Trane Oa1D Oa2D Oa3D Indirect Gas Fired Electric Heat Installation And Maintenance Manual OAU SVX01E EN (17 Apr 2014)

2015-04-02

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Page Count: 56

Introduction
- Warnings, Cautions, and Notices
  - Important Environmental Concerns
  - Important Responsible Refrigerant Practices
Model Number Descriptions
- Horizon Outdoor Air Unit
General Information
Unit Clearances, Curb Dimensions, and Dimensional Data
Unit Weight and Rigging
Sequence of Operation
- Space Control with Indirect Gas- Fired or Electric Heat and Modulating HGRH, ERV, and Powered Ex.
  - Sequence of Operation—”Occupied”
  - Sequence of Operation—”Unoccupied”
- Discharge Air Control with Indirect Gas-Fired or Electric Heat and Modulating HGRH, ERV, and Powered Ex.
  - Sequence of Operation—”Occupied”
  - Sequence of Operation—”Unoccupied”
Installation
System Configuration and Pre-Start
Start-Up
- Indirect Gas-Fired Heating Start-Up
  - Start-Up Procedure
  - Safety Controls
Maintenance
- Monthly Maintenance
- Final Process
Performance Data
- Superheat and Refrigeration Circuit Data
Alarms and Troubleshooting
Appendix
- OAU Filter Guide

SAFETY WARNING

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.

Installation, Operation,

and Maintenance

Important: Proper execution of the tasks outlined in this Installation, Operation, and Maintenance manual

require and assume the technician has been certified as a start up technician for the Horizon Outdoor

Air unit. This includes working knowledge of the Tracer TU program.

Horizon™ Outdoor Air Unit

Indirect Gas-Fired/Electric Heat

Models: OA1D, OA2D, OA3D

OAU-SVX01E-EN

April 2014

Introduction

Read this manual thoroughly before operating or servicing

this unit.

Warnings, Cautions, and Notices

Safety advisories appear throughout this manual as

required. Your personal safety and the proper operation of

this machine depend upon the strict observance of these

precautions.

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.

Important 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.

The three types of advisories are defined as follows:

WARNING Indicates a potentially hazardous

situation which, if not avoided, could

result in death or serious injury.

CAUTIONsIndicates 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.

NOTICE: Indicates a situation that could result in

equipment or property-damage only

accidents.

WARNING

Proper Field Wiring and Grounding

Required!

Failure to follow code could result in death or serious

injury. 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.

WARNING

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 PPE required for the work being

undertaken (Examples; cut resistant gloves/sleeves,

butyl gloves, safety glasses, hard hat/bump cap, fall

protection, electrical PPE and arc flash clothing).

ALWAYS refer to appropriate Material Safety Data

Sheets (MSDS)/Safety Data Sheets (SDS) and OSHA

guidelines for proper PPE.

• When working with or around hazardous chemicals,

ALWAYS refer to the appropriate MSDS/SDS and

OSHA/GHS (Global Harmonized System of

Classification and Labelling of Chemicals) guidelines

for information on allowable personal exposure

levels, proper respiratory protection and handling

instructions.

• If there is a risk of energized electrical contact, arc, or

flash, technicians MUST put on all PPE in accordance

with OSHA, NFPA 70E, or other country-specific

requirements for arc flash protection, PRIOR to

servicing the unit. NEVER PERFORM ANY

SWITCHING, DISCONNECTING, OR VOLTAGE

TESTING WITHOUT PROPER ELECTRICAL PPE AND

ARC FLASH CLOTHING. ENSURE ELECTRICAL

METERS AND EQUIPMENT ARE PROPERLY RATED

FOR INTENDED VOLTAGE.

Failure to follow instructions could result in death or

serious injury.

Introduction

OAU-SVX01E-EN 3

This document and the information in it are the property of

Trane, and may not be used or reproduced in whole or in

part without written permission. Trane reserves the right

to revise this publication at any time, and to make changes

to its content without obligation to notify any person of

such revision or change.

Trademarks

All trademarks referenced in this document are the

trademarks of their respective owners.

Revision History

OAU-SVX01E-EN (17 Apr 2014)

• Model number updates

WARNING

Contains Refrigerant!

System contains oil and refrigerant under high

pressure. Recover refrigerant to relieve pressure before

opening the system. See unit nameplate for refrigerant

type. Do not use non-approved refrigerants, refrigerant

substitutes, or refrigerant additives.

Failure to follow proper procedures or the use of non-

approved refrigerants, refrigerant substitutes, or

refrigerant additives could result in death or serious

injury or equipment damage.

WARNING

Hazard of Explosion and Deadly Gases!

Never solder, braze or weld on refrigerant lines or any

unit components that are above atmospheric pressure

or where refrigerant may be present. Always remove

refrigerant by following the guidelines established by

the EPA Federal Clean Air Act or other state or local

codes as appropriate. After refrigerant removal, use dry

nitrogen to bring system back to atmospheric pressure

before opening system for repairs. Mixtures of

refrigerants and air under pressure may become

combustible in the presence of an ignition source

leading to an explosion. Excessive heat from soldering,

brazing or welding with refrigerant vapors present can

form highly toxic gases and extremely corrosive acids.

Failure to follow all proper safe refrigerant handling

practices could result in death or serious injury.

4 OAU-SVX01E-EN

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Warnings, Cautions, and Notices . . . . . . . . 2

Important Environmental Concerns . . . . . 2

Important Responsible Refrigerant Practices

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Model Number Descriptions . . . . . . . . . . . . . . 6

Horizon Outdoor Air Unit . . . . . . . . . . . . . . . 6

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

Overview of Manual . . . . . . . . . . . . . . . . . . 9

Model Number Description . . . . . . . . . . . . 9

Unit Nameplate . . . . . . . . . . . . . . . . . . . . . 9

Compressor Nameplate . . . . . . . . . . . . . . . 9

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

Indoor Fan Failure Input . . . . . . . . . . . . . . 9

Low Pressure Control ReliaTel Control . . 9

Refrigerant Circuits . . . . . . . . . . . . . . . . . . 9

High Pressure Control ReliaTel Control . . 9

Space Temperature / RH Sensor (Optional)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

High Temperature Sensor . . . . . . . . . . . . 10

Outdoor Air Temperature and Relative Hu-

midity Sensor . . . . . . . . . . . . . . . . . . . . . . 10

Control Input (Occupied / Unoccupied) . 10

Hot Gas Reheat . . . . . . . . . . . . . . . . . . . . . 10

100 Percent Outdoor Air Hood with Damper

and Filters . . . . . . . . . . . . . . . . . . . . . . . . . 10

Modulating Indirect Gas-Fired Burner . . 10

Through the Base Electrical with Disconnect

Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Through the Base Gas Piping . . . . . . . . . 10

Hinged Access Doors . . . . . . . . . . . . . . . . 10

Modulating Electric Heat . . . . . . . . . . . . . 10

Unit Inspection . . . . . . . . . . . . . . . . . . . . . . . 11

First Aid Measures . . . . . . . . . . . . . . . . . . 11

Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Unit Clearances . . . . . . . . . . . . . . . . . . . . 11

Unit Clearances, Curb Dimensions, and Dimen-

sional Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

OA1 Units . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Unit Clearances . . . . . . . . . . . . . . . . . . . . 12

Curb Dimensions . . . . . . . . . . . . . . . . . . . .12

Dimensional Data . . . . . . . . . . . . . . . . . . . .13

OA2 Units . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Unit Clearances . . . . . . . . . . . . . . . . . . . . .14

Curb Dimensions . . . . . . . . . . . . . . . . . . . .15

Dimensional Data . . . . . . . . . . . . . . . . . . . .15

OA3 Units . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Unit Clearances . . . . . . . . . . . . . . . . . . . . .16

Curb Dimensions . . . . . . . . . . . . . . . . . . . .17

Dimensional Data . . . . . . . . . . . . . . . . . . . .17

Unit Weight and Rigging . . . . . . . . . . . . . . . . .18

Unit Weight . . . . . . . . . . . . . . . . . . . . . . . . .18

Corner Weight . . . . . . . . . . . . . . . . . . . . . .19

Rigging . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Sequence of Operation . . . . . . . . . . . . . . . . . . .21

Space Control with Indirect Gas-Fired or Elec-

tric Heat and Modulating HGRH, ERV, and

Powered Ex. . . . . . . . . . . . . . . . . . . . . . . . . . .21

Sequence of Operation—”Occupied” . . .21

Sequence of Operation—”Unoccupied” .22

Discharge Air Control with Indirect Gas-Fired

or Electric Heat and Modulating HGRH, ERV,

and Powered Ex. . . . . . . . . . . . . . . . . . . . . . .23

Sequence of Operation—”Occupied” . . .23

Sequence of Operation—”Unoccupied” .24

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . .25

General Unit Requirements . . . . . . . . . . . .25

Main Electrical Power Requirements . . . .26

Condensate Drain Configuration . . . . . . .26

Filter Installation . . . . . . . . . . . . . . . . . . . . .26

Field Installed Power Wiring . . . . . . . . . . .26

Main Unit Power . . . . . . . . . . . . . . . . . . . . . .28

Standard Wiring . . . . . . . . . . . . . . . . . . . . .28

Voltage Imbalance . . . . . . . . . . . . . . . . . . .28

Electrical Phasing (Three-Phase Motors) .29

Compressor Crankcase Heaters . . . . . . . .29

Main Unit Display and ReliaTel Controls .30

Field-Installed Control Wiring . . . . . . . . . .30

Control Power Transformer . . . . . . . . . . .30

OAU-SVX01E-EN 5

Controls Using 24 Vac . . . . . . . . . . . . . . . 30

Controls Using DC Analog Input/Output

(Standard Low Voltage Multiconductor Wire)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

DC Conductors . . . . . . . . . . . . . . . . . . . . . . . 31

System Configuration and Pre-Start . . . . . . 33

Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Indirect Gas-Fired Heating Start-Up . . . . . 36

Start-Up Procedure . . . . . . . . . . . . . . . . . 36

Safety Controls . . . . . . . . . . . . . . . . . . . . . 39

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Monthly Maintenance . . . . . . . . . . . . . . . . . 40

Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Supply/Return Air Smoke Detector Mainte-

nance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Cooling Season . . . . . . . . . . . . . . . . . . . . 40

Heating Season . . . . . . . . . . . . . . . . . . . . 40

Condenser Coil Cleaning . . . . . . . . . . . . . 40

Final Process . . . . . . . . . . . . . . . . . . . . . . . . . 41

Performance Data . . . . . . . . . . . . . . . . . . . . . . 42

Superheat and Refrigeration Circuit Data 48

Alarms and Troubleshooting . . . . . . . . . . . . 52

Microprocessor Control . . . . . . . . . . . . . . 52

System Alarms . . . . . . . . . . . . . . . . . . . . . 52

Sensor Failure Alarm Display . . . . . . . . . 52

RTRM Failure Modes . . . . . . . . . . . . . . . . 54

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

OAU Filter Guide . . . . . . . . . . . . . . . . . . . . . 55

6 OAU-SVX01E-EN

Model Number Descriptions

Horizon Outdoor Air

Unit

Digit 1, 2 — Unit Type

OA = Outdoor Air

Digit 3 — Cabinet Size

1 = 625 cfm–4,000 cfm

2 = 1,500 cfm–9,000 cfm

3 = 3,750 cfm–13,500 cfm

Digit 4 — Major Design

Sequence

C = Revision 4

D = Revision 5

E = Heat Pump

Digit 5, 6, 7 — Normal Gross

Cooling Capacity (MBh)

000= No Cooling

060= 5 Tons High Efficiency

072= 6 Tons High Efficiency

084= 7 Tons High Efficiency

096= 8 Tons High Efficiency

120 = 10 Tons High Efficiency

144 = 12 Tons High Efficiency

180 = 15 Tons High Efficiency

210 = 17 Tons High Efficiency

240= 20 Tons High Efficiency

264= 22 Tons High Efficiency

300= 25 Tons High Efficiency

360= 30 Tons High Efficiency

420= 35 Tons High Efficiency

480= 40 Tons High Efficiency

540= 45 Tons High Efficiency

600= 50 Tons High Efficiency

648= 54 Tons High Efficiency

Digit 8 — Minor Design

Sequence

Digit 9 — Voltage Selection

1 = 115/60/1

2 = 208-230/60/1

3 = 208-230/60/3

4 = 460/60/3

5 = 575/60/3

Digit 10 — Reserved for Future

Use

Digit 11 — Evaporator Type

0 = No Cooling

A = DX 3-Row

B = DX 4-Row

C = DX 4-Row Interlaced

D = DX 6-Row Interlaced

E = DX 8-Row

F = Glycol/Chilled Water Coil

G = DX 4-Row with

MSP® Technology

Digit 12 — Hot Gas Reheat

0= No HGRH

1 = Fin and Tube Modulating

2 = Fin and Tube On/Off

3 = Microchannel Modulating

4 = Microchannel On/Off

Digit 13 — Compressor

0= No Compressors

A = Scroll Compressors

B = Digital Scroll (1st Circuit Only)

C = Digital Scroll (1st and 2nd Circuit)

D = Variable Speed Scroll (1st

Circuit Only)

E = Variable Speed Scroll (1st and

2nd Circuit)

Digit 14 — Condenser

0 = No Condenser

1 = Air-Cooled Fin and Tube

2 = Air-Cooled Fin and Tube

w/Head Pressure On/Off Control

3 = Water-Cooled DX Condenser

Copper/Steel

4 = Air-Cooled Fin and Tube

w/Head Pressure Variable Speed

5 = Air-Cooled Microchannel

6 = Air-Cooled Microchannel

w/Head Pressure On/Off Control

7 = Air-Cooled Microchannel

Variable Speed

8 = Water-Cooled DX Condenser

Copper/Nickel

Digit 15 — Refrigerant Capacity

Control

0 = No RCC Valve

A = RCC Valve on 1st Circuit

B = RCC Valve on 1st and 2nd Circuit

C = ERCC Valve on 1st Circuit

D = ERCC Valve on 1st and 2nd Circuit

E = HGBP Valve on 1st Circuit

F = HGBP Valve on 1st and

2nd Circuit

Digit 16 — Indoor Fan Motor

(IFM)

0 = Direct Drive w/VFD

1 = Direct Drive (VFD by Others)

2 = Belt Drive

3 = Belt Drive w/VFD

4 = Direct Drive w/Shaft Grounding

Ring w/VFD

5 = Special Motor Option

Digit 17 — Indoor Fan Wheel

A=122

B = 122.6

C=150

D = 150.6

E=165

F = 165.6

G=182

H = 182.6

J=200

K = 200.6

L = 182 X 2

M = 182.6 X 2

Digit 18 — Indoor Fan Motor

Power (hp)

A = 1/2 hp—1800 rpm

B = 1/2 hp—3600 rpm

C = 3/4 hp—1800 rpm

D = 3/4 hp—3600 rpm

E = 1 hp—1800 rpm

F = 1 hp—3600 rpm

G = 1.5 hp—1800 rpm

H = 1.5 hp—3600 rpm

J = 2 hp—1800 rpm

K = 2 hp—3600 rpm

L = 3 hp—1800 rpm

M = 3 hp—3600 rpm

N = 5 hp—1800 rpm

P = 5 hp—3600 rpm

R = 7.5 hp—1800 rpm

S = 7.5 hp—3600 rpm

T = 10 hp—1800 rpm

U = 10 hp—3600 rpm

V = 15 hp—1800 rpm

W = 15 hp—3600 rpm

Digit 19 — Reserved for Future

Use

Digit 20 — Heat Type (PRI/SEC)

0 = No Heat

A = Indirect-Fired (IF)

B = Direct-Fired (DF)

C = Electric—4-Stage

D = Electric—SCR Modulating

E = Dual Fuel (PRI-IF/SEC-DF)

