Bradford White OmniTech BONH1250 User manual

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician, qualied
in hot water boiler and heater installation and maintenance. Improper installation and/or operation could create
carbon monoxide gas in ue gases which could cause serious injury, property damage, or death. Improper
installation and/or operation will void the warranty.
WARNING
If the information in this manual is not followed
exactly, a re or explosion may result causing
property damage, personal injury or loss of life.
Do not store or use gasoline or other ammable
vapors and liquids in the vicinity of this or any
other unit.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any unit.
• Do not touch any electrical switch; do not use
any phone in your building.
• Immediately call your gas supplier from a
nearby phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call the
re department.
Installation and service must be performed by
a qualied installer, service agency, or gas supplier.
AVERTISSEMENT
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au minimum
le risque d’incendie ou d’explosion ou pour éviter
tout dommage matériel, toute blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ni d’autres
vapeurs ou liquides inammables dans le voisinage de
cet appareil ou de tout autre appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous servir des
téléphones dansle bâtiment où vous êtes.
• Appelez immédiatement votre fournisseur de gaz depuis
un voisin. Suivez les instructions du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur de gaz,
appelez le service des incendies.
L’installation et l’entretien doivent être assurés par un
installateur ou un service d’entretien qualié ou par le
fournisseur de gaz.
H2408600C
Boiler Water Heater
Model BONH1250 Model BONV1250
1,250 MBTU/h 1,250 MBTU/h
Model BONH1500 Model BONV1500
1,500 MBTU/h 1,500 MBTU/h
Model BONH1750 Model BONV1750
1,750 MBTU/h 1,750 MBTU/h
Model BONH2000 Model BONV2000
2,000 MBTU/h 2,000 MBTU/h
Model BONH2500 Model BONV2500
2,500 MBTU/h 2,500 MBTU/h
Model BOCH3000 Model BOCV3000
3,000 MBTU/h 3,000 MBTU/h
Installation and Operation Instructions for
Installation and Operation Instructions Document 1472C
®
Brute OmniTech
Category II and IV Venting
with touchscreen controls

Page 2
Table of Contents
i
SECTION 1 General Information
1.A Introduction.................................................5
1.B Warranty ..................................................... 5
1.C Model Identication.....................................5
1.D Safety Notes ...............................................6
1.E Unit Dimensions and Components .............8
1.E.1 Model 1250 / 1500......................................8
1.E.2 Model 1750...............................................10
1.E.3 Models 2000 / 2500 ..................................12
1.F Unpacking.................................................14
1.G Locating the Unit.......................................14
1.H Clearances ...............................................14
SECTION 2 Venting and Combustion Air
2.A General Venting Info.................................15
2.A.1 Vent and Air Pipe Sizing ..........................15
2.A.1.a Category II Vent........................................16
2.A.1.b Category IV Vent ......................................16
2.A.2 Vent and Air Pipe Material ........................16
2.A.3 Exhaust Vent Terminal..............................17
2.A.4 Air for Combustion and Ventilation ...........17
2.A.4.a Combustion Air From Room ..................... 17
2.A.4.b Ducted Combustion Air.............................17
2.B Common Venting ......................................18
2.B.1 Common Venting ...................................... 18
2.B.2 Removing a Boiler From an
Existing Common Vent System................ 18
2.C Locating Vent & Combustion
Air Terminals.............................................20
2.C.1 Side Wall Vent Terminal............................20
2.C.2 Side-wall Combustion Air Terminal ..........21
2.C.3 Vertical Vent Terminal ............................... 21
2.C.4 Vertical Combustion Air Terminal ..............21
2.D Outdoor Installation ..................................23
2.E Installations in the
Commonwealth of Massachusetts ........... 24
SECTION 3 Gas supply and Piping
3.A Gas Supply and Piping .............................24
3.B Gas Pipe Sizing ........................................25
SECTION 4 Water Flow and Headloss Data
4.A General Water Flow Information...............25
4.B Boiler Water Flow & Headloss Data .........26
4.C Water Heater Flow and Headloss Data ....26
4.D Recovery Data..........................................27
SECTION 5 Piping
5.A Boiler Water Piping ................................... 28
5.A.1 Boiler Water Connections .........................28
5.A.2 Cold Water Make-Up ................................28
5.A.3 Freeze Protection .....................................28
5.A.4 Suggested Boiler Piping Schematics...29-31
5.B Water Heaters...........................................32
5.B.1 Water Quality ............................................ 32
5.B.2 Heater Water Connections .......................32
5.B.3 Cold Water Make-Up ................................32
5.B.4 Freeze Protection ....................................32
5.B.5 Suggested Piping Schematics .................32
SECTION 6 Condensate Drain Trap..............34
SECTION 7 Electrical Connections
7.A Installation Warnings ................................ 34
7.B Main Power Connections.......................... 35
7.C Main Power Data ......................................35
7.D Control Panel Layout ................................ 36
7.E Field Connections ..................................... 36
7.E.1 Power .......................................................37
7.E.2 Boiler Pump ..............................................37
7.E.3 Dry Contacts............................................. 37
7.E.4 Alarm Bell .................................................37
7.E.5 Sensors ....................................................37
7.E.6 Heat Demands..........................................38
7.E.7 Spare Inputs .............................................38
7.E.8 Inputs, BMS .............................................38
7.E.9 Outputs, Pump..........................................38
7.E.10 Dry Contacts (Run & Alarm) .....................38
7.E.11 RS 485 for Cascade (Lead Lag) .............38
7.E.12 RS485 BMS..............................................39
7.F Modbus/BACnet Memory Map ............41-43
7.G Wiring Diagrams, High Voltage.................44
7.H Ladder Diagrams .................................49-55
7.I Wiring Diagram.........................................56
SECTION 8 Control Operation
8.A The Home Screen ....................................58
8.A.1 Home Screen Active Icons .......................58
8.A.2 Keypad Operations................................... 59
8.B Login to Lock / Unlock the Disp Screen.... 60
8.C Quick Start ..............................................61
8.C.1 CH (Central Heat).................................... 61
8.C.1.a CH1 (Central Heat, One) 1 ......................62
8.C.1.b CH2 (Central Heat, Two) 2 .....................62
8.C.2 DHW (Domestic Hot Water) ....................62
8.C.3 Outdoor Reset ......................................... 62
8.C.4 Warm Weather Shut Down .....................63
8.C.5 Anti-Short Cycle .......................................64
8.C.6 Time & Date .............................................64

