Osburn 3500 User manual

CONTACT LOCAL BUILDING OR FIRE OFFICIALS ABOUT RESTRICTIONS AND INSTALLATION INSPECTION REQUIREMENTS IN LOCAL AREA.
READ THIS ENTIRE MANUAL BEFORE INSTALLATION AND USE OF THIS WOOD STOVE. FAILURE TO FOLLOW THESE
INSTRUCTIONS COULD RESULT IN PROPERTY DAMAGE, BODILY INJURY OR EVEN DEATH.
Installation and Operation Manual
OSBURN 3500
(OB03505 model)
Distributed by
My Fireplace Australia PTY Ltd
www.myfireplaceaustralia.com.au
20 Auto Way
Pakenham, Victoria 3810 AUSTRALIA
Phone: [phone]
Fax: [phone]
Email: [email protected]
Printed in Canada
READ AND KEEP THIS MANUAL FOR REFERENCE
46295A
2021-12-03
This manual is available for free download on the distributor’s web site. It is a copyrighted document. Re-sale is strictly
prohibited. The distributor 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.

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Installation and Operation Manual - Osburn 3500
We want to congratulate you
on your purchase and wish
to help you get maximum
satisfaction from your wood
fire. In the pages that follow,
we will give you advice on
wood heating and controlled
combustion as well as
technical specifications
regarding installation,
operation and maintenance of
the model you have chosen.
The instructions pertaining to
the installation of your wood
fire comply with AS/NZS
4012/4013 (2014) and AS/NZS
2918:2001 standards.
Please read this entire manual
before you install and use your
new wood fire. Failure to follow
instructions may result in
property damage, bodily injury,
or even death. It is important
that you follow the installations
guidelines exactly.
Consult your local city,
borough or shire council about
restrictions and installations
requirements in your area and
the need to obtain a permit.
KEEP THIS INSTRUCTION
MANUAL FOR FUTURE
REFERENCE.
THANK YOU FOR CHOOSING
THIS WOOD FIRE.
If this wood fire is not
installed properly, heat
sensitive materials
near it may overheat
and catch fire.
To reduce the
risk of fire, follow
the installation
instructions in this
manual.
ONLINE WARRANTY REGISTRATION
If the unit requires repairs during the warranty period, proof of purchase must be provided. The
purchase invoice must be kept. The date indicated on it establishes the warranty period. If it
can not be provided, the warranty period will be determined by the date of manufacture of the
product.
It is also highly recommended to register the warranty online at
http://osburn-australia.com/warranty-registration.aspx
Registering the warranty will help to quickly find the information needed on the unit.

Page 4 Installation and Operation Manual - Osburn 3500
TABLE OF CONTENTS
PART A - OPERATION AND MAINTENANCE .............................................................................. 7
1. Safery information................................................................................................................... 7
2. General Information ................................................................................................................ 8
2.1 Specifications..................................................................................................................... 8
2.2 Dimensions ........................................................................................................................ 9
2.2.1 Combustion Chamber Dimensions.............................................................................10
2.3 Zone Heating and How to Make it Work for You...................................................................11
2.4 Osburn’s Commitment to You and the Environment .............................................................11
2.4.1 What is This Wood fire Made Of? ..............................................................................11
3. Fuel ........................................................................................................................................ 12
3.1 MATERIALS THAT SHOULD NOT BE BURNED ...................................................................12
3.2 How to Prepare or Buy Good Firewood...............................................................................12
3.2.1 What is Good Firewood? ..........................................................................................12
3.2.2 Tree Species ............................................................................................................12
3.2.3 Log Length ..............................................................................................................13
3.2.4 Piece Size................................................................................................................13
3.2.5 How to dry firewood.................................................................................................14
3.2.7 Compressed Wood Logs ..........................................................................................15
4. Operating Your Wood fire ..................................................................................................... 15
4.1 The Use of a Fire Screen....................................................................................................16
4.2 Using a BlowerUsing a Blower............................................................................................16
4.3 Your first fires ....................................................................................................................17
4.4 Lighting fires .....................................................................................................................17
4.4.1 Conventional fire starting ..........................................................................................17
4.4.2 The Top Down Fire ...................................................................................................18
4.4.3 Two Parallel Logs .....................................................................................................18
4.4.4 Using Fire Starters....................................................................................................18
4.5 Maintaining Wood Fires......................................................................................................18
4.5.1 General Advice.........................................................................................................18
4.5.2 Ash Removal............................................................................................................19
4.5.3 Raking Charcoal.......................................................................................................19
4.5.4 Firing Each New Load Hot ........................................................................................20
4.5.5 Turning down the Air Supply ....................................................................................20
4.6 Building different fires for different needs.............................................................................20
4.6.1 Small Fires to Take the Chill Off the House.................................................................21