F = Dual Fuel (PRI-ELEC/SEC-DF)

G = Dual Fuel (PRI-IF/SEC-ELEC)

H = Dual Fuel (PRI-ELEC/SEC-ELEC)

J= Hot Water

K = Steam

Digit 21 — Primary Fuel Type

0 = No Heat

1= Natural Gas

2= Propane

3 = Electric—Open Coil

4 = Electric—Sheathed Coil

5=Hot Water

6 = Steam

OA2D300A4-D1A1A0GM-G1KB0AC3CJ -A41B102A0

1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839

Model Number Descriptions

OAU-SVX01E-EN 7

Digit 22 — Heat Capacity

(Primary Heat Source)

Digit 23 — Heat Capacity

(Secondary Heat Source)

Digit 24 — Corrosive

Environment Package

0 = No Corrosive Package

1 = S/S Cabinet, Basepan,

Eco-Coated Coils

2 = S/S Cabinet, Basepan

3 = S/S Basepan, Eco-Coated Coils

4 = S/S Coil Casing

5 = S/S Interior Casing

6 = Eco-Coated Coils

7 = S/S Coil Casing with

Eco-Coated Coils

8 = Copper/Copper Condenser,

Evap, HGRH Coils

Digit 25, 26 — Unit Controls

00 = Non-DDC—Electromechanical

AA = Trane—Discharge Air Control

w/LON Read-Write w/Display

AB = Trane—Space Control w/LON

Read-Write w/Display

AC = Trane—Discharge Air Control

w/BACnet® (No Display)

AD = Trane—Space Control

w/BACnet (No Display)

AF = Trane—Discharge Air Control

w/BACnet w/Display

AG = Trane—Space Control

w/BACnet w/Display

AH = Trane—Discharge Air Control

w/BACnet w/Display

AI = Trane—Discharge Air Control

w/LON Read-Write (No Display)

AJ = Trane—Space Control

w/LON Read-Write (No Display)

AK = Trane—Multi-Zone VAV Control

w/LON Read-Write w/Display

AL = Trane—Multi-Zone VAV Control

w/BACnet w/Display

AM= Trane—Multi-Zone VAV Control

w/LON Read-Write (No Display)

AN = Trane—Multi-Zone VAV Control

w/BACnet (No Display)

AO = Trane—Single-Zone VAV Control

w/LON Read-Write w/Display

AP = Trane—Single-Zone VAV Control

w/BACnet w/Display

AQ = Trane—Single-Zone VAV Control

w/LON Read-Write (No Display)

AR = Trane—Single-Zone VAV Control

w/BACnet (No Display)

Digit 27 — Powered Exhaust Fan

Motor (PFM) and Exhaust

Dampers

0 = No Powered Exhaust

1 = Direct Drive w/VFD and Gravity

Dampers

2 = Direct Drive (VFD by Others)

3 = Belt Drive

4 = Belt Drive w/VFD

5 = Special Motor Option

6 = Direct Drive w/VFD and

Barometric Relief Damper

7 = Direct Drive w/VFD and Isolation

Dampers w/End Switch

8 = Barometric Relief Dampers

(NO PFM)

Digit 28 — Powered Exhaust Fan

Wheel

0 = No Powered Exhaust

A= 122

B = 122.6

C= 150

D = 150.6

E= 165

F = 165.6

G= 182

H = 182.6

J= 200

K = 200.6

L = 182 X 2

M = 182.6 X 2

Digit 29 — Powered Exhaust Fan

Motor Power

0 = No Powered Exhaust

A = 1/2 hp—1800 rpm

B = 1/2 hp—3600 rpm

C = 3/4 hp—1800 rpm

D = 3/4 hp—3600 rpm

E = 1 hp—1800 rpm

F = 1 hp—3600 rpm

G = 1.5 hp—1800 rpm

H = 1.5 hp—3600 rpm

J = 2 hp—1800 rpm

K = 2 hp—3600 rpm

L = 3 hp—1800 rpm

M = 3 hp—3600 rpm

N = 5 hp—1800 rpm

P = 5 hp—3600 rpm

R = 7.5 hp—1800 rpm

S = 7.5 hp—3600 rpm

T = 10 hp—1800 rpm

U = 10 hp—3600 rpm

V = 15 hp—1800 rpm

W = 15 hp—3600 rpm

Digit 30 — Reserved for Future

Use

Digit 31 — ERV (Requires

Powered Exhaust)

0= No ERV

A = ERV-Composite Construction

B = ERV—Composite Construction

with Frost Protection w/VFD

C = ERV—Composite Construction

with Bypass

D = ERV—Composite Construction

with Frost Protection and Bypass

E = ERV—Aluminum Construction

F = ERV—Aluminum Construction

with Frost Protection w/VFD

G = ERV—Aluminum Construction

with Bypass

H = ERV—Aluminum Construction

with Frost Protection and Bypass

Digit 32 — ERV Size

0= No ERV

1= 3014

2 = 3622

3 = 4136

4 = 4634

5 = 5856

6 = 6488

7 = 6876

8= 74122

Digit 33 — Damper Options

0 = 100% OA 2-Position Damper

1 = 100% OA 2-Position Damper

w/RA 2-Position Damper

2 = Modulating OA and RA Dampers

w/Economizer

Digit IF ELEC

0 No Heat No Heat

A50 MBh10 kW

B75 MBh20 kW

C100 MBh24 kW

D125 MBh28 kW

E150 MBh32 kW

F200 MBh40 kW

G250 MBh48 kW

H300 MBh60 kW

J350 MBh68 kW

K400 MBh79 kW

L500 MBh99 kW

M 600 MBh 111 kW

N 700 MBh 119 kW

P 800 MBh 139 kW

R 1000 MBh 159 kW

S179 kW

T199 kW

U215 kW

X Special Heater Option

Digit IF ELEC DF

0 No Heat/No Secondary Heat

A 50 MBh 10 kW 300 MBh

B 75 MBh 20 kW 600 MBh

C 100 MBh 24 kW 900 MBh

D 125 MBh 28 kW 1200 MBh

E150 MBh32 kW

F200 MBh40 kW

G250 MBh48 kW

H300 MBh60 kW

J350 MBh68 kW

K400 MBh79 kW

L500 MBh99 kW

M 600 MBh 111 kW

N 700 MBh 119 kW

P 800 MBh 139 kW

R 1000 MBh 159 kW

S179 kW

T199 kW

U215 kW

Model Number Descriptions

8 OAU-SVX01E-EN

Digit 34 — Filtration Options

A = Aluminum Mesh Intake Filters

(ALM)

B = MERV-8,30%, and ALM

C = MERV-13, 80%, and ALM

D = MERV-14, 95%, and ALM

E = MERV-8 30%, MERV-13 80%, and

ALM

F = MERV-8 30%, MERV-14 95%, and

ALM

G = MERV-8, 30%, and ALM, with

UVC

H = MERV-13, 80%, and ALM, with

UVC

J = MERV-14, 95%, and ALM, with

UVC

K = MERV-8 30%, MERV-13 80%,

ALM, and UVC

L = MERV-8 30%, MERV-14 95%,

ALM, and UVC

M = MERV-8 30%, ALM, and TCACS

N = MERV-13 80%, ALM, and TCACS

P = MERV-14 95%, ALM, and TCACS

Q = MERV-8 30%, MERV-13 80%,

ALM, and TCACS

R = MERV-8 30%, MERV-14 95%,

ALM, and TCACS

X = Special Filter Options

Digit 35 — Smoke Detector

(Factory-Installed)

0= No Smoke Detector

1 = Supply Smoke Detector

2 = Return Smoke Detector

3 = Supply and Return Smoke

Detector

Digit 36 — Electrical Options

0 = Non-Fused Disconnect

A = Fused Disconnect Switch

B = Non-Fused Disconnect

w/Convenience Outlet

C = Fused Disconnect Switch

w/Convenience Outlet

D=Dual Point Power

w/Convenience Outlet

F = 65 SCCR Electrical Rating

w/Non-Fused Disconnect

G = 65 SCCR Electrical Rating

w/Fused Disconnect

H = 65 KAIC Electrical Rating

w/Non-Fused Disconnect

J = 65 KAIC Electrical Rating

w/Fused Disconnect

Digit 37 — Air Flow Monitoring

0 = No Airflow Monitoring

1 = Airflow Monitoring—IFM

Piezo Ring

2 = Airflow Monitoring—PE

Piezo Ring

3 = Airflow Monitoring—Outdoor Air

with Display and IFM

w/Piezo Ring

4 = Airflow Monitoring—IFM

Piezo Ring and PE Piezo Ring

5 = Airflow Monitoring—Outdoor Air

Monitoring w/Display Supply

Air and Exhaust Air

w/Piezo Rings

Digit 38 — Accessories

0 = No Options

A = Hailguards

B = LED Service Light and

C = Hailguards and LED Service

Light

Digit 39 — Altitude

0 = Sea Level to 1,000 Feet

1 = 1,001 to 2,000 Feet

2 = 2,001 to 3,000 Feet

3 = 3,001 to 4,000 Feet

4 = 4,001 to 5,000 Feet

5 = 5,001 to 6,000 Feet

6 = 6,001 to 7,000 Feet

7 = Above 7,000 Feet

OAU-SVX01E-EN 9

General Information

Overview of Manual

Note: One copy of this document ships inside the control

panel of each unit and is customer property. It must

be retained by the unit’s maintenance personnel.

This booklet describes proper installation, operation, and

maintenance procedures for air cooled systems. By

carefully reviewing the information within this manual

and following the instructions, the risk of improper

operation and/or component damage will be minimized.

It is important that periodic maintenance be performed to

help assure trouble free operation. A maintenance

schedule is provided at the end of this manual. Should

equipment failure occur, contact a qualified service

organization with qualified, experienced HVAC technicians

to properly diagnose and repair this equipment.

Model Number Description

All products are identified by a multiple-character model

number that precisely identifies a particular type of unit.

An explanation of the alphanumeric identification code is

provided (see “Model Number Descriptions,” p. 6). Its use

will enable the owner/operator, installing contractors, and

service engineers to define the operation, specific

components, and other options for any specific unit.

When ordering replacement parts or requesting service,

be sure to refer to the specific model number and serial

number printed on the unit nameplate.

Unit Nameplate

A Mylar® unit nameplate is located on the unit’s corner

support next to the control box. It includes the unit model

number, serial number, electrical characteristics,

refrigerant charge, as well as other pertinent unit data.

Compressor Nameplate

The nameplate for the compressors are located on the side

of the compressor.

Unit Description

Before shipment, each unit is leak tested, dehydrated,

charged with refrigerant and compressor oil, and run

tested for proper control operation.

The condenser coils are aluminum fin, mechanically

bonded to copper tubing.

Direct-drive, vertical discharge condenser fans are

provided with built-in thermal overload protection.

The Outdoor Air Unit Main Unit Display and ReliaTel™

Control Module (RTRM) are microelectronic control

systems. The acronym RTRM is extensively throughout

this document when referring to the control system

network.

The Main Unit Display and the RTRM are mounted in the

Main Control Panel. The Main Unit Display and RTRM

receive information from sensors and customer binary

contacts to satisfy the applicable request for ventilation,

cooling, dehumidification and heating.

Indoor Fan Failure Input

The Indoor Fan Failure Switch (IFFS) is connected to verify

indoor fan operation.

When there is a call for the indoor fan to be energized, the

differential pressure switch, connected to the Main Unit

Display, must prove airflow within 30 seconds or the Main

Unit Display will shut off all mechanical operations, lock

the system out and send a diagnostic alarm to the Unit

Display. The system will remain locked out until a reset is

initiated through the MCM via the Alarm Reset Function on

the Unit Display.

Low Pressure Control ReliaTel Control

This input incorporates the compressor low pressure

control (CLP 1/2) of each refrigeration circuit and can be

activated by opening a field supplied contact installed on

the OAUTS.

If this circuit is open before the compressor is started, the

ReliaTel™ control will not allow the affected compressor to

operate. Anytime this circuit is opened for 1 continuous

second during compressor operation, the compressor for

that circuit is immediately turned “Off.” The compressor

will not be allowed to restart for a minimum of 3 minutes

should the contacts close.

If four consecutive open conditions occur during the first

three minutes of operation, the compressor for that circuit

will be locked out, and a manual reset will be required to

restart the compressor.

Refrigerant Circuits

For 5–7 ton units, one refrigerant circuit shall incorporate

a standard 6-row coil. For 8–54 ton units, two independent

refrigerant circuits shall incorporate an interlaced coil. All

circuits shall have thermal expansion valves (TXVs),

service pressure ports and refrigerant line filter driers as

standard. An area will be provided for replacement suction

line driers. Refrigerant circuit one (1st Stage) is equipped

with a factory installed and preset refrigerant capacity

control (RCC) to prevent evaporator coil temperatures

below approximately 38°F (114 lb suction). The refrigerant

capacity device is not installed when the unit is equipped

with a digital scroll.

High Pressure Control ReliaTel Control

The compressor high pressure controls (CHP 1/2/3/4) are

wired in series between the compressor outputs on

RTRM1 (CHP 1/2) and RTRM2 (CHP 3/4) and the

compressor contactor coils. If one of the high pressure

control switches opens, the respective RTRM senses a lack

of current while calling for cooling and locks the

compressor out.

General Information

10 OAU-SVX01E-EN

On dual circuit units, if the high pressure control opens,

the compressor on the affected circuit is locked out. A

manual reset for the affected circuit is required.

Space Temperature / RH Sensor (Optional)

Field installed, wall mounted temperature sensor

(BAYSENS036A) and humidity to control space cooling,

heating and dew point. Refer to “Space Control with

Indirect Gas-Fired or Electric Heat and Modulating HGRH,

ERV, and Powered Ex.,” p. 21 for specific details.

High Temperature Sensor

The Discharge Air Temperature Sensor (DTC) supplies a

continuous signal to the MCM. Factory setting for

Discharge Air Temperature (DTC) Discharge Air

Temperature Setpoint (MDTS) is 90°F (adj 70–100°F), the

unit will be shut down, and require a manual restart if

Discharge Air Temperature exceeds MDTS for 10 minutes

(adj 10–25 minutes). If DAT exceeds Discharge Air High

Temperature Cutoff (DHCS) of 125°F for 10 minutes, the

unit will shut down and require manual restart.

Outdoor Air Temperature and Relative

Humidity Sensor

This factory installed combination outdoor air sensor

located in the outdoor air hood is designed to sense both

outdoor air temperature and relative humidity for use by

the microprocessor controller to make required

ventilation, cooling, dehumidification and heating

decisions. Refer to “Sequence of Operation,” p. 21 for

detailed unit control and operational modes.

Control Input (Occupied / Unoccupied)

Terminals are provided on the terminal strip labeled

OAUTS for a field installed dry contact or switch closure to

put the unit in the Occupied or Unoccupied modes.

Hot Gas Reheat

This option shall consist of a hot-gas reheat coil located on

the leaving air side of the evaporator. Refer to the

“Sequence of Operation,” p. 21 for detailed unit control

and operational modes.

100 Percent Outdoor Air Hood with

Damper and Filters

Factory-installed and -integrated 100 percent outdoor air

hood with damper controlled by a direct coupled actuator

and 2 in. (50.80 mm) permanent and washable aluminum

mesh filters (mist eliminators) removable through a

hinged access panel. The unit is factory equipped with

provisions to accept an optional field installed 100 percent

return air damper controlled by a direct coupled actuator

that is electrically interlocked with the outdoor air damper.

Modulating Indirect Gas-Fired Burner

The unit will have fully modulating, high turndown,

indirect gas-fired heat. The heating section will include

high turn-down burners and a stainless steel tubular heat

exchanger. The heat exchanger will be constructed of

type 439 stainless steel and be a tubular design capable of

draining internal condensate. External flue to be

constructed of type 430 stainless steel.