Page 3
ii
SECTION 8 (continued)
8.D Conguration ............................................65
8.D.1 CH (Central Heat).....................................65
8.D.1.a CH1 (Central Heat, One) .......................... 66
8.D.1.a.1 PID Low ....................................................67
8.D.1.a.2 PID High ...................................................67
8.D.1.b CH2 (Central Heat, Two) ..........................67
8.D.2 DHW (Domestic Hot Water)......................68
8.D.3 Outdoor Reset .........................................69
8.D.4 Cascade (All about Lead / Lag) .................. 70
8.D.4.a Cascade Parameters ...............................75
8.D.4.a.1 Base / Drop Load......................................76
8.D.4.b Rotation ...................................................76
8.D.4.b.1 Rotation Setup......................................... 77
8.D.4.c Redundancy .............................................77
8.D.5 Pumps .....................................................78
8.D.5.a Variable Speed Pump Control ..................79
8.D.6 Manual Firing Rate ..................................80
8.D.6 Temp Limits .............................................80
8.D.7.a Delta T Parameters...................................81
8.D.7.b Flue Limitation Parameters.......................81
8.D.7.c Outlet Limitation Parameters ....................81
8.D.8 External ...................................................82
8.D.8.a External – Remote Set Point ....................83
8.D.8.b External Firing Rate.................................. 83
8.D.9 Time & Date .............................................84
8.D.10 Miscellaneous Features .........................84
8.D.10.a Demands Priorities .................................85
8.D.10.b Anti-Short Cycle .......................................85
8.D.10.c Warm Weather ........................................86
8.D.10.d COM Port, BMS ....................................... 87
8.D.10.e Temperature Conversion .........................88
8.D.10.f Anti-Frost .................................................88
8.D.11 Login ........................................................89
8.E Service Screens .......................................90
8.E.1 Burner (Enable/Disable ............................90
8.E.2 Digital I/O Inputs ......................................91
8.E.2.a Digital Outputs ..........................................91
8.E.3 Analog I/O.................................................92
8.E.4 Screen Settings Timeout ..........................93
8.E.5 History.......................................................93
8.E.6 Restart Touchscreen & Recalibrate .......... 94
8.E.7 Factory Reset ...........................................94
8.E.8 HMI Model OEM only............................... 94
8.E.9 BIC Model OEM only ...............................94
8.E.10 Both Models. OEM only. .........................94
8.E.11 About the Firmware of the touchscreen. .. 94
8.E.12 Dev Fan ...................................................94
8.E.13 Fan Settings ...........................................94
8.F Messages and USB..................................95
8.F.1 Messages .................................................95
8.F.2 USB Functionality .....................................95
8.G Active Demands .......................................96
SECTION 9 Gas Valve Touchscreen,
Menus and Descriptions
9.A About the Gas Valve .................................97
9.B Menu Structure (Example)....................... 98
9.C Gas Valve Display Navigation and Menus 98
9.D Fuel Air Ratio & Ignition, Menus ............. 100
9.D.1 OEM........................................................101
9.D.2 Ignition Menu ...................................102
9.D.3 Base Curve Menu .................................103
9.D.4 Correction Curve Menu ..........................103
9.D.5 Summary Menu ...................................... 106
9.D.6 Load & Save Menu ................................ 106
9.E Diagnostics ............................................ 106
9.F Verication Menu ....................................106
9.G Gas Valve Password & Login Menu ......108
SECTION 10 Parameter Tables .................... 109
SECTION 11 Initial startup Instructions
11.A Filling the Boiler System ......................... 113
11.B Initial Operation ...................................... 114
11.B.1 Initial Burner Operation........................... 114
11.C Shutting Down the Unit........................... 114
11.D Restarting the Unit.................................. 114
11.E Combustion setup................................... 115
11.E.1 Firing Rate for Boiler............................... 115
11.E.2 Combustion at the Gas Valve Display .... 116
SECTION 12 Maintenance
12.A System Maintenance ............................. 117
12.B Maintenance Notes................................. 117
12.B.1 Burner..................................................... 117
12.B.2 Gas Valve / Venturi ................................. 117
12.B.3 Main OmniTherm Controller ................... 118
12.B.4 Valve Control / Display............................ 118
12.B.5 Spark & Flame Sensors Electrodes........ 118
12.B.6 Blower..................................................... 118
12.B.7 Heat Exchanger Tubes ........................... 118
12.B.8 Gas Pressure Switches .......................... 118
SECTION 13 Troubleshooting
13.A Error Codes ............................................120
13.B SV2 Fault Codes ....................................124
SECTION 14 Replacement Parts
14.A General Information................................ 131
14.B Component Illustrations, Parts Lists,
and Part Numbers ...........................131-148

Page 4
OMT 1.5/1.25
INLET
60
8.0
54
20
16
65.6
20.1
85
43
54
28.5
8
14
16
33
(2500)
(2000)
5.7
25.8
Electrical
Connections
Air Inlet
Vent
Cond
Trap
2” NPT Gas
PRV
3” Outlet 3” Inlet
SIDE VIEW
FRONT VIEW
BACK VIEW
®
Brute OmniTech
1750
2000 & 2500
3000
1250 & 1500