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Installation and Operation Manual - Osburn 3500
4.6.2 Long Lasting Low Output Fires..................................................................................21
4.6.3 High Output Fires for Cold Weather ...........................................................................21
4.6.4 Maximum Burn Cycle Times......................................................................................21
4.6.5 North-South Fires Versus East-West Fires..................................................................22
5. Maintaining your wood heating system ............................................................................... 22
5.1 Wood fire maintenance ......................................................................................................22
5.1.1 Plated finish maintenance .........................................................................................22
5.1.2 Cleaning door glass..................................................................................................22
5.2 Glass Door........................................................................................................................23
5.2.1 Cleaning ..................................................................................................................23
5.2.2 Replacement............................................................................................................23
5.2.3 Replacing the glass gasket and/or the glass ..............................................................24
5.3 Door.................................................................................................................................25
5.3.1 Door adjustment ......................................................................................................25
5.3.2 Door Alignment ........................................................................................................26
5.3.3 Replacing the door gasket ........................................................................................27
5.3.4 Cleaning and painting the wood fire...........................................................................27
5.4 Flue and flue system maintenance ......................................................................................27
5.4.1 Why flue system cleaning is necessary ......................................................................27
5.4.2 How often should you clean the flue system?.............................................................27
5.4.3 Cleaning the flue system...........................................................................................28
PART B - INSTALLATION............................................................................................................ 29
6. Safety Information................................................................................................................. 29
6.1 Summary of installation cautions and warnings....................................................................29
6.2 Regulations Covering Wood fire Installation .........................................................................30
7. Clearances to Heat-Sensitive Materials............................................................................... 31
7.1 Location of the Certification Label ......................................................................................31
7.2 Clearances to Walls and Ceiling..........................................................................................31
7.3 Floor Protector ..................................................................................................................32
7.4 Reducing Wall and Ceiling Clearances Safely.......................................................................32
8. The Venting System .............................................................................................................. 34
8.1 General ............................................................................................................................34
8.2 Suitable Chimneys.............................................................................................................34
8.2.1 Factory built insulated flue kits ..................................................................................34
8.2.2 Masonry Flue System ...............................................................................................35

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8.3 Minimum Flue Height .........................................................................................................35
8.4 The Relationship Between the Chimney and the House........................................................36
8.4.1 Why Inside Chimneys Are Preferred...........................................................................36
8.4.2 Why the Chimney Should Penetrate the Highest Heated Space...................................37
8.5 Installing the Flue Connector ..............................................................................................37
Appendix 1: Door Overlay Installation...................................................................................... 39
Appendix 2: Blower and Optional Thermodisc Installation..................................................... 40
Appendix 3: Optional Fresh Air Intake Kit Installation ............................................................. 41
Appendix 4: Optional Fire Screen Installation.......................................................................... 42
Appendix 5: Air Tubes and Baffle Installation .......................................................................... 43
Appendix 6: Decorative Panels Removal ................................................................................. 45
Appendix 7: Exploded Diagram and Parts List........................................................................ 46

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Installation and Operation Manual - Osburn 3500
PART A - OPERATION AND MAINTENANCE
Please see Part B for installation instructions.
1. Safery information
• HOT WHILE IN OPERATION, KEEP CHILDREN, CLOTHING AND FURNITURE AWAY.
CONTACT MAY CAUSE SKIN BURNS. GLOVES MAY BE NEEDED FOR WOOD FIRE
OPERATION.
• Using a wood fire with cracked or broken components, such as glass or firebricks or baffles may
produce an unsafe condition and may damage the wood fire.
• Open the air control fully before opening firing door.
• 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.
• This wood fire is not designed to be used with the door open. the door may be open only during
lighting procedures or reloading. do not leave the wood fire unattended when the door is slightly
opened during ignition. always close the door after ignition.
• NEVER USE GASOLINE, GASOLINE-TYPE LANTERN FUEL (NAPHTHA), FUEL OIL, MOTOR
OIL, KEROSENE, CHARCOAL LIGHTER FLUID, OR SIMILAR LIQUIDS OR AEROSOLS TO
START OR ‘FRESHEN UP’ A FIRE IN THIS WOOD FIRE.KEEP ALL SUCH LIQUIDS OR
AEROSOLS WELL AWAY FROM THE WOOD FIRE WHILE IT IS IN USE.
• Do not connect to any air distribution duct or system.
• Do not store fuel within heater minimum installation clearances.
• Burn only seasoned natural firewood.
• The use of some types of preservative-treated wood as a fuel can be hazardous.
• DO NOT BURN:
- garbage of any kind,
- coal or charcoal,
- treated, painted or coated wood,
- plywood or particle board,
- fine paper, colored paper or cardboard,
- salt water driftwood, or
- railroad ties.
• Do not elevate the fire by using a grate in this wood fire.
• This appliance should be maintained and operated at all times in accordance with these instructions.

