Trane WEHC, WSHC, WFHC, WXHC, WLHC Installation and Maintenance Manual

Installation, Operation, and Maintenance

IntelliPak™ II

Commercial Rooftop Air Handlers with CV, VAV, or SZVAV Controls

‘F0’ and later design sequence

Only qualified personnel should install and service the equipment. The installation, starting up, and servicing of heating, ventilating, and air-conditioning equipment can be hazardous and requires specific knowledge and training. Improperly installed, adjusted or altered equipment by an unqualified person could result in death or serious injury. When working on the equipment, observe all precautions in the literature and on the tags, stickers, and labels that are attached to the equipment.

October 2011 RT-SVX28E-EN

WEHC WSHC WFHC WXHC WLHC

SAFETY WARNING

Warnings, Cautions and Notices

Warnings, Cautions and Notices. Note that warnings, cautions and notices appear at

appropriate intervals throughout this manual. Warnings are provide to alert installing contractors to potential hazards that could result in death or personal injury. Cautions are designed to alert personnel to hazardous situations that could result in personal injury, while notices indicate a situation that could result in equipment or property-damage-only accidents.

Your personal safety and the proper operation of this machine depend upon the strict observance of these precautions.

Read this manual thoroughly before operating or servicing this unit.

ATTENTION: Warnings, Cautions and Notices appear at appropriate sections throughout this

literature. Read these carefully:

WARNI NG

CAUTIONs

NOTICE:

Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

Indicates a potentially hazardous situation which, if not avoided, could result in minor or moderate injury. It could also be used to alert against unsafe practices.

Indicates a situation that could result in equipment or property-damage only accidents.

Important Environmental Concerns!

Scientific research has shown that certain man-made chemicals can affect the earth’s naturally occurring stratospheric ozone layer when released to the atmosphere. In particular, several of the identified chemicals that may affect the ozone layer are refrigerants that contain Chlorine, Fluorine and Carbon (CFCs) and those containing Hydrogen, Chlorine, Fluorine and Carbon (HCFCs). Not all refrigerants containing these compounds have the same potential impact to the environment. Trane advocates the responsible handling of all refrigerants-including industry replacements for CFCs such as HCFCs and HFCs.

Responsible Refrigerant Practices!

Trane believes that responsible refrigerant practices are important to the environment, our customers, and the air conditioning industry. All technicians who handle refrigerants must be certified. The Federal Clean Air Act (Section 608) sets forth the requirements for handling, reclaiming, recovering and recycling of certain refrigerants and the equipment that is used in these service procedures. In addition, some states or municipalities may have additional requirements that must also be adhered to for responsible management of refrigerants. Know the applicable laws and follow them.

WARNING

Proper Field Wiring and Grounding Required!

All field wiring MUST be performed by qualified personnel. Improperly installed and grounded field wiring poses FIRE and ELECTROCUTION hazards. To avoid these hazards, you MUST follow requirements for field wiring installation and grounding as described in NEC and your local/state electrical codes. Failure to follow code could result in death or serious injury.

Personal Protective Equipment (PPE) Required!

Installing/servicing this unit could result in exposure to electrical, mechanical and chemical hazards.

• Before installing/servicing this unit, technicians MUST put on all Personal Protective

• When working with or around hazardous chemicals, ALWAYS refer to the appropriate MSDS

• If there is a risk of arc or flash, technicians MUST put on all Personal Protective Equipment

Failure to follow recommendations could result in death or serious injury.

Overview of Manual

Notes:

• This document is the customer property and must be retained by the unit owner for use by

• The procedures discussed in this manual should only be performed by qualified, experienced

This booklet describes proper installation, start-up, operation, and maintenance procedures for Casings A-C rooftop air handlers designed for Constant Volume (CV), Single Zone Variable Air Volume (SZVAV) and Variable Air Volume (VAV) applications. By carefully reviewing the information within this manual and following the instructions, the risk of improper operation and/ or component damage will be minimized.

Note: One copy of the appropriate service literature ships inside the control panel of each unit.

It is important that periodic maintenance be performed to help assure trouble free operation. Should equipment failure occur, contact a qualified service organization with qualified, experienced HVAC technicians to properly diagnose and repair this equipment.

Warnings, Cautions and Notices

WARNING

Equipment (PPE) recommended for the work being undertaken. ALWAYS refer to appropriate MSDS sheets and OSHA guidelines for proper PPE.

sheets and OSHA guidelines for information on allowable personal exposure levels, proper respiratory protection and handling recommendations.

(PPE) in accordance with NFPA 70E or other country-specific requirements for arc flash protection, PRIOR to servicing the unit.

maintenance personnel.

HVAC technicians.

RT-SVX28E-EN 3

Model Number Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Commonly used Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Unit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Input Devices and System Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Unit Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Pre-Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Overview of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Constant Volume (CV) and Variable Air Volume (VAV) Units . . . . . . . . . 13

Constant Volume (CV) Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Variable Air Volume (VAV) Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Single Zone Variable Air Volume (SZVAV) Only . . . . . . . . . . . . . . . . . . . 17

Space Temperature Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Unit Control Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

General Unit Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Rigging the Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Main Electrical Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Field Installed Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Requirements for Electric Heat Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Requirement for Gas Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Requirements for Hot Water Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Requirements for Steam Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Requirements for Chilled Water Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . 30

O/A Pressure Sensor and Tubing Installation (all units with Statitrac) . . 30

Condensate Drain Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Units with Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Removing Supply and Exhaust Fan Shipping Channels . . . . . . . . . . . . . 31

Spring Isolators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

O/A Sensor and Tubing Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Units with Statitrac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Unit Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Roof Curb and Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Pitch Pocket Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

If a Trane Curb Accessory Kit is not used . . . . . . . . . . . . . . . . . . . . . . . . . 37

Field Converting Horizontal Ductwork from Right to the Left Side . . . . . 38

Unit Rigging and Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Lifting the External Piping Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Gas Heat Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4 RT-SVX28E-EN

Connecting the Gas Supply Line to the Furnace Gas train . . . . . . . . . . . 43

Hot Water Heat Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Steam Heat Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

General Coil Piping and Connection Recommendations . . . . . . . . . . . . . . . . 49

Chilled Water Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

General Coil Piping Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Coil Winterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

External Piping Enclosure Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Disconnect Switch w/External Handle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Electric Heat Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Main Unit Power Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Power Wire Sizing and Protection Devices . . . . . . . . . . . . . . . . . . . . . . . . 61

Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Field Installed Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Controls using 24 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Controls using DC Analog Input/Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 65

Constant Volume System Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Variable Air Volume System Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Constant Volume or Variable Air volume System Controls . . . . . . . . . . 66

Emergency Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Ventilation Override Module (VOM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Temperature vs. Resistance Coefficient . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Cooling Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Gas Heating Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Electric Heat Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

CV Electric Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

VAV Occupied Electric Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Demand Control Ventilation Sequence of Operation . . . . . . . . . . . . . . . . 84

Return Fan Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Wet Heat Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Verifying Proper Fan Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

