Packaged Gas/ElectricRooftop Units

Precedent3 - 10 Tons 60 Hz

RT-PRC006-ENFebruary 2004

2004 American Standard Inc. All rights reserved RT-PRC006-EN

Introduction

PrecedentTM . . . The same Tranequality... with added flexibility.Precedent is a flexible line of packagedunits that covers a wide variety ofapplications.

Electromechanical controls are availablefor simpler applications, and for themore sophisticated, Reliatelmicroprocessor controls. In addition tocontrols, Precedent offers many otheroutstanding features and option choices.

With its sleek compact cabinet, roundedcorners and beveled top, it may just bethe most aesthetically pleasingpackaged unit on the planet. And, ofcourse, Precedent carries the Tranereputation for excellence, quality, andreliability.

From simple applications, to the mostcomplex, Precedent has the solution.

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Contents

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IntroductionFeatures and Benefits

Application Considerations

Selection ProcedureModel Number Description

General Data

Performance DataCooling PerformanceFan PerformanceHeat Performance

Controls

Electric Power

Dimension and Weights

Mechanical Specifications

2

4

10

11

1314

27

27367476

78

86

95

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Features andBenefits

Unit Cabinet

The compact cabinet with roundedcorners takes up less room and is lesscostly to ship. The beveled and ribbedtop is not only aesthetically pleasing, it isdesigned to prevent water from pooling.

Single Point Power

A single electrical connection powers theunit.

Compressors

Precedent contains the bestcompressor technology available toachieve the highest possibleperformance. Our compressor lineincludes Trane built Climatuffreciprocating and scrolls.

Easy Access Panels

Easy access panels reduce the number ofpossible water entry points.

Low Ambient Cooling

All Precedent microprocessor units havecooling capabilities down to 0F asstandard. Electromechanical modelshave cooling capabilites to 40F as built,or to 0F by adding the optional lowambient control (Frostat).

Unit Base

For added water integrity, Precedent hasa raised 11/8" lip around the unitsdownflow supply and return to preventwater from blowing into the ductwork.

Sloped Drain Pans

Every Precedent unit has a non-corrosive, removable, double-slopeddrain pan thats easy to clean andreversible to allow installation of draintrap on either side of the unit.

Through the Base Condensate

Every unit includes provisions forthrough the base condensate drainconnections. This allows the drain tobe connected through the roof curbinstead of a roof penetration.

Foil-Faced Insulation

All panels in the Evaporator section ofthe unit have cleanable foil-facedinsulation. All edges are eithercaptured or sealed to ensure no fibersget into the airstream.

Convertible Units

The units ship in a downflowconfiguration. They can be easilyconverted to horizontal by simplymoving two panels.

Units come complete with horizontalduct flanges so the contractor doesnthave to field fabricate them. Theseduct flanges are a time and cost saver.

Easy Access Panels

Remove two screws for access to thestandardized internal components andwiring.

Easy-Adjust Idler Arm

With the Easy-Adjust Idler Arm, the beltand sheaves on belt drive units can bequickly adjusted without moving themounted fan motor. The result is a majorsavings in time and money.

Patented Condenser Coil

Precedent boasts a patented 1+1+1Hybrid coil, permanently gapped foreasy cleaning.

Colored And Numbered Wiring

You save time and money tracing wiresand diagnosing the unit.

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Features andBenefits

Flexible Applications Only two roof curbs for the 3-10 ton

Precedent line. . .simplifies curbselection. Standard or High Efficiency Cooling. Electromechanical or ReliaTel

microprocessor controls to meet eitherthe simple or the more complexapplication. Low, medium or high gas heat

capacities. Airflow is outstanding. The Precedent

can replace an older machine with oldductwork and, in many cases, improvecomfort through better air distribution.

Belt or direct drive standard oroversized supply fan motors meet awide airflow range.

Precedent offers ultimate flexibility.Options and components are not pre-packaged at the factory. Units are builtto order in our standard shortest inthe industryship cycle time.

Standardized Components

Components are placed in the samelocation on all Precedent units.Familiarize yourself with one Precedentand you are familiar with everyPrecedent.

