

activity

 

 

 

LED is ON

Power ON (normal

continuously.

operation).

 

 

LED blinks (1 blink

The controller is in

per second).

manual output test

 

mode.

 

No diagnostics

 

present.

 

 

LED blinks (2

The controller is in

blinks per second).

manual output test

 

mode.

 

One or more

 

diagnostics are

 

present.

 

 

LED blinks (1/4

Wink mode.

second on, 1/4

 

second off for 10

 

seconds).

 

 

 

LED OFF.

Power is off.

 

Controller failure.

 

Test button is

 

pressed.

 

 

Yellow Comm LED

The yellow Comm LED blinks at the rate the controller receives communication. The yellow LED does not blink when the controller is transmitting communication data.

Table 25: Yellow comm LED activity

Yellow LED

Description

activity

 

 

 

LED OFF

The controller is not

continuously.

detecting any

 

communication. (Normal

 

for standalone

 

applications.)

 

 

LED blinks or

The controller detects

flickers.

communication. (Normal

 

for communicating

 

applications, including

 

data sharing.)

 

 

LED ON

Abnormal condition or

continuously.

extremely high traffic on

 

the link.

 

 

Manual Output Test

The test sequence verifies output and end device operation. The manual output test can be conducted to verify output wiring and actuator operation, without using the Rover service tool, by pressing the test button.

Figure 26: Blue test button

Many service calls are initiated due to unit diagnostics, so the test sequence attempts to clear unit diagnostics and restore normal unit operation prior to testing the outputs. If the diagnostics remain after an attempt to clear diagnostics, the status LED lights in a two-blink pattern, indicating the diagnostic condition is still present.

48

UV-SVP01A-EN

Troubleshooting

If a two-blink pattern remains after an attempt to clear diagnostics, the diagnostic condition is still present and may affect the manual output test. The diagnostic must then be cleared using another method. (See “Resetting Diagnostics” on

page 54.for more information.)

Test Procedure

The procedure for testing is:

1.Press and hold the Test button for at least two seconds, then

release the button to start the test mode.

2.When manual output test mode begins, the controller turns off all outputs and calibrates modulating end devices closed.

3.Press the Test button once to advance through the test sequence.

Note: To help ensure accurate testing do not press the test button more than once per second.

Alternatively, the manual output test can be controlled over the communications network by using Rover.

When conducting the manual output test via communications network, the sequence must start with Step 1 (OFF), as shown in Table 26: Test sequence for non face-and-bypass unit configurations and Table 27: Test sequence for face-and-bypass unit configura-

tions However, subsequent steps may be conducted in any order.

Table 26: Test sequence for non face-and-bypass unit configurations

 

 

 

 

DX, or cool or

Face-and-

Electric heat, or

Outdoor air

Generic/

Step

 

Fan

 

heat/cool changeover

baseboard

 

 

bypass damper

 

heat valve

damper

 

 

 

 

 

valve

 

heat

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J1-1

J1-2

J1-3

J1-5

 

J1-6

J1-7

J1-8

J1-9

 

J1-10

J1-11

J1-12

TB4-1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1: Off1

Off

Off

Off

Off

 

On

NA

NA

Off

 

Hydronic: on

Off

On

Off

 

 

EH: off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2: Fan high2

High

Off

Off

Off

 

Off

NA

NA

Off

 

Off

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3: Fan med3

Off

Med

Off

Off

 

Off

NA

NA

Off

 

Off

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4: Fan low4

Off

Off

Low

Off

 

Off

NA

NA

Off

 

Off

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5: Main open,

High

Off

Off

On

 

Off

NA

NA

Off

 

Off

Off

Off

Off

DX on

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6: Main close,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DX off, aux

High

Off

Off

Off

 

On

NA

NA

On

 

Off

Off

Off

Off

open, EH1 on

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7: Aux open,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EH1 on, exhaust

High

Exh

Off

Off

 

Off

NA

NA

On

 

Off

Off

Off

Off

fan5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8: Aux close,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EH1 off, EH2 on,

High

Off

Off

Off

 

Off

NA

NA

Off

 

On

On

Off

Off

damper open

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9: Damper close

High

Off

Off

Off

 

Off

NA

NA

Off

 

Off

Off

On

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10: Generic /

 

 

 

 

 

 

 

 

 

 

 

 

 

 

baseboard heat

High

Off

Off

Off

 

Off

NA

NA

Off

 

Off

Off

Off

On

energized

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11: Exit6

 

 

 

 

 

 

 

Exit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.Upon entering manual output test mode, the controller turns off all fan, DX, and electric heat outputs and drives all dampers and valves closed (if required).

2.At the beginning of step 2, the controller attempts to clear all diagnostics.

3.If the unit is configured for a 3-speed fan, the medium fan speed output will energize at step 3. If the unit is configured for a 2-speed fan,

the fan remains on high speed at step 3.

4.If the unit is configured for a 3-speed fan, the medium fan speed output energizes at step 3. If the unit is configured for a 2-speed fan, the low fan speed output energizes at step 3. If the unit is configured for a 1-speed fan, the fan remains on high speed at step 3.

5.If the unit is configured for a 1- or 2-speed fan, the exhaust fan output energizes on step 7. The exhaust fan output is shared with medium fan speed.

6.After step 10, the test sequence performs an exit. This initiates a reset and attempts to return the controller to normal operation

UV-SVP01A-EN

49

Troubleshooting

.