System Airflow Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Exhaust Airflow Measurement (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . 91

Traq™ Sensor Airflow Measurement (Optional with all units equipped with

an economizer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Supply Fan (with or without Variable Frequency Drive) . . . . . . . . . . . . . . . . 93

Exhaust Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Return Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Component Static Pressure Drops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

RT-SVX28E-EN 5

Unit Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Economizer Damper Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

To Adjust the Fresh Air Damper Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Chilled Water Cooling Startup (Constant Volume & Variable Air Volume Systems)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Electric, Steam and Hot Water Start-Up (Constant Volume & Variable Air Volume Systems)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Gas Furnace Start-Up (Constant Volume and Variable Air Volume Systems)

Two Stage Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Full Modulating Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

. . . . . . . . . . . . . . . . . 105

Final Unit Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Fan Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

VFD Programming Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Monthly Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Cooling Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Heating Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Coil Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Final Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Warranty and Liability Clause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6 RT-SVX28E-EN

Model Number Descriptions

WEHCA0040A0411F70001A0000A0D0A00000000

1 2 3 4 567 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

DIGIT 1 — UNIT TYPE

W Self-Contained (Packaged

Air Handler)

DIGIT 2 — UNIT FUNCTION

E Electric Heat F Natural Gas Heat L Hot Water Heat S Steam Heat X No Heat

DIGIT3—SYSTEMTYPE

H Single Zone

DIGIT 4 — DEVELOPMENT SEQUENCE

C Third

DIGIT 5 — UNIT SIZE

A 16,000 - 31,000 CFM B 20,000 - 38,000 CFM C 20,000 - 45,000 CFM

DIGIT6—COOLING COIL

0 No Cooling Coil 2 2 Row Chilled Water 4 4 Row Chilled Water 6 6 Row Chilled Water 8 8 Row Chilled Water

DIGIT 7 — CHILLED WATER COIL FIN SERIES

0 No Chilled Water Coil A Series 80 without Turbulators B Series 80 with Turbulators C Series 108 without Turbulators D Series 108 with Turbulators E Series 144 without Turbulators F Series 144 with Turbulators G Series 168 without Turbulators H Series 168 with Turbulators

DIGIT 8 — VOLTAGE SELECTION

4 460/60/3 XL 5 575/60/3 XL

DIGIT 9 — HEAT CAPACITY SELECTION

0 No Heat 1 Electric Heat 90 kW 2 Electric Heat 140 kW 3 Electric Heat 265 kW 4 Electric Heat 300 kW A Low Gas Heat - 2 stage B Medium Gas Heat - 2 stage C High Gas Heat - 2 stage D Low Gas Heat - Modulating E Medium Gas Heat - Modulating F High Gas Heat - Modulating

Low Heat Options

H Low Heat - 1.25 in. (32mm) Valve J Low Heat - 1.5 in. (38mm) Valve K Low Heat - 2.0 in. (50mm) Valve L Low Heat - 2.50 in. (64mm) Valve M Low Heat - 3.0 in. (76mm) Valve

High Heat Options

P High Heat - 1.25 in.(32mm) Valve Q High Heat - 1.5 in. (38mm) Valve R High Heat - 2.0 in. (50mm) Valve T High Heat - 2.50 in. (64mm) Valve U High Heat - 3.0 in. (76mm) Valve

DIGIT 10 & 11— DESIGN SEQUENCE

DIGIT 12 — UNIT CONFIGURATION SELECTION

4 1 Piece Unit - without Blank

Section

5 1 Piece Unit with 4 ft. Blank

Section

6 1 Piece Unit with 8 ft. Blank

Section

DIGIT 13 — AIRFLOW DIRECTION

1 Downflow Supply/Upflow Return 2 Downflow Supply/Horizontal End

Return

3 Downflow Supply/Horizontal

Right Return

4 Right Side Horizontal Supply/

Upflow Return

5 Right Side Horizontal Supply/

Horizontal End Return

6 Right Side Horizontal Supply/

Horizontal Right Return

DIGIT 14 — FAN MOTOR SELECTION

1 Standard Fan 3 Standard Fan w/ TEFC Motor

DIGIT 15 — SUPPLY FAN MOTOR SELECTION

F15Hp G20Hp H25Hp J30Hp K40Hp L50Hp M60Hp N75Hp

DIGIT 16 — SUPPLY FAN RPM SELECTION

7700 8800 9900 A1000 B1100 C 1200 D 1300 E 1400 F 1500 G 1600 H 1700 J 1800 K 1900 L2000

DIGIT 17 — EXHAUST/RETURN FAN OPTIONS

0 None 1 High CFM Exhaust w/o Statitrac

CV Only

2 Low CFM Exhaust w/o Statitrac

CV Only

3 High CFM Exhaust w/o VFD w/

Statitrac

4 Low CFM Exhaust w/o VFD w/

Statitrac

5 High CFM Exhaust w/ VFD w/

Bypass w/ Statitrac

6 Low CFM Exhaust w/ VFD w/

Bypass w/ Statitrac

7 High CFM Exhaust w/ VFD w/o

Bypass w/ Statitrac

8 Low CFM Exhaust w/ VFD w/o

Bypass w/ Statitrac A Return w/o Statitrac CV Only C Return w/ VFD w/ Bypass w/

Statitrac E Return w/ VFD w/o Bypass w/

Statitrac

DIGIT 18 — EXHAUST/RETURN FAN MOTOR SELECTION

0 None D 7.5 Hp E10Hp F15Hp G20Hp H25Hp J30Hp K40Hp L50Hp M60Hp

RT-SVX28E-EN 7

Model Number Descriptions

DIGIT 19 — EXHAUST/RETURN RPM SELECTION

0 None 3300 4400 5500 6600 7700 8800 9900 A1000 B1100 C 1200 D 1300 E 1400

DIGIT 20 — SYSTEM CONTROL SELECTION

1 Constant Volume (Zone

Temperature Control) 2 VAV (Discharge Air Control) 4 VFD Supply w/o Bypass

(Discharge Air Control) 5 VFD Supply w/Bypass (Discharge

Air Control) 6 Single Zone VAV w/VFD w/o Bypass

(Zone Temperature Control) 7 Single Zone VAV w/VFD w/Bypass

(Zone Temperature Control)

DIGIT 21 — FRESH AIR AND ECONOMIZER OPTIONS/ CONTROLS

A 0 - 25% Motorized Damper B Econ w/Dry Bulb C Econ w/Reference Enthalpy D Econ w/Comparative Enthalpy E Econ w/Fresh Air Measure /Dry

Bulb F Econ w/ Fresh Air Measure /Ref

Enth G Econ w/Fresh Air Measure /Comp

Enth H Econ w/DCV /Dry Bulb J Econ w/DCV /Ref Enth K Econ w/DCV /Comp Enth

DIGIT 22 — DAMPER OPTION

0 Standard 1 Low Leak 2 Ultra Low Leak

DIGIT 23 — PRE COOLING COIL FILTER SELECTION

0 2" High Efficiency Throw Away 1 2" Throw Away Rack / Less Filters 2 90 - 95%, Bag Filters w/ Pre Filters 3 Bag Filter Rack / Less Filters 4 90 - 95%, Cartridge Filters w/

