Trane VariTrac Changeover Bypass VAV Systems Thermostat User Manual

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Guide

VariTrac

Changeover-Bypass

VAV Systems

Order No.: VAV-SLM002-EN

Date: March 2002

The VariTrac History

Trane brought their expertise in variable air volume (VAV) controls into

the changeover-bypass zoning market with the introduction of VariTrac in

1989. The concept of changeover-bypass zoning brings the flexibility

and comfort of VAV systems into the light commercial unitary market, at

an affordable price.

The first generation of VariTrac was a 16-zone pressure dependent

system. The zone dampers featured the same electronic zone controller

Trane developed for its VAV boxes, operating in the pressure dependent

mode. The heart of the system was the Comfort Manager™; a panel

which was designed to manage the HVAC unit, bypass damper

functions, and changeover decisions. The functional concept of this

original system continues to be the backbone of today’s zoning system.

In the early 90s, two important enhancements were added to the system:

•

Trane’s new Comm 4 communications link for the damper controllers

The ability to directly communicate with Trane’s new Voyager UCP

electronic rooftop unit controls

In 1995, Trane introduced the second generation of VariTrac. This

generation featured the central control panel (CCP) as the functional

replacement for Comfort Manager. The new panel featured a resin

enclosure, optional relay board for 24 VAC unit control, and the move to

static pressure for bypass control. Improved changeover control was

added to the operating system, and the zone damper controls were

upgraded to UCM Version 3.

Now, in 2002, Trane introduces the next generation of VariTrac controls

which includes all the great features of the original VariTrac system, plus

new features and enhancements. The enhancements are designed to

make this generation of VariTrac the simplest changeover-bypass zoning

system to install, commission, and service of any light commercial

controls system available today.

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Contents

The History of VariTrac................................................. 2

Introduction................................................................... 4

Why Changeover Bypass VAV ............................ 4

The Delivered Systems Concept.......................... 5

Feature and Benefits..................................................... 6

Product Changes at a Glance .............................. 6

Hardware Overview.............................................. 7

VariTrac Function Overview................................. 8

Application Considerations ....................................... 10

Customers Identification............................................ 11

Building Owners ................................................. 11

Consulting Engineers ......................................... 11

Contractors......................................................... 12

Trane Sales Offices............................................ 12

Selling VariTrac Systems ........................................... 13

Competition................................................................. 13

VAV-SLM002-EN

Introduction

Why Changeover-Bypass VAV

Packaged unitary systems offer one of today’s most popular and cost-

effective methods for supplying conditioned air to small commercial

buildings. The unitary machine most commonly used has a constant

volume fan with a fixed outside air damper and a single thermostat.

While this may meet the thermal requirements of the space, it may not

meet all the comfort requirements of the space using a single thermostat

for control.

Changeover-bypass VAV is a design solution for this problem. As the

name implies, these systems deliver a varying volume of air to multiple

zones, each with its own thermostat, while still utilizing a unitary machine

with a constant volume fan. Changeover-bypass-VAV combines the

comfort benefits of VAV with the cost effectiveness of packaged unitary

equipment.

The light commercial HVAC marketplace is known for its high level of

competition. Knowing how to position Trane’s zoning products against

the competition is critical. Over the past couple of years, Trane has

added “value” items to its standard product package. In many instances,

competitors must resort to add-ons or upgraded systems to achieve

similar operating results or benefits obtained by Trane products.

Learning how to leverage both Trane’s value over the competition and

defend against perceived competitor advantage is vital to the company’s

light commercial business and obtaining increased market share.

This marketing guide is designed to help sales personnel prepare for

effective selling of the redesigned VariTrac changeover-bypass zoning

system.

By utilizing an existing product to new product comparison, Trane’s

advantage in areas such as value, flexibility, and integrated controls will

be explained. This enables the sales force to arm themselves with

superior product knowledge of Trane’s zoning systems and their

operation.

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The Delivered Systems Concept

Delivered products represent approximately eighty percent of the light

commercial building market. The term delivered product refers to the

relationship between the manufacturer and the contractor. The

relationship is often limited to the sale and delivery of the product. The

contractor takes full responsibility for installation and service. Delivered

products contrast with applied products, for which the relationship

between manufacturer and contractor extends to product selection,

installation, commissioning, programming, and on-going service support.

Opportunities for Trane to participate in the light commercial market for

delivered products have never been as plentiful as they are today. The

relationships that you foster and maintain with your contractors are

essential to your success in increasing your VariTrac market share.