Units will be suitable for use with natural gas or Liquid

Propane (LP) gas.

Through the Base Electrical with

Disconnect Switch

Factory installed 3-pole, molded case disconnect switch

with provisions for through the base electrical connections

will be included. The disconnect switch, with integral

overcurrent circuit breaker, will be installed in the unit in a

water tight enclosure with access through a hinged door.

Factory wiring will be provided from the switch to the unit

high voltage terminal block. The switch will be UL/CSA

agency recognized.

Through the Base Gas Piping

The unit will include provisions for installing through the

base gas piping. The factory installed option will have all

piping necessary including an external shutoff piping yoke

with pre-assembled, manual gas shut-off valve, elbows,

and union. The manual shut-off valve will include an 1/8 in.

(3.17 mm) NPT pressure tap. This assembly will require

minor field labor to install.

Hinged Access Doors

Hinged access doors with hold open brackets will be

factory-installed.

Modulating Electric Heat

The unit may have fully modulating, SCR, or Vernier-

controlled, electric heat. The primary heating section will

include open coil heating elements, automatic and manual

cut-outs, low voltage controls, air proving switch,

maximum 48 amps per circuit and fusing for heaters over

48 amps. For ductwork installation, refer to “Ductwork,”

p. 25.

General Information

OAU-SVX01E-EN 11

Unit Inspection

As soon as the unit arrives at the job site:

• 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.

Storage

Take precautions to prevent condensate from forming

inside the unit’s electrical compartments and motors if:

• the unit is stored before it is installed; or,

• the unit is set on the roof curb, and temporary heat is

provided in the building. Isolate all side panel service

entrances and base pan openings (e.g., conduit holes,

S/A and R/A openings, and flue openings) from the

ambient air until the unit is ready for start-up.

Note: Do not use the unit’s heater for temporary heat

without first completing the start-up procedure

detailed in “Start-Up,” p. 36.

The manufacturer will not assume any responsibility for

equipment damage resulting from condensate

accumulation on the unit’s electrical and/or mechanical

components.

Unit Clearances

“Unit Clearances, Curb Dimensions, and Dimensional

Data,” p. 12 contains figures that illustrate the minimum

operating and service clearances for either a single or

multiple unit installation: Figure 1, p. 12 and Figure 2, p. 12

for OA1 units,Figure 7, p. 14 through Figure 10, p. 15 for

OA2 units, and Figure 15, p. 16 through Figure 18, p. 17 for

OA3 units. These clearances are the minimum distances

necessary to assure adequate serviceability, cataloged

unit capacity, and peak operating efficiency.

Providing less than the recommended clearances may

result in condenser coil starvation, “short-circuiting” of

exhaust or recirculation of hot condenser air.

WARNING

Fiberglass Wool!

Product may contain fiberglass wool. Disturbing the

insulation in this product during installation,

maintenance or repair will expose you to airborne

particles of glass wool fibers and ceramic fibers known

to the state of California to cause cancer through

inhalation. Glass wool fibers may also cause

respiratory, skin or eye irritation.

Verify that the nameplate data matches the data on

the sales order and bill of lading (including electrical

data).

Verify that the power supply complies with the unit

nameplate specifications.

Visually inspect the exterior of the unit, including the

roof, for signs of shipping damage.

Visually inspect the internal components for shipping

damage as soon as possible after delivery and before

it is stored. Do not walk on the sheet metal base pans.

If concealed damage is discovered, notify the carrier’s

terminal of damage immediately by phone and by

mail. Concealed damage must be reported within

15 days.

Request an immediate joint inspection of the damage

by the carrier and the consignee. Do not remove

damaged material from the receiving location. Take

photos of the damage, if possible. The owner must

provide reasonable evidence that the damage did not

occur after delivery.

Notify the appropriate sales representative before

installing or repairing a damaged unit.

12 OAU-SVX01E-EN

Unit Clearances, Curb Dimensions, and Dimensional

Data

OA1 Units

Unit Clearances

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

WARNING

Combustible Materials!

Maintain proper clearance between the unit heat

exchanger, vent surfaces and combustible materials.

Refer to unit nameplate and installation instructions for

proper clearances. Improper clearances could result in a

fire hazard. Failure to maintain proper clearances could

result in death or serious injury or property damage.

Figure 1. Typical installation clearances for OA1 unit

CLEARANCE 36"

TOP OF UNIT 72"

CLEARANCE 60"

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'-0"

3'-0" 4'-0"

Figure 2. Typical installation clearances for OA1 unit

with auxiliary cabinet

Figure 3. Unit curb data for OA1 5–15 tons

7'0"

6'0"

3'0"

4'0"

3'0"

SUPPLY

RETURN

2öļ

8õļ

7öļ

19ļ

õļ

1ôļ

4ôļ

49ļ

1õļ

öļ

1.00

TYP.

Unit Clearances, Curb Dimensions, and Dimensional Data

OAU-SVX01E-EN 13

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Dimensional Data Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 4. Unit curb data for OA1 5–15 tons with

auxiliary cabinet

Figure 5. Unit dimensional data for OA1 5–15 tons (in.)

GUTTER DETAIL

Ɍļ

ôļ

SUPPLY

GUTTER

RETURN

õļ

19"

8õļ

40"

12ɍļ

3ôļ

Ɍļ

1ôļ

7öļ

4ôļ

49"

1õļ

öļ

1.00

TYP.

28öļ

53.00

59.45

87.12

36.71

87.33

59.23

87.18

29.63

Figure 6. Unit dimensional data for OA1 5–15 tons

with auxiliary cabinet (in.)

87.33

59.23

53.00

131.26

87.12

59.45

35.24

Unit Clearances, Curb Dimensions, and Dimensional Data

14 OAU-SVX01E-EN

OA2 Units

Unit Clearances

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 7. Typical installation clearances for OA2 unit

CLEARANCE 36"CLEARANCE 60"

TOP OF UNIT 72"

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

4'0"

3'0"

Figure 8. Typical installation clearances for OA2 unit

with auxiliary cabinet

Figure 9. Typical installation clearances for OA2 unit

TOP OF UNIT 72"

"63 ECNARAELC"06 ECNARAELC

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

4'0"

3'0"

7'0"

6'0"

Unit Clearances, Curb Dimensions, and Dimensional Data

OAU-SVX01E-EN 15

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Dimensional Data

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 10. Typical installation clearances for OA2 unit

with auxiliary cabinet

Figure 11. Unit curb data for OA2 12–30 tons (in.)

Figure 12. Unit curb data for OA2 12–30 tons with

auxiliary cabinet (in.)

7'0"

6'0"

SUPPLY

RETURN

öļ

1ļ

TYP.

30ļ

29ļ

56ļ

2õļ

5ôļ

9ôļ

ļ

1õļ

SUPPLY

RETURN

GUTTER

1õļ

ļ

16Ɍļ

29ļ

9Ɏļ

56ļ

5ôļ

öļ

õļ

30ļ

58ļ

5ôļ

Ɍļ

1ļ

TYP.

GUTTER DETAIL

Ɍļ

ôļ

Figure 13. Unit dimensional data for OA2 12–30 tons

Figure 14. Unit dimensional data for OA2 12–30 tons

with auxiliary cabinet

80.57 OF AIR INLET

106.45

66.83

106.00

135.52

94.21

43.02

BASE TO BOTTOM

60.00

80.57

106.00

94.21

62.11

66.83

60.00

106.10

200.99

OF AIR INLET

43.02

BASE TO BOTTOM

62.51

Unit Clearances, Curb Dimensions, and Dimensional Data

16 OAU-SVX01E-EN

OA3 Units

Unit Clearances

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 15. Typical installation clearances for OA3 unit

TOP OF UNIT 72"

"63 ECNARAELC"06 ECNARAELC

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

4'0"

3'0"

Figure 16. Typical installation clearances for OA3 unit

with auxiliary cabinet

Figure 17. Typical installation clearances for OA3 unit

CLEARANCE 36"

TOP OF UNIT 72"

CLEARANCE 36"CLEARANCE 60"

CLEARANCE FROM

CLEARANCE 48"

3'0"

4'0"

3'0"

7'0"

6'0"

Unit Clearances, Curb Dimensions, and Dimensional Data

OAU-SVX01E-EN 17

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Dimensional Data

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 18. Typical installation clearances for OA3 unit

with auxiliary cabinet

Figure 19. Unit curb data for OA3 30–54 tons

Figure 20. Unit curb data for OA3 30–54 tons with

auxiliary cabinet

7'0"

6'0"

SUPPLY

RETURN

öļ

33ļ

63ļ

5ôļ

140ļ

13ôļ

1ļ

TYP.

5ɏļ

2õļ

2ɍļ

SUPPLY

RETURN

GUTTER

1ļ

TYP.

63ļ

202ļ

5ɏļ

5ôļ

140ļ

33ļ

öļ

5ɏļ

2õļ

13ôļ

Ɍļ 5ɍļ

2ɍļ

GUTTER DETAIL

Ɍļ

ôļ

Figure 21. Unit dimensional data for OA3 30–54 tons

Figure 22. Unit dimensional data for OA3 30–54 tons

with auxiliary cabinet

144.00

67.00

74.63

144.17

42.00

92.07

98.49

48.62

62.00

67.00

74.63

98.49

144.00

92.07

144.17

35.84

18 OAU-SVX01E-EN

Unit Weight and Rigging

Unit Weight

WARNING

Heavy Objects!

Do not use cables (chains or slings) except as shown.

Each of the cables (chains or slings) used to lift the unit

must be capable of supporting the entire weight of the

unit. Lifting cables (chains or slings) may not be of the

same length. Adjust as necessary for even unit lift.

Other lifting arrangements may cause equipment or

property-only damage. Failure to properly lift unit could

result in death or serious injury. See details below.

WARNING

Improper Unit Lift!

Test lift unit approximately 24 inches to verify proper

center of gravity lift point. To avoid dropping of unit,

reposition lifting point if unit is not level. Failure to

properly lift unit could result in death or serious injury

or possible equipment or property-only damage.

Table 1. Typical unit weight and center-of-gravity

(CG)—units without auxiliary cabinet

Model

Number

Operating

Weight (lb) Shipping

Weight (lb) Center-of-

gravity (in.)

Min Max Min Max Length Width

OA1D060* 1811 2275 1898 2362 40 30

OA1D072* 1811 2330 1898 2417 40 30

OA1D084* 1811 2330 1933 2452 40 30

OA1D096* 1901 2596 2059 2754 40 30

OA1D120* 1901 2596 2089 2784 40 30

OA1D144* 1901 2596 2112 2807 40 30

OA1D180* 1901 2734 2192 3025 40 30

OA2D144* 3125 3790 3335 4000 49 34

OA2D180* 3289 3954 3580 3871 49 34

OA2D210* 3344 4161 3687 4030 49 34

OA2D240* 3372 4189 3764 4156 49 34

OA2D264* 3372 4189 3764 4156 49 34

OA2D300* 3530 4390 4012 4494 49 34

OA2D360* 3338 4198 3820 4302 49 34

OA3D360* 4931 5914 5576 6221 67 38

OA3D420* 5246 6229 5892 6538 67 38

OA3D480* 5339 6351 6014 6689 67 38

OA3D540* 5406 6363 6026 6646 67 38

OA3D600* 5570 6652 6343 7116 67 38

OA3D648* 5582 6664 6355 7128 67 38

Note: Minimum and maximum weights vary widely due to the highly

configurable nature of the product.

Unit Weight and Rigging

OAU-SVX01E-EN 19

Corner Weight

Table 2. Typical unit weight and center-of-gravity

(CG)—units with auxiliary cabinet

Model

Number

Operating

Weight (lb) Shipping

Weight (lb) Center-of-

gravity (in.)

Min Max Min Max Length Width

OA1D060* 2798 3262 2885 3349 56 29

OA1D072* 2743 3262 2830 3349 56 29

OA1D084* 2775 3294 2897 3416 56 29

OA1D096* 2927 3622 3085 3780 56 29

OA1D120* 2927 3622 3115 3810 56 29

OA1D144* 2927 3622 3138 3833 56 29

OA1D180* 2927 3760 3218 4051 56 29

OA2D144* 4508 5173 4718 5383 72 33

OA2D180* 4715 5380 4632 5297 72 33

OA2D210* 5028 5845 4897 5714 72 33

OA2D240* 5056 5873 5023 5840 72 33

OA2D264* 5056 5873 5023 5840 72 33

OA2D300* 5194 6054 5298 6158 72 33

OA2D360* 4936 5796 5040 5900 72 33

OA3D360* 6907 7890 7214 8197 81 37

OA3D420* 7222 8205 7531 8514 81 37

OA3D480* 7315 8327 7653 8665 81 37

OA3D540* 7382 8339 7665 8622 81 37

OA3D600* 7527 8609 7991 9073 81 37

OA3D648* 7539 8621 8003 9085 81 37

Note: Minimum and maximum weights vary widely due to the highly

configurable nature of the product.

Table 3. Corner weights (percent of total weight)

Cabinet Size

Percentage (%)

Corner A Corner B Corner C Corner D

OA1* without

auxiliary cabinet 16.3 20.7 33.3 29.7

OA1* with

auxiliary cabinet 18.2 23.2 27.5 31.1

OA2* without

auxiliary cabinet 20.1 17.2 34.0 28.7

OA2* with

auxiliary cabinet 18.3 24.0 32.5 25.2

OA3* without

auxiliary cabinet 14.9 24.2 29.9 31.0

OA3* with

auxiliary cabinet 16.8 23.6 28.5 31.1

Note: Actual corner weights will vary depending on components selected.

Figure 23. Cabinet corners

OALCabinet

INTAKE

HOOD

OA1,OA2,andOA3Cabinets

INTAKE

HOOD

CONDENSERSECTION

Unit Weight and Rigging

20 OAU-SVX01E-EN

Rigging

Refer to Table 1, p. 18, Table 2, p. 19, and Figure 24, p. 20

for typical unit operating weights rigging before

proceeding.

1. Remove the shipping crate from around the unit.

2. Rig the unit as shown in Figure 24, p. 20. Attach

adequate strength lifting slings to all four lifting

brackets in the unit base rail. Do not use cables, chains,

or slings except as shown.

3. Install a lifting bar, as shown in Figure 24, p. 20, to

protect the unit and to facilitate a uniform lift. The

minimum distance between the lifting hook and the

top of the unit should be 7 feet.

4. Test-lift the unit to ensure it is properly rigged and

balanced, make any necessary rigging adjustments.

5. Lift the unit and position it into place. Remove fork

pockets prior to setting on the curb.

6. Downflow units; align the base rail of the unit with the

curb rail while lowering the unit onto the curb. Make

sure that the gasket on the curb is not damaged while

positioning the unit.

Figure 24. Rigging and center-of-gravity data

SPREADER BARS

LENGTH

WIDTH

LIFTING POINTS

(4 LOCATIONS)

4-point lift

SPREADER BARS

LENGTH

WIDTH

LIFTING POINTS

(6 LOCATIONS)

DETAIL A

SCALE 1 : 12

6-point lift

OAU-SVX01E-EN 21

Sequence of Operation

Space Control with Indirect Gas-

Fired or Electric Heat and

Modulating HGRH, ERV, and

Powered Ex.

Sequence of Operation—”Occupied”

Optional space temperature and/or humidity sensors

must be installed and wired to unit and configured as

“installed” at the main unit controller.

Emergency Stop. When the contacts at Terminal

OAUTS 9 and 10 are open, the unit’s operation will be in

Alarm Status. The Alarm must be reset from either the BAS

or the optional on-board unit display.

Alarms must be reset from the optional on-board unit

display or remote BAS to restart the control sequence. If

optional display is not installed; Tracer TU must be used to

diagnose and clear alarm. If Tracer TU is not available,

cycle main power to unit to clear alarm.

