Osburn OB04010K User manual

45857A
Printed in Canada 2021-08-18
INSTALLATION AND OPERATION MANUAL
HORIZON (OB04010 model)
US ENVIRONMENTAL PROTECTION AGENCY
PHASE II CERTIFIED WOOD FIREPLACE
Listed to standards ULC-S610 and UL 127
www.osburn-mfg.com
Manufactured by:
Stove Builder International Inc.
250 rue Copenhague, Saint-Augustin-de-Desmaures (Quebec), Canada, G3A 2H3
After-sale service: 418-908-8002 E-mail: [email protected]
READ AND KEEP THIS MANUAL FOR REFERENCE
This manual is available for free download on the manufacturer’s web site. It is a copyrighted document.
Re-sale is strictly prohibited. The manufacturer may update this manual from time to time and cannot be
responsible for problems, injuries, or damages arising out of the use of information contained in any manual
obtained from unauthorized sources.

2 HORIZON –Installation and Operation Manual
THANK YOU FOR CHOOSING THIS OSBURN WOOD FIREPLACE
As one of North America’s largest and most respected wood stove and fireplace manufacturers, Stove
Builder International takes pride in the quality and performance of all its products. We want to help you get
maximum satisfaction as you use this product.
In the pages that follow you will find general advice on wood heating, detailed instructions for safe and
effective installation, and guidance on how to get the best performance from this fireplace as you build and
maintain fires, and maintain your wood heating system.
We recommend that our woodburning hearth products be installed and serviced by professionals who are
certified by a “Qualified Agency” such as NFI (National Fireplace Institute®) or CSIA (Chimney Safety
Institute of America) in the United States, in Canada by WETT (Wood Energy Technical Training) or in
Quebec by APC (Association des Professionnels du Chauffage).
Congratulations on making a wise purchase.
If this fireplace is not properly installed, combustible materials near it may overheat. To reduce the risk of
fire, follow the installation instructions in this manual exactly. Contact local building or fire officials about
restrictions and installation inspection requirements in your area.
Please read this entire manual before you install and use your new fireplace. You may need to get a building
permit for the installation of this fireplace and the chimney that it is connected to. Consult your municipal
building department or fire department before installation. We recommend that you also inform your
home insurance company to find out if the installation will affect your policy.
This heating unit is designed to serve as a supplementary heat source. We recommend that a primary heat
source also be available in the home. The manufacturer cannot be responsible for costs associated with the
use of another heating system.
CAUTION
•THE INFORMATION GIVEN ON THE CERTIFICATION LABEL AFFIXED TO THE APPLIANCE ALWAYS
OVERRIDES THE INFORMATION PUBLISHED, IN ANY OTHER MEDIA (OWNER’S MANUAL,
CATALOGUES, FLYERS, MAGAZINES AND/OR WEB SITES).
•MIXING OF APPLIANCE COMPONENTS FROM DIFFERENT SOURCES OR MODIFYING COMPONENTS IS
PROHIBITED AND WILL VOID THE WARRANTY. ANY MODIFICATION OF THE FIREPLACE THAT HAS
NOT BEEN APPROVED IN WRITING BY THE TESTING AUTHORITY IS PROHIBITED AND VIOLATES CSA
B365 (CANADA) AND NFPA 211 (USA).
•STOVE BUILDER INTERNATIONAL INC. (SBI) GRANTS NO WARRANTY, IMPLIED OR STATED, FOR THE
POOR INSTALLATION OR LACK OF MAINTENANCE OF YOUR FIREPLACE AND ASSUMES NO
RESPONSIBILITY OF ANY CONSEQUENTIAL DAMAGES.

HORIZON –Installation and Operation Manual 3
TABLE OF CONTENT
PART A - OPERATION AND MAINTENANCE...............................................................................................6
1Safety Information ...........................................................................................................................6
1.1 Summary of Operation and Maintenance Cautions and Warnings.....................................................6
2General Information.........................................................................................................................8
2.1 Appliance performance(1).....................................................................................................................8
2.2 General features ..................................................................................................................................9
2.3 Measurements...................................................................................................................................10
2.4 Zone heating and how to make it work for you ................................................................................12
2.5 The benefits of low emissions and high efficiency ............................................................................12
2.6 The SBI commitment to you and the environment ...........................................................................12
2.6.1 What is your new fireplace made of?.............................................................................................13
3Fuel................................................................................................................................................13
3.1 How to prepare or buy good firewood..............................................................................................14
3.1.1 What is good firewood? .................................................................................................................14
3.1.2 Tree species ....................................................................................................................................14
3.1.3 Log length .......................................................................................................................................14
3.1.4 Piece size.........................................................................................................................................15
3.1.5 How to dry firewood.......................................................................................................................15
3.1.6 Judging firewood moisture content................................................................................................16
3.2 Manufactured logs.............................................................................................................................16
4Operating Your Fireplace ................................................................................................................17
4.1 Your first fires.....................................................................................................................................17
4.2 Lighting fires.......................................................................................................................................17
4.2.1 BEST PRACTICE: The top down fire .................................................................................................17
4.2.2 Conventional fire starting...............................................................................................................17
4.2.3 Two parallel logs.............................................................................................................................18
4.2.4 Using fire starters ...........................................................................................................................18
4.3 Maintaining wood fires......................................................................................................................18
4.3.1 General advice ................................................................................................................................18
4.3.2 Ash removal....................................................................................................................................19
4.3.3 Raking charcoal ..............................................................................................................................19
4.3.4 Firing each new load hot ................................................................................................................19
4.3.5 Shutting down the air supply..........................................................................................................20
4.3.6 Building different fires for different needs .....................................................................................22
4.3.7 EPA Certification Loading ...............................................................................................................22
4.3.8 Maximum Burn Cycle Times ...........................................................................................................23