Pre Filters 5 Cartridge Rack / Less Filters 6 90 - 95% Low PD Cartridge w/

Pre Filters 7 Low PD Cartridge Rack / Less

Filters

DIGIT 24 — BLANK SECTION APPLICATION OPTIONS

0 None A 90 - 95% Bag w/Pre Filters B 90 - 95% Low PD Cartridge w/

Pre Filters

C 90 - 95%, Cartridge Filters w/

Pre Filters

D 90 - 95% Hi Temp Cartridge w/

Pre Filters E HEPA w/Pre Filters F Hi Temp HEPA w/Pre Filters

DIGIT 25 — FUTURE DEVELOPMENT

DIGIT 26 — UNIT MOUNTED POWER CONNECTION SELECTION

A Terminal Block B Non Fused Disconnect C Non Fused Disconnect w/

Pwrd conv outlet D Circuit Breaker w/ SCWR E Ckt Brkr w/ SCWR/ Pwrd conv

outlet

DIGIT 27 — (FUTURE DEVELOPMENT)

0 None

DIGIT 28 — COIL/DRAIN PAN

D No Drain Pan E Galvanized Drain Pan

DIGIT 29 — CHILLED WATER COIL VALVE

0 None A 1.5" Cooling Valve B 2" Cooling Valve C 2.5" Cooling Valve D 3" Cooling Valve

DIGIT 30 — (FUTURE DEVELOPMENT)

0 None

DIGIT 31 — (FUTURE DEVELOPMENT)

0 None

DIGIT 32 — HIGH DUCT TEMPERATURE THERMOSTAT

0 None 1 High Duct Temp Thermostat

DIGIT 33 — REMOTE HUMAN INTERFACE

0 None 1 RHI & IPCB 2 IPCB

DIGIT 34 — MODULE OPTIONS

0 None A 0-5 Volt GBAS B 0-10 Volt GBAS C 0-5 / 0-10 Volt GBAS F LonTalk Communication Interface

(LCI) D Ventilation Override G 0-5 Volt GBAS / Ventilation

Override H 0-10 Volt GBAS / Ventilation

Override J 0-5 / 0-10 V GBAS / Ventilation

Override L LCI & Ventilation Override M BACnet Communication

Interface (BCI) N BCI & Ventilation Override

DIGIT 35 — ZONE SENSOR OPTION

0 None A Dual Setpoint w/Man/Auto

Changeover B Dual Stpt w/Man/Auto Chgovr &

Sys Lights C Room Sensor w/Timed Override

& Cancel D Room Snsr w/TO & Cancel &

Local Stpt Adj G VAV w/System Lights L Programmable Night Setback

DIGIT 36 — AGENCY APPROVAL OPTION

0 None 1 cULus

DIGIT 37 — SERVICE ENHANCEMENTS

0 Single Side Access Doors A Dual Side Access Doors B Single Side Access Doors /

Marine Lights C Dual Side Access Doors / Marine

Lights

DIGIT 38 — BELT GUARDS/ BURGLAR BARS/MARINE LIGHTS

0 None 1 Belt Guards 2 Burglar Bars 3 Belt Guards / Burglar Bars

8 RT-SVX28E-EN

General Information

Unit Nameplate

One Mylar unit nameplate is located on the outside upper left corner of the control panel door. It includes the unit model number, serial number, electrical characteristics, weight, refrigerant charge, as well as other pertinent unit data. A small metal nameplate with the Model Number, Serial Number, and Unit Weight is located just above the Mylar nameplate, and a third nameplate is located on the inside of the control panel door.

Precautionary Measures

• Avoid breathing fiberglass dust

• Use a NIOSH approved dust/mist respirator

• Avoid contact with the skin or eyes. Wear long-sleeved, loose-fitting clothing, gloves, and eye protection

• Wash clothes separately from other clothing: rinse washer thoroughly

• Operations such as sawing, blowing, tear-out, and spraying may generate fiber concentrations requiring additional respiratory protection. Use the appropriate NIOSH approved respiration in these situations.

First Aid Measures

Eye Contact

– Flush eyes with water to remove dust. If symptoms persist, seek medical attention.

Skin Contact

– Wash affected areas gently with soap and warm water after handling.

Commonly used Acronyms

For convenience, a number of acronyms and abbreviations are used throughout this manual. These acronyms are alphabetically listed and defined below.

• AHU = Air Handler Unit • LCI-I = LonTalk Communication Interface for IntelliPak

• BAS = Building automation systems • LH = Left-hand

• BCI = BACnet Communication Interface module • MWU = Morning warm-up

• CFM = Cubic-feet-per-minute • NSB = Night setback

• CV = Constant volume • O/A = Outside air

• CW = Clockwise • psig = Pounds-per-square-inch, gauge pressure

• CCW = Counterclockwise • R/A = Return air

• E/A = Exhaust air • RH = Right-hand

• ECEM = Exhaust/comparative enthalpy module • RPM = Revolutions-per-minute

• F/A = Fresh air • RTM = Rooftop module

• GBAS = Generic building automation system • S/A = Supply air

• HGBP = Hot gas bypass • SZ = Single-zone (unit airflow)

• HI = Human Interface • SZVAV = Single zone variable air volume

• HVAC = Heating, ventilation and air conditioning • UCM = Unit control modules

• I/O = Inputs/outputs • VAV = Variable air volume

• IOM = Installation/operation/ maintenance manual • VCM = Ventilation control module

• IPC = Interprocessor communications • VOM = Ventilation override module

• IPCB = Interprocessor communications bridge • w.c. = Water column

RT-SVX28E-EN 9

General Information

Unit Description

Each Trane commercial, single-zone rooftop air handler ships fully assembled from the factory.

An optional roof curb, specifically designed for the W_HC units is available from Trane. The roof curb kit must be field assembled and installed according to the latest edition of the roof curb installation manual.

Trane Commercial Rooftop Air Handlers are controlled by a microelectronic control system that consists of a network of modules and are referred to as Unit Control Modules (UCM). The acronym UCM is used extensively throughout this document when referring to the control system network.

These modules through Proportional/Integral control algorithms perform specific unit functions which provide the best possible comfort level for the customer.

They are mounted in the control panel and are factory wired to their respective internal components. They receive and interpret information from other unit modules, sensors, remote panels, and customer binary contacts to satisfy the applicable request for economizing, mechanical cooling, heating, and ventilation. Refer to the following discussion for an explanation of each module function.

