Metasys UNT Series User Manual

Application Specific Controllers Technical Manual 636.3
UNT Controller Section
Technical Bulletin
Issue Date 0398
© 1998 Johnson Controls, Inc.
1
Code No. LIT-6363081 www.johnsoncontrols.com
Introduction Page 5
• Description 5
• Standards Compliance 6
Configuring the Controller 7
• Using HVAC PRO for Windows Configuration Tool 7
• Defining a UNT Control Device Object *7
• Defining a UNT Control Device in Companion Software 9
Installation Procedures 11
• Design Considerations *11
• Tools Needed *11
• Environmental Information 12
• Mounting the Controller *12
• Power Line Wiring Transient Noise Precautions *16
• I/O and Communications Wiring Transient Noise Precautions 18
Wiring Details 19
• Power Source and Loads *19
• Wiring Precautions 21
• Grounding and Isolation UNT110/111, 120/121, 140/141 22
• Grounding and Isolation UNT110/111, UNT120/121,
and UNT140/141 with Separate Load Transformer *23
Unitary Controller (UNT)
* Indicates those sections where changes have occurred since the last printing.

Metasys UNT Series Specifications

General

Communication Protocol	BACnet MS/TP, N2
Dimensions	Varies by model
Weight	Varies by model
Supply Voltage	24 VAC
Inputs	Universal (Analog/Digital)
Outputs	Analog Outputs
Operating Temperature	-40°F to 158°F (-40°C to 70°C)

Summary

Configuring the UNT Controller

Using HVAC PRO for Windows Configuration

Instructions for using HVAC PRO software to configure UNT controllers.

Defining UNT Control Device Objects

Installation Procedures for UNT

UNT Design and Installation Considerations

Mounting the UNT Controller

UNT Power Line Noise Precautions

Provides precautions for power line wiring to prevent transient noise.

UNT I/O and Communications Noise Precautions

UNT Wiring Details and Grounding

UNT Power Source and Load Specifications

Details power transformer compliance and load limitations for UNT units.

UNT Wiring Precautions

UNT Grounding and Isolation (UNT110/111, 120/121, 140/141)

Explains grounding and isolation procedures for UNT models.

UNT Grounding with Separate Load Transformer

Details grounding and isolation for UNTs with separate load transformers.

UNT Terminal Designations and Connections

UNT Analog Input Terminals

UNT Binary Output (Triac) Information

Details UNT binary outputs and triac jumper configuration.

UNT Zone Bus Communication

Networking the UNT Controller

N2 Bus Overview and Characteristics

Provides an overview and characteristics of the N2 Bus for UNT networking.

Wiring UNT to Network Control Unit (NCU)

UNT Downloading and Commissioning

Commissioning Procedures for UNT

UNT Commissioning via Zone Bus

Steps for downloading and commissioning UNTs using the Zone Bus.

UNT Commissioning via N2 Bus

Steps for downloading and commissioning UNTs over the N2 Bus.

Troubleshooting UNT Controllers

Hardware Installation Inspection and Checkout

Troubleshooting UNT with HVAC PRO for Windows

Addresses common UNT malfunctions and corrective actions using HVAC PRO.

Troubleshooting the N2 Bus

Provides guidance for diagnosing and resolving N2 Bus communication issues.

Zone Bus Troubleshooting with HVAC PRO

Troubleshooting Zone Bus communication errors with HVAC PRO.

Appendix A: Rooftop Installation Precautions

Environmental Information for Rooftop Units

Installation Requirements for Rooftop Units

Electrical Noise in Rooftop Units

Precautions to prevent electrical noise interference in rooftop units.

Nuisance Resets in Rooftop Units

Considerations for Gas Ignition Systems

Appendix B: UNT100/101 Specifics

Differences in UNT100/101 Features

UNT100/101 Terminal Designations

Grounding and Isolation for UNT100/101

Isolation requirements for UNT100/101 to protect connected components.

Power Transformer and Load Isolation for UNT100/101