Table 27: Test sequence for face-and-bypass unit configurations

 

 

 

 

DX, or cool or heat/

Face-and-

Electric heat,

Outdoor air

Generic/

Step

 

Fan

 

baseboard

 

 

cool changeover valve

bypass damper

or heat valve

damper

 

 

 

 

heat

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J1-1

J1-2

J1-3

J1-5

J1-6

J1-7

 

J1-8

J1-9

J1-10

J1-11

J1-12

TB4-1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1: Off1

Off

Off

Off

Off

NA

Off

 

On

Off

NA

Off

On

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2: Fan high2

High

Off

Off

Off

NA

On

 

Off

Off

NA

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3: Fan med3

Off

Med

Off

Off

NA

On

 

Off

Off

NA

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4: Fan low4

Off

Off

Low

Off

NA

On

 

Off

Off

NA

Off

Off

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5: Main open,

High

Off

Off

On

NA

On

 

Off

Off

NA

Off

Off

Off

DX on

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6: Main close,

 

 

 

 

 

 

 

 

 

 

 

 

 

DX off, aux

High

Off

Off

Off

NA

On

 

Off

On

NA

Off

Off

Off

open

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7: Aux open,

High

Exh

Off

Off

NA

On

 

Off

On

NA

Off

Off

Off

exhaust fan5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8: Aux close,

High

Off

Off

Off

NA

Off

 

On

Off

NA

On

Off

Off

damper open

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9: Outdoor air

High

Off

Off

Off

NA

Off

 

On

Off

NA

Off

On

Off

damper close

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10: Generic /

 

 

 

 

 

 

 

 

 

 

 

 

 

baseboard heat

High

Off

Off

Off

NA

Off

 

On

Off

NA

Off

Off

On

energized

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11: Exit6

 

 

 

 

 

Exit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.Upon entering manual output test mode, the controller turns off all fan outputs and drives all dampers and valves closed (if required).

2.At the beginning of step 2, the controller attempts to clear all diagnostics.

3.If the unit is configured for a 2-speed fan, the fan remains on high speed at step 3.

4.If the unit is configured for a 2-speed fan, the low fan speed output energizes at step 3. If the unit is configured for a 1-speed fan, the fan remains on high speed at step 3.

5.If the unit is configured for a 1- or 2-speed fan, the exhaust fan output energizes on step 7. The exhaust fan output is shared with medium

fan speed.

6. After step 10, the test sequence performs an exit. This initiates a reset and attempts to return the controller to normal operation.

UV-SVP01A-EN

50

Troubleshooting

Safeties

Freeze Protection

The Tracer ZN.520 controller has two methods of freeze protection.

1.An optional binary freezestat that is wired to a binary input. The freezestat is a capillary tube type and is factory set to 35 °F. When this device opens, a “Low Coil Temp Detect” diagnostic is generated.

2.Using the discharge air temperature sensor, if the discharge air temperature falls below the discharge air low limit, the controller increases the heating capacity to temper the air. If the discharge air temperature remains below the discharge air low limit for 3 minutes, the controller generates a “Low Coil Temp Detect” diagnostic.

Fan Failure

A “Low Air Flow—Fan Failure” diagnostic is generated when a fan status device is present and fails to close after 1 minute of unit start-up or when it opens for more than 1 minute during normal unit operation.

Space Temperature

Failure

If the Tracer ZN.520 has validated a space temperature input and then the input becomes invalid, a space temperature failure diagnostic occurs.

Entering Water

Temperature Failure

If the Tracer ZN.520 has validated an entering water temperature input and then the input becomes invalid, an entering water temperature failure diagnostic occurs.

Discharge Air

Temperature Limit

When the discharge air exceeds the high or low limit setpoint and the unit can not correct it by altering capacity, a “Discharge Air Temp Limit” diagnostic is generated.

Outdoor Air Temperature

Failure

If the Tracer ZN.520 has validated an outdoor air temperature input and then the input becomes invalid, an outdoor air temperature failure diagnostic occurs.

Humidity Input Failure

If the Tracer ZN.520 has validated a relative humidity input and then the input becomes invalid, a humidity input failure diagnostic occurs.

CO Sensor Failure

2

If the Tracer ZN.520 has validated a CO2 input and then the input be-

comes invalid, a CO input failure

2

diagnostic occurs.

Generic AIP Failure

If the Tracer ZN.520 has validated a generic analog input and then the input becomes invalid, a generic analog input failure diagnostic occurs.

Defrosting-Compressor

Lockout

The defrost stat used with Tracer ZN.520 on DX units is wired in series with the condensing unit.

When it opens to indicate a frost condition, the Tracer ZN.520 senses the open circuit and de-energiz- es the condensing unit output. A defrosting diagnostic is generated at this point.

Maintenance Required

Note: If power to the unit is cycled or discontinued for any reason, all maintenance timers are automatically reset.

The “Maintenance Required” diagnostic is generated when the fan run-time exceeds the configurable limit. This diagnostic is useful for filter change notification.

Local Fan Mode Failure

If the hardwired fan mode input to the Tracer ZN.520 controller is present and then becomes invalid, a local fan mode failure diagnostic is generated.

Local Setpoint Failure

If the hardwired setpoint input to the Tracer ZN.520 controller is present and then becomes invalid, a local setpoint failure diagnostic is generated.

Generic Temperature

Failure

If the Tracer ZN.520 has validated a generic temperature input and then the input becomes invalid, a generic temperature input failure diagnostic occurs.

Invalid Unit

Configuration

If the Tracer ZN.520 has been configured improperly or loses its configuration, an invalid unit configuration diagnostic is generated. The unit must be re-configured with a valid configuration to correct this problem.

UV-SVP01A-EN

51

Troubleshooting

Diagnostics

Table 28: Tracer™ ZN.520 Unit Controller diagnostics

Diagnostic

Unit Response

Latching/non-

Reset

latching

 

 

 

 

 

 

 

 

 

 

 

 

Fan—OFF

 

Auto reset once within 24hrs. If

 

Valves—OPEN

 

 

 

safety generates a diagnostic

Low Coil Temperature

Outdoor air damper—CLOSED

 

Latching

more than once a communi-

Detect2

Face bypass damper—BYPASS

 

cated or manual reset will be

 

DX/electric heat—OFF

 

 

 

necessary.