Rooftop Module (RTM - Standard on all units)

The rooftop Module (RTM) responds to cooling, heating, and ventilation requests by energizing the proper unit components based on information received from other unit modules, sensors, remote panels, and customer supplied binary inputs. It initiates supply fan, exhaust fan, exhaust damper, or variable frequency drive output, and economizer operation based on that information.

Human Interface Module (HI - standard on all units)

The Human Interface module enables the operator to adjust the operating parameters for the unit using a 16 key keypad. The 2 line, 40 character LCD screen provides status information for the various unit functions as well as menus for the operator to set or modify the operating parameters.

Heat Module (used on heating units)

The Heat module, upon receiving a request for Heating, energizes the appropriate heating stages or strokes the Modulating Heating valve as required.

Table 1. Resistance input vs. setpoint temperature

RTM cooling or heating setpoint

input used as the source for a

ZONE temp setpoint (F)

40 40 1084

45 45 992

50 50 899

55 55 796

60 60 695

65 65 597

70 70 500

75 75 403

80 80 305

n/a 85 208

n/a 90 111

RTM cooling setpoint input used as the source for SUPPLY AIR temp setpoint cooling (F)

Resistance

(Ohms) Max.

Tolerance 5%

10 RT-SVX28E-EN

General Information

Table 2. Resistance value vs. system operating mode

Resistance applied to RTM MODE

input Terminals (Ohms) Max.

Tolerance 5% Constant Volume Units

2320 Auto Off

4870 Auto Cool

7680 Auto Auto

10770 On Off

13320 On Cool

16130 On Auto

19480 Auto Heat

Ventilation Override Module (VOM - Optional)

Important: The ventilation override system should not be used to signal the presence of smoke

caused by a fire as it is not intended nor designed to do so.

The Ventilation Override module initiates specified functions such as; space pressurization, exhaust, purge, purge with duct pressure control, and unit off when any one of the five (5) binary inputs to the module are activated. If more than one ventilation sequence is activated, the one with the highest priority is initiated.

Interprocessor Communications Board (IPCB - Optional used with the Optional Remote Human Interface)

The Interprocessor Communication Board expands communications from the unit UCM network to a Remote Human Interface Panel. DIP switch settings on the IPCB module for this application should be; Switches 1 and 2 "Off", Switch 3 "On".

Lontalk/BACnet Communication Interface Module (LCI/BCI - Optional - used

™

on units with Trane ICS

or 3rd party Building Automation Systems)

The LonTalk/BACnet Communication Interface modules expand communications from the unit UCM network to a Trane Tracer Summit™ or a 3rd party building automation system and allow external setpoint and configuration adjustment and monitoring of status and diagnostics.

Exhaust/Comparative Enthalpy Module (ECEM - Optional used on units with Statitrac and/or comparative enthalpy options)

The Exhaust/Comparative Enthalpy module receives information from the return air humidity sensor, the outside air humidity sensor, and the return air temperature sensor to utilize the lowest possible humidity level when considering economizer operation. In addition, it receives space pressure information which is used to maintain the space pressure to within the setpoint controlband. Refer to Figure 1, p. 12 for the Humidity vs. Voltage input values.

RT-SVX28E-EN 11

General Information

Figure 1. Humidity vs. current

Ventilation Control Module (VCM)

The Ventilation Control Module (VCM) is located in the filter section of the unit and is linked to the unit UCM network. Using a "velocity pressure" sensing ring located in the fresh air section allows the VCM to monitor and control the quantity of fresh air entering the unit to a minimum airflow setpoint.

An optional temperature sensor can be connected to the VCM which enables it to control a field installed fresh air preheater.

An optional CO adjusts the minimum CFM upward as the CO (reset) setpoint value for fresh air entering the unit is limited to the systems operating CFM. The following table lists the Minimum Outside Air CFM vs. Input Voltage.

sensor can be connected to the VCM to control CO2 reset. The reset function

concentrations increase. The maximum effective

Table 3. Minimum outside air setpoint w/VCM and Traq™ sensing

Unit Input Volts CFM

Casings A-Cs 0.5 - 4.5 VDC 0 - 45000

The velocity pressure transducer/solenoid assembly is illustrated below. Refer to the “Units with

Traq™ Sensor,” p. 81 section for VCM operation.

Table 4. Velocity pressure transducer/solenoid assembly

12 RT-SVX28E-EN

Generic Building Automation System Module (GBAS - Optional used with non-Trane building control systems)

The Generic Building Automation System (GBAS) module allows a non-Trane building control system to communicate with the air handler unit and accepts external setpoints in the form of analog inputs for cooling, heating, supply air pressure, and a binary Input for demand limit. Refer to the "Field Installed Control Wiring" section for the input wiring to the GBAS module and the various desired setpoints with the corresponding DC voltage inputs for CV, VAV, and SZ VAV applications.

Input Devices and System Functions

The descriptions of the following basic Input Devices used within the UCM network are to acquaint the operator with their function as they interface with the various modules. Refer to the unit electrical schematic for the specific module connections.

Constant Volume (CV) and Variable Air Volume (VAV) Units

Chilled Water Valve Control

The 0 to 10 VDC output from the heat module doubles as the chilled water controller. The unit has isolating relays to switch between heat and cool.

Supply Air Temperature Sensor

An analog input device used with CV and VAV applications that monitors the supply air temperature for: supply air temperature control (VAV), supply air temperature reset (VAV), supply air temperature low limiting (CV), supply air tempering (CV/VAV). It is mounted in the supply air discharge section of the unit and is connected to the RTM.

General Information

Return Air Temperature Sensor

An analog input device used with a return humidity sensor on CV and VAV applications when the comparative enthalpy option is ordered. It monitors the return air temperature and compares it to the outdoor temperature to establish which temperature is best suited to maintain the cooling requirements. It is mounted in the return air section and is connected to the ECEM.

Filter Switch

A binary input device used on CV and VAV applications that measures the pressure differential across the unit filters. It is mounted in the filter section and is connected to the RTM. A diagnostic SERVICE signal is sent to the remote panel if the pressure differential across the filters is at least 0.5" w.c. The contacts will automatically open when the pressure differential across the filters decrease to 0.4" w.c. The switch differential can be field adjusted between 0.17" w.c. to 5.0" w.c. ± 0.05" w.c.

Supply and Exhaust Airflow Proving Switches

Supply Airflow Proving Switch is a binary input device used on CV and VAV applications to signal the RTM when the supply fan is operating. It is located in the supply fan section of the unit and is connected to the RTM. During a request for fan operation, if the differential switch is detected to be open for 40 consecutive seconds; heat operation is turned "Off", the request for supply fan operation is turned "Off" and locked out, exhaust dampers (if equipped) are "closed", economizer dampers (if equipped) are "closed", and a manual reset diagnostic is initiated.