Page 5
1.C Model Identication
SECTION 1 General Information
1.A Introduction 1.B Warranty.
Prices E󰀨ective Nov 11th, 2019 Document 6120A
Customer Service and Product Support: 800.900.9276 • Fax [phone]
Headquarters: 20 Industrial Way, Rochester, NH, USA 03867 • 603. 335. 6300 • Fax [phone]
9 Brigden Gate, Halton Hills, Ontario, Canada L7G 0A3 • 905.203. 0600 • Fax [phone]
www.Laars.com Printed in U.S.A. © Laars Heating Systems 20-02 Document 6120A
OMNITHERM®
ASME "H" stamp (OCH) Multiple, independent heat demands Outdoor reset with sensor (OCH)
ASME "HLW" stamp (OCV) Sealed combustion chamber High & low gas pressure switches
160 psi maximum working pressure Pre-mix stainless steel burner Vent temperature cutoff
Certified for Category II & IV vent Control cascades with up to Normally open alarm contact
Cat IV horizontal or vertical direct vent eight OmniTherm OCH / OCV units Air filter
Cat IV vent & air pipe lengths of up to VARI-PRIME boiler pump control Water flow switch
100 equivalent feet (each) with fixed delta T control for Temperature & pressure gauge
Indoor / outdoor variable flow through boiler (OCH) Low water cutoff
Low NOx system exceeds the Accepts 4-20ma or 0-10VDC 75 psi (517kPa) ASME rated
most stringent NOx regulations external modulation or external pressure relief valve (OCH)
Sophisticated gas/air valve allows set point control 125 psi (861kPa) ASME rated
for constant control of combustion Modbus RTU & BACnet MSTP pressure relief valve (OCV)
Stainless steel heat exchanger on board Groove lock fittings
with welded construction Multiple pump control, each with delay (optional flange adapter)
Electronic PID modulating control with Indirect DHW priority (OCH) Burner site glass
large touchscreen and color display Domestic water sensor 10-yr limited warranty
12 3 4567 8 9 10 11 12 13
OC 1
1250
1500
1750
2000
2500
3000
X- std OCH, 75psi PRV, H-Stamp N- OCV w/ H-Stamp, 30psi PRV
W- std OCV, 125psi PRV, HLW-Stamp P- OCV w/ H-Stamp, 50psi PRV X- None H- Gateway LONworks
A- 30psi PRV R- OCV w/ H-Stamp, 60psi PRV A- Gateway, BACnet IP & alarm bell
B- 50psi PRV S- OCV w/ H-Stamp, 75psi PRV B- Gateway, LONworks J- Gateway LONworks
C- 60psi PRV T- OCV w/ H-Stamp, 125psi PRV C- Alarm bell & high limits
D- OCV 75psi PRV U- OCV w/ H-Stamp, 150psi PRV D- Auto & manual K- Gateway LONworks
E- OCH 125psi PRV 2- Flange kit, OCV H-Stamp, 30psi PRV high limits & alarm bell
F- 150psi PRV 3- Flange kit, OCV H-Stamp, 50psi PRV E- Gateway BACnet IP & high limits
G- Flange kit & 30psi PRV 4- Flange kit, OCV H-Stamp, 60psi PRV & alarm bell L- Alarm & high limits
H- Flange kit & 50psi PRV 5- Flange kit, OCV H-Stamp, 75psi PRV F- Gateway BACnet IP
J- Flange kit & 60psi PRV 6- Flange kit, OCV H-Stamp, 125psi PRV & high limits
K- Flange kit & 75psi PRV 7- Flange kit, OCV H-Stamp, 150psi PRV G- Gateway BACnet IP
L- Flange kit & 125psi PRV & alarm bell
M- Flange kit & 150psi PRV & high limits
Usage
Waterway Options
Additional Options
C- 208V, single phase (1500-2500)
OmniTherm - Category II / IV Vent
Commercial Boiler / Water Heater OCH & OCV with Laars Linc Control
Standard Features
J- CSD-1 B- 220/240V, single ph (1500-2500)
Model Nomenclature
Series Size / MBH Fuel Construction Electrical System Revision
OC - OmniTherm N- Nat X- Standard A- 120V, single phase (1250-2000) 1- First
Cat II & IV
D- 208V, three phase (2500-3000)
H - Hydronic E- 480V, three phase (2500-3000)
V - Volume Water F- 600V, three phase (2500-3000)
Consult the rating plate on the unit. The following
information describes the model number structure.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bradford White
OC- Cat I I / I V
B O C
This manual provides information necessary for the
installation, operation, and maintenance of Bradford
White OmniTech appliances. Read it carefully before
starting the installation.
All application and installation procedures should
be reviewed completely before proceeding with the
installation. Consult the Bradford White factory, or local
factory representative, with any problems or questions
regarding this equipment. Experience has shown that
most operating problems are caused by improper
installation.
OmniTech is protected against over pressurization. A
pressure relief valve is included with each OmniTech.
Some OmniTechs may require that the PRV be installed
prior to lling the system. Refer to Figures 1-7 for PRV
locations.
Bradford White OmniTechs are covered by a limited
warranty. The owner should complete the warranty
registration at www.BradfordWhite.com.
All warranty claims must be made to an authorized
Bradford White representative. Claims must include the
serial number and model (this information can be found
on the rating plate), installation date, and name of the
installer. Shipping costs are not included in the warranty
coverage.