Page 8 Installation and Operation Manual - Osburn 3500
2. General Information
2.1 Specifications
Model # Osburn 3500 (OB03505)
Colour Metallic Black
Combustible Hardwood
Recommended heating area* 220 to 370 m2
Test Standard (safety) AS/NZS 2918 (2001)
Test Standards (emissions) AS/NZS 4012/4013/4014.1 (2014)
Optimum efficiency – hardwood 66%
Average efficiency – hardwood 61%
Average emissions – hardwood 0.6 g/kg
Average peak power – hardwood 11.8 kW
Maximum average power - hardwood 8.1 kW
Type of blower 130 CFM blower with variable speed control
Burn Time* 5-7 hours
Flue Spigot Diameter 152 mm
Flue system Triple skin flue system with Deco-Mesh
Minimum Flue Height (from floor protector) 4.6 meters
Steel thickness (top) 7 mm
Ceramic glass thickness 4 mm
Maximum Log Length 435 mm sideways**
Log loading Sideways**
Firebox Volume 0,087 m3
Shipping Weight 238 kg
Baffle Material C-Cast
* Burn time and heating capacity may vary subject to location in home, flue system draft, flue
system diameter, locality, heat loss factors, climate, fuels and other variables.
** Sideways: through the door you see the sides of the logs.

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Installation and Operation Manual - Osburn 3500
2.2 Dimensions
26 1/2"
674mm
11 3/4"
297mm
18 5/8"
473mm
22 1/2"
573mm
33 3/4"
857mm 27 1/2"
697mm
32 3/4"
832mm
34 3/4"
883mm
O
6"
153mm
11 1/2"
291mm
14 3/8"
366mm
28 7/8"
733mm
Figure 1: Top view
26 1/2"
674mm
11 3/4"
297mm
18 5/8"
473mm
22 1/2"
573mm
33 3/4"
857mm 27 1/2"
697mm
32 3/4"
832mm
34 3/4"
883mm
O
6"
153mm
11 1/2"
291mm
14 3/8"
366mm
28 7/8"
733mm
26 1/2"
674mm
11 3/4"
297mm
18 5/8"
473mm
22 1/2"
573mm
33 3/4"
857mm 27 1/2"
697mm
32 3/4"
832mm
34 3/4"
883mm
O
6"
153mm
11 1/2"
291mm
14 3/8"
366mm
28 7/8"
733mm
Figure 2: Front view Figure 3: Side view

Page 10 Installation and Operation Manual - Osburn 3500
2.2.1 Combustion Chamber Dimensions
19"
483mm
9 7/8"
249mm
Figure 4: Door opening
22 7/8"
581mm
3/16"
5mm
5/16"
8mm
20 1/8"
510mm
12 7/8"
327mm
Figure 5: Front view - Combustion chamber Figure 6: Side view

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Installation and Operation Manual - Osburn 3500
2.3 Zone Heating and How to Make it Work for You
Your new Savannah wood fire 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.
Although the wood fire 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 wood fire, the size, layout and age of your home and your climate zone. Three-
season vacation homes can usually be heated with smaller wood fires than houses that are
heated all winter.
The Benefits of Low Emissions and High Efficiency
The low smoke emissions produced by the special features inside the Osburn 3500 firebox mean
that your household will release up to 90 percent less smoke into the outside environment than if
you used an older conventional wood fire. 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 wood fire releases all the heat energy from the
wood instead of wasting it as smoke up the flue system. 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 wood fire can only work properly
if your fuel is in the correct moisture content range of 15 to 20 percent. See Section 3 of this
manual for suggestions on preparing fuelwood and judging its moisture.
2.4 Osburn’s Commitment to You and the Environment
The Osburn 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.
2.4.1 What is This Wood fire Made Of?
The baffle is made of vermiculite compressed with a binder to form a rigid board. Vermiculite
can withstand temperatures above 2,000°F. It is not considered hazardous waste. Disposal at a
waste management center is recommended.
The paint coating on your wood fire is very thin. Its VOC content (Volatile Organic Components)
is very low. VOCs can be responsible for smog, so all the paint used during the manufacturing
process meets the latest air quality requirements with regards to VOC reduction or elimination.
The air tubes are stainless steel, which can also be recycled.