 

Baseboard heat—OFF

 

 

 

 

 

 

 

 

 

Fan—OFF

 

 

 

Valves—CLOSED

 

 

Low Air Flow - Fan Failure2

Outdoor air damper—CLOSED

Latching

Communicated or manual reset

Face bypass damper—BYPASS

 

 

 

 

DX/electric heat—OFF

 

 

 

Baseboard heat—OFF

 

 

 

 

 

 

 

Fan—OFF

 

 

 

Valves—CLOSED

 

 

Space Temperature

Outdoor air damper—CLOSED

Non-latching

Communicated or manual reset

Failure2,4

Face bypass damper—BYPASS

 

 

 

DX/electric heat—OFF

 

 

 

Baseboard heat—OFF

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED3

 

 

Entering Water Temp

Outdoor air damper—ENABLED3

Non-latching

Communicated or manual reset

Failure4

Face bypass damper—ENABLED3

 

 

 

DX/electric heat—ENABLED3

 

 

 

Baseboard heat—OFF

 

 

 

 

 

 

 

Fan—OFF

 

Auto reset once within 24hrs. If

 

Valves—OPEN

 

 

 

safety generates a diagnostic

 

Outdoor air damper—CLOSED

 

Discharge Air Temp Limit2

Latching

more than once a communi-

Face bypass damper—BYPASS

 

 

cated or manual reset will be

 

DX/electric heat—OFF

 

 

 

necessary.

 

Baseboard heat—OFF

 

 

 

 

 

 

 

 

 

Fan—OFF

 

 

 

Valves—CLOSED

 

 

Discharge Air Temp

Outdoor air damper—CLOSED

Non-latching

Communicated or manual reset

Failure2,4

Face bypass damper—BYPASS

 

 

 

DX/electric heat—OFF

 

 

 

Baseboard heat—OFF

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

 

Outdoor air damper—MINIMUM

 

 

Outdoor Air Temp Failure4

POSITION5

Non-latching

Communicated or manual reset

 

Face bypass damper—ENABLED

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

UV-SVP01A-EN

52

Troubleshooting

Table 28: Tracer™ ZN.520 Unit Controller diagnostics

Diagnostic

Unit Response

Latching/non-

Reset

latching

 

 

 

 

 

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Humidity Input Failure4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

CO2 Sensor Failure4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Generic AIP Failure4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Defrosting - Cmpr Lockout4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—OFF

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Maintenance Required

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Local Fan Mode Failure4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/Electric Heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Local Setpoint Failure4

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

 

Fan—ENABLED

 

 

 

Valves—ENABLED

 

 

Generic Temperature

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Failure

Face bypass damper—ENABLED

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

UV-SVP01A-EN

53

Troubleshooting

Table 28: Tracer™ ZN.520 Unit Controller diagnostics

Diagnostic

Unit Response

Latching/non-

Reset

latching

 

 

 

 

 

 

 

 

 

 

 

 

Fan—DISABLED

 

 

 

Valves—DISABLED

 

 

Invalid Unit Configuration2

Outdoor air damper—DISABLED

Non-latching

Communicated or manual reset

Face bypass damper—DISABLED

 

 

 

 

DX/electric heat—DISABLED

 

 

 

Baseboard heat—DISABLED

 

 

 

 

 

 

 

Fans—ENABLED

 

 

 

Valves—ENABLED

 

 

Normal

Outdoor air damper—ENABLED

Non-latching

Communicated or manual reset

Face bypass damper—ENABLED

 

 

 

 

DX/electric heat—ENABLED

 

 

 

Baseboard heat—ENABLED

 

 

 

 

 

 

Note1: The generic binary output (TB4-1, TB4-2) state is unaffected by all unit diagnostics.

Note2: During manual output test, these diagnostics make the green status LED light in a two-blink pattern. For more information see, Manual Output Test, on page 48 for more information.)

Note3: When the entering water temperature is required but not present, the Tracer™ ZN.520 Unit Controller generates a diagnostic to indicate the sensor loss condition. The controller automatically clears the diagnostic once a valid entering water temperature value is present (non-latching diagnostic). When the entering water temperature sensor fails, the controller prohibits all hydronic cooling operation, but allows the delivery of heat when heating is required. In the COOL mode, all hydronic cooling is locked-out, but normal fan and outdoor air damper operation is permitted.

Note4: These diagnostics are non-latching and automatically reset when the input is present and valid.

Note5: When the outdoor air temperature sensor has failed or is not present, the Tracer™ ZN.520 Unit Controller generates a diagnostic to indicate the sensor loss condition. The controller automatically clears the diagnostic once a valid outdoor air temperature value is present (non-latching diagnostic). When the outdoor air temperature sensor fails or is not present, the controller prohibits economizer operation. A value of Enable or Disable for nviEconEnable overrides these decisions, regardless of the presence of an outdoor air temperature value or failure.For more information see, Interoperability, on page 12 for more information.)For more information see, Data Sharing—LonWorks, on page 46 for more information.)

Translating Multiple Diagnostics

The controller senses and records each diagnostic independently of other diagnostics. It is possible to have multiple diagnostics present simultaneously. The diagnostics are reported in the order they occur.

Resetting

Diagnostics

There are many ways to reset unit diagnostics:

qBy cycling the fan switch from off to any speed setting

Automatically

The Tracer™ ZN.520 Unit Controller includes an automatic diagnostic reset function. This function attempts to automatically recover a unit when the Low Coil Temperature Detection diagnostic occurs. When this diagnostic occurs, the controller responds as defined in

Table 28: Tracer™ ZN.520 Unit Controller

diagnostics.

qAutomatically by the controller

qBy initiating a manual output test at the controller

qBy cycling power to the controller

qBy using a building automation system

qBy using the Rover service tool

After the controller detects the Low Coil Temperature Detection diagnostic, the unit waits 30 minutes before invoking the automatic diagnostic reset function. The automatic diagnostic reset function clears the Low Coil Temperature Detection diagnostic and attempts to restore the controller to normal operation. The controller resumes normal operation until another di-

agnostic occurs.