4 HORIZON –Installation and Operation Manual
4.3.9 How to place the logs .....................................................................................................................23
5Maintaining Your Wood Heating System.........................................................................................24
5.1 Fireplace maintenance.......................................................................................................................24
5.1.1 Plated finish maintenance..............................................................................................................24
5.1.2 Glass door cleaning ........................................................................................................................24
5.1.3 Door adjustment.............................................................................................................................25
5.1.4 Door alignment...............................................................................................................................26
5.1.5 Replacing the door gasket..............................................................................................................27
5.1.6 Replacing the door glass.................................................................................................................28
5.1.7 Cleaning and painting the fireplace ...............................................................................................29
5.2 Chimney and chimney liner maintenance .........................................................................................29
5.2.1 Why chimney cleaning is necessary ...............................................................................................29
5.2.2 How often should you clean the chimney?.....................................................................................30
5.2.3 Cleaning the chimney .....................................................................................................................30
5.2.4 Fire baffle removal prior to cleaning the chimney .........................................................................31
5.2.5 Chimney fire....................................................................................................................................31
PART B –INSTALLATION ........................................................................................................................32
6Safety Information .........................................................................................................................32
6.1 Summary of installation cautions and warnings................................................................................32
6.2 Regulations covering fireplace installation........................................................................................33
6.3 Fireplace installation..........................................................................................................................33
6.3.1 Standoff installation .......................................................................................................................33
6.3.2 Transportation packaging ..............................................................................................................34
6.3.3 Locating the HORIZON....................................................................................................................34
6.3.4 Clearances to combustible materials .............................................................................................34
6.3.5 Hearth extension construction options ..........................................................................................35
6.3.6 Minimum Heart Extension Requirements ......................................................................................42
6.3.7 Framing construction......................................................................................................................43
6.3.8 Facing .............................................................................................................................................46
6.3.9 Installation of a non-combustible shelf ..........................................................................................47
7The Venting System........................................................................................................................48
7.1 General...............................................................................................................................................48
7.2 Suitable chimneys ..............................................................................................................................48
7.3 Minimum chimney height..................................................................................................................48
7.4 The relationship between the chimney and the house.....................................................................48
7.4.1 Why the chimney should penetrate the highest heated space ......................................................48
7.5 Chimney installation notes ................................................................................................................49
7.6 Chimney Installation Instructions ......................................................................................................52

HORIZON –Installation and Operation Manual 5
7.6.1 Examples of typical chimney installation .......................................................................................52
7.6.2 Exterior offset installation ..............................................................................................................53
7.6.3 Installation instructions ..................................................................................................................53
7.6.4 Offset chimney installation.............................................................................................................55
7.6.5 Rafter protection ............................................................................................................................57
7.7 Angled wall radiation shield...............................................................................................................57
7.8 Chimney support installation.............................................................................................................57
7.8.1 Universal roof support....................................................................................................................57
7.8.2 Universal offset support .................................................................................................................58
7.9 Installation instructions for masonry application..............................................................................58
7.9.1 Installation instructions ..................................................................................................................59
7.10 Supply of combustion air ...................................................................................................................59
7.10.1 Air intake in conventional houses...................................................................................................59
Appendix 1 - Warm Air Circulation Grille –Modern Style (AC01378).......................................................61
Appendix 2 - Forced Air Distribution Kit* (VA4460) ................................................................................62
Appendix 3 - Blower Maintenance or Replacement................................................................................64
Appendix 4 - Installing the Fresh Air Intake Kit .......................................................................................66
Appendix 5 - Refractory Slabs Replacement ...........................................................................................70
Appendix 6 - Installation of Secondary Air Tubes and Baffle ...................................................................71
Appendix 7 –Air Control Snap Disc Replacement ...................................................................................73
Appendix 8 –Electrical Wiring ...............................................................................................................74
Appendix 9 - Exploded Diagram and Parts List........................................................................................76
OSBURN LIMITED LIFETIME WARRANTY.................................................................................................81
REGISTER YOUR WARRANTY ONLINE
To receive full warranty coverage, you will need to show evidence of the date you
purchased your stove. Keep your sales invoice. We also recommend that you register
your warranty online at:
http://www.osburn-mfg.com/en/service-support/warranty-registration
Registering your warranty online will help us to quickly track the information we
need about your stove.