Important: Cycling power to unit to clear alarm may not

resolve alarm condition.

Starting Sequence

When 3-phase is powered to unit the main unit controller

and the RTRM will initialize. Initialization process requires

approximately 3 minutes.

The unit is placed in occupied operation via either the BAS

or by closing connection between unit terminals OAUTS 7

and 8. The unit must not be in lockout.

Starting Sequence with No Return Air Damper

Installed

The outdoor air damper will be commanded to open. The

damper end switch will make causing the main unit

controller to initialize the indoor fan starting sequence by

sending a preset run signal (field adjustable between

50 percent and 100 percent) to the indoor fan VFD. If after

30 seconds the indoor fan proving switch does not prove

the indoor fan on, the main unit controller will command

the indoor fan off and signal an alarm.

Starting Sequence with Optional Return Air

Damper Installed

Identical to sequence with no return air damper except the

outdoor air and return air dampers will be commanded to

move to their preset occupied positions. Outdoor air

damper end switch is disabled when the return air damper

is installed.

Operating Modes

A. Economizer (Ventilation)

B. Heating

C. Dehumidification

D. Cooling

All modes are enabled by the main unit control module.

The control module calculates dewpoint based on sensed

air temperature and humidity.

A. Economizer Mode. Economizer mode is enabled

based on outdoor air dewpoint. Operation in economizer

mode is enabled when the outdoor air dewpoint remains

below the outdoor air economizer enable dewpoint

setpoint. Operation in economizer mode continues until

outdoor air conditions call for either dehumidification,

cooling or heating mode. Space call for heating,

dehumidification or cooling will cancel call for economizer

operation.

B. Heating Mode. Heating mode is enabled on space

heating setpoint. The main unit controller will modulate

the heating output to maintain the space heating setpoint.

Maximum discharge air heating temperature is

adjustable—default maximum is 90ºF. Hot gas reheat is

disabled when heating is enabled.

C. Dehumidification Mode. Dehumidification mode is

enabled on space dewpoint setpoint if no call for heating

is enabled. The unit’s controller will activate the

dehumidification mode when space dewpoint is higher

than or equal to space dewpoint setpoint. Compressor

control is based on evaporator leaving air temperature

setpoint. With dehumidification enabled, if evaporator

leaving air temperature is above setpoint first stage

dehumidification (Compressor 1) will start. If after a

3-minute minimum delay the evaporator leaving air

temperature is still above the setpoint, the second, third,

and fourth stages of dehumidification (Compressor 2, 3,

and 4) will be staged on sequentially following individual

3-minute minimum delays between each call.

Dehumidification mode will remain active if outdoor air is

above outdoor air dehumidification setpoint. Space call

for heating will cancel outdoor air dehumidification.

During operation in dehumidification mode, the main unit

controller will enable hot gas reheat. Hot gas reheat will

modulate to maintain the space cooling setpoint.

D. Cooling Mode . Cooling mode is enabled on space

cooling setpoint if no call for heating or dehumidification

is present. Compressor staging is identical to

dehumidification however control temperature is space

cooling setpoint.

During operation in cooling mode hot gas reheat is

enabled. Hot gas reheat is controlled to maintain space

cooling setpoint.

Sequence of Operation

22 OAU-SVX01E-EN

Optional Features

Digital Compressors

Main unit controller will modulate digital compressor to

maintain either evaporator leaving or space temperature

setpoints depending on mode of operation. Remaining

compressors will be staged as described in mode.

ERV and Powered Exhaust

ERV and powered exhaust are interlocked with indoor fan

operation in occupied heating, dehumidification or

cooling modes. Outdoor air sensors sending temperature

and Rh signals to the main unit controller to make mode

calls are relocated downstream of the ERV. Outdoor air

heating and dehumidification override setpoints will be

based on ERV leaving conditions. Additional sensors will

be installed in the non-ERV outdoor air position for

information purposes and those outdoor air readings may

be viewed at the main unit controller or via the BAS. When

operating in economizer mode the ERV is disabled and the

ERV by-pass damper(s) open, powered exhaust remains

on and is adjusted to 100 percent capacity by the main unit

controller. The main unit controller will end ERV operation

and open ERV bypass dampers if outdoor air/return air

conditions could cause ERV frosting, powered exhaust

remains on.

Note: For units with optional ERV defrost heater, the

control sequence will engage heater at frost

condition rather than stop ERV.

The powered exhaust fan speed is factory set to run

between 50 percent and 100 percent (field adjustable).

Hot Gas Reheat

Following continuous 30-minute hot gas reheat operation

at less than 100 percent reheat capacity a purge cycle will

be initiated. During the purge cycle the, hot gas reheat

signal is set and held at 100 percent for a period of

3 minutes. Following the purge cycle, normal operation

resumes.

Sequence of Operation—”Unoccupied”

Emergency Stop. When the contacts at Terminal

OAUTS 9 and 10 are open, the unit’s operation will be in

Alarm Status. The Alarm must be reset from either the BAS

or the optional on-board unit display.

Starting Sequence

Indoor fan proving sequence is identical to occupied

operation.

Starting Sequence with Optional Return Air

Damper Installed

The outdoor air damper will be commanded to close and

the return air damper will open. Outdoor air damper end

switch is disabled when the return air damper is installed.

Starting Sequence with No Return Air Damper

Installed. Identical to occupied sequence no return air

damper installed.

Operating Modes

A. Unoccupied Heating

B. Unoccupied Dehumidification

C. Unoccupied Cooling

A. Heating Mode. Unoccupied heating is enabled

based on unoccupied space heating setpoint. Unoccupied

heating is enabled when space temperature reaches

unoccupied space heating setpoint - 2°. The modulating

gas heat or SCR electric heat will continue to raise the

discharge air temperature to a maximum of 90°F and

continue to supply heated 90° air to the space until the

space temperature reaches setpoint + 2°. Unit operation is

discontinued when unoccupied space heating is satisfied.

B. Dehumidification Mode. When no call for

unoccupied heating exists, unoccupied dehumidification

is enabled based on unoccupied space dewpoint setpoint.

During unoccupied dehumidification operation

dehumidification capacity is restricted to 50 percent (only

half of the compressors are allowed to come on).

Unoccupied dehumidification is enabled when space

temperature reaches unoccupied space dehumidification

setpoint + 1°. Dehumidification stops at setpoint - 1°. Unit

operation is discontinued when unoccupied space

dehumidification is satisfied.

C. Cooling Mode. When no call for unoccupied heating

or unoccupied dehumidification exists, unoccupied

cooling is enabled based on unoccupied space cooling

setpoint. During unoccupied space cooling operation

cooling capacity is restricted to 50 percent (only half of the

compressors are allowed to come on). Unoccupied

cooling is enabled when space temperature reaches

unoccupied space cooling setpoint + 2°. Cooling stops at

setpoint - 2°. Unit operation is discontinued when

unoccupied space cooling is satisfied.

Powered Exhaust/ERV Sequence of Operation

Powered Exhaust/ERV operation is disabled during unit

“Unoccupied” operating modes.

Sequence of Operation

OAU-SVX01E-EN 23

Discharge Air Control with

Indirect Gas-Fired or Electric Heat

and Modulating HGRH, ERV, and

Powered Ex.

Sequence of Operation—”Occupied”

Emergency Stop. When the contacts at Terminal

OAUTS 9 and 10 are open, the unit’s operation will be in

Alarm Status. The Alarm must be reset from either the BAS

or the optional on-board unit display.

Alarms must be reset from the optional on-board unit

display or remote BAS to restart the control sequence. If

optional display is not installed; Tracer TU must be used to

diagnose and clear alarm. If Tracer TU is not available,

cycle main power to unit to clear alarm.

Important: Cycling power to unit to clear alarm may not

resolve alarm condition.

Starting Sequence

When 3-phase is powered to unit the main unit controller

and the RTRM will initialize. Initialization process requires

approximately 3 minutes.

The unit is placed in occupied operation via either the BAS

or by closing connection between unit terminals OAUTS 7

and 8. The unit must not be in lockout.

Starting Sequence with No Return Air Damper

Installed

The outdoor air damper will be commanded to open. The

damper end switch will make causing the main unit

controller to initialize the indoor fan starting sequence by

sending a preset run signal (field adjustable between

50 percent and 100 percent) to the indoor fan VFD. If after

30 seconds the indoor fan proving switch does not prove

the indoor fan on, the main unit controller will command

the indoor fan off and signal an alarm.Starting Sequence

with Optional Return Air Damper Installed

Identical to sequence with no return air damper except the

outdoor air and return air dampers will be commanded to

move to their preset occupied positions. Outdoor air

damper end switch is disabled when the return air damper

is installed.

Operating Modes

A. Economizer (Ventilation)

B. Heating

C. Dehumidification

D. Cooling

All modes are enabled by the main unit control module.

The control module calculates dewpoint based on sensed

outdoor air temperature and humidity.

A. Economizer Mode. Operation in economizer mode

is enabled when the outdoor air temperature is between

the Outdoor Air Cooling Setpoint and the Outdoor Air

Heating setpoint and no call for dehumidification exists.

Operation in economizer mode continues until outdoor air

conditions call for either dehumidification, cooling or

heating mode.

B. Heating Mode. Heating mode is enabled on outdoor

air heating setpoint. The main unit controller will

modulate the heating capacity to maintain the discharge

air heating setpoint. Hot gas reheat is disabled when

heating is enabled. Heating will be disabled at outdoor air

heating setpoint + 2°.

C. Dehumidification Mode. Dehumidification mode is

enabled on outdoor air dewpoint enable setpoint if no call

for heating is enabled. The unit’s controller will activate the

dehumidification mode when outdoor air dewpoint is

higher than or equal to outdoor air dewpoint setpoint.

Compressor control is based on evaporator leaving air

temperature setpoint. With dehumidification enabled, if

evaporator leaving air temperature is above setpoint first

stage dehumidification (Compressor 1) will start. If after a

3-minute minimum delay the evaporator leaving air

temperature is still above the evaporator leaving air

temperature setpoint, the second, third, and fourth stages

of dehumidification (Compressor 2, 3, and 4) will be

staged on sequentially following individual 3-minute

minimum delays between each call. Dehumidification

mode will be disabled at outdoor air dewpoint setpoint

- 2°.

During operation in dehumidification mode, the main unit

controller will enable hot gas reheat. Hot gas reheat will

modulate to maintain the discharge air cooling setpoint.

C. Cooling Mode. Cooling mode is enabled on outdoor

air cooling setpoint if no call for heating or

dehumidification is present. Compressor staging is

identical to dehumidification; however, control

temperature is discharge air cooling setpoint. Cooling will

be disabled at outdoor air cooling setpoint - 2°.

During operation in cooling mode hot gas reheat is

enabled. Hot gas reheat is controlled to maintain discharge

air cooling setpoint.

Optional Features

Digital Compressors

Main unit controller will modulate digital compressor to

maintain either evaporator leaving or discharge air

temperature setpoints depending on mode of operation.

Remaining compressors will be staged as described in

mode.

ERV and Powered Exhaust

ERV and powered exhaust are interlocked with indoor fan

operation in occupied heating, dehumidification or

cooling modes. Outdoor air sensors sending temperature

and Rh signals to the main unit controller to make mode

Sequence of Operation

24 OAU-SVX01E-EN

calls are relocated downstream of the ERV. Mode calls will

be based on ERV leaving conditions. Additional sensors

will be installed in the non-ERV outdoor air position for

information purposes and those outdoor air readings may

be viewed at the main unit controller or via the BAS. When

operating in economizer mode the ERV is disabled and the

ERV by-pass damper(s) open, powered exhaust remains

on and is adjusted to 100 percent capacity by the main unit

controller. The main unit controller will end ERV operation

and open ERV bypass dampers if outdoor air/return air

conditions could cause ERV frosting, powered exhaust

remains on.

Note: For units with optional ERV defrost heater, the

control sequence will engage heater at frost

condition rather than stop ERV.

The powered exhaust fan speed is factory set to run

between 50 percent and 100 percent (field adjustable).

Hot Gas Reheat

Following continuous 30-minute hot gas reheat operation

at less than 100 percent reheat capacity a purge cycle will

be initiated. During the purge cycle the, hot gas reheat

signal is set and held at 100 percent for a period of

3 minutes. Following purge cycle normal operation

resumes.

Sequence of Operation—”Unoccupied”

Optional space temperature and/or humidity sensors

must be installed and wired to unit and configured as

“installed” at the main unit controller to enable

unoccupied sequences.

Emergency Stop. When the contacts at Terminal

OAUTS 9 and 10 are open, the unit’s operation will be in

Alarm Status. The Alarm must be reset from either the BAS

or the optional on-board unit display.

Starting Sequence

Indoor fan proving sequence is identical to occupied

operation.

Starting Sequence with Optional Return Air

Damper Installed

The outdoor air damper will be commanded to close and

the return air damper will open. Outdoor air damper end

switch is disabled when the return air damper is installed.

Starting Sequence with No Return Air Damper

Installed

Identical to occupied sequence no return air damper

installed.

Operating Modes

A. Unoccupied Heating

B. Unoccupied Dehumidification

C. Unoccupied Cooling

A. Heating Mode. Unoccupied heating is enabled

based on unoccupied space heating setpoint. Unoccupied

heating is enabled when space temperature reaches

unoccupied space heating setpoint - 2°. The modulating

gas heat or SCR electric heat will continue to raise the

discharge air temperature to a maximum of 90°F and

continue to supply heated 90° air to the space until the

space temperature reaches setpoint + 2°. Unit operation is

discontinued when unoccupied space heating is satisfied.

B. Dehumidification Mode. When no call for

unoccupied heating exists, unoccupied dehumidification

is enabled based on unoccupied space dewpoint setpoint.

During unoccupied dehumidification operation

dehumidification capacity is restricted to 50 percent (only

half of the compressors are allowed to come on).

Unoccupied dehumidification is enabled when space

temperature reaches unoccupied space dehumidification

setpoint + 1°. Dehumidification stops at setpoint - 1°. Unit

operation is discontinued when unoccupied space

dehumidification is satisfied.

C. Cooling Mode. When no call for unoccupied heating

or unoccupied dehumidification exists, unoccupied

cooling is enabled based on unoccupied space cooling

setpoint. During unoccupied space cooling operation

cooling capacity is restricted to 50 percent (only half of the

compressors are allowed to come on). Unoccupied

cooling is enabled when space temperature reaches

unoccupied space cooling setpoint + 2°. Cooling stops at

setpoint - 2°. Unit operation is discontinued when

unoccupied space cooling is satisfied.

Powered Exhaust/ERV Sequence of Operation

Powered Exhaust/ERV operation is disabled during unit

“Unoccupied” operating modes.

OAU-SVX01E-EN 25

Installation

Ductwork

Elbows with turning vanes or splitters are recommended

to minimize air noise due to turbulence and to reduce static

pressure.

When attaching the ductwork to the unit, provide a water-

tight flexible connector at the unit to prevent operating

sounds from transmitting through the ductwork.

All outdoor ductwork between the unit and the structure

should be weather proofed after installation is completed.

Note: For sound consideration, cut holes in the roof deck

only for the ductwork penetrations. Do not cut out

the roof deck within the entire curb perimeter. All

duct work must be installed and connected to top of

roof curb before the unit is set on curb.

If a Curb Accessory Kit is not used:

1. Be sure to use flexible duct connections at the unit.

2. Gaskets must be installed around the curb perimeter

flange and the supply and return air opening flanges.

Note: For units will electric heat in the primary heating

position, refer to Figure 25.

General Unit Requirements

The checklist listed below is a summary of the steps

required to successfully install a commercial unit. 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.

WARNING

Hazardous Service Procedures!