If a Low Coil Temperature Detection diagnostic recurs within 24 hours after an automatic diagnostic reset, you must manually reset the diagnostic. See other possible methods for resetting diagnostics in this section.

Manual output test

The TEST button on the controller may be used either during installation to verify proper end device operation or during troubleshooting. When depressed, the Test button, the controller exercises all outputs in a predefined sequence. The first and last steps of the sequence reset the controller diagnostics. (See “Manual Output Test” on

page 48.for more information.)

Cycling power

When turned-off, the controller's 24 VAC power, and re-applies

UV-SVP01A-EN

54

Troubleshooting

power, the unit cycles through a power-up sequence and clears all timers.

By default, the controller attempts to reset all diagnostics at powerup. Diagnostics present at powerup and those that occur after pow- er-up are handled according to the defined unit diagnostics sequences (For more information see,Table

28: Tracer™ ZN.520 Unit Controller diag-

nostics, on page 52 for more information.).

Building automation system

Some building automation sys-

tems (i.e., Tracer Summit building automation system) can reset diagnostics in the Tracer™ ZN.520 unit controller. For more complete information, refer to the product literature for the building automation system.

Rover service tool

Rover service tool can reset diagnostics in the Tracer™ ZN.520 unit controller. For more complete information, refer to the Rover Installation, Operation, and Programming manual.

Diagnostic reset

Any device that can communicate the network variable nviRequest (enumeration “clear_alarm”) can reset diagnostics in the Tracer™ ZN.520 unit controller. The controller also attempts to reset diagnostics whenever power is cycled.

Cycling the fan switch

If the user cycles the fan speed switch from OFF to any speed, the controller resets all diagnostics. Diagnostics may recur immediately if the problem still exists.

Questionable unit operation

Fans

Table 29: Fan outputs do not energize

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the fan relays and contacts must be present and correct

for normal fan operation.

 

 

 

 

If the controller does not have power, the unit fan does not operate. For the Tracer™ ZN.520 Unit

No power to the controller

Controller to operate normally, it must have an input voltage of 24 VAC. When the green LED is off

 

continuously, the controller does not have sufficient power or has failed.

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the fans may not work correctly.

 

 

 

Random-start observed

After power-up, the controller always observes a random-start from 5 to 30 seconds. The controller

remains off until the random-start time expires.

 

 

 

 

When power-up control wait is enabled (non-zero time), the controller remains off until one of two

Power-up control

conditions occurs:

 

wait

1. The controller exits power-up control wait once it receives communicated information.

 

2. The controller exits power-up control wait once the power-up control wait time expires.

 

 

Diagnostic present

A specific list of diagnostics affects fan operation. For more information see, Tracer™ ZN.520 Unit

Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the unit fan may not

 

be on. For more information see, Manual Output Test, on page 48 for more information.)

 

 

Fan mode OFF

When a local fan mode switch (provided on the Trane zone sensor) determines the fan operation, the

off position controls the unit OFF.

 

 

 

Requested mode OFF

You can communicate a desired operating mode (such as OFF, HEAT, and COOL) to the controller. When

OFF is communicated to the controller, the unit controls the fan OFF. There is no heating or cooling.

 

 

 

UNOCCUPIED operation

When the controller is in the UNOCCUPIED mode, the fan is cycled.

 

 

 

The controller operates the fan continuously when in the OCCUPIED, OCCUPIED STANDBY, or OCCUPIED

Cycling fan operation/continuous

BYPASS mode. When the controller is in the unoccupied mode, the fan is cycled between HIGH speed and

 

OFF with capacity.

UV-SVP01A-EN

55

Troubleshooting

Valves

Table 30: Valves stay closed

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the valve(s) must be present and correct for normal

valve operation.

 

 

 

Random-start observed

After power-up, the controller always observes a random-start from 5 to 30 seconds. The controller

remains off until the random-start time expires.

 

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the valves may not work correctly.

 

 

 

 

When power-up control wait is enabled (non-zero time), the controller remains off until one of two

Power-up control

conditions occurs:

wait

The controller exits power-up control wait once it receives communicated information.

 

The controller exits power-up control wait once the power-up control wait time expires.

 

 

Diagnostic present

A specific list of diagnostic affects valve operation. For more information see, Tracer™ ZN.520 Unit

Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the valve(s) may not

 

be open. For more information see, Manual Output Test, on page 48 for more information.)

 

 

Fan mode off

When a local fan mode switch (provided on the Trane zone sensor) determines the fan operation, the

off position controls the unit off and valves to close.

 

 

 

 

You can communicate a desired operating mode (such as OFF, HEAT, and COOL) to the controller. When

Requested mode off

OFF is communicated to the controller, the unit controls the fan OFF. There is no heating or cooling

 

(valves are closed).

 

 

 

The controller includes entering water temperature sampling logic which is automatically invoked

 

during 2-pipe and 4-pipe changeover when the entering water temperature is either too cool or too hot

 

for the desired heating or cooling. For more information see, Entering Water Temperature Sampling,

Sampling logic

on page 43 for more information.)

Example: A 2-pipe heat/cool changeover unit will not cool if the entering water temperature is too

 

 

warm for cooling or if the entering water sensor is not present. The unit will not heat if the entering

 

water temperature is too cool for heating. If failed the controller will close valve for one hour then

 

reattempt sampling routine.

 

 

Table 31: Valves stay open

 

 

 

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the valve(s) must be present and correct for normal

valve operation.

 

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the valves may not work correctly.

 

 

 

Diagnostic present

A specific list of diagnostic affects valve operation. For more information see, Tracer™ ZN.520 Unit

Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the valve(s) may be

 

open.For more information see, Manual Output Test, on page 48 for more information.)

