Bradford White LAARS OmniTherm OCH1250 User manual

Document 1464
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.
H2408400-
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.
Installation and Operation Instructions
Boiler Water Heater
Model OCH1250 Model OCV1250
1,250 MBTU/h 1,250 MBTU/h
Model OCH1500 Model OCV1500
1,500 MBTU/h 1,500 MBTU/h
Model OCH1750 Model OCV1750
1,750 MBTU/h 1,750 MBTU/h
Model OCH2000 Model OCV2000
2,000 MBTU/h 2,000 MBTU/h
Model OCH2500 Model OCV2500
2,500 MBTU/h 2,500 MBTU/h
Model OCH3000 Model OCV3000
3,000 MBTU/h 3,000 MBTU/h
Installation and Operation Instructions for
®
OMNITHERM
with Laars Linc®
Category II and IV Venting

LAARS Heating Systems
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.............................................19
2.C.1 Side Wall Vent Terminal............................19
2.C.2 Side-wall Combustion Air Terminal ..........20
2.C.3 Vertical Vent Terminal...............................20
2.C.4 Vertical Combustion Air Terminal..............20
2.D Outdoor Installation ..................................22
2.E Installations in the
Commonwealth of Massachusetts ...........23
SECTION 3 Gas supply and Piping
3.A Gas Supply and Piping.............................23
3.B Gas Pipe Sizing........................................24
SECTION 4 Water Flow and Headloss Data
4.A General Water Flow Information...............24
4.B Boiler Water Flow & Headloss Data .........25
4.C Water Heater Flow and Headloss Data ....25
4.D Recovery Data..........................................26
SECTION 5 Piping
5.A Boiler Water Piping...................................27
5.A.1 Boiler Water Connections.........................27
5.A.2 Cold Water Make-Up................................27
5.A.3 Freeze Protection .....................................27
5.A.4 Suggested Boiler Piping Schematics...28-30
5.B Water Heaters...........................................31
5.B.1 Water Quality............................................31
5.B.2 Heater Water Connections .......................31
5.B.3 Cold Water Make-Up................................31
5.B.4 Freeze Protection ....................................31
5.B.5 Suggested Piping Schematics .................31
SECTION 6 Condensate Drain Trap..............33
SECTION 7 Electrical Connections
7.A Installation Warnings ................................33
7.B Main Power Connections..........................34
7.C Main Power Data......................................34
7.D Control Panel Layout................................35
7.E Field Connections.....................................35
7.E.1 Power .......................................................36
7.E.2 Boiler Pump..............................................36
7.E.3 Dry Contacts.............................................36
7.E.4 Alarm Bell .................................................36
7.E.5 Sensors ....................................................36
7.E.6 Heat Demands..........................................37
7.E.7 Spare Inputs .............................................37
7.E.8 Inputs, BMS .............................................37
7.E.9 Outputs, Pump..........................................37
7.E.10 Dry Contacts (Run & Alarm) .....................37
7.E.11 RS 485 for Cascade (Lead Lag) .............37
7.E.12 RS485 BMS..............................................37
7.F Modbus/BACnet Memory Map ............39-41
7.G Wiring Diagrams, High Voltage.................42
7.H Ladder Diagrams.................................47-53
7.I Wiring Diagram.........................................54
SECTION 8 Control Operation
8.A The Home Screen ....................................56
8.A.1 Home Screen Active Icons .......................56
8.A.2 Keypad Operations...................................57
8.B Login to Lock / Unlock the Disp Screen....58
8.C Quick Start ..............................................59
8.C.1 CH (Central Heat)....................................59
8.C.1.a CH1 (Central Heat, One) 1......................60
8.C.1.b CH2 (Central Heat, Two) 2 .....................60
8.C.2 DHW (Domestic Hot Water) ....................60
8.C.3 Outdoor Reset .........................................60
8.C.4 Warm Weather Shut Down .....................61
8.C.5 Anti-Short Cycle .......................................62
8.C.6 Time & Date .............................................62