The maintenance and troubleshooting procedures

recommended in this section of the manual could result

in exposure to electrical, mechanical or other potential

safety hazards. Always refer to the safety warnings

provided throughout this manual concerning these

procedures. When possible, disconnect all electrical

power including remote disconnect and discharge all

energy storing devices such as capacitors before

servicing. Follow proper lockout/tagout procedures to

ensure the power can not be inadvertently energized.

When necessary to work with live electrical

components, have a qualified licensed electrician or

other individual who has been trained in handling live

electrical components perform these tasks. Failure to

follow all of the safety warnings provided could result

in death or serious injury.

Figure 25.

Important: Bottom discharge units with open coil

electric heater in primary heat location

require discharge duct with 90° elbow. This

is a MANDATORY installation requirement.

Check the unit for shipping damage and material

shortage. File a freight claim and notify appropriate

sales representative if damage or shortage is

discovered.

Verify that the unit nameplate model, options, and

voltage are correct.

Verify that the installation location of the unit will

provide the required clearance for proper operation.

Assemble and install the roof curb (if applicable).

Refer to the latest edition of the curb installers guide

that ships with each curb kit. Check curb for level

installation; if not level, shim as required.

Rigging unit (refer to “Unit Weight and Rigging,”

p. 18).

Set the unit onto the curb; check for level.

Ensure unit-to-curb seal is tight and without buckles

or cracks.

Install and connect proper condensate drain line to

the evaporator condensate pan drain connection (see

Figure 26, p. 26).

48" Minimum

Airflow

Installation

26 OAU-SVX01E-EN

Main Electrical Power Requirements

Note: All field-installed wiring must comply with NEC

and applicable local codes.

Condensate Drain Configuration

OAU units are selected based on dehumidification

capability. As such, condensate can form at a high rate.

Therefore, the OAU drain pan and condensate line are

sized and designed accordingly. However, an often-

overlooked element of proper condensate drainage is

proper P-Trap and drain line sizing and installation. An

incorrectly-designed and -installed P-Trap can restrict

condensate flow or cause water in the condensate drain

pan to “spit” or “geyser” which may cause condensate

overflow. Carefully install and trap the drain pan to ensure

adequate condensate removal under all conditions.

An evaporator condensate drain connection is provided

on each unit. Refer to Figure 28, p. 27, Figure 29, p. 27, and

Figure 30, p. 27 for the appropriate drain location.

A condensate trap must be installed at the unit due to the

drain connection being on the “negative pressure” side of

the fan. Install the P-Trap using the guidelines in Figure 26.

Pitch drain lines connected to P-Trap at least 1/2 inch for

every 10 feet of horizontal run to assure proper

condensate flow. Do not allow the horizontal run to sag

causing a possible double-trap condition which could

result in condensate backup due to “air lock”.

Filter Installation

Each unit ships with 2-inch permanent filters (mist

eliminators) installed in the air inlet hood. The quantity of

filters is determined by unit size. Access to the filters is

through the hinged filter access panel on the air intake

hood. In addition to the filters in the intake hood, there is

a separate bank of filters accessible through the

evaporator coil compartment door. Filter type, size, and

quantity are determined by selected filter option and unit

size.

Note: Do not operate the unit without filters.

Field Installed Power Wiring

An overall dimensional layout for the standard field

installed wiring entrance into the unit is illustrated in

Figure 28, p. 27, Figure 29, p. 27, and Figure 30, p. 27. To

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 switch

and to the main power terminal block (HTB1) in the

unit control panel.

 Connect properly-sized earth ground.

Figure 26. Condensate trap installation

D = Pipe diameter; see Figure 28, p. 27, Figure 29, p. 27, and

Figure 30, p. 27 for correct pipe diameter

H = Internal static pressure (in wg) +1 in.

J = H + 0.5

L = H + J +D

Notes:

1. Pitch drain at least 1/2 in. per 10 ft horizontal run.

2. Condensate drain pan will not drain properly if P-trap is not primed

and of adequate height to allow for cabinet operating negative

pressure.

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.

PANEL ENCLOSURE

D" NPT FEMALE

CONNECTOR

CLEANOUT PLUG

Installation

OAU-SVX01E-EN 27

ensure that the unit’s supply power wiring is properly sized

and installed, refer to the following guidelines.

Figure 27. Main power entrance

Figure 28. OA1D utility connections

Table 4. OA1D Unit

MBh Pipe Connection (in.)

50 1/2

75 1/2

100 1/2

125 1/2

150 3/4

200 3/4

250 3/4

300 3/4

350 1

MAIN POWER ENTRANCE

FOR UNIT

3/4" NPT

CONDENSATE DRAINELECTRICAL

DISCONNECT

THROUGH BASE

ELECTRIC

18.13

54.26

23.37

8.74

3.21

46.58

GAS INLET

NPT SIZE VARIES

Figure 29. OA2 utility connections

Table 5. OA2D Unit

MBh Pipe Connection (in.)

150 3/4

200 3/4

250 3/4

300 3/4

350 1

400 1

500 1

600 1-1/4

700 1-1/4

800 1-1/4

Figure 30. OA3 utility connections

ELECTRIC

THROUGH BASE

DISCONNECT

ELECTRICAL

1" NPT

CONDENSATE DRAIN

GAS INLET

NPT SIZE VARIES

74.04

13.33

54.49

9.09

2.50

18.95

THROUGH

THE BASE

ELECTRIC

GAS INLET

NPT SIZE VARIES

1-1/4" NPT

CONDENSATE DRAIN

ELECTRICAL

DISCONNECT

9.76

21.56

104.33

144.00

67.00

17.74

11.78

Installation

28 OAU-SVX01E-EN

Note: All field installed wiring must conform to NEC

guidelines as well as State and Local codes.

Verify that the power supply available is compatible with

the unit’s nameplate ratings. The available supply power

must be within 10 percent of the rated voltage stamped on

the nameplate. Use only copper conductors to connect the

power supply to the unit.

Main Unit Power

Standard Wiring

The electrical service must be protected from over current

and short circuit conditions in accordance with NEC

requirements. Protection devices must be sized according

to the electrical data on the nameplate.

1. Location of the applicable electrical service entrance is

illustrated in Figure 28, p. 27, Figure 29, p. 27, and

Figure 30, p. 27. Complete the unit’s power wiring

connections onto either; the main terminal block HTB1

inside the unit control panel, the factory mounted non-

fused disconnect switch (UCD) or circuit breaker (UCB),

or the electric heat non-fused disconnect switch. Refer

to the customer connection diagram that shipped with

the unit for specific termination points.

2. Provide proper grounding for the unit in accordance

with local and national codes.

Use the following checklist in conjunction with the

checklist in “General Unit Requirements,” p. 25 to ensure

that the unit is properly installed and ready for operation.

Voltage Imbalance

Three phase electrical power to the unit must meet

stringent requirements for the unit to operate properly.

Measure each leg (phase-to-phase) of the power supply.

Each reading must fall within the utilization range stamped

on the unit nameplate. If any of the readings do not fall

Table 6. OA3D Unit

MBh Pipe Connection (in.)

300 3/4

350 1

400 1

500 1

600 1-1/4

700 1-1/4

800 1-1/4

1000 1-1/4

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote

disconnects before servicing. Follow proper lockout/

tagout procedures to ensure the power can not be

inadvertently energized. Failure to disconnect power

before servicing could result in death or serious injury.

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types

of conductors. Failure to use copper conductors could

result in equipment damage.

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.

Verify that the correct size and number of filters are in

place.

Inspect the interior of the unit for tools and debris and

install all panels in preparation for starting the unit.

Check all electrical connections for tightness and

“point of termination” accuracy.

Verify condenser airflow is unobstructed.

Verify that the condenser and indoor fans turn freely

without rubbing and are properly tightened on the

shafts.

Check motor mounting bolts and inlet cone for

tightness. Free spin wheel by hand to check for proper

alignment of motor, wheel, and inlet cone. Record

motor nameplate amps at unit-rated voltage.

Check proper indoor fan wheel rotation. Wheel

housing will be marked to indicate direction of proper

rotation.

With access doors closed and secured, operate

blower at 100 percent speed. Check amp readout of

amps output to indoor fan at VFD display to confirm

operation within motor amp capacity.

WARNING

Live Electrical Components!

During installation, testing, servicing and

troubleshooting of this product, it may be necessary to

work with live electrical components. Have a qualified

licensed electrician or other individual who has been

properly trained in handling live electrical components

perform these tasks. Failure to follow all electrical

safety precautions when exposed to live electrical

components could result in death or serious injury.

Installation

OAU-SVX01E-EN 29

within the proper tolerances, notify the power company to

correct this situation before operating the unit.

Excessive three phase voltage imbalance between phases

will cause motors to overheat and eventually fail. The

maximum allowable voltage imbalance is 2.0 percent.

Measure and record the voltage between phases 1, 2, and

3 and calculate the amount of imbalance as follows:

V1, V2, V3 = Line Voltage Readings

VD = Line Voltage reading that deviates the farthest from

the average voltage.

Example: If the voltage readings of the supply power

measured 221, 230, and 227, the average volts would be:

VD (reading farthest from average) = 221

The percentage of Imbalance equals:

The 2.2 percent imbalance in this example exceeds the

maximum allowable imbalance of 2.0 percent. This much

imbalance between phases can equal as much as a

20 percent current imbalance with a resulting increase in

motor winding temperatures that will decrease motor life.

If the voltage imbalance is over 2.0 percent, notify the

proper agencies to correct the voltage problem before

operating this equipment.

Electrical Phasing (Three-Phase Motors)

The compressor motor(s) and the supply fan motor are

internally connected for the proper rotation when the

incoming power supply is phased as A to L1, B to L2, and

C to L3.

Proper electrical supply phasing can be quickly

determined and corrected before starting the unit by using

an instrument such as an Associated Research Model 45

Phase Sequence Indicator and following these steps:

Compressor Crankcase Heaters

To prevent injury or death from electrocution, it is the

responsibility of the technician to recognize this hazard

and use extreme care when performing service

procedures with the electrical power energized.

Each compressor shall be equipped with a crankcase

heater. The proper operation of the crankcase heater is

important to maintain an elevated compressor oil

temperature during the “Off” cycle to reduce oil foaming

during compressor starts. Oil foaming occurs when

refrigerant condenses in the compressor and mixes with

the oil. In lower ambient conditions, refrigerant migration

to the compressor could increase.

When the compressor starts, the sudden reduction in

crankcase pressure causes the liquid refrigerant to boil

rapidly causing the oil to foam. This condition could

damage compressor bearings due to reduced lubrication

and could cause compressor mechanical failures.

% Voltage Imbalance = 100 X AV - VD where;

AV (Average Voltage) = Volt 1 + Volt 2 + Volt 3

221 + 230 + 227 = 226 Avg.

100 X 226 - 221 = 2.2%

226

WARNING

Live Electrical Components!

During installation, testing, servicing and

troubleshooting of this product, it may be necessary to

work with live electrical components. Have a qualified

licensed electrician or other individual who has been

properly trained in handling live electrical components

perform these tasks. Failure to follow all electrical

safety precautions when exposed to live electrical

components could result in death or serious injury.

Turn off the main source feeding power to the unit

field-supplied or factory-installed main disconnect

device (switch or circuit breaker).

Close the unit disconnect device cover, leaving

disconnect switch in the off position, and turn main

source power on.

Observe the ABC and CBA phase indicator lights on

the face of the sequencer. The ABC indicator light will

glow if the phase is ABC. If the CBA indicator light

glows, turn main source power off and then open the

unit main disconnect device cover and reverse any

two power wires.

Restore the main source power and recheck the

phasing. If the phasing is correct, turn main source

power off then open the unit main disconnect device

cover, remove the phase sequence indicator, reinstall

disconnect device cover and, leaving disconnect

device in the off position, turn main power source to

unit on.

WARNING

Live Electrical Components!

During installation, testing, servicing and

troubleshooting of this product, it may be necessary to

work with live electrical components. Have a qualified

licensed electrician or other individual who has been

properly trained in handling live electrical components

perform these tasks. Failure to follow all electrical

safety precautions when exposed to live electrical

components could result in death or serious injury.

Installation

30 OAU-SVX01E-EN

Before initial start up, or if main power has been off for an

extended period of time, compressor crankcase heater(s)

should be operated for a minimum of 8 hours prior to

compressor operation. With main power OFF, remove

jumper between OAUTS terminals 9 and 10 (E-Stop). Turn

main power to energize crankcase heater(s). At end of

warm up period turn main power off, install 9-10 jumper,

turn main power on, and resume normal operation.

Following crankcase heater warm-up, turn main power

disconnect off, and install jumper on E-Stop terminals 9

and 10.

Turn Main disconnect “On”.

Main Unit Display and ReliaTel Controls

When first powered “On”, the controls perform self-

diagnostic initialization to check that all internal controls

are functional. The Status LED located on the Main Unit

Display and the Liteport LED located on the RTRM module

is turned “On” within one second of power-up if internal

operation is okay.

Field-Installed Control Wiring

An overall layout of the various control options available

with the required number of conductors for each control

device is illustrated in Figure 31, p. 31 and Figure 32, p. 32.

Note: All field wiring must conform to NEC guidelines as

well as state and local codes.

Control Power Transformer

The 24-volt control power transformers are to be used only

with the accessories called out in this manual.

Transformers rated greater than 50 VA are equipped with

internal circuit breakers. If a circuit breaker trips, turn “Off”

all power to the unit before attempting to reset it.

The transformers are located in the control panel. The

circuit breaker is located on the left side of the

transformers and can be reset by pressing in on the black

reset button.

Controls Using 24 Vac

Before installing any connecting wiring, refer to Figure 28,

p. 27, Figure 29, p. 27, and Figure 30, p. 27 for the electrical

access locations provided on the unit and Table 7 for AC

conductor sizing guidelines, and:

1. Use copper conductors unless otherwise specified.

2. Ensure that the AC control wiring between the controls

and the unit’s termination point does not exceed three

(3) ohms/ conductor for the length of the run.

Note: Resistance in excess of 3 ohms per conductor

may cause component failure due to

insufficient AC voltage supply.

3. Be sure to check all loads and conductors for grounds,

shorts, and mis-wiring.

4. Do not run the AC low-voltage wiring in the same

conduit with the high-voltage power wiring.

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.

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote

disconnects before servicing. Follow proper lockout/

tagout procedures to ensure the power can not be

inadvertently energized. Failure to disconnect power

before servicing could result in death or serious injury.

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote

disconnects before servicing. Follow proper lockout/

tagout procedures to ensure the power can not be

inadvertently energized. Failure to disconnect power

before servicing could result in death or serious injury.

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types

of conductors. Failure to use copper conductors could

result in equipment damage.

Table 7. 24 Vac conductors

Distance from Unit to Control Recommended Wire Size

000–460 feet

000–140 m 18 gauge

0.75 mm2

461–732 feet

104–223 m 16 gauge

1 mm2

Installation

OAU-SVX01E-EN 31

Controls Using DC Analog Input/Output

(Standard Low Voltage Multiconductor

Wire)

Before installing any connecting wiring between the unit

and components utilizing a DC analog input\output signal,

refer to Figure 28, p. 27, Figure 29, p. 27, and Figure 30,

p. 27 for the electrical access locations provided on the

unit.

1. Table 8, p. 31 lists the conductor sizing guidelines that

must be followed when interconnecting the DC binary

output devices and the system components utilizing a

DC analog input\output signal to the unit.

Note: Resistance in excess of 2.5 ohms per conductor

can cause deviations in the accuracy of the

controls.

2. Ensure that the wiring between controls and the unit’s

termination point does not exceed 2.5 ohms/

conductor for the length of the run.

3. Do not run the electrical wires transporting DC signals

in or around conduit housing high voltage wires.

DC Conductors

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote

disconnects before servicing. Follow proper lockout/

tagout procedures to ensure the power can not be

inadvertently energized. Failure to disconnect power

before servicing could result in death or serious injury.