6 HORIZON –Installation and Operation Manual
PART A - OPERATION AND MAINTENANCE
1SAFETY INFORMATION
1.1 Summary of Operation and Maintenance Cautions and Warnings
CAUTION - OPERATION
•USING A FIREPLACE WITH CRACKED OR BROKEN COMPONENTS, SUCH AS GLASS OR FIREBRICKS OR
BAFFLES MAY PRODUCE AN UNSAFE CONDITION AND MAY DAMAGE THE FIREPLACE.
•OPERATE ONLY WITH DOOR FULLY CLOSED. IF DOOR IS LEFT PARTLY OPEN, GAS AND FLAME MAY
BE DRAWN OUT OF THE OPENING, CREATING RISKS FROM BOTH FIRE AND SMOKE.
•OPEN THE AIR CONTROL FULLY BEFORE OPENING THE LOADING DOOR.
•NEVER USE GASOLINE, LANTERN FUEL (NAPHTHA), FUEL OIL, MOTOR OIL, KEROSENE, CHARCOAL
LIGHTER FLUID, OR SIMILAR LIQUIDS OR AEROSOLS TO START A FIRE IN THIS FIREPLACE. KEEP ALL
SUCH LIQUIDS OR AEROSOLS WELL AWAY FROM THE FIREPLACE WHILE IT IS IN USE.
•HOT WHILE IN OPERATION, KEEP CHILDREN, CLOTHING AND FURNITURE AWAY. CONTACT MAY
CAUSE SKIN BURNS. GLOVES MAY BE NEEDED FOR FIREPLACE OPERATION.
•DO NOT STORE FUEL WITHIN HEATER MINIMUM INSTALLATION CLEARANCES.
•BURN ONLY SEASONED NATURAL FIREWOOD.
•DO NOT BURN SCRAP OR GARBAGE, TREATED WOOD OR WOOD SUCH AS DRIFTWOOD FROM THE
OCEAN WHICH HAS BEEN EXPOSED TO SALT OR OTHER CHEMICALS. SALT OR CHEMICALS CAN
CORRODE THE FIREBOX AND CHIMNEY. DO NOT BURN LARGE AMOUNTS OF PAPER, CARDBOARD,
TREE BRANCHES OR BUILDING CONSTRUCTION MATERIALS. INTENSE FIRING WITH THESE
MATERIALS MAY OVERHEAT THE FIREPLACE, CAUSING DAMAGE TO THE UNIT, A HOME FIRE OR
EVEN POSSIBLY IGNITING A CHIMNEY FIRE IF THE CHIMNEY IS CREOSOTED.
•THIS APPLIANCE SHOULD BE MAINTAINED AND OPERATED AT ALL TIMES IN ACCORDANCE WITH
THESE INSTRUCTIONS.
•DO NOT ELEVATE THE FIRE BY MEANS OF GRATES, ANDIRONS OR OTHER MEANS.
•DO NOT OBSTRUCT AIR INTLETS. THIS FIREPLACE NEEDS AIR FOR ITS GOOD OPERATION.
•DO NOT BLOCK THE HOT AIR VENTS TO THE FIREPLACE AS THIS WILL CAUSE THE FIREPLACE TO
OVERHEAT.
•THIS WOOD HEATER NEEDS PERIODIC INSPECTION AND REPAIRS FOR THE PROPER OPERATION. IT IS
AGAINST FEDERAL REGULATIONS TO OPERATE THIS WOOD HEATER IN A MANNER INCONSISTENT
WITH OPERATING INSTRUCTIONS IN THIS GUIDE.
•A SMOKE DETECTOR, A CARBON MONOXIDE DETECTOR AND A FIRE EXTINGUISHER SHOULD BE
INSTALLED IN THE HOUSE. THE LOCATION OF THE FIRE EXTINGUISHER SHOULD BE KNOWN BY ALL
FAMILY MEMBERS.