Page 6
WARNING
Carbon Monoxide Hazard
Improper adjustment of the burners may lead to poor
combustion quality, increasing the amount of carbon
monoxide produced. Excessive carbon monoxide
levels may lead to personal injury or death.
WARNING
This unit must be installed in accordance with the
procedures detailed in this manual, or the manufacturers
warranty will be voided. The installation must conform
to the requirements of the local jurisdiction having
authority, and, in the United States, to the latest edition
of the National Fuel Gas Code, ANSI Z223.1/NFPA54.
In Canada, the installation must conform to the latest
edition of CSA B149.1 Natural Gas and Propane Gas
Installation Code, and/or local codes. Where required
by the authority having jurisdiction, the installation of
these units must conform to the Standard for Controls
and Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1. Any modifi cations to the boiler, its
gas controls, or wiring may void the warranty. If fi eld
conditions require modifi cations, consult the factory
representative before initiating such modifi cations.
WARNING
• Water temperature over 125°F (52°C) can cause
severe burns instantly or death from scalds.
• Children, disabled and
elderly are at highest
risk of being scalded.
• See instruction manual
before setting temperature
at the unit.
• Feel water before bathing
or showering.
• If this unit is used
to produce water that could scald if too hot, such
as domestic hot water use, adjust the outlet control
(limit) or use temperature limiting valves to obtain a
maximum water temperature of 125°F (52°C).
WARNING
The inlet gas pressure to the unit must not
exceed 13” W.C. (3.2kPa).
WARNING
Fire or Explosion Hazard
Improper confi guration can cause fuel buildup and
explosion. Improper user operation may result in
property loss, severe physical injury, or death.
Any changes to safety-related confi guration
parameters must only be done by experienced and/or
licensed burner/boiler operators and mechanics.
If any odor of gas is detected, or if the gas burner does
not appear to be functioning in a normal manner, close
the main gas shutoff valve. Do not shut off the power
switch. Contact your heating contractor, gas company,
or factory representative.
NOTE: This unit is protected against hydronic
over-pressurization. A pressure relief valve is included
with each unit.
WARNING
Indicates an imminently hazardous situation which, if not
avoided, can or will result in death or serious injury and can
or will result in catastrophic property damage.
CAUTION
Indicates a potentially hazardous situation which, if not avoided,
may result in moderate injury and/or property damage.
NOTE:
Indicates instructions that are important to that topic but not
related to personal injury or property damage.
Safety Notes are used thoughout this manual to bring attention to the presence of hazards with various risk
levels and to off er important information concering the life of this product. There are 3 basic types.
WARNING
CANCER AND REPRODUCTIVE HARM.
WWW.P65WARNINGS.CA.GOV.
AS REQUIRED BY THE STATE OF
CALIFORNIA PROPOSITION 65.
1
2
3
1.D Safety Notes

Page 7
WARNING
Electrical Shock Hazard
Electrical shock can cause severe injury, death or
property damage. Disconnect the power supply before
beginning installation or changing the wiring to prevent
electrical shock or damage to the equipment. It may be
necessary to turn off more than one power supply
to disconnect.
All electrical wiring is to be done in accordance with
local codes, or in the absence of local codes, with: 1)
The National Electrical Code ANSI/NFPA No. 70 - latest
Edition, or 2) CSA STD. C22.1 “Canadian Electrical Code
- Part 1.” This appliance must be electrically grounded in
accordance with these codes.
WARNING
The Repair Parts list designates parts that contain
refractory ceramic fi bers (RCF). RCF has been classifi ed
as a possible human carcinogen. When exposed to
temperatures above 180ºF, such as during direct fl ame
contact, RCF changes into crystalline silica, a known
carcinogen. When disturbed as a result of servicing or
repair, these substances become airborne and, if inhaled,
may be hazardous to your health.
Do not remove or replace RCF parts or attempt any
service or repair work involving RCF without wearing
the following protective gear:
1. A National Institute for Occupational Safety and
Health (NIOSH) approved respirator.
2. Long sleeved, loose fi tting clothing.
3. Gloves.
4. Eye Protection.
NOTE: All installations must be made in accordance with
1) American National Standard Z223.1/NFPA54-Latest
Edition “National Fuel Gas Code” or
2) CSA B149.1 “Natural Gas and Propane Installation
Code” or in Canada reference the B149.1 latest
edition and with the requirement of the local utility or
other authorities having jurisdiction. Such applicable
requirements take precedence over the general
instructions contained herein. All electrical wiring is to
be done in accordance with the local codes, or in the
absence of local codes, with: 1) The National Electrical
Code ANSI/NFPA No. 70-latest Edition, or
2) CSA STD. C22.1 “Canadian Electrical Code - Part
1”. This appliance must be electrically grounded in
accordance with these codes.
CAUTION
The supply voltage to this unit must not be
disengaged, except for service or isolation, or unless
otherwise instructed by procedures outlined in this
manual. To signal a call for heat, use the correct
terminals as instructed in the Electrical Connections,
Field Wiring 7.E on page 36 of this manual.

Page 8
Gas Train as viewed from the front of the unit
1.E Unit Dimensions and Components
1.E.1 Model 1250 / 1500
21
10.3
66
58
48.4
17.5
5
6.2
11.5
17.7
Electrical
Connections
Cond
Trap
6"
Air Inlet
PRV
6"
Vent
2" NPT
Gas
Conn.
39
26.7
24
24.5
62
2 1/2" Outlet 2 1/2" Inlet
Gas Valve Reset
Sight
Glass
All dimensions are in inches.

Page 9
Gas Valve
Touchscreen
Control
Panel
Power
Pack
Air Filter Box
Manual
gas valve
Water Outlet
Water Inlet
Vent
Condensate
Trap
Heat Exchanger
Blower Gas Valve
System Controls
Touchscreen
Power
Connections
Power
Connections
Conduit

Page 10
1.E.2 Model 1750
43
53
32.0
31.6
65
69
55.6
44
8.0
5.7 20.1
22.7
16
20.2
29
Cond.
Trap
3" Inlet
3" Outlet
8"
Vent
2" NPT
Gas Inlet
8" NPT
Air Inlet
PRV
Electrical
Connection
Gas Valve Reset
Sight
Glass
Note: The gas train layout is the same for Models 1750 up to 3000 with only the
size of the components increasing to suit the increased size of that model.
Gas Train as viewed from the front of the unit
All dimensions are in inches.