 

 

 

The controller includes entering water temperature sampling logic which automatically invoked during

Sampling logic

2-pipe and 4-pipe changeover when the entering water temperature is either too cool or too hot for the

desired heating or cooling. For more information see, Entering Water Temperature Sampling, on page

 

 

43 for more information.)

 

 

UV-SVP01A-EN

56

Troubleshooting

Table 31: Valves stay open

Probable cause

Possible Explanation

When the fan is off with no demand for capacity (0%) and the outdoor air temperature is below the Freeze avoidance freeze avoidance setpoint, the controller opens the water valves (100%) to prevent coil freezing. This

includes unoccupied mode when there is no call for capacity or any other time the fan is off.

Normal operation

The controller opens and closes the valves to meet the unit capacity requirements.

DX/Electric Heat

Table 32: DX or electric output(s) does not energize

Probable cause

Possible Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the end devices must be present and correct for normal

operation.

 

 

 

Unit configuration

The controller must be properly configured based on the actual installed end devices and application.

When the unit configuration does not match the actual end devices, the unit may not work correctly.

 

 

 

Diagnostic present

A specific list of diagnostics affect compressor and electric heat operation. For more information see,

Tracer™ ZN.520 Unit Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the DX or electric

 

outputs may be OFF. For more information see, Manual Output Test, on page 48 for more information.)

 

 

 

When the fan is OFF with no demand for capacity (0%) and the outdoor air temperature is below the

Freeze avoidance

freeze avoidance setpoint, the controller disables compressors and electric heat outputs. This includes

 

UNOCCUPIED mode when there is no call for capacity or any other time the fan is OFF.

 

 

Normal operation

The controller energizes the outputs only as needed to meet the unit capacity requirements.

 

 

Outside Air Damper

Table 33: Outdoor air damper stays closed

Probable cause

 

Explanation

 

 

 

 

Unit wiring

The wiring between the controller outputs and the outdoor air damper must be present and correct for

normal damper operation.

 

 

 

 

The controller must be properly configured based on the actual installed end devices and application.

Unit configuration

When the unit configuration does not match the actual end devices, the damper may not work

 

correctly.

 

 

Random-start observed

After power-up, the controller always observes a random-start from 5 to 30 seconds. The controller

remains OFF until the random-start time expires.

 

 

 

 

When power-up control wait is enabled (non-zero time), the controller remains OFF until one of two

 

conditions occurs:

Power-up control wait

1.

The controller exits power-up control wait once it receives communicated information.

 

 

2.

The controller exits power-up control wait once the power-up control wait time expires.

 

 

Diagnostic present

A specific list of diagnostics affects outdoor air operation. For more information see, Tracer™ ZN.520

Unit Controller diagnostics, on page 52 for more information.)

 

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the unit damper

 

may not be open. For more information see, Manual Output Test, on page 48 for more information.)

 

 

Fan mode OFF

When a local fan mode switch (provided on the Trane zone sensor) determines the fan operation, the

OFF position controls the unit OFF and damper to close.

 

UV-SVP01A-EN

57

Troubleshooting

Table 33: Outdoor air damper stays closed

Probable cause

Explanation

 

 

 

 

 

 

You can communicate a desired operating mode (such as OFF, HEAT, and COOL) to the controller. When

 

Requested mode OFF

OFF is communicated to the controller, the unit controls the fan OFF. There is no heating or cooling

 

(valves are closed).

 

 

 

When the fan is OFF and the outdoor air temperature is below the freeze avoidance setpoint, the

Freeze avoidance

controller disables economizing and keeps the outdoor air damper closed. This includes UNOCCUPIED

 

mode when there is no call for capacity or any other time the fan is OFF.

 

 

UNOCCUPIED mode

When the controller is in the UNOCCUPIED mode, the outdoor air damper remains closed unless

economizing is enabled.

 

 

 

 

The controller includes both a morning warm up and cool-down sequence to keep the outdoor air

Warm up and cool-down

damper closed during the transition from UNOCCUPIED to OCCUPIED. This is an attempt to bring the

 

space under control as quickly as possible.

 

 

 

The controller opens and closes the outdoor air damper based on the controller's occupancy mode and

 

fan operation. Normally, the outdoor air damper is open during OCCUPIED, OCCUPIED STANDBY, and

Normal operation

OCCUPIED BYPASS mode when the fan is running and closed during UNOCCUPIED mode unless the

 

controller is economizing. For more information see, Modulating Outdoor Air Operation, on page 43 for

 

more information.)

 

 

 

Table 34: Outdoor air damper stays open

 

 

Probable Cause

Explanation

 

 

 

 

 

 

Unit wiring

The wiring between the controller outputs and the outdoor air damper must be present and correct for

normal damper operation.

 

 

 

 

The controller must be properly configured based on the actual installed end devices and application.

Unit configuration

When the unit configuration does not match the actual end devices, the damper may not work

 

correctly.

 

 

 

The controller includes a manual output test sequence you can use to verify output operation and

Manual output test

associated output wiring. However, based on the current step in the test sequence, the unit damper

 

may be open. For more information see, Manual Output Test, on page 48 for more information.)

 

 

 

The controller opens and closes the outdoor air damper based on the controller's occupancy mode and

 

fan operation. Normally, the outdoor air damper is open during OCCUPIED, OCCUPIED STANDBY, and

Normal operation

OCCUPIED BYPASS mode when the fan is running and closed during UNOCCUPIED mode unless the

 

controller is economizing. For more information see, Modulating Outdoor Air Operation, on page 43 for

 

more information.)

 

 

 

UV-SVP01A-EN

58

Replacing Circuit Boards

Tracer ZN.520 Unit Controller Replacement

1.Disconnect power or disable the circuit breaker to unit.

2.Remove bad or questionable Tracer ZN.520 controller circuit board.

3.Install controller in the unit with the heat-sink placement at the top of the control box. (See page 32).