Training your contractors to become self-sufficient in selling, applying,

installing, and servicing VariTrac systems requires that you invest time to

train them. The potential return on your investment is well worth the

time. This relationship, in which you represent Trane as both supplier

and educator, is your business opportunity.

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Features and Benefits

The primary advantage of Trane’s zoning systems is that they are

completely integrated systems with Trane’s unitary equipment. Another

benefit is that these systems are so simple to install, operate and

service, that contractors and installers can take advantage of the

delivered concept versus the applied world of design, engineering, and

programming. For more information, refer to the table below which

describes and compares the features and benefits of Trane’s newest

changeover-bypass VAV offering to the existing product.

Product Changes at a Glance

VariTrac II

New VariTrac III

CCP

CCP with 3 piece enclosure design and optional Operator Display

Optional relay board with installation kit

Quick snap-in optional relay board with easy to wire terminal strip

Duct mounted pressure and temperature sensors hard

wired back to the CCP

Communicating sensor assembly including a UCM 4 with integral

temperature and pressure sensor, and output to the bypass damper(s)

Bypass damper hardwired back to the CCP

Bypass damper with factory installed wiring harness for plug-in connection

to communicating sensor assembly

16 zones

24 zones

Zone dampers with UCM 3 boards

Zone dampers with UCM 4 boards with:

•

Zone occupancy sensor input

Zone CO2 sensor input

Round zone damper sizes:

Added new rectangular zone dampers in sizes:

8x12, 8x14, 8x16, 10x16, 10x20, 14x18

•

6”, 8”, 10”, 12”, 14”, and 16”

•

Comm 4 communications to the zone dampers

Comm 3 communications to Tracker

Same Comm 4 communications to the zone dampers for reliable

operation and backward compatibility

Supports Comm 5 communications to the new Tracker Version 10 panel

PC edit terminal required for interfacing with the

system (HyperTerminal)

Optional touch-screen operator display with built in 7-day time clock .

Windows based PC software.

Round bypass damper sizes:

Bypass dampers now come with factory installed wiring harness for plug-

in connection to communicating sensor assembly

•

6”, 8”, 10”, and 12”

Rectangular bypass damper sizes:

14x12, 16x16, 20x20, 30x20

•

Manual analog zone sensors only

Not applicable

Digital display zone temperature sensor

Zone occupancy sensor

Not applicable

Zone CO2 sensor

Duct mount CO2 sensor

Pressure independent boxes

Add local heat

Ability to use pressure independent boxes

Ability to add local heat

VAV-SLM002-EN

Hardware Overview

Central Control Panel Enclosure

The new VariTrac Central Control Panel (CCP) has a three-piece

enclosure for simplified installation. All wiring is done on large, easily

accessible terminal strips located in the wall mount base plate. The

electronics are located in the middle section, which is snapped onto the

base plate after mounting. The top section is either a blank face plate, or

the optional operator display.

Central Control Panel Operator Display

The optional operator display (OD) is a back-lit liquid crystal display with

touch-screen programming capability. Through the display you can

access system status and zone status, and do basic set-up of the zone

UCMs and the CCP system operating parameters. It is designed to give

an installer the ability to commission a VariTrac system without requiring

a PC. Additionally, the OD has a seven-day time clock built in to provide

stand alone scheduling capability of the VariTrac system. Zones may be

divided into four groups, each with its own schedule if desired. If there is

no Tracker system on the job, the CCP must be ordered with a display.

If Tracker is available, the CCP may have a blank cover plate installed

instead of an OD. All set-up information for the CCP may then be

accessed from the Tracker.

Central Control Panel Optional Relay Board

The new relay board does not require any mounting hardware or time

consuming installation. It simply snaps into place. The terminal strip is

now internally jumpered, so it may be wired directly to an HVAC unit low

voltage terminal strip using the same terminal designations as an

industry standard thermostat subbase.

Communicating Sensor/Bypass Control Assembly

The VariTrac duct sensors have been combined with a UCM into one

factory-wired assembly, so it now resides on the Comm 4 link along with

the zone dampers and Voyager/Precedent™ rooftop unit. The bypass

damper is also wired to this assembly. This eliminates the multiple

conductors and terminations between the CCP, the duct sensors and the

bypass damper, where most installation errors occurred.

Bypass Damper Installation Harness

All bypass dampers will now be shipped with a 12-foot plenum-rated

wiring harness attached to the damper at the factory. The harness has a

polarized plug on the end which is plugged into the communicating

sensor assembly control board. This eliminates bypass damper wiring

errors during installation.