Page 11
Gas Valve
Touchscreen
(Behind Top Panel)
Manual
gas valve
Manual
Gas Valve
Power
Pack
Control
Panel
Air Filter Box
Gas Inlet
Blower
Gas Valve
Water Outlet
Water Inlet
Vent
Condensate
Trap
PRV
Heat Exchanger
System Controls
Touchscreen
Power
Connections
Power
Connections
Conduit

Page 12
1.E.3 Models 2000 / 2500 and 3000
32.0
78
60
42.8
53 1.8
3" WATER INLET
GROOVE LOCK
OR FLANGE
8
AIR INLET
20.2
5.8
8.0
22.7
60
65.8
85
60.2
71.5
10”
10”
5.7
20.1
54.3
65.6
2" NPT
GAS
COND
TRAP
PRV
ELECTRICAL
CONNECTIONS
8"
VENT
OMT 2000 & 2500
2000 & 2500
3000
Gas Valve Reset
Sight
Glass
Note: The gas train layout is the same for Models 1750 up to 3000 with only the
size of the components increasing to suit the increased size of that model.
Gas Train as viewed from the front of the unit
All dimensions are in inches.

Page 13
Gas Valve
Touchscreen
Heat
Exchanger
Control
Panel
Power
Pack
Air Filter Box
Power
Connections
Manual gas valve
System Controls
Touchscreen
Blower
Water Outlet
Water Inlet
Vent
Condensate
Trap
PRV
Gas Valve
Power
Connections
Conduit
Gas Inlet
Note: The Model 3000 is 7" taller
than the Model 2000 and
Model 2500
2000 / 2500
3000

Page 14
1.F Unpacking
This unit is shipped in a single crate. Carefully
disassemble the crate and inspect the unit for any
damage during shipping. Included in the crate and yet
outside of the unit is the ‘Installation Kit’ box.
Inspect the contents of the the Installation Kit box, making
sure that all parts are included and not damaged.
1. Installation Instructions for Sensors (3)
2. Box containing Outdoor Sensor
3. Box containing System Sensor
4. Tank Sensor
5. Spring Clip (used to hold tank sensor in sensor well)
6. Nylon Bushing
7. Cable Tie
NOTE: A condensate neutralizer is NOT included.
The unit should not be located in an area where leakage
of any connections will result in damage to the area
adjacent to the unit, or to lower oors of the structure.
When this type of location is not available, install a
suitable drain pan, adequately drained, under the unit.
This unit is design-certied by CSA-International for
installation on combustible ooring; in basements; in
utility rooms, alcoves, or closets. Boilers must never be
installed on carpeting. The location for the unit should
be chosen with regard to the vent pipe lengths and
external plumbing.
The unit shall be installed such that the gas ignition
system components are protected from water (dripping,
spraying, rain, etc.) during operation and service (circulator
replacement, control replacement, etc.).
When vented vertically, the unit must be located as close
as practical to the vertical section of the vent. If the vent
terminal and/or combustion air terminal terminate through
a wall, and there is potential for snow accumulation in
the local area, both terminals should be installed at an
appropriate level above grade or the maximum expected
snow line.
The dimensions and requirements that are shown in
Table 1 should be met when choosing the location for the
unit.
Ensure the location takes into account the maximum
allowable vent length shown in SECTION 2 of this
manual.
NOTE : The unit shall be installed such that the gas
ignition system components are protected from water
(dripping, spraying, rain, etc.) during operation and
service (circulator replacement, control
replacement, etc.).
1.H Clearances
Table 1. Clearances
1.G Locating the Unit
This unit may be installed indoors or outdoors. If
installing outdoors in a location that may experience
freezing temperatures, precautions must be taken to
prevent water in the heat exchanger and condensate
inside and outside of the boiler from freezing. For units
installed outdoors, the minimum outdoor operating
temperature is 5ºF (-15ºC).Damage due to freezing water
or condensate is not covered by the warranty.
Choose a location for the unit which allows clearances on
all sides for maintenance and inspection. See Table 1.
Always install the unit on a rm, level surface. It is
recommended that the unit is installed on a raised 4” pad
so that there is elevation for a condensate neutralizer kit
(not included with unit).
Clearances
inches cm inches cm inches cm inches cm inches cm
1250-3000 closet* -00000000
*With required openings
inches cm inches cm inches cm inches cm inches cm
1250-1500 24 61 24 61 820 820 18 46
1750-3000 24 61 24 61 820 820 17 43
Suggested Service Clearances
TopRightLeftBackFront
Model
Certified Clearances to Combustibles
Model Front Back Left Right Top