Table 8. Zone sensor module wiring

Distance from Unit to Control Recommended Wire Size

000–150 feet

0–45.7 m 22 gauge

0.33 mm2

151–240 feet

46–73.1 m 20 gauge

0.50 mm2

241–385 feet

73.5–117.3 m 18 gauge

0.75 mm2

386–610 feet

117.7–185.9 m 16 gauge

1.3 mm2

611–970 feet

186.2–295.7 m 14 gauge

2.0 mm2

Figure 31. OAUTS Connection B

Installation

32 OAU-SVX01E-EN

Figure 32. OAUTS Connection C

OAU-SVX01E-EN 33

System Configuration and Pre-Start

The following procedure must be completed prior to

performing the start-up procedure in the system Start-Up

section in this document. This section describes

procedures to navigate the various displays on the Unit

Display and configure the Outdoor Air Unit Main Unit

Display system setpoints and operating parameters.

Important: This section is intended to provide

guidelines for navigation through the

remote operator display screens. For

additional control system information, refer

to Integration Guide: Tracer™ UC600

Programmable Controller for Packaged

Outdoor Air Unit (BAS-SVP18A-EN, or the

most recent revision). The unit is configured

at the factory with the default settings as

described in “Sequence of Operation—

”Unoccupied”,” p . 2 4 ; also refer to

“Sequence of Operation,” p. 21 for details

concerning setup and operating setpoints.

System Configuration and Pre-Start

34 OAU-SVX01E-EN

Table 9. Menu descriptions

Screen Menu Point List Min/Inactive Default Max/Active BAS

Point?

Alarms Active Alarms List of all active alarms

All Alarms List of all previous alarms

Reports

(continued

on next

page)

Custom Graphics *NOT USED*

System Status

Program Control Discharge Air Control Space ControlSpace ControlY

Heat Cool Mode Active Heat --- Cool N

Occupancy Status Occupied|Unoccupied|Occupied Bypass|Occupied Standby|Unknown Y

Compressor 1 Command Off --- On N

Compressor 2 Command Off --- On N

Compressor 3 Command Off --- On N

Compressor 4 Command Off --- On N

Digital Scroll Command 0% --- 100% N

Dehumidification Command Disabled Enabled N

Discharge Air Temperature Local Analog Input

Economizer Mode Disabled Enabled N

Evap Leaving Temp Local Analog Input

Heat Capacity 0% --- 100% N

Heating Output Command 0% --- 100% N

Heat 1 Command Off --- On N

Heat 2 Command Off --- On N

Heat 3 Command Off --- On N

Inducer Command Off --- On N

Gas Valve Status Binary Input

HGRH Command 0% --- 100% N

OA Damper End Switch Binary Input

Outdoor Air Damper Command Closed --- Open N

OAD Position Local Binary Input

Outdoor Air Relative Humidity Local Analog Input

Outdoor Air Temperature Local Analog Input

Space Dewpoint Active Analog Input

Space Temperature Local Analog Input

Supply Fan Start Stop Command Off --- Off N

Filter Status Clean --- Dirty N

System Lockout Normal Normal Lockout N

UNOCC Cooling Mode Off --- On N

UNOCC Dehumid Mode Off --- On N

UNOCC Heating Mode Off --- On N

ERV Command Disable --- Enable N

ERV Leaving Air Temperature Local Analog Input

PEVFD Command 0% 80% 100% Y

Discharge Airflow Local Analog Input

ERV Leaving Air Humidity Local Analog Input

System Configuration and Pre-Start

OAU-SVX01E-EN 35

Reports

(continued

from

page)

System Setpoints

DAT High Temp Cutout 100°F 125°F 150°F Y

DAT Low Temp Cutout 35°F 35°F 50°F Y

DAT Temp Cutout Time 10 min. 10 min. 25 min. Y

Discharge Air Cooling Setpoint 55°F 55°F 75°F Y

Discharge Air Heating Setpoint 65°F 85°F 90°F Y

ERV Wheel Frost Cutout Setpoint 32°F 34°F 40°F Y

EVAP Leaving Temp Setpoint 45°F 53°F 70°F Y

IVFD Signal 50% 100% 100% Y

Maximum Discharge Air Temperature 70°F 90°F 100°F Y

Minimum Discharge Air Cooling Setpoint 40°F 50°F 65°F Y

Minimum Discharge Air Heating Setpoint 50°F 55°F 60°F Y

Maximum OA Damper Position 0% 100% 100% Y

Minimum OA Damper Position 0% 100% 100% Y

Occupied Space Cooling Setpoint 65°F 74°F 90°F Y

Occupied Space Heating Setpoint 60°F 70°F 75°F Y

Outdoor Air Cooling Setpoint (OACS) 70°F 75°F 85°F Y

Outdoor Air Dewpoint Setpoint (OADS) 49°F 58°F 65°F Y

Outdoor Air Heating Setpoint (OAHS) 40°F 70°F 70°F Y

PEVFD Setpoint 0% 80% 100% Y

Space Dewpoint Setpoint (SPDS) 50°F 59°F 68°F Y

UNOCC Space Cooling Setpoint 60°F 80°F 90°F Y

UNOCC Space Dewpoint Setpoint 49°F 65°F 68°F Y

UNOCC Space Heating Setpoint 50°F 60°F 70°F Y

System Setup

Program Control Discharge Air Control Space ControlSpace ControlY

Compressor Count 004N

Heater Count 002N

Split Manifold Burner Not Installed Installed Installed N

ERV Option Not Installed Installed Installed N

Powered Exhaust Option Not Installed Installed Installed N

Return Air Damper Option Not Installed Installed Installed N

Space Temp/Humidity Sensor Installed Not Installed Installed Installed N

Heat Type No Heat|Gas Heat|Electric Heat|Other N

Alarm Reset Off Off On Y

Supply Fan Failure Reset Off Off On Y

Override Summary List of active overrides - same as selecting Override button at top of screen

All Point Report List of all points (AO/AI/BO/BI/MS/etc …) in the configuration file

About Controller Name listed is the version of the program installed in the UC600

Expansion Modules Provides status of expansion modules

TGP2 Programs List of all TGP2 programs loaded on the UC600

Data Graphs *NOT USED*

Settings

Schedules - Refer to UC600 IOM for scheduling functions

Display Preferences

Language

Date and Time

Clean Touchscreen

Table 9. Menu descriptions (continued)

Screen Menu Point List Min/Inactive Default Max/Active BAS

Point?

36 OAU-SVX01E-EN

Start-Up

Indirect Gas-Fired Heating

Start-Up

Notes:

1. This furnace module does not have a pilot. It is

equipped with a direct spark ignition device that

automatically lights the gas burner. DO NOT try to light

burners by hand.

2. BEFORE OPERATING, leak test all gas piping up to

heater gas valve. Smell around the unit area for gas. If

gas is smelled, do NOT attempt to place heater in

operation until source of gas leak is identified and

corrected.

3. Use only hand force to operate the gas control lever to

the “ON” position. NEVER use tools. If lever does not

operate by hand, replace gas valve prior to staring the

unit. Forcing or attempting to repair the gas valve may

result in fire or explosion.

4. Do not attempt to operate unit, if there is indication that

any part or control has been under water. Any control

or component that has been under water must be

replaced prior to trying to start the unit.

Refer to “Sequence of Operation,” p. 21 for additional

information.

Tools Required

• Voltage Meter (μA)

•Amp Meter

• Gas Manometer (2)

• Temperature Probe

• Small Refrigeration Screwdriver

• 5/16-in. Nut Driver

• 3/16-in. Allen Wrench

• 3/32-in. Allen Wrench

• 1/8-in. NPT barbed pressure taps (3)

• 1/2-in. Open End Wrench

Start-Up Procedure

1. Check Inlet Gas Pressure

Check to insure the gas pressure supplied to the unit is

within the pressure requirement listed on the

nameplate. DO NOT expose gas controls to pressures

above 1/2 psi (14 in. wc). The gas supply line should be

installed with an external manual shutoff and pressure

tap.

2. Verify Indoor Fan Failure Switch Operation

Indoor Fan Failure Switch (IFFS) is located in the unit

electrical control compartment above the heater.

Indoor fan failure switch will fail if not proven within

30 seconds of call for indoor fan—ON.

All unit air filters must be clean before proceeding to

properly complete this verification.

Important: If the unit air filters are not clean, unit

performance could be affected. Remove

and clean or replace air filters as required

prior to proceeding with the burner

pressure testing.

In the event that the pressure switch fails to operate,

check the pick-up tubes to be certain that the tubes are

not obstructed and confirm that the tube connections

to IFFS are tight and secure.

WARNING

Hazardous Service Procedures!

The maintenance and troubleshooting procedures

recommended in this section of the manual could result

in exposure to electrical, mechanical or other potential

safety hazards. Always refer to the safety warnings

provided throughout this manual concerning these

procedures. When possible, disconnect all electrical

power including remote disconnect and discharge all

energy storing devices such as capacitors before

servicing. Follow proper lockout/tagout procedures to

ensure the power can not be inadvertently energized.

When necessary to work with live electrical

components, have a qualified licensed electrician or

other individual who has been trained in handling live

electrical components perform these tasks.

Do not attempt the following procedures until all

electrical and gas connections to the unit have been

completed and the outdoor air damper and evaporator

fan operation have been verified and are operating

correctly.

Failure to follow all of the safety warnings provided

could result in death or serious injury.

WARNING

Hazard of Explosion!

Never use an open flame to detect gas leaks. It could

result in an explosion. Use a leak test solution for leak

testing. Failure to follow recommended safe leak test

procedures could result in death or serious injury or

equipment or property-only-damage.

Start-Up

OAU-SVX01E-EN 37

3. Confirm Gas Flow at Unit

Open door to unit vestibule housing the gas heater.

Move gas control lever to “OFF” position. Remove

1/8-in. pressure taps (see Figure 34, p. 39) from both

modulating and on-off sections of the split heater

manifold. Install a barbed fitting in both 1/8-in. tapped

holes for connection to individual gas manometers.

Note: There is a third 1/8-in. gas pressure tap located in

the pipe connecting the main valve/regulator and

modulating valve. Maximum pressure into

modulating valve is 5-in. The On-Off gas valve

includes a regulator adjustment device that is

located on the top of the valve. Use this device to

regulate valve output to modulating valve as

required.

Wait 5 minutes for any gas to clear. If you smell gas, see

Step 2 and correct leak. If you don’t smell gas or have

corrected any leaks, go to Step 4.

4. Burner Starting Sequence and Burner Ignition

Figure 34, p. 39 illustrates indirect gas-fired furnace

components.

5. Main Gas Supply

Turn manual gas cock “ON”.

6. Split Manifold High Fire and Burner Test

Open all manual gas valves. Turn power on at unit’s

main disconnect switch. Open gas supply manual shut-

off valve. Using unit display (or computer with Trane

Tracer TU), proceed to System Status Display and

Override all Compressor stages OFF, Disable

Dehumidification, Disable Economizer Mode, Disable

ERV. If two heaters are installed, test heating with split

manifold first by overriding burner 2 OFF. Override

heating Output Command to 100.0 percent if one

heater is installed and to 49 percent if two heaters are

installed. Override Heat Cool Mode Active to Heat. This

will enable call for heat to split manifold heater.

Depending on outdoor air temperature, at time of

startup, heater high limit temperature may be

exceeded causing limit switch to trip. Limit switch is

auto-reset. Limit switch must be jumpered out of the

circuit if OA temperature dictates.

With limit switch closed, the draft inducer will run on

high speed for 10 seconds for proof of high and low

airflow switch closure, then begin a 30-second pre-

purge period. At the end of the pre-purge the direct

spark will be energized and On-Off gas valve will open

for a 5-second ignition trial. Following successful

ignition, the inducer remains on high for 10-second

flame stabilization, followed by 30-second warm up.

Should the flame go out or the burner fail to light, an

ignition retry will initiate following a 15-second inter-

purge period.

Following successful ignition, manifold pressure

should be 1.2 in. wc during the warm-up period. The

manifold pressure will rise to 3.5 in. wc at 100 percent

firing rate. Following these sequences to check low fire

gas pressure for modulating section, reduce Heating

Output Command to 0 percent. Inducer speed will

reduce to low speed. Correct gas pressure for

modulating manifold section of heater at 0 percent

output signal or low fire will be 0.17 in. For modulating

sections, the outlet gas pressure from main/regulator

valve into the modulating valve is 5-in. wc.

Main On-Off valves in 1/2-in. gas line require 3/32-in.

Allen wrench to adjust outlet gas pressure. Valves in

3/4-in. gas line require flat blade screwdriver to adjust

outlet gas pressure. Following these sequences,

inducer speed will reduce to low speed and will now be

speed-controlled by the heater controller based on gas

input to burners.

With heating command at 100 percent and with a

single split manifold heater installed, the On-Off

section of the heater will require the modulating

section to prove ON before the On-Off section will

enable. Inducer speed high at all times the On-Off

section is in ignition sequence or firing. On-Off section

sequence includes a 1-second ignition pre-purge

followed by 4-second ignition trial. Ignition or flame

failure will be followed by 30-second inter-purge for

two ignition retry then 5-minute lockout period if both

retry attempts fail. Correct manifold gas pressure for

On-Off heater section is 3.5 in. wc.

For units including an additional separate On-Off

heater, set heat command output to 49 percent to run

modulating heater start-up. When complete with

modulating heater start-up, increase heat output

command to 100 percent to start up the second heater.

Failure to Ignite

•On the initial start-up, or after unit has been off long

periods of time, the first ignition trial may be

unsuccessful due to need to purge air from

manifold at start-up.

•If ignition does not occur on the first trial, the gas

and spark are shut-off by the ignition control and

the control enters an inter-purge period of

15 seconds, during which the draft inducer

continues to run.

•At the end of the inter-purge period, another trial for

ignition will be initiated.

•Control will initiate up to three ignition trials on a

call for heat before lockout of control occurs.

WARNING

Hazardous Voltage and Gas!

Turn off the gas supply and disconnect all electric

power, including remote disconnects before servicing

unit. Follow proper lockout/tagout procedures to

ensure the power can not be inadvertently energized

and the gas can not be inadvertently turned on. Failure

to turn off gas or disconnect power before servicing

could result in death or serious injury.

Start-Up

38 OAU-SVX01E-EN

•Control can be brought out of lockout by cycling call

for heat at the Main Unit Display.

Prior to completing the start-up, check the appearance

of the main burner flame. Refer to Figure 33, p. 38 for

flame characteristics of properly adjusted natural gas

systems.

Main burner flame

•The burner flame should be predominately blue in

color and well defined and centered at the tube

entry as shown in Figure 33 above. Distorted flame

or yellow tipping of natural gas flame, or a long

yellow flame on propane, may be caused by lint and

dirt accumulation inside burner or at burner ports,

at air inlet between burner and manifold pipe, or

debris in the main burner orifice. Soft brush or

vacuum clean affected areas.

•Poorly defined, substantially yellow flames, or

flames that appear lazy, indicate poor air supply to

burners or excessive burner input. Verify gas

supply type and manifold pressure with rating

plate.

•Poor air supply can be caused by obstructions or

blockage in heat exchanger tubes or vent discharge

pipe. Inspect and clean as necessary to eliminate

blockage. Vacuum any dirt or loose debris. Clean

heat exchanger tubes with stiff brush. Poor flame

characteristics can also be caused by flue gas

recirculation into combustion air supply. If

surrounding buildings or prevailing winds cause

recirculation, a flue extension may be required to

prevent recirculation. Contact manufacturer prior

to making any flue adjustments.

•Reduced air delivery can also be the result of

inducer fan blade slippage, dirt accumulation in the

fan blade or low voltage to draft inducer motor.

Inspect draft fan assembly and be sure fan blade is

secure to motor shaft. Check line voltage to heater.