4.Connect the power to the circuit board ONLY.

5.Connect Rover and properly configure the controller, unless a previously configured board is purchased.

6.Power down.

7.Connect the remaining input and output wiring to the controller.

8.Reapply power.

9.Complete sequence 7 and 8 above in the installation section of this manual.

10.Refer to BAS manual for instructions on how to install the new ZN.520 into BAS system.

UV-SVP01A-EN

59

Appendix

Hardwired Setpoint Adjustment

Table 35: Hardwired setpoint adjustment

Resistance (Ω) Setpoint (Deg F)

889.450

733.658

577.966

500

70

422.174

344.278

266.482

188.586

110.690

Fan Switch Resistance Values

Table 36: Resistance values

 

Resistance (Ω )

 

 

Switch Position

 

 

16,300

 

 

High

 

 

 

 

10,700

 

 

Low

 

 

 

 

2,320

 

 

Auto

 

 

 

 

4,870

 

 

Off

 

 

Hardwired Thermistor Values

 

 

Table 37: Hardwired 10k Ω thermistor values

 

 

 

 

Resistance

 

Temperature

 

Resistance

 

Temperature

 

 

 

 

 

87.5k Ω

 

0° F

 

10.0k Ω

 

77°F

 

74.6k Ω

 

5° F

 

9.3kΩ

 

80°F

 

63.8k Ω

 

10° F

 

8.2kΩ

 

85°F

 

54.6k Ω

 

15° F

 

7.3kΩ

 

90°F

 

46.9k Ω

 

20° F

 

6.5kΩ

 

95°F

 

40.4k Ω

 

25° F

 

5.8kΩ

 

100 °F

 

34.8k Ω

 

30° F

 

5.2kΩ

 

105 °F

 

30.2k Ω

 

35° F

 

4.7kΩ

 

110 °F

 

26.2k Ω

 

40° F

 

4.2kΩ

 

115 °F

 

22.8k Ω

 

45° F

 

3.8kΩ

 

120 °F

 

20.0k Ω

 

50° F

 

3.4kΩ

 

125 °F

 

17.5k Ω

 

55° F

 

3.1kΩ

 

130 °F

 

15.3k Ω

 

60° F

 

2.8kΩ

 

135 °F

 

13.5k Ω

 

65° F

 

2.5kΩ

 

140 °F

 

11.9k Ω

 

70° F

 

2.3kΩ

 

145 °F

 

10.5k Ω

 

75° F

 

2.1kΩ

 

150 °F

 

 

 

 

 

 

 

 

 

60

UV-SVP01A-EN

Appendix—Binary

Configuration

Binary Configuration

Table 38: Binary configuration details

Binary input

Function

Configuration

or output

 

 

BI 1

Low temp

Normally closed

detection

 

 

BI 2

Condensate

Normally closed

overflow

 

 

BI 3

Occupancy

Normally closed

 

 

Normally open

BI 4

Fan status2

Normally open

Defrost

Defrost

NA

J1-1

Fan high

Normally open

J1-2

Fan

Normally open

Medium\Exhust

 

 

J1-3

Fan low

Normally open

TB4-1 and TB4-

Generic binary

Normally open

2

output/base board

heat

 

 

 

 

 

 

Description

Closed: BIP 1 is Normal (no diagnostic)

Open: BIP 1 is Active (diagnostic)

Closed: BIP 2 is Normal (no diagnostic)

Open: BIP 2 is Active (diagnostic)

Closed: BIP 3 is Normal (Occupied)

Open: BIP 3 is Active (Unoccupied)1

Open: BIP 3 is Normal (Occupied)

Closed: BIP 3 is Active (Unoccupied)1

When the controller commands the fan on and the binary input remains open for one minute, BIP is normal (diagnostic).

When the controller commands the fan on and the binary input closes, BIP is active (no diagnostic).

When input is Open, BIP is Active (Defrost activated)

When input is Closed, BIP is Normal (no Defrost)

De-energized: Fan off

Energized: Fan high

De-energized: Fan\Exhaust off

Energized: Fan Medium\Exhust on

De-energized: Fan off

Energized: Fan low

De-energized: Output off (de-energized)

Energized: Output on (energized)

1.The occupancy input applications vary for standalone and communicated instances. For more information, see Occupancy arbitration tables in the Appendix.

2.The fan status device is normally closed during normal fan operation. When the fan is off either from a fan failure or the controller commanding the fan off, the binary input device opens.

UV-SVP01A-EN

61

Appendix—Unit Operation

Unit Operation Based On The Effective HEAT/COOL Output

Table 39: Unit operation based on the effective heat/cool output

Application mode input

Heat/cool mode input

Effective heat/ cool

mode output

(nviApplicMode)

(nviHeatCool)

(nvoHeatCool)

 

 

 

Auto

Determined by controller

 

Heat

Heating

 

Morning warm up

Morning warm up

 

Cooling

Cooling

Auto

Pre-cool

Pre-cool

 

Off

Off

 

Test

Test

 

Fan only

Fan only

 

Not present

Determined by controller

Heat

Any state

Heating

Morning warm up

Any state

Morning warm up

 

 

 

Unit Operation

Fan—Enabled

Heating—Enabled

Cooling—Enabled

Damper—Enabled

Fan—Enabled

Heating—Enabled

Cooling—Disabled

Damper—Enabled

Fan—Enabled

Heating—Enabled

Cooling—Disabled

Damper—Disabled

Fan—Enabled

Heating—Disabled1

Cooling—Enabled

Damper—Enabled

Fan—Enabled

Heating—Disabled1

Cooling—Enabled

Damper—Disabled

Fan—Disabled

Heating—Disabled

Cooling—Disabled

Damper—Disabled

Fan—Enabled

Heating—Enabled

Cooling—Enabled

Damper—Enabled

Fan—Enabled

Heating—Disabled

Cooling—Disabled

Damper—Enabled

Fan—Enabled

Heating—Enabled

Cooling—Enabled

Damper—Enabled

Fan—Enabled

Heating—Enabled

Cooling—Disabled

Damper—Enabled

Fan—Enabled

Heating—Enabled

Cooling—Disabled

Damper—Disabled

62

UV-SVP01A-EN

Appendix—Unit Operation cont.