Page 15
SECTION 2 Venting and Combustion Air
WARNING
All venting must be installed according to this manual
and any other applicable local codes, including but not
limited to, ANSI Z223.1/NFPA 54, CSA B149.1, CSA
B149.2 and ULC S636. Failure to follow this manual
and applicable codes may lead to property damage,
severe injury or death.
WARNING
Warning: When an existing Cat I appliance is removed
or replaced, the original venting system may no longer
be sized to properly vent the attached appliances.
Under no circumstances should an improperly sized
vent be used. An improperly sized vent may cause
operational and safety problems, and could result in
serious injury, death, or property damage.
WARNING
For indoor installations, as an additional measure of
safety, the manufacturer strongly recommends installation
of suitable Carbon Monoxide detectors in the vicinity of
this appliance and in any adjacent occupied spaces.
ADVERTISSEMENT
Tous les évents doivent être installés conformément à ce
manuel et à tout autre code local applicable, y compris,
mais sans s'y limiter, ANSI Z223.1 / NFPA 54, CSA
B149.1, CSAB149.2 et ULC S636. Le non-respect de
ce manuel et des codes applicables peut entraîner des
dommages matériels, des blessures graves ou la mort.
ADVERTISSEMENT
Pour les installations intérieures, comme mesure de sécurité
supplémentaire, Laars recommande fortement l'installation de
détecteurs de monoxyde de carbone appropriés à proximité
de cet appareil et dans tout espace occupé adjacent.
2.A General Venting Info
This unit is certied to vent as a Category II (negative
pressure condensing) or Category IV (positive pressure
condensing) appliance. The vent can terminate through
the roof, or through an outside wall.
All vent systems which discharge horizontally (without the
use of a power venter) are considered Category IV vent
systems.
All installations must be done following the vent supplier’s
recommended installation techniques. If these are not
available, refer to the manufacturer's recommendations
for the material used.
2.A.1 Vent and Air Pipe Sizing
Table 2. Vent/Air Pipe Sizes
Venting
Information
inches cm inches cm ft* m inches cm inches cm ft* mft* mft* m inches cm
1250 6 15 615 100 30.5 615 615 0*** 031100 30.5 12 30
1500 6 15 615 100 30.5 615 615 0*** 031100 30.5 12 30
1750 8 20 820 100 30.5 820 820 0*** 031100 30.5 14 36
2000 8 20 820 100 30.5 820 820 0*** 031100 30.5 14 36
2500 8 20 820 100 30.5 820 820 0*** 031100 30.5 16 41
3000 10 25 10 25 100 30.5 10 25 10 25 0*** 031100 30.5 16 41
*Equivalent Feet: To calculate, measure the linear feet of the pipe and add 5 ft (1.5m) for each elbow used.
**Category II vent pipe size must be engineered for vent system configuration, and may differ from what is shown.
***Appliance needs to vent outdoors using approved vent caps and following all guidelines as noted in our IO manual.
Proper protection against debris in the air intake (through using a downward spout and/or screen) to avoid
debris pick-up / falling into the appliance is required.
NOTES:
1. Installations in the U.S. require exhaust vent pipe that is stainless steel complying with UL1738.
2. Intake air pipe may be single-wall galvanized steel pipe, polypropylene, ABS, PVC, or CPVC, properly sealed.
Ducted Air
Pipe Size
Minimum
Category IV
Intake Air
Pipe Length
Minimum
Category IV
Vent Pipe
Length
Maximum
Category IV
Vent Pipe
Length
Typical**
Category II
Vent Pipe
Size
Category IV
Vent Pipe
Size
Air Collar
Size
Vent Collar
Size
Model
Maximum
Ducted Air
Pipe Length

Page 16
Selkirk Duravent NovaFlex
Safe-T Vent EZ Seal FasNSeal Z Flex
90° Elbow 9x14 FSELB90xx
Pipe 9x07 FSVLxxxx
Horizontal Air Inlet 9xTERM FSAIHxx
Vertical Termination 5x00CI FSRCx
Boiler Adapter
Manufacturer
Approved Hanger Straps
Distance between Hanger
Straps (Horizontal Run) - 6’ MAX
Distance between Hanger
Straps (Horizontal Run) - 6’ MAX
Distance between Hanger
Straps (Horizontal Run) - 4’ MAX
Distance between Hanger
Straps (Vertical Run) - 16’ MAX
Distance between Hanger
Straps (Vertical Run) - 12’ MAX
Distance between Hanger
Straps (Vertical Run) - 30’ MAX
5x01BOI FSAAUx
Component
Manufacturer Model Numbers (abbreviated)
2SVEExx90
2SVEPxxxx
2SVSTEXxx90
25VSRCxx
25VSAxx
2.A.1.a Category II Vent
Non-positive pressure vent systems are generally
vertically-terminated. Table 2 gives guidelines for vent
and air pipe sizes, but the draft must be measured to
ensure that it remains between -0.001” w.c. and -0.10”
w.c. at all ring rates. The vent system must be sealed
stainless steel.
2.A.1.b Category IV Vent
Positive pressure vent systems may be either horizontally
or vertically vented. The vent system must be sealed
stainless steel. Approved manufacturers and Category IV
component part numbers are shown in Table 3.
Table 3. Manufacturer's Model Numbers (abbreviated
2.A.2 Vent and Air Pipe Material
WARNING
Failure to use the appropriate vent material, installation
techniques, or glues and sealants could lead to vent
failure causing property damage, personal injury, or
death.
This unit requires a special venting system. See Table 4 and Table 5 for a list of allowable exhaust vent and combustion
air pipe materials. Refer to venting supplier’s instructions for complete parts list and method of installation. The
manufacturers and product lines listed in Table 3 have been tested and authorized to safely operate with this equipment.
Suppliers of stainless steel that are not listed on these tables are not permitted for use with this appliance.
Do not mix venting suppliers and models in venting systems. Failure to comply could result in personal injury, property
damage, or death. Installations must comply with applicable national, state and local codes.
Material United States Canada
Stainless Steel UL 1738 The vent pipe material must be chosen based upon the intended application
of the boiler or water heater and must be installed according to the vent
manufacturer’s installation instructions.
Table 4. Required Exhaust Vent Material
Route the vent pipe to the heater as directly as possible. Seal all joints and provide adequate hangers as required in
the venting system manufacturer’s installation instructions. Horizontal portions of the venting system must be supported
to prevent sagging and may not have any low sections that could trap condensate. The unit must not support the
weight of the vent pipe. Horizontal runs must slope upwards not less than ¼ inch per foot (2 cm/m) from the unit to the
vent terminal. Up to 100 equivalent feet of vent can be used. For each elbow subtract 5 ft of vent length from the total
allowable length of vent pipe.
Vent and Air Pipe Sizing (continued)