Exhaust Airflow Proving Switch is a binary input device used on all air handler units equipped with an exhaust fan. It is located in the exhaust fan section of the unit and is connected to the RTM. During a request for fan operation, if the differential switch is detected to be open for 40 consecutive seconds, the economizer is closed to the minimum position setpoint, the request for exhaust fan operation is turned "Off" and locked out, and a manual reset diagnostic is initiated. The fan failure lockout can be reset at the Human Interface located in the unit control panel, by Tracer, or by cycling the control power to the RTM Off/On).

RT-SVX28E-EN 13

General Information

Supply and Exhaust Fan Circuit Breakers

The supply fan and exhaust fan motors are protected by circuit breakers. They will trip and interrupt the power supply to the motors if the current exceeds the breaker's "must trip" value. The rooftop module (RTM) will shut all system functions "Off" when an open fan proving switch is detected.

Outdoor Air Humidity Sensor

An analog input device used on CV and VAV applications with 100% economizer. It monitors the outdoor humidity levels for economizer operation. It is mounted in the fresh air intake section and is connected to the RTM.

Return Air Humidity Sensor

An analog input device used on CV and VAV applications with the comparative enthalpy option. It monitors the return air humidity level and compares it to the outdoor humidity level to establish which conditions are best suited to maintain the cooling requirements. It is mounted in the return air section and is connected to the ECEM.

Space Humidity Sensor

Analog input device used on CV and VAV applications with modulating dehumidification option and/or humidification field installed option. It is used to monitor the humidity level in the space and compared to dehumidification and humidification setpoints to maintain space humidity requirements. It is field mounted in the space and connected to the RTM.

Status/Annunciator Output

An internal function within the RTM module on CV and VAV applications that provides:

1. diagnostic and mode status signals to the remote panel (LEDs) and to the Human Interface

2. control of the binary Alarm output on the RTM

3. control of the binary outputs on the GBAS module to inform the customer of the operational status and/or diagnostic conditions

Table 5. Transducer voltage output vs. pressure input w/ multiple sensors

Space Pressure Transducer

An analog input device used on CV and VAV applications with the Statitrac option. It modulates the exhaust dampers to keep the space pressure within the building to a customer designated controlband. It is mounted in the filter section just above the exhaust damper actuator and is

14 RT-SVX28E-EN

General Information

connected to the ECEM. Field supplied pneumatic tubing must be connected between the space being controlled and the transducer assembly.

Morning Warm-Up—Zone Heat

When a system changes from an unoccupied to an occupied mode, or switches from STOPPED to AUTO, or power is applied to a unit with the MWU option, the heater in the unit or external heat will be brought on if the space temperature is below the MWU setpoint. The heat will remain on until the temperature reaches the MWU setpoint. If the unit is VAV, then the VAV box/unocc relay will continue to stay in the unoccupied position and the VFD output will stay at 100% during the MWU mode. When the MWU setpoint is reached and the heat mode is terminated, then the VAV box/unocc relay will switch to the occupied mode and the VFD output will be controlled by the duct static pressure. During Full Capacity MWU the economizer damper is held closed for as long as it takes to reach setpoint. During Cycling Capacity MWU the economizer damper is allowed to go to minimum position after one hour of operation if setpoint has not been reached.

Supply Air Temperature Low Limit

Uses the supply air temperature sensor input to modulate the economizer damper to minimum position in the event the supply air temperature falls below the occupied heating setpoint temperature.

Freezestat - Heating

A binary input device used on CV and VAV units with Hydronic Heat. It is mounted in the heat section and connected to the Heat Module. If the temperature of the air entering the heating coil falls to 40 F, the normally open contacts on the freezestat closes signalling the Heat Module and the Rooftop Module (RTM) to:

1. drive the Hydronic Heat Actuator to the full open position

2. turn the supply fan "Off"

3. closes the outside air damper

4. turns "On" the SERVICE light at the Remote Panel

5. initiates a "Freezestat" diagnostic to the Human Interface

Freezestat - Cooling

A binary input device used on CV and VAV units with Chilled Water. The freezestat is mounted on the upstream side of the cooling coil. If the temperature of the air entering the cooling coil falls to 40 F, the normally closed contacts on the freezestat open signalling the Rooftop Module (RTM) to:

1. drive the Chilled Water Actuator to the full open position

2. turn the supply fan "Off"

3. closes the outside air damper

4. turns "On" the SERVICE light at the Remote Panel

5. initiates a "Freezestat" diagnostic to the Human Interface

Chilled Water Valve Control

The 0 to 10 VDC output from the heat module doubles as the chilled water controller. The unit has isolating relays to switch between heat and cool.

Constant Volume (CV) Units

Zone Temperature—Cooling

Relies on input from a sensor located directly in the space, while a system is in the occupied "Cooling" mode. It modulates the economizer (if equipped) and/or stages the mechanical cooling "On and Off" as required to maintain the zone temperature to within the cooling setpoint deadband.

RT-SVX28E-EN 15

General Information

Zone Temperature—Heating

Relies on input from a sensor located directly in the space, while a system is in the occupied "Heating" mode or an unoccupied period, to stage the heat "on and off" or to modulate the heating valve (hydronic heat only) as required to maintain the zone temperature to within the heating setpoint deadband. The supply fan will be requested to operate any time there is a requested for heat. On gas heat units, the fan will continue to run for 60 seconds after the furnace is turned off.

Supply Air Tempering

On CV units equipped with staged heat, if the supply air temperature falls 10 F below the occupied heating setpoint temperature while the heater is "Off", the first stage of heat will be turned "On". The heater is turned "Off" when the supply air temperature reaches 10º F above the occupied heating setpoint temperature.

Variable Air Volume (VAV) Units

Occupied Heating—Supply Air Temperature

When a VAV unit is equipped with "Modulating Heat", and the system is in an occupied mode, and the field supplied changeover relay contacts have closed, the supply air temperature will be controlled to the customer specified supply air heating setpoint. It will remain in the heating status until the changeover relay contacts are opened.

Occupied Cooling—Supply Air Temperature

When a VAV unit is in the occupied mode, the supply air temperature will be controlled to the customer specified supply air cooling setpoint by modulating the economizer and/or staging the mechanical cooling "On and Off" as required. The changeover relay contacts must be open on units with "Modulating Heat" for the cooling to operate.

Daytime Warm-up

On VAV units equipped with heat, if the zone temperature falls below the daytime warm-up initiate temperature during the occupied mode, the system will switch to full airflow. During this mode, the VAV box/unocc relay will be energized (this is to signal the VAV boxes to go to 100%). After the VAV box max stroke time has elapsed (factory set at 6 minutes), the VFD output will be set to 100%. The airflow will be at 100% and the heat will be turned on to control to the occupied heating setpoint. When the zone temperature reaches the daytime warm-up termination setpoint, the heat will be turned off, the relay will be de-energized, releasing the VAV boxes, the VFD output will go back to duct static pressure control and the unit will return to discharge air control. If the occ zone heating setpoint is less than the DWU terminate setpoint, the heat will turn off when the occ zone heat setpoint is reached, but it will stay in DWU mode and cycle the heat to maintain setpoint.