HORIZON –Installation and Operation Manual 7
CAUTION - INSTALLATION
•DO NOT INSTALL THE FIREPLACE OUTDOORS.
•THE FIREPLACE AND CHIMNEY MUST BE IN AN ENCLOSURE UP TO THE ATTIC.
•SOME JURISDICTIONS IN THE USA REQUIRE A SUPPLY OF OUTDOOR COMBUSTION AIR FOR THE
FIREPLACE. IN CANADA, AN OUTDOOR AIR SUPPLY IS NOT REQUIRED, IF A CARBON MONOXIDE (CO)
DETECTOR/ALARM IS LOCATED IN THE ROOM IN WHICH THE FIREPLACE IS INSTALLED. THE CO
DETECTOR WILL PROVIDE WARNING IF FOR ANY REASON THE WOOD FIREPLACE FAILS TO FUNCTION
CORRECTLY. IF YOU ARE REQUIRED TO INSTALL AN OUTDOOR AIR SUPPLY, WE RECOMMEND THAT
YOU ALSO INSTALL A CO DETECTOR/ALARM TO PROVIDE WARNING IF SMOKE SPILLAGE FROM THE
FIREPLACE OCCURS.
•KEEP COMBUSTIBLE MATERIALS AT LEAST 48 INCHES AWAY FROM THE FRONT OF THE FIREPLACE
OPENING.
•DO NOT USE A FIREPLACE INSERT AND OTHER PRODUCTS NOT SPECIFIED FOR USE WITH THIS
FIREPLACE.
•DO NOT INSTALL IN A MOBILE HOME (CANADA) OR MANUFACTURED HOME (USA).
WARNING
•DO NOT USE MATERIALS OTHER THAN THOSE LISTED IN THE REPLACEMENT PARTS SECTION DURING
INSTALLATION AS THEY MAY BE SAFETY HAZARDS AND A FIRE COULD RESULT.
•THIS FIREPLACE HAS NOT BEEN TESTED WITH AN UNVENTED OR VENTED GAS LOG SET. TO REDUCE
RISK OF FIRE OR INJURY, DO NOT INSTALL AN UNVENTED GAS LOG SET INTO THIS FIREPLACE.
PLEASE NOTE THAT THE PICTURES SHOWN IN THIS MANUAL ARE GENERIC AND
MAY NOT MATCH EXACTLY THE LOOK OF YOUR FIREPLACE.
WARNING: This product can expose you to chemicals including carbon
monoxide, which is known to the State of California to cause cancer, birth defects
or other reproductive harm. For more information go to www.P65warnings.ca.gov/

8 HORIZON –Installation and Operation Manual
2GENERAL INFORMATION
2.1 Appliance performance(1)
Fuel type
Dry cordwood
Recommended heating area[*]
1,000 to 2,800 ft2(93 to 260 m2)
Firebox volume
4,28 ft3(0,113 m3)
Maximum burn time[*]
11 h
Overall heat output rate (min. to max)(2)(3)
16,900 BTU/h to 43,000 BTU/h
(5.0 kW to 12,6 kW)
Average overall efficiency(3) - Dry cordwood
64.0% (HHV(4))
69.0% (LHV(5))
Optimum efficiency(2)(6)
70.0%
Average particulate emissions rate(7)
1.6 g/h (EPA)
Average CO(8)
159.0 g/h
[*] Recommended heating area and maximum burn time may vary subject to location in home, chimney draft, heat
loss factors, climate, fuel type and other variables. The recommended heated area for a given appliance is defined
by the manufacturer as its capacity to maintain a minimum acceptable temperature in the designated area in case
of a power failure.
(1) Values are as measured per test method, except for the recommended heating area, firebox volume, maximum
burn time and maximum heat output.
(2) The maximum heat output (dry cordwood) is based on a loading density varying between 15 lb/ft3and 20 lb/ft3.
Other performances are based on a fuel load prescribed by the standard. The specified loading density varies
between 7 lb/ft3and 12 lb/ft3. The moisture content is between 19% and 25%.
(3) As measured per CSA B415.1-10 stack loss method.
(4) Higher Heating Value of the fuel.
(5) Lower Heating Value of the fuel.
(6) Optimum overall efficiency at a specific burn rate (LHV).
(7) This appliance is officially tested and certified by an independent agency.
(8) Carbon monoxide.

HORIZON –Installation and Operation Manual 9
2.2 General features
Maximum log length1
25 in (635 mm) east-west*
Flue outlet diameter
8 in (203 mm)
Chimney diameter
8 in (203 mm)
Type of chimney
CAN/ULC S629, UL 103 HT (2100 °F)
Baffle material
C-Cast
Approved for alcove installation
Not approved
Approved for mobile home installation‡
Not approved
Type of door
Double, glass with cast iron frame
Type of glass
Ceramic glass
Blower
Included (up to 176 CFM)
Particulate emission standard
EPA / ASTM WK47329
USA standard (safety)
UL 127
Canadian standard (safety)
ULC-S610
*East-west: through the door you see the longitudinal sides of the logs; north-south: through the door you see the tips
of the logs.
‡Mobile home (Canada) or manufactured home (USA): The US department of Housing and Urban Development
describes “manufactured homes” better known as “mobile homes” as followed; buildings built on fixed wheels and
those transported on temporary wheels/axles and set on a permanent foundation. In Canada, a mobile home is a
dwelling for which the manufacture and assembly of each component is completed or substantially completed prior to
being moved to a site for installation on a foundation and connection to service facilities and which conforms to the
CAN/CSA-Z240 MH standard.
1The recommended log length is 16 inches, placed in the north-south orientation. For more details see section 3 –
Fuel.