Table 39: Unit operation based on the effective heat/cool output

 

 

Application mode input

 

Heat/cool mode input

 

Effective heat/ cool

 

 

 

 

 

 

 

 

mode output

Unit Operation

 

(nviApplicMode)

 

(nviHeatCool)

 

 

 

 

(nvoHeatCool)

 

 

 

 

 

 

 

 

Cool

 

Any state

 

Cool

Fan—Enabled

 

 

 

 

 

 

Heating—Disabled1

 

 

 

 

 

 

Cooling—Enabled

 

 

 

 

 

 

Damper

 

Pre-cool

 

Any state

 

Pre-cool

Fan—Enabled

 

 

 

 

 

 

Heating—Disabled1

 

 

 

 

 

 

Cooling—Enabled

 

 

 

 

 

 

Damper—Disabled

 

Off

 

Any state

 

Off

Fan—Disabled

 

 

 

 

 

 

Heating—Disabled

 

 

 

 

 

 

Cooling—Disabled

 

 

 

 

 

 

Damper—Disabled

 

Test

 

Any state

 

Determined by controller

Fan—Enabled

 

 

 

 

 

 

Heating—Enabled

 

 

 

 

 

 

Cooling—Enabled

 

 

 

 

 

 

Damper—Enabled

 

Fan only

 

Any state

 

Fan only

Fan—Enabled

 

 

 

 

 

 

Heating—Disabled

 

 

 

 

 

 

Cooling—Disabled

 

 

 

 

 

 

Damper—Enabled

 

 

 

 

 

 

 

1.Use of heat for supply air tempering and dehumidification remains available.

2.Night purge, Emergency heat, and Nul modes are not supported by the Tracer™ ZN.520 Unit Controller. If one of these modes is received by the controller, it is interpreted as Auto.

UV-SVP01A-EN

63

Appendix—Data Lists

Data Lists

Table 70 provides an input/output listing for the Tracer ZN.520 unit controller. The content of the lists conforms to both the LonMark Space Comfort Controller Functional Profile and the LonMark node object.

Table 40 Input/output listing1

 

 

 

 

 

 

 

 

 

Input

 

SNVT type

 

 

Output

 

 

SNVT type

 

 

 

 

 

 

 

nviRequest

 

SNVT_obj_request

 

 

nvoStatus

 

 

SNVT_obj_status

 

nviSpaceTemp

 

SNVT_temp_p

 

 

nvoFileDirectory

 

 

SNVT_address

 

nviSetpoint

 

SNVT_temp_p

 

 

nvoSpaceTemp

 

 

SNVT_temp_p

 

nviSetptOffset

 

SNVT_temp_p

 

 

nvoUnitStatus

 

 

SNVT_hvac_status

 

nviOccSchedule

 

SNVT_tod_event

 

 

nvoEffectSetpt

 

 

SNVT_temp_p

 

nviOccManCmd

 

SNVT_occupancy

 

 

nvoEffectOccup

 

 

SNVT_occupancy

 

nviOccSensor

 

SNVT_occupancy

 

 

nvoHeatCool

 

 

SNVT_hvac_mode

 

nviApplicMode

 

SNVT_hvac_mode

 

 

nvoSetpoint

 

 

SNVT_temp_p

 

nviHeatCool

 

SNVT_hvac_mode

 

 

nvoDischAirTemp

 

 

SNVT_temp_p

 

nviFanSpeedCmd

 

SNVT_switch

 

 

nvoTerminalLoad

 

 

SNVT_lev_percent

 

nviComprEnable

 

SNVT_switch

 

 

nvoSpaceRH

 

 

SNVT_lev_percent

 

nviAuxHeatEnable

 

SNVT_switch

 

 

nvoOutdoorTemp

 

 

SNVT_temp_p

 

nviValveOverride

 

SNVT_hvac_overid

 

 

nvoSpaceCO2

 

 

SNVT_ppm

 

nviEmergOverride

 

SNVT_hvac_emerg

 

 

nvoEnterWaterTemp

 

 

SNVT_temp_p

 

nviSourceTemp

 

SNVT_temp_p

 

 

 

 

 

 

 

nviSpaceRH

 

SNVT_lev_percent

 

 

 

 

 

 

1. LonMark certification pending

 

 

 

 

 

 

 

 

Table 41 Configuration properties1

 

 

 

 

 

 

 

Configuration property

 

SNVT type

 

SCPT reference

 

Description

 

 

 

 

 

nciSndHrtBt

 

SNVT_time_sec

 

SCPTmaxSendTime (49)

 

Send heartbeat

 

nciSetpoints

 

SNVT_temp_setpt

 

SCPTsetPnts (60)

 

Occupancy temperature setpoints

 

nciUnitType

 

SNVT_hvac_type

 

SCPThvacUnitType (169)

 

Unit type

 

nciMinOutTm

 

SNVT_time_sec

 

SCPTminSendTime (52)

 

Minimum send time

 

nciRcvHrtBt

 

SNVT_time_sec

 

SCPTmaxRcvTime (48)

 

Receive heartbeat

 

nciLocation

 

SNVT_str_asc

 

SCPTlocation (17)

 

Location label

 

nciBypassTime

 

SNVT_time_min

 

SCPTbypassTime (34)

 

Local bypass time

 

nciSpaceRHSetpt

 

SNVT_lev_percent

 

 

 

 

Space RH Setpoint

 

nciOAMinPos

 

SNVT_lev_percent

 

 

 

 

Minimum outside air position during

 

 

 

 

 

 

 

 

occupied mode

Note1 : LonMark certification pending

 

 

 

 

 

 

 

 

64

UV-SVP01A-EN

Appendix—Timeclock

Setting the Time Clock

The time clock must be programmed for the unit to operate in occupied mode (under load). If

not programmed, the unit will run in the unoccupied mode. Power must be supplied to the unit for the

time clock to be set.