Page 12 Installation and Operation Manual - Osburn 3500
The baffle is made of vermiculite compressed with a binder to form a rigid board. Vermiculite
can withstand temperatures above 2,000°F. It is not considered hazardous waste. Disposal at a
waste management center is recommended.
Firebrick is mainly composed of silicon dioxide, also known as silica, an earth derived product.
It is most commonly found in nature in the form of sand and clay. Disposal at a landfill is
recommended.
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 5 mm thick ceramic material that contains no toxic chemicals. It is basically
made of raw earth materials such as sand and quartz that are combined in such a way to form
a glass at high temperatures. Ceramic glass will not re-melt in the same way as normal glass,
so it should not be recycled with your regular household products. Disposal at a landfill is
recommended.
3. Fuel
3.1 MATERIALS THAT SHOULD NOT BE BURNED
- MATERIALS THAT SHOULD NOT BE BURNED
- GARBAGE OF ANY KIND,
- COAL OR CHARCOAL,
- TREATED, PAINTED OR COATED WOOD,
- PLYWOOD OR PARTICLE BOARD,
- FINE PAPER, COLORED PAPER OR CARDBOARD,
- SALT WATER DRIFTWOOD,
- MANUFACTURED LOGS CONTAINING WAX OR CHEMICAL ADDITIVES,
- RAILROAD TIES,
- LIQUIDS SUCH AS KEROSCENE OR DIESEL FUEL TO START A FIRE.
3.2 How to Prepare or Buy Good Firewood
3.2.1 What is Good Firewood?
Good firewood has been cut to the correct length for the wood fire, split to a range of sizes and
stacked in the open until its moisture content is reduced to 15 to 20 per cent.
3.2.2 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
such as gums, Manuka or ironbark are denser than softwoods. Hard wood will produce long-
lasting coal beds combined to more heat and longer burn cycles.
Old, leaky cast iron wood fires 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 less wood
and give the forest a break at the same time.

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Installation and Operation Manual - Osburn 3500
3.2.3 Log Length
Logs should be cut about 25 mm (1") shorter than the
firebox so they fit in easily. Pieces that are slightly too
long make loading the wood fire very difficult. The most
common standard length of firewood is 400 mm (16").
The pieces should be a consistent length, with a
maximum of 25 mm (1") variation from piece to piece.
3.2.4 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 75 mm (3")
should be split to encourage drying.
Wood should be split to a range of sizes, from about 75 mm to 150 mm (3" to 6")
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.

Page 14 Installation and Operation Manual - Osburn 3500
3.2.5 How to dry firewood
Firewood that is not dry enough to burn is the cause of most complaints about wood fires. The
complaints usually involve a lack of heat and dirty door glass.
Here are some facts to consider in estimating drying time:
− Firewood takes a long time to dry;
− 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;
− 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;
− Hardwoods like gums, Manuka and ironbark 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;
− Firewood that is ready to burn has a moisture content between 15 and 20% by weight and will allow
your wood fire to produce its highest possible efficiency.
3.2.6 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
coloured 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.

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Installation and Operation Manual - Osburn 3500
3.2.7 Compressed Wood Logs
Do not burn manufactured logs made of wax impregnated
sawdust or logs with any chemical additives. Manufactured
logs made of 100% compressed sawdust can be burned,
but use caution in the number of these logs burned at one
time. Start with one manufactured log and see how the wood
fire reacts. You can increase the number of logs burned at a
time to making sure the temperature never rises higher than
246°C (475°F) on a magnetic thermometer for installation on
wood fire flue. The thermometer should be placed about 450
mm (18") above the wood fire. Higher temperatures can lead
to overheat and damage your wood fire.
4. Operating Your Wood fire
Before using the stove, the following steps should be completed :
• Install the door overlay (see «Appendix 1: Door Overlay Installation»),
• Install the blower (see «Appendix 2: Blower and Optional Thermodisc Installation»)
• Install the ash lip pan.
Figure 7: Installing the ash lip pan
The following steps are optional :
• Install the fresh air intake (see «Appendix 3: Optional Fresh Air Intake Kit Installation»)
• Install the thermodisc (see «Appendix 2: Blower and Optional Thermodisc Installation»)
• NEVER OVERFIRE YOUR WOOD FIRE. IF ANY PART OF THE WOOD FIRE STARTS TO
GLOW RED, OVER FIRING IS HAPPENING. READJUST THE AIR INTAKE CONTROL AT A
LOWER SETTING.
• NEVER LOAD YOUR WOOD FIRE UP TO THE BAFFLE. ALWAYS LEAVE 5 TO 10 CENTIMETERS
TO ALLOW PROPER COMBUSTION THROUGH SECONDARY AIR OPENINGS (NEVER PUT
WOOD ABOVE THE FIREBRICK LINING ON THE FIREBOX). THIS WILL ALSO PREVENT
OVERFIRING OF YOUR WOOD FIRE.
• SHOULD THERE BE A SOOT OR CREOSOTE FIRE IN YOUR FLUE SYSTEM, CLOSE THE AIR
CONTROL COMPLETELY. IMMEDIATELY CALL THE FIRE DEPARTMENT.

