Trane OA1D, OA2D, OA3D Installation and Maintenance Manual

Installation, Operation,
and Maintenance

Horizon™ Outdoor Air Unit

Indirect Gas-Fired/Electric Heat
Models: OA1D, OA2D, OA3D

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

require and assume the tec hnician has been certified as a start up technician for the Horiz on Outdoor
Air unit. This includes working knowledge of the Tracer TU program.

SAFETY WARNING

Only qualified personnel should install and service the equipment. The installation, starting up, and servicing of heating, ventilating, and air­conditioning 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 pr ecautions in the literature and
on the tags, stickers, and labels that are attached to the equipment.

April 2014

OAU-SVX01E-EN

Introduction

Read this manual thoroughly before operating or servicing
this unit.

Warnings, Cautions, and Notices

Safety advisories appear throughout this manual as
required. Y our personal safety and the proper operation of
this machine depend upon the strict observance of these
precautions.

The three types of advisories are defined as follows:

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, y ou MUST f ollow r equir ements for
field wiring installation and grounding as described in
NEC and your local/state electrica l codes.

WARNING

CAUTIONs

NOTICE:

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

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

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

Important Environmental Concerns

Scientific research has shown that certain man-made
chemicals can affect the earth’s naturally occurring
stratospheric ozone layer when released to the
atmosphere. In particular, several of the identified
chemicals that may af fect 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. T rane advocates the responsible handling of
all refrigerants-including industry replacements for CFCs
such as HCFCs and HFCs.

Important Responsible Refr iger ant Pr actices

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

WARNING

Personal Protective Equipment (PPE)
Required!

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

• Before installing/servi cin g th is un it, technicians
MUST put on all PPE required for the work being
undertaken (Examples; cut r esistant glo v es/sleeves,
butyl gloves, saf ety 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 ar ound hazar dous chemi cals,
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 ener gized electr ical contac t, arc, or
flash, technicians MUS T put on all PPE in accor dance
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.

© 2014 Trane All rights reserved OAU-SVX01E-EN

WARNING

Contains Refrigerant!

System contains oil and refrigerant under high
pressure. Recover refriger ant 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 non­approved 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
refr igerants 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.

Introduction

Copyright

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

OAU-SVX01E-EN 3

Table of Contents

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

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

Important Environmental Concerns . . . . . 2

Important Responsible Refrigerant Practice s

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 Dimen­sional 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 Elec­tric Heat and Modulating HGRH, ERV, and
Powered Ex.

Sequence of Operation—”Occupied” . . .21
Sequence of Operation—”Unoccupied” .22

. . . . . . . . . . . . . . . . . . . . . . . . . .21

Discharge Air Control with Indirect Gas-Fired
or Electric Heat and Modulating HGRH, ERV,
and Powered Ex.

Sequence of Operation—”Occupied” . . .23
Sequence of Operation—”Unoccupied” .24

. . . . . . . . . . . . . . . . . . . . . .23

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 Relia T el Controls .30

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

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

4 OAU-SVX01E-EN

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

OAU-SVX01E-EN 5

Model Number Descriptions

OA2D300A4 -D1A1A0GM-G1KB0AC3CJ -A41B102A0

1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839

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

A
B

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 (1
C = Digital Scroll (1
D = Variable Speed Scroll (1

E = Variable Speed Scroll (1

Circuit Only)

nd

2

Circuit)

st

Circuit Only)

st

and 2nd Circuit)

st

st

and

Digit 14 — Condenser

0 = No Condenser
1 = Air-Cooled Fin and Tube
2 = Air-Cooled Fin and Tube

3 = Water-Cooled DX Condenser
4 = Air-Cooled Fin and Tube
5 = Air-Cooled Microchannel

6 = Air-Cooled Microchannel
7 = Air-Cooled Microchannel
8 = Water-Cooled DX Condenser

w/Head Pressure On/Off Control
Copper/Steel
w/Head Pressure Variable Speed

w/Head Pressure On/Off Control
Variable Speed
Copper/Nickel

Digit 15 — Refrigerant Capacity
Control

0 = No RCC Valve
A = RCC Valve on 1
B = RCC Valve on 1
C = ERCC Valve on 1
D = ERCC Valve on 1
E = HGBP Valve on 1
F = HGBP Valve on 1

nd

2

Circuit

st

Circuit

st

and 2nd Circuit

st

Circuit

st

and 2nd Circuit

st

Circuit

st

and

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

5 = Special Motor Option

Ring w/VFD

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

6 OAU-SVX01E-EN

Model Number Descriptions

Digit 22 — Heat Capacity
(Primary Heat Source)

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 23 — Heat Capacity
(Secondary Heat Source)

Digit

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

IF ELEC DF

Digit 24 — Corrosive
Environment Package

0 = No Corrosive Package
1 = S/S Cabinet, Basepan,

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

8 = Copper/Copper Condenser,

Eco-Coated Coils

Eco-Coated Coils
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 — Pow ered 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 — Pow ered 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 — Pow ered 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 Da mpers

w/Economizer

OAU-SVX01E-EN 7

Model Number Descriptions

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

8 OAU-SVX01E-EN

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 dama ge 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.