Unoccupied Heating—Zone Temperature

When a VAV unit is equipped with gas, electric, or hydronic heat and is in the unoccupied mode, the zone temperature will be controlled to within the customer specified setpoint deadband. During an unoccupied mode for a VAV unit, the VAV box/unocc relay will be in the unoccupied position and the VFD output will be at 100%. This means that if there is a call for heat (or cool) and the supply fan comes on, it will be at full airflow and the VAV boxes in the space will need to be 100% open as signaled by the VAV box/unocc relay.Supply Air Tempering

On VAV units equipped with "Modulating Heat", if the supply air temperature falls 10 supply air temperature setpoint, the hydronic heat valve will modulate to maintain the supply air temperature to within the low end of the setpoint deadband.

F below the

Supply Duct Static Pressure Control (Occupied)

The RTM relies on input from the duct pressure transducer when a unit is equipped with a Variable Frequency Drive to position the supply fan speed to maintain the supply duct static pressure to within the static pressure setpoint deadband. Refer to Figure 2, p. 17.

16 RT-SVX28E-EN

Figure 2. Transducer voltage output vs. pressure input with multiple sensors

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Pressure (inches w.c.)

Volts

Single Zone Variable Air Volume (SZVAV) Only

The IntelliPak controls platform will support Single Zone VAV as an optional unit control type in order to meet ASHRAE 90.1. The basic control will be a hybrid VAV/CV configured unit that provides discharge temperature control to a varying discharge air temperature target setpoint based on the space temperature and/or humidity conditions. Concurrently, the unit will control and optimize the supply fan speed to maintain the zone temperature to a zone temperature setpoint.

General Information

Supply Fan Output Control

Units configured for Single Zone VAV control will utilize the same supply fan output control scheme as on traditional VAV units except the VFD signal will be based on zone heating and cooling demand instead of the supply air pressure.

VFD Control

Single Zone VAV units will be equipped with a VFD-controlled supply fan which will be controlled via a 0-10VDC signal from the Rooftop Module (RTM). With the RTM supply fan output energized and the RTM VFD output at 0VDC, the fan speed output is 37% (22Hz) from the VFD by default; and at 10VDC the fan speed output is 100% (60Hz). The control scales the 0-10VDC VFD output from the RTM linearly to control between the 37-100% range. The VFD will modulate the supply fan motor speed, accelerating or decelerating as required to maintain the zone temperature to the zone temperature setpoint. When subjected to high ambient return conditions the VFD will reduce its output frequency to maintain operation. Bypass control is offered to provide full nominal airflow in the event of drive failure.

Ventilation Control

Units configured for Single Zone VAV control will require special handling of the OA Damper Minimum Position control in order to compensate for the non-linearity of airflow associated with the variable supply fan speed and damper combinations. Units configured for TRAQ with or without DCV will operate identically to traditional units with no control changes.

RT-SVX28E-EN 17

Space Pressure Control

For units configured with Space Pressure Control with or without Statitrac, the new schemes implemented for economizer minimum position handling require changes to the existing Space Pressure Control scheme in order to prevent over/under pressurization. The overall scheme will remain very similar to VAV units with Space Pressure Control with the exception of the dynamic Exhaust Enable Setpoint.

For SZVAV an Exhaust Enable Setpoint must be selected during the 100% Fan Speed Command. Once selected, the difference between the Exhaust Enable Setpoint and Design OA Damper

General Information

Minimum Position at 100% Fan Speed Command will be calculated. The difference calculated will be used as an offset and added to the Active Building Design OA Minimum Position Target in order to calculate the dynamic Exhaust Enable Target, which will be used throughout the Supply Fan Speed/OA Damper Position range.

The Exhaust Enable Target could be above or below the Active Building Design OA Minimum Position Target Setpoint, based on the Active Exhaust Enable Setpoint being set above or below the Building Design Minimum Position at 100% Fan Speed Command. Note that an Exhaust Enable Setpoint of 0% will result in the same effect on Exhaust Fan control as on VAV applications with and without Statitrac.

Occupied Cooling Operation

For normal cooling operation, cooling capacity will be staged or modulated in order to meet the calculated discharge air target setpoint. If the current active cooling capacity is controlling the discharge air within the deadband, no additional cooling capacity change will be requested. As the Discharge Air Temperature rises above the deadband, the algorithm will request additional capacity as required (additional compressors or economizer). As the Discharge Air Temperature falls below the deadband, the algorithm will request a reduction in active capacity.

Default Economizer Operation

By default, the unit will be setup to optimize the minimum supply fan speed capability during Economizer Only operation. If the economizer is able to meet the demand alone, due to desirable ambient conditions, the supply fan speed will be allowed to increase above the minimum prior to utilizing mechanical cooling if discharge air setpoint falls below the discharge air Lower Limit (Cooling) setpoint.

Unoccupied Mode

In Unoccupied mode the unit will utilize setback setpoints, 0% Minimum OA Damper position, and Auto Fan Mode operation as on normal CV units. The Supply Fan speed, and cooling and modulating types of heat, will be controlled to the discharge air target setpoint as is done during occupied periods. The Supply fan speed during staged heat control will be forced to 100% as on normal CV units.

Occupied Heating Operation

Occupied heating operation has two separate control sequences; staged and modulated. All staged heating types will drive the supply fan to maximum flow and stage heating to control to the Zone Heating Setpoint. For units with Hydronic and Gas heat, modulated SZVAV Heating. On an initial call for heating, the supply fan will drive to the minimum heating airflow. On an additional call for heating, the heat will control in order to meet the calculated discharge air target setpoint. As the load in the zone continues to request heat operation, the supply fan will ramp-up while the control maintains the heating discharge air temperature. Heating can be configured for either the energy saving SZVAV Heating solution as described above, or the traditional, less efficient CV Heating solution.

Compressor (DX) Cooling

Compressor control and protection schemes will function identical to that of a traditional unit. Normal compressor proving and disable input monitoring will remain in effect as well as normal 3-minute minimum on, off, and inter-stage timers. Also, all existing head pressure control schemes will be in effect.

Cooling Sequence

If the control determines that there is a need for active cooling capacity in order to meet the calculated discharge air target setpoint, once supply fan proving has been made, the unit will begin to stage compressors accordingly. Note that the compressor staging order will be based on unit configuration and compressor lead/lag status.

18 RT-SVX28E-EN

Once the discharge air target setpoint calculation has reached the Minimum Setpoint and compressors are being utilized to meet the demand, as the discharge air target setpoint value continues to calculate lower the algorithm will begin to ramp the supply fan speed up toward 100%. Note that the supply fan speed will remain at the compressor stage’s associated minimum value (as described below) until the discharge air target setpoint value is calculated below the discharge air temperature Minimum Setpoint (limited discharge air target setpoint).