VAV-SLM002-EN

Digital Display Zone Sensor

The new digital display zone sensor has the look and functionality of the

standard Trane zone sensor, but includes an LCD digital display of the

space temperature and setpoint adjustment in degrees F or C. The

sensor has ON and CANCEL buttons, and a communications jack which

can be accessed without removing the cover. The sensor requires 24

volts, and may share a power supply with UCM.

Zone Occupancy Sensor

The new zone occupancy sensor is a ceiling-mount infrared motion

detector to be used with VariTrac zone damper UCM for controlling the

occupied zone standby function. It can detect motion over a 360 degree

range (adjustable) for up to a 1200 square foot area. It has SPDT

isolated contacts for connection to the UCM occupancy input. The

sensor requires 24 volts, and may share a power supply with UCM.

Zone CO2 Sensor

The zone CO2 sensor is a compact transmitter for use with the VariTrac

UCM CO2 input for doing demand control ventilation. The sensor is a

available in either wall- or duct-mount enclosures. The sensor requires

24 volts, and may share a power supply with UCM.

VariTrac PC Software

Advanced set-up functions in VariTrac are now done with a new

Windows®-based, graphical PC software program. Connection between

the PC and the CCP is done with a standard serial port cable connection.

VariTrac Function Overview

Increased Zone Count

The new VariTrac system now support 24 zones instead of 16. The

zones may be VariTrac dampers, or any type of VariTrane VAV box

including fan-powered boxes or boxes with factory-installed local heat.

Automatic Configuration and Start-up

The VariTrac system performs automatic configuration on start-up by

locating all zone dampers or VAV boxes on the communications link and

creating a database of zones, complete with default names. VariTrac

takes control of all the zone dampers and calibrates them. It then

calibrates the bypass system, establishes its own static pressure

setpoint, and begins heating/cooling operation.

Discharge Air Control

VariTrac now does discharge air control. When there is a demand for

heating or cooling from a zone, the CCP will control the discharge air

temperature to the discharge air setpoint default (55°F cooling, 110°F

heating), using as many stages as necessary. This allows VariTrac to do

true capacity control under part-load conditions, and better manage the

load created by increased ventilation air requirements.

VAV-SLM002-EN

Supply Air Tempering

It is now possible to enable the Supply Air Tempering function in a

Voyager via the CCP. This allows the Voyager to cycle a stage of heat

on and off to warm up the supply air stream and better manage the load

created by increased ventilation air requirements.

CO2 Based Demand Control Ventilation

CO2 sensors many now be connected to VariTrac zone UCMs. Up to

one sensor per zone on the system may be applied. The CCP Demand

Control Ventilation configuration screen allows you to set a minimum

ventilation damper position for the Voyager/Precedent unit, and a

maximum ventilation damper position. You also configure a normal CO2

setting and an alarm CO2 setting. As the CO2 rises between the normal

setpoint and the alarm setpoint, the CCP resets the damper position to

increase ventilation. The CCP can be configured to gather CO2

measurements from one specific sensor, or to gather information from all

the sensors on the system and select the highest value.

Zone Occupied Standby Function

A VariTrac UCM can now have an occupancy sensor connected to it,

and can be configured to perform an occupied standby function. This

mode is available whenever the VariTrac system is in the occupied

mode. The zone will be in standby using its unoccupied setpoints if

motion is not detected by the zone occupancy sensor. When motion is

detected in the space, the UCM shifts to its occupied setpoints, and will

remain that way until 30 minutes (adjustable) after motion ceases.

System Balance Mode

A VariTrac system can be placed in the balance mode from the operator

display or the PC software using a single button selection. In this mode,

the CCP automatically prepares the VariTrac system for balancing by

starting the supply fan, disabling heating and cooling, closing the bypass

damper, and opening all zone dampers to their maximum position. The

system can then be balanced as a single zone system using mechanical

hand balancing dampers.

Global Sensor Setpoint Limit Set-up

If the zone setpoint thumbwheels are enabled, their functional range

should be limited to about a 5 degree span to avoid nuisance

changeover. This requires you to access each individual UCM and

manually adjust the limits. The new VariTrac CCP allows you to create a

single set of limits, and then broadcast them to all the zones on the

system at one time by pushing a single button.

VAV-SLM002-EN

Application Considerations for

Changeover-Bypass-VAV

A building with varying loads due to occupancy, time-of-day, or other

special needs is a likely candidate for a changeover-bypass VAV system.

Also, any structure required to meet the higher ventilation requirements

associated with ASHRAE Standard 62 is a prime target. These

applications include:

•

Offices and small manufacturing buildings – Varying occupancy

places varying demands on the HVAC system.