7. Flame Sensor Current Check

Flame current is the current which passes through the

flame from the sensor to ground. A flame signal of 0.5

to 1.0 microamp (μA) is marginal. For dependable

operation, a flame signal of greater than 1.0 μA is

required. To measure flame current, connect a meter

capable of reading micro-amp current so the flame

signal will be read thru the meter’s COM and μA

connections. The meter should read greater than

1.0 μA.

Note: If the meter reads below “0” on scale, meter

leads are reversed; disconnect power and

reconnect meter leads for proper polarity.

Figure 33. Flame characteristics of properly-adjusted

natural gas systems

Burner flame at start-up: 1.2 in. wc manifold pressure

draft inducer—high speed

Burner flame at high fire: 3.5 in. wc manifold pressure

draft inducer—high speed

NOTICE:

Meter Damage!

Do NOT measure voltage with meter connected to a

circuit. Failure to follow these instructions could result

in meter damage.

Start-Up

OAU-SVX01E-EN 39

Safety Controls

Air Pressure Switch. An air pressure switch is provided

as part of the control system to verify airflow through draft

inducer by monitoring the difference in pressure between

the draft inducer and the atmosphere. If sufficient negative

pressure is not present, indicating lack of proper air

movement through heat exchanger, the switch opens

shutting off gas supply though the ignition control

module. On units with two speed draft inducer operation,

a dual air pressure switch is used, monitoring high and low

speed pressures. The air pressure switches have fixed

settings and are not adjustable.

Rollout Switch (Manual Reset). The furnace module

is equipped with manual reset rollout switch(es) in the

event of burner flame rollout. The switch will open on

temperature rise and shut-off gas supply through the

ignition control module. Flame rollout can be caused by

insufficient airflow for the burner firing rate (high gas

pressure), blockage of the vent system or in the heat

exchanger. The furnace module should not be placed back

in operation until the cause of rollout condition is

identified and corrected. The rollout switch can be reset by

pressing the button on top of the switch.

High Limit Switch. The furnace module is equipped

with a fixed temperature high limit switch mounted on the

vestibule panel that shuts off gas to the heater through the

ignition control module in the event of reduced airflow

over the heat exchanger tubes. Reduced airflow can be

caused by indoor fan failure, dirty or blocked filters, or

restriction of the air inlet or outlet to the unit. The high limit

switch will automatically reset when the air temperature

drops to approximately 30°F below the limit setpoint.

Determine the cause of the reduced air flow and correct.

Figure 34. OA1/OA2/OA3 indirect gas-fired furnace components

INDUCER MOTOR

INLET PRESSURE TAP

IGNITION

ON/OFF GAS VALVE

MANIFOLD GAS

PRESSURE = 14" W.C.

AIR-PROVING

PRESSURE TAP

SWITCH

MAXIMUM INLET

PRESSURE TAP

MANIFOLD GAS

ROLLOUT SWITCH

CONTROLLERS

MAXIMUM INLET

PRESSURE = 14" W.C.

CONDENSATE DRAIN

(TYP. 2)

INDUCER BLOWER

MODULATING VALVE

FLAME

SENSOR

HIGH LIMIT

SWITCH

ROLLOUT

SWITCH

MODULATING

GAS VALVE

40 OAU-SVX01E-EN

Maintenance

Make sure all personnel are standing clear of the unit

before proceeding. The system components will start

when the power is applied.

Monthly Maintenance

Before completing the following checks, turn the unit OFF

and lock the main power disconnect switch open.

Filters

• Inspect the return air filters. Clean or replace them if

necessary. Refer to the unit Service Facts for filter

information and refer to “OAU Filter Guide” in

“Appendix,” p. 55 for exact replacement dimensions.

Supply/Return Air Smoke Detector

Maintenance

Airflow through the unit is affected by the amount of dirt

and debris accumulated on the indoor coil and filters.

To insure that airflow through the unit is adequate for

proper sampling by the return air smoke detector,

complete adherence to the maintenance procedures,

including recommended intervals between filter changes,

and coil cleaning is required.

Periodic checks and maintenance procedures must be

performed on the smoke detector to insure that it will

function properly.

For detailed instructions concerning these checks and

procedures, refer to the appropriate section(s) of the

smoke detector Installation and Maintenance Instructions

provided with the literature package for this unit.

Cooling Season

• Check the unit’s drain pans and condensate piping to

ensure that there are no blockages.

• Inspect the evaporator and condenser coils for dirt,

bent fins, etc. If the coils appear dirty, clean them

according to the instructions described in “Condenser

Coil Cleaning,” p. 40.

• Manually rotate the condenser fan(s) to ensure free

movement and check motor bearings for wear. Verify

that all of the fan mounting hardware is tight.

• Inspect the F/A-R/A damper hinges and pins to ensure

that all moving parts are securely mounted. Keep the

blades clean as necessary.

• Verify that all damper linkages move freely; lubricate

with white grease, if necessary.

• Check supply fan motor bearings; repair or replace the

motor as necessary.

• Check the fan shaft bearings for wear. Replace the

bearings as necessary.

• Verify that all wire terminal connections are tight.

• Remove any corrosion present on the exterior surfaces

of the unit and repaint these areas.

• Generally inspect the unit for unusual conditions (e.g.,

loose access panels, leaking piping connections, etc.).

• Make sure that all retaining screws are reinstalled in

the unit access panels once these checks are complete.

• With the unit running, check and record the: ambient

temperature; compressor suction and discharge

pressures (each circuit); superheat (each circuit);

Record this data on an “operator’s maintenance log”

like the one shown in Table 10, p. 41. If the operating

pressures indicate a refrigerant shortage, measure the

system superheat.

Note: Do NOT release refrigerant to the atmosphere! If

adding or removing refrigerant is required, the

service technician must comply with all federal,

state and local laws.

Heating Season

• Inspect the unit’s air filters. If necessary, clean or

replace them.

• Check supply fan motor bearings; repair or replace the

motor as necessary.

• Inspect both the main unit control panel and heat

section control box for loose electrical components

and terminal connections, as well as damaged wire

insulation. Make any necessary repairs.

• Verify that the electric heat system operates properly.

Condenser Coil Cleaning

Regular coil maintenance, including annual cleaning,

enhances the unit’s operating efficiency by minimizing:

compressor head pressure and amperage draw;

evaporator water carryover; fan brake horsepower, due to

increase static pressure losses; airflow reduction.

At least once each year, or more often if the unit is located

in a “dirty” environment, clean the condenser coils using

the instructions outlined below. Be sure to follow these

instructions as closely as possible to avoid damaging the

coils.

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote

disconnects before servicing. Follow proper lockout/

tagout procedures to ensure the power can not be

inadvertently energized. Failure to disconnect power

before servicing could result in death or serious injury.

Maintenance

OAU-SVX01E-EN 41

Microchannel (MCHE) Coils

Due to the soft material and thin walls of the MCHE coils,

the traditional field maintenance method recommended

for Round Tube Plate Fin (RTPF) coils does not apply to

microchannel coils.

Moreover, chemical cleaners are a risk factor to MCHE due

to the material of the coil. The manufacturer does not

recommend the use of chemical cleaners to clean

microchannel coils. Using chemical cleaners could lead to

warranty claims being further evaluated for validity and

failure analysis.

The recommended cleaning method for microchannel

condenser coils is pressurized water or air with a non-

pinpoint nozzle and an ECU of at least 180 with pressure no

greater than 600 psi. To minimize the risk of coil damage,

approach the cleaning of the coil with the pressure washer

aimed perpendicular to the face of the coil during cleaning.

Optimum clearance between the sprayer nozzle and the

microchannel coil is 1 in.–3 in.

Final Process

For future reference, you may find it helpful to record the

unit data requested below in the blanks provided.

(1) Complete Unit Model Number:

_____________________________________________________

(2) Unit Serial Number:

_____________________________________________________

(3) Wiring Diagram Numbers (from unit control panel)

— schematic(s)

_____________________________________________________

— connection(s)

_____________________________________________________

NOTICE:

Coil Damage!

DO NOT use any detergents with microchannel

condenser coils. Use pressurized water or air ONLY,

with pressure no greater than 600psi. Failure to do so

could result in coil damage.

For additional information regarding the proper

microchannel coil cleaning procedure, refer to

RT-SVB83*-EN.

Table 10. Sample maintenance log

Date

Current

Ambient

Temp F/C

Refrigerant Circuit #1 Refrigerant Circuit #2

Compr.

Oil Level

Suct.

Press.

Psig/kPa

Disch.

Press

Psig/kPa

Liquid

Press

Psig/kPa Super-

heat F/C Sub-cool

F/C Compr.

Oil Level

Suct.

Press.

Psig/kPa

Disch.

Press

Psig/kPa

Liquid

Press

Psig/kPa Super-

heat F/C Sub-cool

F/C

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

- ok

- low - ok

- low

42 OAU-SVX01E-EN

Performance Data

Table 11. OA1 General Data—Cooling 5–8 Tons High Efficiency

5 Tons Downflow 6 Tons Downflow 7 Tons Downflow 8 Tons Downflow

OA1D060A OA1D072A OA1D084 OA1D096

Cooling Performance

Gross Cooling Capacity, Btu (kW) 61,464 (18.01) 73,757 (21.62) 86,050 (25.22) 98,342 (28.82)

Nominal cfm (m3/h) 625–1250 (1062–2124) 750–1500 (1274–2549) 875–1750 (1487–2973) 1000–2000 (1699–3398)

Compressor

Number 1112

Type Scroll Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 13 (1.21) 13 (1.21) 13 (1.21) 24 (2.23)

Rows 2222

FPI 12121212

Indoor Coil

Type High Performance High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 6 (0.56) 6 (0.56) 6 (0.56) 9 (0.84)

Rows 6666

FPI 12121212

Refrigerant Control TXV TXV TXV TXV

Drain Connection Size, in. (mm) 3/4 (20) 3/4 (20) 3/4 (20) 3/4 (20)

Outdoor Fan

Type Propeller Propeller Propeller Propeller

Number Used 1112

Diameter, in. (mm) 24 (609.6) 24 (609.6) 24 (609.6) 24 (609.6)

Drive Type Direct Direct Direct Direct

No. Speeds 1111

CFM (m3/h) 6,500 (11,044) 6,500 (11,044) 6,500 (11,044) 13,000 (22,087)

Number Motors 1112

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined Backward Inclined

Number Used 1111

Diameter Varies Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive Direct Drive

Number Motors 1111

Motor HP (kW), Standard–Oversized 1.0–3.0 (0.75–2.24) 1.0–3.0 (0.75–2.24) 1.0–3.0 (0.75–2.24) 1.0–5.0 (0.75–3.73)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate See Nameplate

Performance Data

OAU-SVX01E-EN 43

Table 12. OA1 General Data—Cooling 10–15 Tons High Efficiency

10 Tons Downflow 12 Tons Downflow 15 Tons Downflow

OA1D120A OA1D144A OA1D144A

Cooling Performance

Gross Cooling Capacity, Btu (kW) 121,904 (35.73) 147,514 (43.23) 184,392 (54.04)

Nominal cfm (m3/h) 1250–2500 (2124–4248) 1500–3000 (2549–5097) 1875–3750 (3186–6371)

Compressor

Number 2 2 2

Type Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 24 (2.23) 24 (2.23) 24 (2.23)

Rows 2 2 2

FPI 121212

Indoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 9 (0.84) 9 (0.84) 9 (0.84)

Rows 6 6 6

FPI 121212

Refrigerant Control TXV TXV TXV

Drain Connection Size, in. (mm) 3/4 (20) 3/4 (20) 3/4 (20)

Outdoor Fan

Type Propeller Propeller Propeller

Number Used 2 2 2

Diameter, in. (mm) 24 24 24

Drive Type Direct Direct Direct

No. Speeds 1 1 1

CFM (m3/h) 13,500 (22,937) 13,500 (22,937) 13,500 (22,937)

Number Motors 2 2 2

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined

Number Used 1 1 1

Diameter Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive

Number Motors 1 1 1

Motor HP (kW), Standard–Oversized 1.0–5.0 (0.75–3.73) 1.0–5.0 (0.75–3.73) 1.0–5.0 (0.75–3.73)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate

Performance Data

44 OAU-SVX01E-EN

Table 13. OA2 General Data—Cooling 12–20 Tons High Efficiency

12 Tons Downflow 15 Tons Downflow 17 Tons Downflow 20 Tons Downflow

OA2D144A OA2D180A OA2D210A OA2D240A

Cooling Performance

Gross Cooling Capacity, Btu (kW) 147,514 (43.23) 184,392 (54.04) 208,973 (61.24) 245,856 (72.05)

Nominal cfm (m3/h) 1500–3000 (2549–5097) 1875–3750 (3186–6371) 2125–4250 (3610–7221) 2500–5000 (4248–8495)

Compressor

Number 2222

Type Scroll Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 24 (2.23) 30 (2.79) 38 (3.53) 38 (3.53)

Rows 2333

FPI 12121212

Indoor Coil

Type High Performance High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 9 (0.84) 10 (0.93) 15 (1.39) 15 (1.39)

Rows 6666

FPI 12121212

Refrigerant Control TXV TXV TXV TXV

Drain Connection Size, in. (mm) 1 (25) 1 (25) 1 (25) 1 (25)

Outdoor Fan

Type Propeller Propeller Propeller Propeller

Number Used 2333

Diameter, in. (mm) 24 (609.6) 24 (609.6) 24 (609.6) 24 (609.6)

Drive Type Direct Direct Direct Direct

No. Speeds 1111

CFM (m3/h) 19,500 (33,131) 19,500 (33,131) 19,500 (33,131) 19,500 (33,131)

Number Motors 3333

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined Backward Inclined

Number Used 1111

Diameter Varies Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive Direct Drive

Number Motors 1111

Motor HP (kW), Standard–Oversized 1.0–5.0 (0.75–3.73) 1.0–5.0 (0.75–3.73) 1.0–7.5 (0.75–5.6) 1.0–7.5 (0.75–5.6)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Refer to “OAU Filter

Guide” in “Appendix,”

p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate See Nameplate

Performance Data

OAU-SVX01E-EN 45

Table 14. OA2 General Data—Cooling 22–30 Tons High Efficiency

22 Tons Downflow 25 Tons Downflow 30 Tons Downflow

OA2D264A OA2D300A OA2D360A

Cooling Performance

Gross Cooling Capacity, Btu (kW) 270,442 (79.26) 307,320 (90.07) 368,784 (108.08)

Nominal cfm (m3/h) 2750–5500

(4692–9345) 3125–6250

(5309–10619) 3750–7500

(6371–12743)

Compressor

Number 2 2 2

Type Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 38 (3.53) 38 (3.53) 38 (3.53)

Rows 3 3 3

FPI 12 12 12

Indoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 15 (1.39) 20 (1.86) 20 (1.86)

Rows 6 6 6

FPI 12 12 12

Refrigerant Control TXV TXV TXV

Drain Connection Size, in. (mm) 1 (25) 1 (25) 1 (25)

Outdoor Fan

Type Propeller Propeller Propeller

Number Used 3 3 3

Diameter, in. (mm) 24 (609.6) 24 (609.6) 24 (609.6)

Drive Type Direct Direct Direct

No. Speeds 1 1 1

CFM (m3/h) 19,500 (33,131) 19,500 (33,131) 19,500 (33,131)

Number Motors 3

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined

Number Used 1 1 1

Diameter Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive

Number Motors 1 1 1

Motor HP (kW), Standard–Oversized 1.0–7.5 (0.75–5.6) 1.0–15.0 (0.75–11.19) 1.0–15.0 (0.75–11.19)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter Guide”

in “Appendix,” p. 55 Refer to “OAU Filter Guide”

in “Appendix,” p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate

Performance Data

46 OAU-SVX01E-EN

Table 15. OA3 General Data—Cooling 30–40 Tons High Efficiency

30 Tons Downflow 35 Tons Downflow 40 Tons Downflow

OA3D360A OA3D420A OA3D480A

Cooling Performance

Gross Cooling Capacity, Btu (kW) 368,784 (108.08) 430,248 (126.09) 491,712 (144.11)