As the cooling load in the zone decreases the zone cooling algorithm will reduce the speed of the fan down to minimum per compressor stage and control the compressors accordingly. As the compressors begin to de-energize, the supply fan speed will fall back to the Cooling Stage’s associated minimum fan speed, but not below. As the load in the zone continues to drop, cooling capacity will be reduced in order to maintain the discharge air within the ± ½ discharge air target deadband.

Space Temperature Averaging

Space temperature averaging for Constant Volume applications is accomplished by wiring a number of remote sensors in a series/parallel circuit.

The fewest number of sensors required to accomplish space temperature averaging is four. The Space Temperature Averaging with Multiple Sensors figure illustrates a single sensor circuit (Single Zone), four sensors wired in a series/parallel circuit (Four Zone), nine sensors wired in a series/parallel circuit (Nine Zone). Any number squared, is the number of remote sensors required.

Wiring termination will depend on the type of remote panel or control configuration for the system. Refer to the wiring diagrams that shipped with the unit.

General Information

Table 6. Space temperature averaging with multiple sensors

RT-SVX28E-EN 19

General Information

Return/

Exhaust

Fan

Fresh Air Dampers

Supply Fan

Heating Section

Exhaust Damper

Hood

Variable

Frequency

Drive (VFD)

Filter Section

Chilled Water Coil

Fresh Air Dampers

Return Air Dampers

Flue Vent

Access

Variable

Frquency

Drive (VFD)

Hot Water/Steam

Hydronic Connection

valves and actuator

Outside Air

Static Kit and

sensors

Baysens set

Controls

Table 7. Unit component layout and "ship with" locations

Unit Control Modules

Unit control modules are microelectronic circuit boards designed to perform specific unit functions. These modules, through proportional/integral control algorithms, provide the best possible comfort level for the customer. They are mounted in the control panel and are factory wired to their respective internal components. They receive and interpret information from other unit modules, sensors, remote panels, and customer binary contacts to satisfy the applicable request for economizing, mechanical cooling, heating, and ventilation. Figure 3, p. 21 illustrates the typical location of each designated module.

20 RT-SVX28E-EN

Figure 3. Control module locations

BCI

General Information

RT-SVX28E-EN 21

Dimensional Data

Blank Section

Cool

Coil

(F)

Fltr

(F)

Sup

Mtr

Sup VFD

Fltr (R)

Cool Coil

(R)

Heat

(L&R)

OptionStd

As Req. As Req.StdStd

Std

Rtn Mtr

Rtn

VFD

As Req.

Std

ER Fltr

(L&R) (F)

Std

ER Fltr

(L&R) (R)

Std

Final Filter

Fnl

Fltr (F)

As Req.

Fnl

Fltr (R)

As Req.

Filters

VFD

Heat

VFD

Ctrl Box

(L&R)

Std

Exhaust

Air

Exh

AH R

AH L

C Box

Unit Clearance

Figure 4. Minimum required clearance

(i) Unit drawing is representative only and may not accurately depict all models.

Table 8. Minimum required clearance

Door Location Availability A,B,C

Exhaust Motor Std 2' 2" * * * * *

Exhaust VFD As Req. * 2' 2" * * * *

Filter (Front) Std2' 8"*****

Filter (Rear) Option * * * * 2’ 2" *

Cooling Coil (Front) Std 2' 2" * * * * *

Cooling Coil (Rear) Std 2' 8" * * * * *

or Cooling Coil (Rear)Option******

Supply Motor Std2' 8"*****

Supply VFD As Req. * * 2' 2" * * *

Heat (Left & Right) As Req. * * * 2' 2" * *

Final Filter (Front) As Req. * * * * * 2' 2"

Final Filter (Rear) As Req. * * * * * 2' 2"

Control Box (L & R)Std3' 2"*****

Minimum Required Clearance (Ft.)

AH_L AH_R Exh

8’ 8’ 8’ 6’

(i)

Fresh

Unit Option Selection (Door Swing Ft. and In.)

Standard VFD Heat

Return/ Exhaust Supply

Control

Box

Electric/

Water/

Steam

Hot

Two-side

Access Final Filter

22 RT-SVX28E-EN

Figure 5. Multiple units placement

Outdoor

Air Intake

Outdoor

Air Intake

Exhaust Air

Outdoor

Air Intake

Outdoor

Air Intake

Exhaust Air

Dimensional Data

Important: Stagger units to minimize span deflection which deters sound transmission and to

maximize proper diffusion of the exhaust air before it reaches the adjacent unit fresh air intake.

RT-SVX28E-EN 23

Dimensional Data

1-1/4 NPT. DRAIN 2X TYP. LEFT & RIGHT SIDES OF UNIT

Detail A

Unit Dimensions

Figure 6. Unit top/front view

24 RT-SVX28E-EN

Table 9. Unit dimensions (In.)

ONE-PIECE Dimensions

Lifting Lug Locations

Unit Dimensions Air Handler Side Unit Width

Blank

Casing

A, B, C

Section A B C1C2C3C4 M N

None 334 2/16 159 15/16 66 252 14/16 n/a n/a 139 13/16 143 8/16

4Ft 382 5/16 159 15/16 66 252 14/16 368 6/16 n/a 139 13/16 143 8/16

8Ft 430 9/16 159 15/16 66 252 14/16 416 10/16 n/a 139 13/16 143 8/16

Unit Height

Return

Fan

Exhaust

Fan

Casing O P J K

103 12/16 97 9/16 29 3/16 17

A, B, C

103 12/16 97 9/16 29 3/16 17

Table 10. Downflow/horizontal airflow configuration dimensions (in.)

Dimensional Data

Casing Gas Heat

No Gas None 14 13/16 8 14/16 48 3/16 121 15/16 14 13/16 42 14/16 48 3/16 53 14/16