The following procedure covers:

qsetting the current time and day

qsetting the program (events)

qreviewing and changing the programs, and

qoverriding programs (manually)

Automatic

Run Symbol

Set the Time and Day

The time clock (Figure 36) is located behind the access door on the

top right of the unit.

1.Press Res. (Reset) to clear the display and any program data. The “day” numbers (1-7) will blink.

2.Hold h (Hour) in and toggle

±1h to select military or a.m./ p.m. mode. If a.m/p.m. is

LED Display

elected, AM appears in the display. Release h.

3.Press and hold (¹) (Run). If daylight savings time is in effect, ±1h should appear in

the display. If not, press ±1h to clear.

4.Still holding (¹) down, set the current hour and minutes by

pressing h and m respectively. Then set the day with the Day key using the number corresponding to the day of

Hour

Minute

the week (1 is Monday, 7 is Sunday).

5.Release (¹) and the colon “:” in the display will begin flashing.

Set the Program

Determine in advance how you want the unit to operate.

For normal occupied operation, the unit “load” is set ON, whether

in heating or cooling. This means

UV-SVP01A-EN

65

Appendix—Timeclock

the unit will respond differently to changing conditions and maintain a higher comfort level.

For unoccupied operation or “no load” conditions, a lower comfort

level is provided. The load can be switched off by using the program for periods when the room will be

unoccupied.

Note: If the room will be

unoccupied, the time clock should be programmed accordingly to conserve

energy. The position of the outside damper can allow too much outside air in an

unoccupied space if the unit’s time clock is set for “load” or occupied mode and can result

in unnecessary unit cycling and undesirable heat transfer.

Remember that the program is easily changed and can also be overridden after it is initially

set.

1.Press the Prog. key. Spaces or fields for entering time (hours and minutes) appear as dashes separated by a colon.

2.Press Prog. again. The number of free (available) programs is given in this case to be “Fr20” or 20.

3.Press Prog. again to return to the event time mode.

4.Toggle the “Load” key on ( O ) 1or off (O) to link the time with the action.

In the example from the preceding step, you would set the load ON.

5.Enter the time for the first program event.

For example, should you want

the unit to operate under load for an occupied period at 8:00 a.m., enter “08:00AM on

the display using the h and m keys. Better yet, enter the time

a half hour or so before the arrival of people, so the unit will bring the room up (or

down” to the preset occupied temperature setpoints).

6.If the program event you just entered will be the same every

day (as indicated by all seven day numbers at the top of the display) you can press Prog.

to lock in that event and go to the next event. If not and the program will vary during the

week (e.g. different program for the weekend), don’t press Prog. go to the following step.

Note: If you press Prog. by mistake, simply continue to

press Prog. until the event comes up in review and make the change.

7.With the time and hour for the

event set, select the day or days for which the event applies by pressing the Day

key. Toggling the Day key gives you ten options for individual days or combinations

that can be applied. Select one and lock it in by pressing

Prog.

In the example, if you only want the unit to operate under

load for the time set for weekdays, you would select “1 2 3 4 5” by pressing Day, then

select another program event for the weekend.

8.Repeat the preceding steps to set the next program event. A

“load: event is followed by an “unload” event. For example if the unit is programmed for a

load condition in the morning, you could program the unit to unload later in the day or at

night when the room will become unoccupied for a period. If the occupied and

unoccupied periods vary widely but predictably, you can program a cycle of events

during any day or combination of days (up to 20 events)

9.Note: If only one event is programmed, the unit will remain

in that load or unload condition all the time.

10.When all the events are programmed, press the (¹) (run)

key for normal operation. The current time as set will be displayed, along with the run symbol (¹).

Review and Change

Programs

To review a program and events at

any time, press Prog . at any time. Programs events will be displayed in the sequence they were entered

with repeated presses of Prog.

To change a program, select the

event as in the previous paragraph and alter the new data (day, hour minute) as desired to overwrite the

old program. Press Prog to store the data.

To delete a program event, select the event again and press h and m until dashes appear in the time dis-

play. Press either Prog. or ( ¹) until the dashes flash in the display.

To reset all program data, press

Res.

Override Program

(Manual Operation)

While in the Run mode (¹ symbol

in display), press the hand key

to reverse the load status (e.g. if the load was ON, it is now OFF). A

hand symbol appears to indicate the override is active.

At the next scheduled event, automatic (program) control will resume eliminating the override.

To switch the load permanently

ON, press the key a second time. [ O ] appears in the display.

66

UV-SVP01A-EN

Appendix—Timeclock

To switch the load permanently

OFF, press the key a third time. [O] appears in the display.

To return to automatic (pro-

grammed) operation, press the key a fourth time. Run ¹ appears in the display.

NOTE: The Main Power Disconnect switch is located

on the lower right side of the unit behind the right front cabinet panel. It is only used

to remove power to the unit for servicing.

UV-SVP01A-EN

67

Appendix—Location Identifier

This area provided for the removable tag.

68

UV-SVP01A-EN

Location Identifier

UV-SVP01A-EN

69

Location Identifier

70

UV-SVP01A-EN

Location Identifier

UV-SVP01A-EN

71

The Trane Company

Worldwide Applied Systems Group LaCrosse, Wisonsin www.trane.com

Literature Order Number

UV-SVP01A-EN

File Number

SV-TD-UV-000-SVP01A-EN-0700

Supersedes

New

Stocking Location

La Crosse

Since The Trane Company has a policy of continuous product improvement, it reserves the right to change design and specifications without notice.

An American Standard Company