10 HORIZON –Installation and Operation Manual
2.3 Measurements

HORIZON –Installation and Operation Manual 11

12 HORIZON –Installation and Operation Manual
2.4 Zone heating and how to make it work for you
Your new Horizon wood fireplace is a space heater, which means it is intended to heat the area it is
installed in, as well as spaces that connect to that area, although to a lower temperature. This is called zone
heating and it is an increasingly popular way to heat homes or spaces within homes.
Zone heating can be used to supplement another heating system by heating a particular space within a
home, such as a basement family room or an addition that lacks another heat source.
Houses of moderate size and relatively new construction can be heated with a properly sized and located
wood fireplace. Whole house zone heating works best when the fireplace is located in the part of the house
where the family spends most of its time. This is normally the main living area where the kitchen, dining
and living rooms are located. By locating the fireplace in this area, you will get the maximum benefit of the
heat it produces and will achieve the highest possible heating efficiency and comfort. The space where you
spend most of your time will be warmest, while bedrooms and basement (if there is one) will stay cooler. In
this way, you will burn less wood than with other forms of heating.
Although the fireplace may be able to heat the main living areas of your house to an adequate temperature,
we strongly recommend that you also have a conventional oil, gas or electric heating system to provide
backup heating.
Your success with zone heating will depend on several factors, including the correct sizing and location of
the fireplace, the size, layout and age of your home and your climate zone. Three-season vacation homes
can usually be heated with smaller fireplaces than houses that are heated all winter.
2.5 The benefits of low emissions and high efficiency
The low smoke emissions produced by the special features inside the Horizon firebox mean that your
household will release up to 90 percent less smoke into the outside environment than if you used an older
conventional stove. But there is more to the emission control technologies than protecting the
environment.
The smoke released from wood when it is heated contains about half of the energy content of the fuel. By
burning the wood completely, your fireplace releases all the heat energy from the wood instead of wasting
it as smoke up the chimney. Also, the features inside the firebox allow you to reduce the air supply to
control heat output, while maintaining clean and efficient flaming combustion, which boosts the efficient
delivery of heat to your home.
The emission control and advanced combustion features of your fireplace can only work properly if your
fuel is in the correct moisture content range of 15 to 20 percent. see Section 3 - Fuel of this manual for
suggestions on preparing fuel wood and judging its moisture.
2.6 The SBI commitment to you and the environment
The SBI team is committed to protecting the environment, so we do everything we can to use only
materials in our products that will have no lasting negative impact on the environment.

HORIZON –Installation and Operation Manual 13
2.6.1 What is your new fireplace made of?
The body of your fireplace, which is most of its weight, is carbon steel. Should it ever become necessary
many years in the future, almost the entire fireplace can be recycled into new products, thus eliminating
the need to mine new materials.
The paint coating on your fireplace is very thin. Its VOC content (Volatile Organic Compounds) is very low.
VOCs can be responsible for smog, so all the paint used during the manufacturing process meets the latest
air quality requirements regarding VOC reduction or elimination.
The air tubes are stainless steel, which can also be recycled.
The C-Cast baffle is made of an aluminosilicate fibre material that is compressed with a binder to form a
rigid board. C-Cast can withstand temperatures above 2,000 °F. It is not considered hazardous waste.
Disposal at a landfill is recommended.
Moulded refractory bricks are mainly composed of silicon dioxide, also known as silica, a product processed
from a mined mineral. It is most commonly found in nature in the form of sand and clay. Disposal at a
landfill is recommended. The steel mesh contained in some refractory bricks can be recycled.
The door and glass gaskets are fibreglass which is spun from melted sand. Black gaskets have been dipped
into a solvent-free solution. Disposal at a landfill is recommended.
The door glass is a 4 mm thick ceramic material that contains no toxic chemicals. It is made of natural raw
materials such as sand and quartz that are combined in such a way to form a high temperature glass.
Ceramic glass cannot be recycled in the same way as normal glass, so it should not be disposed of with your
regular household products. Disposal at a landfill is recommended.
3FUEL
CAUTION
•DO NOT BURN SCRAP OR GARBAGE, TREATED WOOD OR WOOD SUCH AS DRIFTWOOD FROM THE
OCEAN WHICH HAS BEEN EXPOSED TO SALT OR OTHER CHEMICALS. SALT OR CHEMICALS CAN
CORRODE THE FIREBOX AND CHIMNEY. DO NOT BURN LARGE AMOUNTS OF PAPER, CARDBOARD,
TREE BRANCHES OR BUILDING CONSTRUCTION MATERIALS. INTENSE FIRING WITH THESE
MATERIALS MAY OVERHEAT THE FIREPLACE, CAUSING DAMAGE TO THE UNIT, A HOME FIRE OR
EVEN POSSIBLY IGNITING A CHIMNEY FIRE IF THE CHIMNEY IS CREOSOTED.
•DO NOT OVER FIRE THIS HEATER OVER FIRING CAN RESULT IN A SAFETY HAZARD AND CAN
PERMANENTLY DAMAGE THE FIREPLACE AND CHIMNEY.