Schools – Heightened concerns about indoor air quality (IAQ) affect

both new and existing applications.

Strip malls, movie theaters, health clubs – Variable vacancy and

special needs for conditioned air apply in these buildings.

Clinics, nursing homes, small hospitals – These buildings can be

multi-purpose and almost always have special requirements for

conditioned air.

VAV-SLM002-EN

Customer Identification

In technical sales, it is important to understand the answer to a

fundamental question: Who needs this product and why?

Ideal customers for VariTrac changeover-bypass VAV systems include:

•

customers with buildings having significant variable occupancy

(schools, office buildings, etc.)

customers with buildings that want better tenant comfort, at a

reasonable price

building owners or facility managers that receive constant complaints

about hot or cold areas in their building

customers with buildings operating in locations requiring compliance

with IAQ codes and standards.

customers that value Trane’s ability to bring a simple, pre-

engineered, integrated solution to the job

Regardless of the customer, Trane’s message to the marketplace is that

it is the entire packaged comfort system that matters, not the parts and

pieces of one manufacturer over another.

Building Owners

Most building owners readily understand the concept of “total cost of

ownership.” They are concerned not only with the first cost of their

building’s HVAC system, but also with the on-going operating costs

associated with that equipment. Trane’s changeover-bypass VAV

system can reduce both first cost and the on-going operating costs

normally associated with a larger, more complex system.

Consulting Engineers

With the increasingly rapid changes in technology, engineers are

pressed to keep up with the more complex building codes and standards,

let alone, the control systems that must adhere to these measures. With

Trane’s changeover-bypass VAV, the systems are simple, yet they

address customers’ concerns regarding the latest issues with IAQ.

Local, state, and federal building codes increasingly set forth

requirements that are associated with adherence to ASHRAE 62 to

assure that IAQ is a design requirement, especially for new construction.

As a result, consulting engineers are looking for proven ways to address

the IAQ issue.

VAV-SLM002-EN

Contractors

The first cost benefits associated with Trane’s changeover-bypass-VAV

systems are important to contractors because:

•

at the top of their list is a “delivered” system that requires very little

programming, virtually no engineering, and is simple to install,

operate, and service

•

auto-configuring saves hours over having to locate and match

terminal units in the field to the software in the main controller

a one-step balance mode saves hours over the traditional method of

balancing a VAV system

an integrated bypass sensor assembly that does not require running

wires back to the central controller will reduce wiring errors in the

field

Trane Sales Force

The Trane sales force has the opportunity to sell both equipment and

controls in one integrated package. Trane provides a complete solution.

This one-stop shopping capability is backed by the considerable

resources that Trane offers on all of its products.

VAV-SLM002-EN

Selling Changeover-Bypass-VAV

Systems

Trane’s largest competitor for selling VAV zoning systems is Trane! We

sell more rooftops with programmable thermostats than our competitors

do selling their VAV zoning systems. In other words, even though we

have a formidable competitor with Carrier’s VVT system, we would and

could hold a similar share in the marketplace by selling Trane’s VariTrac

over single units with programmable stats without even worrying about

our competition.

The most effective way to sell Trane’s zoning systems against the

competition is based on system simplicity, auto-configuration, an

integrated system, and the new digital display. In addition, many other

new features and functions have been added. Refer to the table on page

6 for more information.

Finally, we need to capitalize on our contractor relationships. In many

areas of the country we have not begun to call on these light commercial

contractors, or maintain the relationships that exist today. The key to

success is to take full advantage of the delivered products that are now

available, call on and educate your contractors, then sit back and take

orders.

Competition

VAV zoning controls are available from a variety of sources, however,

most of them do not offer an integrated package with the equipment.

Many of these companies do not offer a pre-engineered package that

comes as a standard offering. Instead they supply parts or pieces of the

whole system. There is significant risk in working with these companies

up-front and after installation. Coordinating mechanical and electronic

builds between multiple suppliers is difficult and it is possible that these

suppliers will not be able to respond to service or reliability issues.

Trane is the leading system controls supplier on new equipment, and

holds the leading share of the new construction controls market. Trane

has made significant effort to become the premier integrated systems

leader, and the competition is not even close.

VAV-SLM002-EN

Literature Order Number

Date

VAV-SLM002-EN

March 2002

New

Trane

Supersedes

An American Standard Company

www.trane.com

Stocking Location

LaCrosse

For more information contact your local district

office or e-mail us at comfort@trane.com

Since Trane has a policy of continuous product and product data improvement, it reserves the right to

change design and specifications without notice.

VAV-SLM002-EN

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