Page 17
Material United States Canada
ABS ANSI / ASTM D1527 The air pipe material must be chosen
based upon the intended application
of the boiler or water heater and must
be installed according to the vent
manufacturer’s installation instructions.
PVC, sch. 40 ANSI / ASTM D1785 or D2665
CPVC, sch. 40 ANSI / ASTM F441
Single wall galv. Steel 26 gauge
Polypropylene ULC S636 Class 2C
Table 5. Required Combustion Air Pipe Material
An exhaust vent terminal must be installed. If an exhaust vent terminal is not available with the certied vent system, the
manufacturer suggests the use of a coupler tting from the certied vent system into which the vent terminal screen can be
installed. Laars o󰀨ers vent terminals, shown in Table 6. Be sure to locate both vent and combustion air terminals per the
instructions in section 2.C Locating Vent & Combustion Air Terminals.
2.A.3 Exhaust Vent Terminal
Size Laars Part Number
Exhaust Vent Inlet Air
1250 D2012004 CA011904
1500
1750 D2012001 CA011901
2000
2500
3000 D2012002 CA011902
Boilers and water heaters must have provisions for
combustion and ventilation air in accordance with Section
9.3, Air for Combustion and Ventilation, of the National Fuel
Gas code, ANSI Z223.1, or Sections 7.2, 7.3, or 7.4 of CSA
B149.1, Installation Codes, or applicable provisions of the
local building codes.
The unit may receive combustion air from the space in
which it is installed, or it can be ducted directly to the unit
from the outside. Ventilation air must be provided in either
case.
2.A.4.a Combustion Air From Room
In the United States, the most common requirements
specify that the space shall communicate with the outdoors
in accordance with method 1 or 2, which follow. Where
ducts are used, they shall be of the same cross-sectional
area as the free area of the openings to which they
connect.
Method 1: Two permanent openings, one commencing
within 12 inches (30 cm) of the top and one commencing
within 12 inches (30 cm) of the bottom, of the enclosure
2.A.4 Air for Combustion and Ventilation
Table 6. Horizontal Vent and Air Terminations
shall be provided. The openings shall communicate
directly, or by ducts, with the outdoors or spaces
that freely communicate with the outdoors. When
directly communicating with the outdoors, or when
communicating to the outdoors through vertical ducts,
each opening shall have a minimum free area of 1
square inch per 4000 Btu/hr (5.5 square cm/kW) of total
input rating of all equipment in the enclosure. When
communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of
not less than 1 square inch per 2000 Btu/hr (11 square
cm/kW) of total input rating of all equipment in the
enclosure.
Method 2: One permanent opening, commencing
within 12 inches (30 cm) of the top of the enclosure, shall
be permitted. The opening shall directly communicate
with the outdoors or shall communicate through a
vertical or horizontal duct to the outdoors or spaces that
directly communicate with the outdoors and shall have a
minimum free area of 1 square inch per 3000 Btu/hr (7
square cm/kW) of the total input rating of all equipment

Page 18
2.B Common Venting
2.B.1 Common Venting
This unit can be common vented; however, the common
venting must be a professionally designed and approved
system. When common venting a fan-assisted unit
with other appliances through one shared vertical duct
called a “common vent”, special care must be taken by
the installer to ensure safe operation. In the event that
the common vent is blocked, it is possible, especially
for fan-assisted devices, to vent backwards through
non-operating appliances sharing the vent, allowing
combustion products to inltrate occupied spaces. If the
appliances are allowed to operate in this condition,
serious injury or death may occur.
It is for this reason that, in addition to following proper
vent sizing, construction and safety requirements from
the National Fuel Gas Code, ANSI Z223.1 or in Canada,
from CSA B149.1 as well as all applicable local codes, it
is required that installers provide some means to prevent
operation with a blocked common vent. It is suggested
that a blocked vent safety system be employed such that
all appliances attached to the vent be locked out and
prevented from operating under blockage conditions.
As an additional precaution, it is recommended that a
Carbon Monoxide (CO) alarm be installed in all enclosed
spaces containing combustion appliances. If assistance
is required in determining how a blocked vent safety
system should be connected to a LAARS product,
please call Application Engineering at the Rochester
phone number listed on back cover of this manual.
Refer to the installation and operating instructions on
all appliances to be common vented for instructions,
warnings, restrictions and safety requirements. If safe
operations of all appliances connected to a common
vent cannot be assured, including prevention of spillage
of ue gasses into living spaces, common venting should
not be applied, and appliances should each be vented
separately.
2.B.2 Removing a Boiler From an Existing
Common Vent System
NOTE: This section does not describe a method for
common venting this unit. It describes what must
be done when a unit is removed from a common
vent system. Contact the factory or your factory
representative if you have questions about common
venting this unit.
When an existing boiler is removed from a common
venting system, the common venting system is likely
to be too large for proper venting of the appliances
remaining connected to it.
WARNING
Operation of appliances with a blocked common vent
may lead to serious injury or death. Safety devices
must be implemented to prevent blocked common vent
operation. If safe operation of all appliances connected
to a common vent cannot be assured, including
prevention of spillage of ue gasses into living spaces,
common venting should not be applied, and appliances
should each be vented separately.
ADVERTISSEMENT
Le fonctionnement des appareils avec un évent
commun bloqué peut entraîner des blessures graves
ou la mort. Des dispositifs de sécurité doivent être mis
en place pour empêcher le fonctionnement de l'évent
commun bloqué. Si le fonctionnement en toute sécurité
de tous les appareils connectés à un évent commun
ne peut être assuré, y compris la prévention du
déversement de gaz de combustion dans les espaces
de vie, une ventilation commune ne doit pas être
appliquée et les appareils doivent chacun être ventilés
séparément.
located in the enclosure. This opening must not be less
than the sum of the areas of all vent connectors in the
conned space.
Other methods of introducing combustion and ventilation
air are acceptable, providing they conform to the
requirements in the applicable codes listed above. In
Canada, consult local building and safety codes, or, in
absence of such requirements, follow CSA B149.1.
2.A.4.b Ducted Combustion Air
The combustion air can be taken through the wall, or
through the roof. When taken from the wall, it must be
taken from out-of-doors by means of the Laars horizontal
wall terminal. When taken from the roof, a eld-supplied
rain cap or an elbow arrangement must be used to
prevent entry of rain water (see Figure 3).
Use pipe of the appropriate size and material (see
sections 2.A.1 and 2.A.2), for the combustion air intake.
Route the intake to the heater as directly as possible.
Seal all joints with tape. Provide adequate hangers. The
unit must not support the weight of the combustion air
intake pipe. Maximum linear pipe length allowed is 100
feet (30.4m). subtract 5 allowable linear feet (1.5m) for
every additional elbow used.
In addition to air needed for combustion, air shall also
be supplied for ventilation, including all air required for
comfort and proper working conditions for personnel.
The unit loses less than 1 percent of its input rating to the
room, but other heat sources may be present.