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 Fa ilure Switc h (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 pro ve 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
ReliaT el™ control will not allow the af fected 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

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

OAU-SVX01E-EN 9

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 (1
with a factory installed and preset refrigerant capacity
control (RCC) to prevent evaporator coil temperatures
below approximately 38°F (1 14 lb suction). The refrigerant
capacity device is not installed when the unit is equipped
with a digital scroll.

st

Stage) is equipped

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 re spective RTRM senses a lack
of current while calling for cooling and locks the
compressor out.

General Information

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
Disch arge 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 sens e 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 switc h 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.

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 tubu lar 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 electri cal 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 switc h 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 Vernier­controlled, 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.

100 Percent Outdoor Air Hood with Damper and Filters

Factory-installed an d -in t eg rated 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

10 OAU-SVX01E-EN

General Information

Unit Inspection

WARNING

Fiberglass Wool!

Product may contain fiberglass wool. Disturbing the
insulation in this product during installation,
maintenance or rep air 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.

As soon as the unit arrives at the job site:

 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 e vidence that the damage did not
occur after delivery.

 Notify the appropriate sales representative before

installing or repairing a damaged uni t.

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. Isolat e al l side p anel servi ce
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, an d 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.

• Avoid breathing fibergl as s dust.

• Use a NIOSH approved dust/mist respirator.

• Avoid contact with the skin or eyes. W ear 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.

OAU-SVX01E-EN 11

Unit Clearances, Curb Dimensions, and Dimensional

CLEARANCE 36"

TOP OF UNIT 72"

CLEARANCE 60"

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'-0"

3'-0"

3'-0"

4'-0"

7'0"

6'0"

3'0"

3'0"

4'0"

3'0"

S

U

P

PL

Y

R

E

T

U

R

N

2öļ

8õļ

7öļ

19ļ

õļ

1ôļ

4ôļ

49ļ

1õļ

öļ

1.00
TYP.

Data

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.

OA1 Units

Unit Clearances

Figure 1. Typical installation clearances for OA1 unit

Figure 2. Typical installation clearances for OA1 unit

with auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

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

12 OAU-SVX01E-EN

Unit Clearances, Curb Dimensions, and Dimensional Data

GUTTER DETAIL

Ɍļ

ôļ

S

U

P

PL

Y

GUTTER

R

E

T

U

R

N

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

87.33

59.23

53.00

131.26

87.12

59.45

35.24

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

auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Dimensional Data

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

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

with auxiliary cabinet (in.)

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

OAU-SVX01E-EN 13

Unit Clearances, Curb Dimensions, and Dimensional Data

CLEARANCE 36"CLEARANCE 60"

TOP OF UNIT 72"

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

3'0"

4'0"

3'0"

TOP OF UNIT 72"

"63 ECNARAELC"06 ECNARAELC

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

3'0"

4'0"

3'0"

7'0"

6'0"

OA2 Units

Unit Clearances

Figure 7. Typical installation clearances for OA2 unit

Figure 8. Typical installation clearances for OA2 unit

with auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 9. Typical installation clearances for OA2 unit

14 OAU-SVX01E-E N

Unit Clearances, Curb Dimensions, and Dimensional Data

7'0"

6'0"

SU

PPL

Y

R

ET

UR

N

öļ

1ļ

TYP.

30ļ

29ļ

56ļ

2õļ

5ôļ

9ôļ

ļ

1õļ

S

U

P

PL

Y

R

E

T

U

R

N

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

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

Figure 10. Typical installation clearances for OA2 unit

with auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

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

Dimensional Data

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

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

with auxiliary cabinet

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

auxiliary cabinet (in.)

Note: Certain options require auxiliary cabinet. Refer to

Note: Certain options require auxiliary cabinet. Refer to

OAU-SVX01E-EN 15

project-specific unit submittals.

project-specific unit submittals.

Unit Clearances, Curb Dimensions, and Dimensional Data

TOP OF UNIT 72"

"63 ECNARAELC"06 ECNARAELC

CLEARANCE 36"

CLEARANCE FROM

CLEARANCE 48"

3'0"

3'0"

4'0"

3'0"

CLEARANCE 36"

TOP OF UNIT 72"

CLEARANCE 36"CLEARANCE 60"

CLEARANCE FROM

CLEARANCE 48"

3'0"

3'0"

4'0"

3'0"

7'0"

6'0"

OA3 Units

Unit Clearances

Figure 15. Typical installation clearances for OA3 unit

Figure 16. Typical installation clearances for OA3 unit

with auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Figure 17. Typical installation clearances for OA3 unit

16 OAU-SVX01E-EN

Unit Clearances, Curb Dimensions, and Dimensional Data

7'0"

6'0"

S

U

P

PL

Y

R

E

T

U

R

N

öļ

33ļ

63ļ

5ôļ

140ļ

13ôļ

1ļ

TYP.

5ɏļ

2õļ

2ɍļ

S

U

P

PL

Y

R

E

T

U

R

N

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

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

Figure 18. Typical installation clearances for OA3 unit

with auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Curb Dimensions

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

Dimensional Data

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

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

with auxiliary cabinet

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

auxiliary cabinet

Note: Certain options require auxiliary cabinet. Refer to

project-specific unit submittals.

Note: Certain options require auxiliary cabinet. Refer to

OAU-SVX01E-EN 17

project-specific unit submittals.