The
OMNITHERM
ii
SECTION 8 (continued)
8.D Conguration ............................................63
8.D.1 CH (Central Heat).....................................63
8.D.1.a CH1 (Central Heat, One)..........................64
8.D.1.a.1 PID Low....................................................65
8.D.1.a.2 PID High...................................................65
8.D.1.b CH2 (Central Heat, Two) ..........................65
8.D.2 DHW (Domestic Hot Water)......................66
8.D.3 Outdoor Reset .........................................67
8.D.4 Cascade (All about Lead / Lag) ..................68
8.D.4.a Cascade Parameters ...............................73
8.D.4.a.1 Base / Drop Load......................................74
8.D.4.b Rotation ...................................................74
8.D.4.b.1 Rotation Setup.........................................74
8.D.4.c Redundancy .............................................75
8.D.5 Pumps .....................................................76
8.D.5.a Vari-Prime.................................................77
8.D.6 Manual Firing Rate ..................................78
8.D.6 Temp Limits .............................................78
8.D.7.a Delta T Parameters...................................79
8.D.7.b Flue Limitation Parameters.......................79
8.D.7.c Outlet Limitation Parameters....................79
8.D.8 External ...................................................80
8.D.8.a External – Remote Set Point....................81
8.D.8.b External Firing Rate..................................81
8.D.9 Time & Date .............................................82
8.D.10 Miscellaneous Features .........................82
8.D.10.a Demands Priorities .................................83
8.D.10.b Anti-Short Cycle .......................................83
8.D.10.c Warm Weather .......................................84
8.D.10.d COM Port, BMS .......................................85
8.D.10.e Temperature Conversion .........................86
8.D.10.f Anti-Frost .................................................86
8.D.11 Login ........................................................87
8.E Service Screens .......................................88
8.E.1 Burner (Enable/Disable ............................88
8.E.2 Digital I/O Inputs......................................89
8.E.2.a Digital Outputs..........................................89
8.E.3 Analog I/O.................................................90
8.E.4 Screen Settings Timeout ..........................91
8.E.5 History.......................................................91
8.E.6 Restart Touchscreen & Recalibrate..........92
8.E.7 Factory Reset ...........................................92
8.E.8 HMI Model OEM only...............................92
8.E.9 BIC Model OEM only...............................92
8.E.10 Both Models. OEM only. .........................92
8.E.11 About the Firmware of the touchscreen. ..92
8.E.12 Dev Fan ...................................................92
8.E.13 Fan Settings ...........................................92
8.F Messages and USB..................................93
8.F.1 Messages.................................................93
8.F.2 USB Functionality.....................................93
8.G Active Demands .......................................94
SECTION 9 Gas Valve Touchscreen,
Menus and Descriptions
9.A About the Gas Valve.................................95
9.B Menu Structure (Example).......................96
9.C Gas Valve Display Navigation and Menus96
9.D Fuel Air Ratio & Ignition, Menus ...............98
9.D.1 OEM..........................................................99
9.D.2 Ignition Menu ...................................100
9.D.3 Base Curve Menu .................................101
9.D.4 Correction Curve Menu ..........................101
9.D.5 Summary Menu ......................................104
9.D.6 Load & Save Menu ................................104
9.E Diagnostics ............................................104
9.F Verication Menu ....................................104
9.G Gas Valve Password & Login Menu ......106
SECTION 10 Parameter Tables ....................107
SECTION 11 Initial startup Instructions
11.A Filling the Boiler System......................... 111
11.B Initial Operation ......................................112
11.B.1 Initial Burner Operation...........................112
11.C Shutting Down the Unit...........................112
11.D Restarting the Unit..................................112
11.E Combustion setup...................................113
11.E.1 Firing Rate for Boiler...............................113
11.E.2 Combustion at the Gas Valve Display ....114
SECTION 12 Maintenance
12.A System Maintenance .............................115
12.B Maintenance Notes.................................115
12.B.1 Burner.....................................................115
12.B.2 Gas Valve / Venturi.................................115
12.B.3 Main OmniTherm Controller ...................116
12.B.4 Valve Control / Display............................116
12.B.5 Spark & Flame Sensors Electrodes........116
12.B.6 Blower.....................................................116
12.B.7 Heat Exchanger Tubes...........................116
12.B.8 Gas Pressure Switches..........................116
SECTION 13 Troubleshooting
13.A Error Codes............................................118
SECTION 14 Replacement Parts
14.A General Information................................122
14.B Component Illustrations, Parts Lists,
and Part Numbers ...........................122-140

LAARS Heating Systems
O MNI T HERM
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
1750
2000 & 2500
3000
1250 & 1500

Page 5
The
OMNITHERM
Consult the rating plate on the unit. The following
information describes the model number structure.
1.C Model Identication
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)
SECTION 1 General Information
1.A Introduction
This manual provides information necessary for the
installation, operation, and maintenance of LAARS
Heating Systems OmniTherm appliances. Read it
carefully before starting the installation.
All application and installation procedures should
be reviewed completely before proceeding with the
installation. Consult the LAARS Heating Systems 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.
OmniTherm is protected against over pressurization. A
pressure relief valve is included with each OmniTherm.
Some OmniTherms may require that the PRV be
installed prior to lling the system. Refer to Figures 4-7
for PRV locations.
1.B Warranty
LAARS Heating Systems OmniTherm appliances are
covered by a limited warranty. The owner should complete
the warranty registration at www.Laars.com.
All warranty claims must be made to an authorized
LAARS Heating Systems 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
LAARS Heating Systems
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 CSAB149.1 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 forAutomatically 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
The
OMNITHERM
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 CodeANSI/NFPANo. 70 - latest
Edition, or 2) CSASTD. 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. ANational 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) CSAB149.1 “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
CodeANSI/NFPANo. 70-latest Edition, or
2) CSASTD. 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 35 of this manual.

Page 8
LAARS Heating Systems
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
The
OMNITHERM
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
LAARS Heating Systems
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.