14 HORIZON –Installation and Operation Manual
3.1 How to prepare or buy good firewood
3.1.1 What is good firewood?
Good firewood has been cut to the correct length for the fireplace, split to a range of sizes and stacked in
the open until its moisture content is reduced to 15% to 20%.
3.1.2 Tree species
The tree species the firewood is produced from is less important than its moisture content. The main
difference in firewood from various tree species is the density of the wood. Hardwoods are denser than
softwoods. People who live in the coldest regions of North America usually have only spruce, birch and
poplar, other low-density species to burn and yet they can heat their homes successfully.
Homeowners with access to both hardwood and softwood fuel sometimes use both types for different
purposes. For example, softer woods make good fuel for relatively mild weather in spring and fall because
they light quickly and produce less heat Softwoods are not as dense as hardwoods so a given volume of
wood contains less energy. Using softwoods avoids overheating the house, which can be a common
problem with wood heating in moderate weather. Harder woods are best for colder winter weather when
more heat and longer burn cycles are desirable.
Note that hardwood trees like oak, maple, ash and beech are slower growing and longer lived than softer
woods like poplar and birch. That makes hardwood trees more valuable. The advice that only hardwoods
are good to burn is outdated. Old, leaky cast iron stoves wouldn’t hold a fire overnight unless they were fed
large pieces of hardwood. That is no longer true. You can successfully heat your home by using the less
desirable tree species and give the forest a break at the same time.
3.1.3 Log length
Logs should be cut at least 1” (25 mm) shorter than the firebox so they fit in easily. Pieces that are even
slightly too long make loading the fireplace very difficult. The log length recommended for your fireplace is
16"(406mm).
The pieces should be a consistent length, with a
maximum of 1" (25 mm) variation from piece to
piece.

HORIZON –Installation and Operation Manual 15
3.1.4 Piece size
Firewood dries more quickly when it is split. Large unsplit rounds can take years to dry enough to burn.
Even when dried, unsplit logs are difficult to ignite because they don’t have the sharp edges where the
flames first catch. Logs as small as 3” (75 mm) should be split to encourage drying.
Wood should be split to a range of sizes, from about 3"to 6"(75 mm to 150 mm) in cross section. Having a
range of sizes makes starting and rekindling fires much easier. Often, the firewood purchased from
commercial suppliers is not split finely enough for convenient stoking. It is sometimes advisable to resplit
the wood before stacking to dry.
3.1.5 How to dry firewood
Firewood that is not dry enough to burn is the cause of most complaints about wood fireplaces. Continually
burning green or unseasoned wood produces more creosote and involves lack of heat and dirty glass door.
See Section 5 - Maintaining Your Wood Heating System for concerns about creosote.
Here are some things to consider in estimating drying time:
•Firewood takes a long time to dry;
•Drying happens faster in dry weather than in
damp, maritime climates;
•Drying happens faster in warm summer
weather than in winter weather;
•Small pieces dry more quickly than large
pieces;
•Split pieces dry more quickly than unsplit
rounds;
•Softwoods take less time to dry than
hardwoods;
•Firewood that is ready to burn has a
moisture content between 15 and 20% by
weight and will allow your fireplace to
produce its highest possible efficiency;
•Firewood bought from a dealer is rarely dry
enough to burn, so it is advisable to buy the wood
in spring and dry it yourself;
•Softwoods like pine, spruce, and poplar/aspen can
be dry enough to burn after being stacked in the
open for only the summer months;
•Hardwoods like oak, maple and ash can take one,
or even two years to dry fully, especially if the
pieces are big;
•Firewood dries more quickly when stacked in the
open where it is exposed to sun and wind; it takes
much longer to dry when stacked in a wood shed.

16 HORIZON –Installation and Operation Manual
3.1.6 Judging firewood moisture content
You can find out if some firewood is dry enough to burn by using these guidelines:
•Cracks form at the ends of logs as they dry;
•As it dries in the sun, the wood turns from white or cream colored to grey or yellow;
•Bang two pieces of wood together; seasoned wood sounds hollow and wet wood sounds dull;
•Dry wood is much lighter in weight than wet wood;
•Split a piece, and if the fresh face feels warm and dry it is dry enough to burn; if it feels damp, it is too
wet;
•Burn a piece; wet wood hisses and sizzles in the fire and dry wood does not.
You could buy a wood moisture meter to test
your firewood.
3.2 Manufactured logs
Manufactured logs made of 100% wood residues
can be burn in your fireplace. However, they must
be used carefully. Therefore, you cannot place a
large quantity of such logs into your fireplace.
Manufactured logs typically release a much larger
heat output over a short period of time. Start with
one log and see how the fireplace reacts. You can
increase the number of logs burned at a time to a
maximum of three. Burning more than three
manufactured logs at one time can overheat and
damage your stove.
CAUTION
•DO NOT BURN ANY MANUFACTURED LOGS CONTAINING CHEMICAL ADDITIVES. YOU MAY
OVERHEAT YOUR FIREPLACE, THEREFORE CAUSING A FIRE HAZARD AND VOIDING YOUR
WARRANTY.
•DO NOT POKE OR STIR THE LOGS WHILE THEY ARE BURNING.
•USE ONLY FIRELOGS THAT HAVE BEEN TESTED FOR USE IN FIREPLACES (SEE ULC/ORD-C127,
COMPOSITE FIRELOGS) AND PRIOR TO USE, REFER TO FIRELOG WARNINGS AND CAUTIONS
MARKINGS ON PACKAGING.