Nominal cfm (m3/h) 3750–7500

(6371–12743) 4375–8750

(7433–14866) 5000–10000

(8495–16990)

Compressor

Number 233

Type Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 48 (4.46) 53 (4.92) 63 (5.85)

Rows 233

FPI 121212

Indoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 23 (2.14) 23 (2.14) 29 (2.69)

Rows 666

FPI 121212

Refrigerant Control TXV TXV TXV

Drain Connection Size, in. (mm) 1-1/4 (32) 1-1/4 (32) 1-1/4 (32)

Outdoor Fan

Type Propeller Propeller Propeller

Number Used 4 4 4

Diameter, in. (mm) 24 24 24

Drive Type Direct Drive Direct Drive Direct Drive

No. Speeds 111

CFM (m3/h) 26,000 (44,174) 26,000 (44,174) 26,000 (44,174)

Number Motors 444

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined

Number Used 1 1 1 or 2

Diameter Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive

Number Motors 1 1 1 or 2

Motor HP (kW), Standard–Oversized 1.5–15 (1.12–11.19) 1.5–15 (1.12–11.19) 2.0–15 (1.49–11.19)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter Guide”

in “Appendix,” p. 55 Refer to “OAU Filter Guide”

in “Appendix,” p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate

Performance Data

OAU-SVX01E-EN 47

Table 16. OA3 General Data—Cooling 45–54 Tons High Efficiency

45 Tons Downflow 50 Tons Downflow 54 Tons Downflow

OA3D540A OA3D600A OA3D648A

Cooling Performance

Gross Cooling Capacity, Btu (kW) 553,176 (162.12) 614,640 (180.13) 663,811 (194.54)

Nominal cfm (m3/h) 5625–11250

(9557–19114) 6250–12500

(10619–21238) 6750–13500

(11468–22937)

Compressor

Number 344

Type Scroll Scroll Scroll

Outdoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Face Area, ft2 (m2) 63 (5.85 63 (5.85 63 (5.85

Rows 444

FPI 121212

Indoor Coil

Type High Performance High Performance High Performance

Tube Size—OD, in. (mm) 1/2 (12.7) 1/2 (12.7) 1/2 (12.7)

Face Area, ft2 (m2) 29 (2.69) 29 (2.69) 29 (2.69)

Rows 666

FPI 121212

Refrigerant Control TXV TXV TXV

Drain Connection Size, in. (mm) 1-1/4 (32) 1-1/4 (32) 1-1/4 (32)

Outdoor Fan

Type Propeller Propeller Propeller

Number Used 4 4 4

Diameter, in. (mm) 24 (609.6) 24 (609.6) 24 (609.6)

Drive Type Direct Direct Direct

No. Speeds 111

CFM (m3/h) 26,000 (44,174) 26,000 (44,174) 26,000 (44,174)

Number Motors 444

Motor HP (kW), per motor 1.0 (0.75) 1.0 (0.75) 1.0 (0.75)

Motor RPM 1140 1140 1140

Indoor Fan

Type Backward Inclined Backward Inclined Backward Inclined

Number Used 1 or 2 1 or 2 1 or 2

Diameter Varies Varies Varies

Drive Type Direct Drive Direct Drive Direct Drive

Number Motors 1 or 2 1 or 2 1 or 2

Motor HP (kW), Standard–Oversized 2.0–15 (1.49–11.19) 3.0–15 (2.24–11.19) 3.0–15 (2.24–11.19)

Motor RPM, Standard–Oversized 1750–3500 1750–3500 1750–3500

Motor Frame Size, Standard–Oversized Varies Varies Varies

Filters

Type Furnished Refer to “OAU Filter Guide”

in “Appendix,” p. 55 Refer to “OAU Filter Guide”

in “Appendix,” p. 55

Number Size Recommended

Refrigerant Charge, lb of R-410A

Downflow See Nameplate See Nameplate See Nameplate

Performance Data

48 OAU-SVX01E-EN

Superheat and Refrigeration

Circuit Data

Figure 35. Refrigeration diagram: Single compressor

without reheat

Figure 36. Refrigeration diagram: Single compressor

with reheat

Performance Data

OAU-SVX01E-EN 49

Figure 37. Refrigeration diagram: dual compressor no

reheat Figure 38. Refrigeration diagram: dual compressor with

reheat

Performance Data

50 OAU-SVX01E-EN

Figure 39. Refrigeration diagram: triple compressor

with no reheat Figure 40. Refrigeration diagram: triple compressor

with reheat

Performance Data

OAU-SVX01E-EN 51

Figure 41. Refrigeration diagram: quad compressor

with no reheat Figure 42. Refrigeration diagram: quad compressor

with reheat

52 OAU-SVX01E-EN

Alarms and Troubleshooting

Microprocessor Control

The Main Unit Display and RTRM have the ability to

provide the service personnel with some unit diagnostics

and system status information.

1. Verify that the Liteport LED on the RTRM is burning

continuously. If the LED is lit, go to Step 3.

2. If the LED is not lit, verify that 24 Vac is presence

between J1-1 and J1-2. If 24 Vac is present, proceed to

Step 3. If 24 Vac is not present, check the unit main

power supply, check transformer (TNS1). Proceed to

Step 3 if necessary.

3. Utilizing “Method 1” in the RTRM “System Status

Checkout Procedure”, check the following:

•System status

•Cooling status

If a System failure is indicated, proceed to Step 4. If no

failures are indicated, proceed to Step 5.

4. If a System failure is indicated, recheck Step 1 and Step

2. If the LED is not lit in Step 1, and 24 Vac is present in

Step 2, the RTRM has failed. Replace the RTRM.

5. If no failures are indicated, use one of the override

options to start the unit. Following the Override

procedure will allow you to check all of the operating

modes, and all of the external controls (relays,

contactors, etc.) for each respective mode.

6. Refer to the sequence of operations for each mode, to

assist in verifying proper operation. Make the

necessary repairs and proceed to Step 7.

7. If no abnormal operating conditions appear in the

Override mode, release the override and turn the

power “Off” at the main power disconnect switch.

System Alarms

The Main Unit Display has built in alarms to help the

operator troubleshoot system failures. This section will

describe these alarms and provide a guide to

troubleshooting the all unit operating modes.

Comprehensive system alarms and diagnostics are

accessed through the Alarms icon at the unit display

discussed later in the section, or through Tracer TU

programming on connected computer. Sensor failures

may be viewed through the Alarms icon.

If an alarm is present, the main indicator light on the

UC600 will blink red. If the optional unit display is installed,

the Alarm icon on the display will register ALARM,

illuminate red and flash.

Important: The space temperature sensor (SPTC) and

space relative humidity sensor (SPHC) will

read failed if they are not connected; they

will Alarm as “In Fault.”

Sensor Failure Alarm Display

Press the Alarm button on the Home display of the Unit

Display to display system sensor status as described in

Table 17 and Table 18, p. 53.

WARNING

Hazardous Service Procedures!

The maintenance and troubleshooting procedures

recommended in this section of the manual could result

in exposure to electrical, mechanical or other potential

safety hazards. Always refer to the safety warnings

provided throughout this manual concerning these

procedures. When possible, disconnect all electrical

power including remote disconnects before servicing.

Follow proper lockout/tagout procedures to ensure the

power can not be inadvertently energized. When

necessary to work with live electrical components, have

a qualified licensed electrician or other individual who

has been trained in handling live electrical components

perform these tasks. Failure to follow all of the safety

warnings provided could result in death or serious

injury.

Table 17. TOAU UC600 alarms

Point Diagnostic Possible Cause

1Indoor Fan

Failure

VFD not operating

Outdoor and/or Return Air Dampers not

Operating Properly

Indoor Fan Motor Failure

Indoor Fan Failure Switch IFFS (pressure)

Failure

IFFS Tubing damaged or not properly

connected

Refer to startup procedure

3OAD Proving

Switch

No voltage at actuator

Failed OAD power transformer

No continuity thru end switch (check at UC)

Note: If unit optional RA damper is

installed, send switch on OAD is always

proven

6Discharge Air

Temp Source

Failure

BAS communication down

Failed sensor or improper sensor

installation

8 Fire Shutdown BAS ONLY

10 Low Temp

Lockout

Heat Overridden OFF

Compressor(s) Overridden ON

Setpoint Failures Incorrect

DAT sensor malfunction

Reference Table 18, p. 53 for heat failure

issues

Alarms and Troubleshooting

OAU-SVX01E-EN 53

11 Space Temp

Source Failure

BAS communication down

Failed sensor or improper sensor

installation

13 OA Temp Source

Failure

BAS communication down

Failed sensor or improper sensor

installation

14 OA Humidity

Source Failure

BAS communication down

Failed sensor or improper sensor

installation

Humidity Wiring is polarity sensitive

15 High Temp

Lockout

Heat Overridden ON

Low discharge air volume

Dirty air filters

High gas heater manifold pressure

OA/RA damper position incorrect

High temp limit not properly installed or

wired

DAT sensor malfunction

17 System Lockout Check all Alarms

External safety device failed open

19 Space RH Source

Failure

BAS communication down

Failed sensor or improper sensor

installation

Humidity Wiring is polarity sensitive

32 ERV Leaving Air

Condition Failure

Failed RH or temperature sensor

Incorrectly installed or connect RH or Temp

sensor

42 Heat Failure

Applies to 5:1 and 10:1 Gas Heaters Only

Trips after heat command “ON” and no GV

status offer 1 minute

Refer to unit “Service Facts” heat control

LED status legend

No gas, low gas pressure or high gas

pressure to unit

Unit Manual shutoffs closed

Heater inducer failure

Heat relay failure

Loose or incorrect wiring

Table 18. TOAU UC60 troubleshooting

Trouble Possible Cause

Unit Not Running

No power supply to unit disconnect switch

Power disconnect tripped

Lockout alarm mode

Emergency Stop condition exists

Unit in Unoccupied mode

Discharge air sensor failed or not installed and

connected to unit

Table 17. TOAU UC600 alarms (continued)

Point Diagnostic Possible Cause

No Heat

No gas supply to unit

Unit manual gas valve(s) closed

Heater high limit tripped

Heat relay not energized

Conditions do not warrant call for heat

Heater control module malfunction

Roll out switch trip

Main gas on-off switch OFF

Inducer fan failure

Heater air proving switch not making or failed

No Compressor

Compressor limit switch(es) open

Compressor relay not energized or failed

Conditions do not warrant call for cooling or

dehumidification

Wide Discharge

Temp Swings

Discharge air sensor position must be at least

4 ft.-0 in. away from unit outlet

Min and Max gas heater manifold pressures not set

correctly

Space too Hot,

Cold or Humid

Setpoints no adjusted properly

Space sensors not correctly located or wired

Malfunctioning space sensor

IFM or PEX VFD OC

Trip

Overcurrent alarm requires max Hz setting on VFD

be checked and set to not exceed motor

nameplate amps

EX VFD only run to

Min HZ Setting

If supplied with RA pressure transducer and

modulating damper setup is not installed or

properly wired.

ERV Will Not Run ERV leaving air temp below 34°F low temp cutout

Interlocked with Exhaust fan if exhaust is not

running ERV will be OFF

Unit Trips Heater

High Limit

High fire gas manifold pressure too high

Supply fan speed too low

Dirty or clogged filters

Restricted discharge air duct

Temperature of air entering heater too high

Defective high limit

Protonode Not

Communicating Change Baud rate on UC600 to 38,400

Table 18. TOAU UC60 troubleshooting (continued)

Trouble Possible Cause

Alarms and Troubleshooting

54 OAU-SVX01E-EN

RTRM Failure Modes

Following is the listing of RTRM failure indication causes.

System Failure

Check the voltage between RTRM terminals 6 and 9 on J6,

it should read approximately 32 Vdc. If no voltage is

present, a System failure has occurred. Refer to Step 4 in

“Microprocessor Control,” p. 52 for the recommended

troubleshooting procedure.

Cooling Failure

• CLP1 has opened during the 3 minute minimum “on

time” during four consecutive compressor starts,

check CLP1 or CLP2 by testing voltage between the

J1-8 and J3-2 terminals on the RTRM and ground. If

24 Vac is present, the CLPs have not tripped. If no

voltage is present, CLPs have tripped.

System Failure

Measure the voltage between terminals J6-9 & J6-6.

Normal Operation = approximately 32 Vdc

System Failure = less than 1 Vdc, approximately 0.75 Vdc

Cool Failure

Measure the voltage between terminals J6-8 and J6-6.

Cool Operating = approximately 32 Vdc

Cool Off = less than 1 Vdc, approximately 0.75 Vdc

Cooling Failure = voltage alternates between 32 Vdc and

0.75 Vdc

WARNING

Live Electrical Components!

During installation, testing, servicing and

troubleshooting of this product, it may be necessary to

work with live electrical components. Have a qualified

licensed electrician or other individual who has been

properly trained in handling live electrical components

perform these tasks. Failure to follow all electrical

safety precautions when exposed to live electrical

components could result in death or serious injury.

OAU-SVX01E-EN 55

Appendix

OAU Filter Guide

Table 19. OA1D Units

Evaporator

Thickness MERV Qty Height Width

2 in. 8, 13 216 20

216 25

4 in. 14 216 20

216 25

Auxiliary Module

Return Air

Thickness MERV Qty Height Width

2 in. 8 2 20 24

Outside Air

Thickness MERV Qty Height Width

2 in. 8 2 20 24

Inlet

Thickness Material Qty Height Width

2 in. Aluminum Mesh 3 16 25

Table 20. OA2D Units

Evaporator

Thickness MERV Qty Height Width

2 in. 8, 13 9 20 18

4 in. 14 6 20 25

Auxiliary Module (46XX ERV)

Return Air

Thickness MERV Qty Height Width

2 in. 8 225 20

125 16

Outside Air

Thickness MERV Qty Height Width

2 in. 8 225 20

125 16

Auxiliary Module (58XX/ 64XX ERV)

Return Air

Thickness MERV Qty Height Width

2 in. 8 8 20 18

Outside Air

Thickness MERV Qty Height Width

2 in. 8 8 20 18

Inlet

Thickness Material Qty Height Width

2 in. Aluminum Mesh 6 20 20

Table 21. OA3D Units

Evaporator

Thickness MERV Qty Height Width

2 in. 8, 13 9 24 20

4 in. 14 9 24 20

Auxiliary Module (58XX ERV)

Return Air

Thickness MERV Qty Height Width

2 in. 8 6 18 20

Outside Air

Thickness MERV Qty Height Width

2 in. 8 6 18 20

Auxiliary Module (68XX / 74XX ERV)

Return Air

Thickness MERV Qty Height Width

2 in. 8 8 25 20

Outside Air

Thickness MERV Qty Height Width

2 in. 8 8 25 20

Inlet

Thickness Material Qty Height Width

2 in. Aluminum Mesh 10 16 25

Trane optimizes the performance of homes and buildings around the world. A business of Ingersoll Rand, the leader in

creating and sustaining safe, comfortable and energy efficient environments, Trane offers a broad portfolio of advanced

controls and HVAC systems, comprehensive building services, and parts. For more information, visit www.Trane.com.

Trane has a policy of continuous product and product data improvement and reserves the right to change design and specifications without notice.

We are committed to using environmentally

conscious print practices that reduce waste.

OAU-SVX01E-EN 17 Apr 2014

Supersedes OAU-SVX01D-EN (05 Feb 2014)

Trane Oa1D Oa2D Oa3D Indirect Gas Fired Electric Heat Installation And Maintenance Manual OAU SVX01E EN (17 Apr 2014)

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