Easy Access Low Voltage Terminal Board

Precedents Low Voltage Terminal Boardis external to the electrical controlcabinet. It is extremely easy to testoperation of all unit functions. This isanother cost and time saving installationfeature.

Low Voltage Connections

The wiring of the low voltageconnections to the unit and the zonesensors is as simple as 1-1, 2-2, and 3-3.This simplified system makes it easy forthe installer to wire.

Single-Side Service

Single-side service is standard on allPrecedent units.

Progressive Tubular Heat Exchanger

The compact cabinet features a tubularheat exchanger in low, medium and highheat capacities.

The heat exchanger is fabricated usingstainless steel burners and corrosion-resistant aluminized steel tubes asstandard on all models. It has an induceddraft blower to pull the gas mixturethrough the burner tubes. The heaterhas a direct spark ignition system whichdoubles as a safety device to prove theflame.

Gas electric Precedent models exceed allCalifornia seasonal efficiencyrequirements. They also perform betterthan required to meet the California NOxemission requirments.

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Features andBenefits

Micro Controls

Several years ago, Trane was the first tointroduce microprocessor controls intothe Light Commercial Market. Thatdesign, along with immeasurableexperience, has provided the technologyfor Tranes second-generation ReliaTelmicroprocessor controls.

ReliaTel Micro:

Provides unit control for heating,cooling, and ventilating by utilizinginput from sensors that measureoutdoor and indoor temperature.

Improves quality and reliabilitythrough the use of time-testedmicroprocessor controls and logic.

Prevents the unit from short cycling,considerably improving compressorlife.

Ensures that the compressor will runfor a specific amount of time, whichallows oil to return for betterlubrication, enhancing the reliability ofthe compressor.

Reduces the number of componentsrequired to operate the unit, therebyreducing possibilities for componentfailure.

Eliminates the need for field-installedcomponents with its built-in anti-short-cycle timer, time delay relay andminimum on time controls. Thesecontrols are factory tested to assureproper operation.

Requires no special tools to run thePrecedent unit through its pacesduring testing. Simply place a jumperbetween Test 1 and Test 2 terminals onthe Low Voltage Terminal Board andthe unit will walk through itsoperational steps. The unitautomatically returns control to thezone sensor after stepping through thetest mode a single time, even if thejumper is left on the unit.

As long as the unit has power and theLED is lit, the Micro is operational. Thelight indicates that the Micro isfunctioning properly.

Features expanded diagnosticcapabilities when used with TranesIntegrated Comfort TM Systems.

As an energy benefit, softens electricalspikes by staging on fans,compressors and heaters.

The Intelligent Fallback or AdaptiveControl is a benefit to the buildingoccupant. If a component goes astray,the unit will continue to operate atpredetermined temperature set points.

Intelligent Anticipation is a standardfeature of the Micro. Functioningconstantly, the Micro and zone sensorswork together in harmony, to providetight comfort control.

Electromechanical Controls

For the simpler job that does notrequire a building automation system,or expanded diagnostics capabilities,Precedent offers electromechanicalcontrols. This 24-volt control includesthe control transformer and contactorpressure lugs for power wiring.

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Features andBenefits

Factory-installed OptionsDehumidification (Hot Gas Reheat)Option

This option allows for increased outdoorair ventilation. It reduces humidity levelswhile increasing comfort level in the airspace. Cooling can operate without ademand for dehumidification. The hotgas reheat coil is designed to delivermaximum reheat temperatures andpivot to allow for easy access cleaning.

Hinged Access Doors

These doors permit easy access to thefilter, fan/heat, and compressor/controlsections. They reduce the potential roofdamage from screws or sharp accessdoor corners.

Economizer

Equipped with either dry bulb, referenceor comparative enthalpy sensing, thisfeature provides free cooling as theoutdoor temperature and/or humiditydecreases. Economizers, correctlyinstalled, offer valuable energy savings.Factory-installed economizers save timeand ensure proper installation.

Through the Base Utility Access

Factory provided through the baseopenings simplify electrical wiringand gas piping. Because these utilityopenings frequently minimize thenumber of roof penetrations, the integrityof roofing materials is enhanced.

Phase Monitor

Phase monitor shall provide 100%protection for motors and compressorsagainst problems caused by phase loss,phase imbalance, and phase reversal.Pha