HORIZON –Installation and Operation Manual 17
4OPERATING YOUR FIREPLACE
This wood heater has a manufacturer-set minimum low burn rate that must not be altered. It is against
federal regulations to alter this setting or otherwise operate this wood heater in a manner inconsistent with
operating instructions in this manual.
4.1 Your first fires
Two things will happen as you burn your first few fires: the paint cures and the internal components of the
fireplace are conditioned.
As the paint cures, some of the chemicals vaporize. The vapors are not poisonous, but they do smell bad.
Fresh paint fumes can also cause false alarms in smoke detectors. So, when you first light your fireplace, be
prepared by opening doors and/or windows to ventilate the house. As you burn hotter and hotter fires,
more of the painted surfaces reach the curing temperature of the paint. The smell of curing paint does not
disappear until you have burned one or two very hot fires.
Burn one or two small fires to begin the curing and conditioning process. Then build bigger and hotter fires
until there is no longer any paint smell from the fireplace. Once the paint smell disappears, your fireplace is
ready for serious heating.
4.2 Lighting fires
Each person who heats with wood develops their own favorite way to light fires. Whatever method you
choose, your goal should be to get a hot fire burning quickly. A fire that starts fast produces less smoke and
deposits less creosote in the chimney. Here are three popular and effective ways to start wood fires.
4.2.1 BEST PRACTICE: The top down fire
The top down fire starting method solves two problems with the conventional method: first, it does not
collapse and smother itself as it burns; and second, it’s cleaner. The top down method only works properly
if the wood is well-seasoned.
Start by crisscrossing around 10 finely split and dry kindling (0.5 to 1 in) leaving air space between the
pieces. Then put at least 5 news paper sheets to the top of the pieces. The best way to have your ignition
clean and environmentally friendly is to roll the news papers to make a long cylinder, then to make 2 knots
with it. The goal is to have the news papers as compact as possible to make it burn slowly. After the ignition
of the news paper, let the door open of 1 in for 5-10 minutes. The air control should be open.
When you have a small coal bed, it’s the time to crisscross three or four medium-sized split pieces (2-3 in)
of dry firewood in the firebox. You can close the door as soon as you loaded the pieces. Let burn until you
have a good coal bed. You are now ready for the main load.
4.2.2 Conventional fire starting
The conventional way to build a wood fire is to bunch
up 5 to 10 sheets of plain newspaper and place them in
the firebox. Next, place 10 or so pieces of fine kindling
on the newspaper. This kindling should be very thin;
less than 1” (25 mm). Next, place some larger kindling
pieces on the fine kindling. Open the air control fully
and light the newspaper. If you have a tall, straight
venting system you should be able to close the door
immediately and the fire will ignite. Once the fire has
ignited, close the door and leave the air control fully
open.
A conventional kindling fire.

18 HORIZON –Installation and Operation Manual
DO NOT LEAVE THE FIREPLACE UNATTENDED WHEN THE DOOR IS SLIGHTLY OPENED. ALWAYS CLOSE AND
LATCH THE DOOR AFTER THE FIRE IGNITES.
After the kindling fire has mostly burned, you can add standard firewood pieces until you have a fire of the
right size for the conditions.
CAUTION: PLACE THE WOOD LOGS FAR ENOUGH FROM THE GLASS TO ALLOW PROPER PRIMARY AIR
FLOW
4.2.3 Two parallel logs
Place two split logs in the firebox. Place a few sheets of twisted newspaper between the logs. Now place
some fine kindling across the two logs and some larger kindling across those, log cabin style. Light the
newspaper.
4.2.4 Using fire starters
Many people like to use commercial fire starters instead of newspaper. Some of these starters are made of
sawdust and wax and others are specialized flammable solid chemicals. Follow the package directions for
use.
Gel starter may be used but only if there are no hot embers present. Use only in a cold firebox to start a
fire.
DO NOT USE FLAMMABLE LIQUIDS SUCH AS GASOLINE, NAPHTHA, FUEL OIL, MOTOR OIL, OR AEROSOLS
TO START OR REKINDLE THE FIRE.
4.3 Maintaining wood fires
4.3.1 General advice
Wood heating with a space heater is very different than other forms of heating. There will be variations in
the temperature in different parts of the house and there will be variations in temperature throughout the
day and night. This is normal, and for experienced wood burners these are advantages of zone heating with
wood.
Do not expect steady heat output from your fireplace. It is normal for its surface temperature to rise after a
new load of wood is ignited and for its temperature to gradually decline as the fire progresses. This rising
and falling of temperature can be matched to your household routines. For example, the area temperature
can be cooler when you are active, such as when doing housework or cooking, and it can be warmer when
you are inactive, such as when reading or watching television.
IMPORTANT: Wood burns best in cycles. A cycle starts when a new load of wood is ignited by hot coals and
ends when that load has been consumed down to a bed of charcoal about the same size as it was when the
wood was loaded. Do not attempt to produce a steady heat output by placing a single log on the fire at
regular intervals. Always place at least 5 to 8 pieces on the fire at a time in the North-South orientation so
that the heat radiated from one piece helps to ignite the pieces next to it. Each load of wood should provide
several hours of heating. The size of each load can be matched to the amount of heat needed.
When you burn in cycles, you rarely need to open the fireplace’s loading door while the wood is flaming.
This is an advantage because there is more chance that smoke will leak from the fireplace when the door is
opened as a full fire is burning.
IF YOU MUST OPEN THE DOOR WHILE THE FUEL IS FLAMING, OPEN THE AIR CONTROL FULLY FOR A FEW
MINUTES, THEN UNLATCH AND OPEN THE DOOR SLOWLY.