Page 19
At the time of removal of an existing boiler, the following
steps shall be followed with each appliance remaining
connected to the common venting system placed
in operation, while the other appliances remaining
connected to the common venting system are not in
operation.
1. Seal any unused openings in the common venting
system.
2. Visually inspect the venting system for proper
size and horizontal pitch and determine there is
no blockage or restriction, leakage, corrosion and
other deciencies which could cause an unsafe
condition.
3. Insofar as it is practical, close all building doors
and windows and all doors between the space in
which the appliances remaining connected to the
common venting system are located and other
spaces of the building. Turn on clothes dryers
and any appliance not connected to the common
venting system. Turn on any exhaust fans, such
as range hoods and bathroom exhausts, so they
will operate at maximum speed. Do not operate a
summer exhaust fan. Close replace dampers.
4. Place in operation the appliance being inspected.
Follow the lighting instructions. Adjust thermostat
so appliance will operate continuously.
5. Test for spillage at the draft hood relief opening
after 5 minutes of main burner operation. Use
the ame of a match or candle, or smoke from a
cigarette, cigar or pipe.
6. After it has been determined that each appliance
remaining connected to the common venting
system properly vents when tested as outlined
above, return doors, windows, exhaust fans,
replace dampers and any other gas burning
appliance to their previous conditions of use.
7. Any improper operation of the common venting
system should be corrected so that the installation
conforms to the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and/or CSA B149.1, Installation
Codes. When resizing any portion of the common
venting system, the common venting system
should be resized to approach the minimum size as
determined using the appropriate tables in Part II of
the National Fuel Gas Code, ANSI Z223.1/NFPA 54
and/or CSA B149.1, Installation Codes.
2.B.2 Véricationdeséventscommuns—
Chaudières
Lorsqu’une chaudière existante est déconnectée du réseau
d’évents commun, ce réseau d’évents commun devient
probablement trop grand pour les appareils qui lui restent
connectés. Lorsqu’une chaudière existante est retirée, les
étapes suivantes doivent être accomplies pour chaque
appareil qui reste connecté au réseau d’évents commun
utilisé, alors que les autres appareils qui sont encore
connectés au réseau commun d’évents ne sont pas en
fonctionnement.:
1. Sceller toutes les ouvertures non utilisées du système
d’évacuation.
2. Inspecter de façon visuelle le système d’évacuation
pour déterminer la grosseur et l’inclinaison horizontale
qui conviennent et s’assurer que le système est exempt
d’obstruction, d’étranglement, de fuite, de corrosion
et autres défaillances qui pourraient présenter des
risques.
3. Dans la mesure du possible, fermer toutes les
portes et les fenêtres du bâtiment et toutes les
portes entre l’espace où les appareils toujours
raccordés au système d’évacuation sont installés et
les autres espaces du bâtiment. Mettre en marche
les sécheuses, tous les appareils non raccordés au
système d’évacuation common et tous les ventilateurs
d’extraction comme les hottes de cuisinière et les
ventilateurs des salles de bain. S’assurer que ces
ventilateurs fonctionnent à la vitesse maximale. Ne
pas faire fonctionner les ventilateurs d’été. Fermer les
registres des cheminées.
4. Mettre l’appareil inspecté en marche. Suivre les
instructions d’allumage. Réegler le thermostat de façon
continue.
5. Faire fonctionner le brûleur principal pendant 5 min
ensuite, déterminer si le coupe-tirage déborde à
l’ouverture de décharge. Utiliser la amme d’une
allumette ou d’une chandelle ou la fumée d’une
cigarette, d’un cigare ou d’une pipe.
6. Une fois qu’il a été déterminé, selon la méthode
indiquée ci-dessus, que chaque appareil raccordé
au système d’évacuation est mis à l’air libre de façon
adéquate. Remettre les portes et les fenêtres, les
ventilateurs, les registres de cheminées et les appareils
au gaz à leur position originale.
7. Tout mauvais fonctionnement du système d’évacuation
commun devrait être corrigé de façon que l’installation
soit conforme au National Fuel Gas Code, ANSI
Z223.1/NFPA 54 et (ou) aux codes d’installation
CSA-B149.1. Si la grosseur d’une section du système
devrait être modié, le système devrait être modié
pour respecter les valeurs minimales des tableaux
pertinents de l’appendice F du National Fuel Gas Code,
ANSI Z223.1/NFPA 54 et (ou) les codes d’installation
CSA-B149.1

Page 20
2.C Locating Vent & Combustion Air
Terminals
2.C.1 Side Wall Vent Terminal
An appropriate quality side wall vent terminal must be
used.
The terminal provides a means of installing the vent
piping through the building wall and must be located in
accordance with ANSI Z223.1/NFPA 54 and applicable
local codes. In Canada, the installation must be in
accordance with CSA B149.1 or .2 and local applicable
codes. Consider the following when installing the
terminal:
1. Figure 2 shows the requirements for mechanical vent
terminal clearances for the U.S. and Canada.
2. Vent terminals for condensing appliances or
appliances with condensing vents are not permitted
to terminate above a public walkway, or over an area
where condensate or vapor could create a nuisance
or hazard.
3. Locate the vent terminal so that vent gases cannot be
drawn into air condition system inlets.
4. Locate the vent terminal so that vent gases cannot
enter the building through doors, windows, gravity
inlets or other openings. Whenever possible,
locations under windows or near doors should be
avoided.
5. Locate the vent terminal so that it cannot be blocked
by snow. The installer may determine that a vent
terminal must be higher than the minimum shown in
codes, depending upon local conditions.
6. Locate the terminal so the vent exhaust does not
settle on building surfaces or other nearby objects.
Vent products may damage such surfaces or objects.
7. If the boiler or water heater uses ducted combustion
air from an intake terminal located on the same wall,
locate the vent terminal at least 7 feet (213 cm)
horizontally from the combustion air terminal, and
locate the vent terminal at least 1 foot (0.3m) above
the combustion air terminal.