No Gas 4Ft 14 13/16 8 14/16 48 3/16 121 15/16 14 13/16 42 14/16 48 3/16 53 14/16

A, B, C

No Gas 8Ft 14 13/16 8 14/16 48 3/16 121 15/16 14 13/16 42 14/16 48 3/16 53 14/16

Gas None 14 13/16 8 14/16 48 3/16 121 15/16 14 13/16 42 14/16 48 3/16 53 14/16

Gas 8Ft 14 13/16 8 14/16 48 3/16 121 15/16 14 13/16 42 14/16 48 3/16 53 14/16

Casing Gas Heat

No Gas None 256 1/16 13 47 14/16 102 8/16

No Gas 4Ft 304 4/16 13 47 14/16 102 8/16

A, B, C

No Gas 8Ft 352 8/16 13 47 14/16 102 8/16

Gas None 256 1/16 13 47 14/16 102 8/16

Gas 8Ft 352 8/16 13 47 14/16 102 8/16

Casing Gas Heat

No Gas None 9 5/16 10 10/16 54 12/16 84 15/16 6 5/16 8 3/16 35 3/16 127 2/16

No Gas 4Ft 9 5/16 10 10/16 54 12/16 84 15/16 6 5/16 8 3/16 35 3/16 127 2/16

A, B, C

No Gas 8Ft 9 5/16 10 10/16 54 12/16 84 15/16 6 5/16 8 3/16 35 3/16 127 2/16

Gas None 9 5/16 10 10/16 54 12/16 84 15/16 6 5/16 8 3/16 35 3/16 127 2/16

Gas 8Ft 9 5/16 10 10/16 54 12/16 84 15/16 6 5/16 8 3/16 35 3/16 127 2/16

DOWNFLOW Opening Dimensions

Return Opening—with or

without Exhaust Fan

Return Opening—with Return Fan

Blank

SectionX1Y1W1L1X1Y1W1L1

DOWNFLOW Opening Dimensions

Supply Opening

Blank

Section X2 Y2 W2 L2

HORIZONTAL Opening Dimensions

Return Side Opening Return End Opening

Blank

SectionX3Y3W3H1X1Y3H3H1

RT-SVX28E-EN 25

Dimensional Data

3 4

1 4

3 4

Ø3

5 8

Ø1

7 8

Marine lights

customer supplied power service entrance

Unit power

External customer connection points

Outside edge of base rail

5 8

Ø1

Table 10. Downflow/horizontal airflow configuration dimensions (in.)

HORIZONTAL Opening Dimensions

Supply Opening

Casing Gas Heat

No Gas None 254 12/16 10 10/16 54 12/16 84 15/16

No Gas 4Ft 302 15/16 10 10/16 54 12/16 84 15/16

A, B, C

No Gas 8Ft 351 3/16 10 10/16 54 12/16 84 15/16

Gas None 254 12/16 10 10/16 54 12/16 66 11/16

Gas 8Ft 351 3/16 10 10/16 54 12/16 84 15/16

Blank

Section X4 Y4 W4 H2

Figure 7. Electrical entry details/bottom view

26 RT-SVX28E-EN

Figure 8. Chilled water piping locations

Dimensional Data

Figure 9. Piping enclosure

RT-SVX28E-EN 27

Pre-Installation

General Unit Requirements

The checklist below is a summary of the steps required to successfully install a commercial rooftop air handler. This checklist is intended to acquaint the installing personnel with what is required in the installation process. It does not replace the detailed instructions called out in the applicable sections of this manual.

• Check the unit for shipping damage and material shortage; file a freight claim and notify Trane office.

• Verify that the installation location of the unit will provide the required clearance for proper operation.

• Assemble and install the roof curb. Refer to the current edition of the roof curb installer’s guide.

• Install and connect condensate drain lines to each cooling coil drain connection.

Figure 10. Sealed ductwork

• Fabricate and install ductwork; secure ductwork to curb. Seal the corners of duct adapters as shown in Figure 10. Ducting attached to the unit should be self supporting. Do not use the unit to support the weight of the ducting

• Install pitch pocket for power supply through building roof. (If applicable)

28 RT-SVX28E-EN

Rigging the Unit

• Set the unit onto the curb; check for levelness.

• Ensure unit-to-curb seal is tight and without buckles or cracks.

• Remove the shipping hold-down bolts and shipping channels from the supply and exhaust fans with spring isolators.

• Check all supply and exhaust fan spring isolators for proper adjustment.

Main Electrical Power Requirements

• Verify that the power supply complies with the unit nameplate specifications.

• Inspect all control panel components; tighten any loose connections.

• Connect properly sized and protected power supply wiring to a field-supplied/installed disconnect and unit

• Properly ground the unit.

• All field-installed wiring must comply with NEC and applicable local codes.

Field Installed Control Wiring

• Complete the field wiring connections for the constant volume controls as applicable. Refer to "Field Installed Control Wiring" for guidelines.

• Complete the field wiring connections for the variable air volume controls as applicable. Refer to "Field Installed Control Wiring" for guidelines.

Note: All field-installed wiring must comply with NEC and applicable local codes.

Pre-Installation

Requirements for Electric Heat Units

• Verify that the power supply complies with the electric heater specifications on the unit and heater nameplate.

• Inspect the heater junction box and control panel; tighten any loose connections.

• Check electric heat circuits for continuity.

Requirement for Gas Heat

• Gas supply line properly sized and connected to the unit gas train.

• All gas piping joints properly sealed.

• Drip leg Installed in the gas piping near the unit.

• Gas piping leak checked with a soap solution. If piping connections to the unit are complete, do not pressurize piping in excess of 0.50 psig or 14 inches w.c. to prevent component failure.

• Main supply gas pressure adequate.

• Flue Tubes clear of any obstructions.

• Factory-supplied flue assembly installed on the unit.

• Connect the 3/4" CPVC furnace drain stubout to a proper condensate drain.

Requirements for Hot Water Heat

• Route properly sized water piping through the base of the unit into the heating section.

• Install the factory-supplied, 3-way modulating valve.

• Complete the valve actuator wiring.

RT-SVX28E-EN 29

Pre-Installation

Base rail

Cleanout Plug

1 4

Inch NPT

Female Connection

Field supplied condensate piping

5.5"

2.5"

Requirements for Steam Heat

• Route properly sized steam piping through the base of the unit into the heating section.

• Install the factory-supplied, 2-way modulating valve

• Complete the valve actuator wiring.

• Install 1/2", 15-degree swing-check vacuum breaker(s) at the top of each coil section. Vent breaker(s) to the atmosphere or merge with return main at discharge side of steam trap.

• Position the steam trap discharge at least 12" below the outlet connection on the coil.

• Use float and thermostatic traps in the system, as required by the application.

Requirements for Chilled Water Cooling

• Install and connect condensate drain lines to each cooling coil drain connection.

• Route properly sized water piping through the back of the unit.

• Install external piping enclosure.

• Install the factory-supplied, 3-way modulating valve.

• Complete the valve actuator wiring.

O/A Pressure Sensor and Tubing Installation (all units with Statitrac)

• O/A pressure sensor mounted to the roof bracket.

• Factory supplied pneumatic tubing installed between the O/A pressure sensor and the connector on the vertical support.

• Field supplied pneumatic tubing connected to the proper fitting on the space pressure transducer located in the filter section, and the other end routed to a suitable sensing location within the controlled space.

Condensate Drain Connections

Each unit provides two 1-1/4" cooling coil condensate drain connections on each side of the unit.

Due to the size of these units, all condensate drain connections must be connected to the cooling coil drain connections. Refer to Detail A in Figure 6, p. 24 for the location of these drain connections.

A condensate trap must be installed due to the drain connection being on the "negative pressure" side of the fan. Install the P-Traps at the unit using the guidelines in Figure 11.

Figure 11. Condensate trap installation

30 RT-SVX28E-EN

+ 100 hidden pages

Trane WEHC, WSHC, WFHC, WXHC, WLHC Installation and Maintenance Manual

Overview of Manual

Table of Contents

Model Number Descriptions

General Information

Dimensional Data

Pre-Installation