HORIZON –Installation and Operation Manual 19
4.3.2 Ash removal
Ash should be removed from the firebox every two or three days of full time heating. Do not let the ash
build up in the firebox because it will interfere with proper fire management.
The best time to remove ash is after an overnight fire when the fireplace is relatively cool, but there is still
some chimney draft to draw the ash dust into the fireplace and prevent it from coming into the room.
After ashes have been removed from the fireplace and placed in a tightly covered metal container, they
should be taken outside immediately. The closed container of ashes should be placed on a non-combustible
floor or on the ground well away from all combustible materials pending final disposal. Ashes normally
contain some live charcoal that can stay hot for several days. If the ashes are disposed of by burial in soil or
otherwise locally dispersed, they should be retained in the closed container until all cinders have
thoroughly cooled. Other waste should not be placed in this container.
NEVER STORE ASHES INDOORS OR IN A NON-METALIC CONTAINER OR ON A WOODEN DECK.
4.3.3 Raking charcoal
Rekindle the fire when you notice that the room temperature has fallen. You will find most of the remaining
charcoal at the back of the firebox, furthest from the door. Rake these coals towards the door before
loading. There are two reasons for this raking of the coals. First, it concentrates them near where most of
the combustion air enters the firebox and where they can ignite the new load quickly, and second, the
charcoal will not be smothered by the new load of wood. If you were to simply spread the charcoal out, the
new load will smoulder for a long time before igniting.
Remove ash first, and then rake charcoal towards the front of the firebox before loading so that it will ignite
the new load.
4.3.4 Firing each new load hot
Place the new load of wood on and behind the charcoal, and not too close to the glass. Close the door and
open the air control fully. Leave the air control fully open until the firebox is full of flames, the wood has
charred to black and its edges are glowing red. Firing each load of wood hot accomplishes a few things:
•Drives the surface moisture from the wood,
•Creates a layer of char on the wood, which slows down its release of smoke,
•Heats the firebox components so they reflect heat back to the fire, and
•Heats the chimney so it can produce strong, steady draft for the rest of the cycle.
DO NOT LEAVE THE FIREPLACE UNATTENDED WHILE A NEW LOAD IS BEING FIRED HOT.
DO NOT OVERFIRE.
When you burn a new load of wood hot, the result will be a surge of heat from the fireplace. This heat surge
is welcome when the room temperature is a little lower than desirable, but not welcome if the space is
already warm. Therefore, allow each load of wood to burn down so that the space begins to cool off a little
before loading. Letting the space cool before loading is one of the secrets to clean burning and effective
zone heating.

20 HORIZON –Installation and Operation Manual
4.3.5 Shutting down the air supply
The fireplace can operate at three different settings: Maximum combustion rate, medium combustion rate
and finally low combustion rate. At the low combustion rate setting, the fireplace is operated with an air
control system that regulates the combustion.
The maximum combustion rate setting is usually for cold startup and when maximum heat is desired
(Position A). At the maximum combustion rate setting, the air control system is not operating.
NOTE
THE AIR CONTROL SYSTEM IS ACTIVATED ONLY WHEN THE AIR INTAKE IS COMPLETLY CLOSED
(POSITION B) AND WHEN THE FIREPLACE IS HOT ENOUGH.
When you close the air intake, you gradually reduce the combustion. Visually you will be able to notice a
considerable reduction of combustion. Under these conditions, you will be at the medium combustion rate.
Using the secondary air intake lever you can adjust your combustion system to eventually reach the
minimum combustion rate.
If the flames diminish to the point of disappearing when you reduce the air supply, your wood can be too
humid. If you have seasoned wood and use the air intake control properly, the flames should decrease, but
remain strong and stable, even when operating at low combustion rate.
Position A: In this position, air supply
is fully open. You should be using this
position for:
•Cold start;
•Maximum burn rate;
Position B: Air control intake is closed.
The air control system is activated.
Position B1: Low combustion rate.
Position B2: Medium combustion rate.
Example of operating sequence:
A: Cold start or Maximum burn rate.
B: Mid-High until the factory setting
temperature is reached.
B-2 or B-1: Mid-Low or Low once the
factory setting is reached.