Page 16 Installation and Operation Manual - Osburn 3500
4.1 The Use of a Fire Screen
This stove has been tested for use with an open door in conjunction with a fire screen, sold
separately. The fire screen must be properly secured on the stove to avoid any risk of sparks
damaging the flooring. When the fire screen is in use, do not leave the stove unattended to
respond promptly in the event of smoke spillage into the room. Potential causes of smoke
spillage are described in Section «8. The Venting System» of this manual. See «Appendix 4:
Optional Fire Screen Installation» for installation instructions.
Operating the stove with a fire screen increases possibilities of generating carbon monoxide. Carbon
monoxide is an odourless gas that is highly toxic which can cause death at high concentration in
air. Installation of a carbon monoxide detector is highly recommended.
4.2 Using a BlowerUsing a Blower
A blower is included with this stove. The blower is already
installed at the back of the stove, the power cord can be
found in the user manual bag. The blower is used to increase
the airflow through the heat exchanger and improve hot air
circulation in the room.
When used regularly, the blower can provide a small increase
in efficiency, up to 2%. However, the use of a blower should
not be used as a way to gain more output from a stove that
is undersized for the space it is intended to heat.
Ensure the blower cord is not in contact
with any surface of the wood fire to prevent
electrical shock or fire damage. Do not run
cord beneath the wood fire.
Figure 8: Air flow with a blower
The blower has a variable speed control that can be adjusted
in three different positions; either from high (HI) to low (LO) or
closed (OFF). Allow the stove to reach operating temperature
(approximately one hour) before turning on the blower, since
increased airflow from the blower will remove heat and affect
the start up combustion efficiency.
The blower can also be equipped with a heat sensor (themodisc),
sold seperatly. When the blower is on (position between HI and
LO), the heat sensor will make the blower start automatically
when the stove is hot enough and will stop it when the stove
has cooled down. Therefore, the blower speed control can
be left at the desired setting. The thermodisc part number is
AC02056 for a quick connect model. See «Appendix 2: Blower
and Optional Thermodisc Installation».
OFF
HI
LO
Figure 9: Blower rheostat

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Installation and Operation Manual - Osburn 3500
4.3 Your first fires
Two things will happen as you burn your first few fires; the paint cures and the internal components
of the wood fire 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 wood fire, 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 wood fire. Once the paint smell
disappears, your wood fire is ready for serious heating.
4.4 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 flue system. Here are three popular and
effective ways to start wood fires.
4.4.1 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 25 mm (1"). 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 flue system you should be able to close
the door immediately and the fire will ignite. If your flue
has elbows or an outside flue system, you may need to
leave the door closed but unlatched for a few minutes
as the newspaper ignites and heat in the flue system
produces some draft. Once the fire has ignited, close the
door and leave the air control fully open.
DO NOT LEAVE THE HEATER UNATTENDED WHEN
THE DOOR IS SLIGHTLY OPEN. ALWAYS CLOSE
AND LATCH THE DOOR AFTER THE FIRE IGNITES.
A conventional kindling fire with
paper under finely split wood.
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.

Page 18 Installation and Operation Manual - Osburn 3500
4.4.2 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 is not necessary to build up the
fire gradually because the firebox is loaded before the fire is lit. A top down fire can provide up
to two hours of heating or more. The top down method only works properly if the wood is well-
seasoned.
Start by placing three or four full-sized split pieces of dry firewood in the firebox. Next, place 4
or 5 more finely split pieces of firewood (50 mm to 75 mm [2" to 3"] in dia.) on the base logs at
right angles (log cabin style). Now place about 10 pieces of finely split kindling on the second
layer at right angles.
The fire is topped with about 5 sheets of newspaper. You can just bunch them up and stuff them
in between the kindling and the underside of the baffle. Or you can make newspaper knots by
rolling up single sheets corner to corner and tying a knot in them. The advantage of knots is that
they don’t roll off the fire as they burn. Light the newspaper and watch as the fire burns from
top to bottom.
4.4.3 Two Parallel Logs
Place two spit 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.
4.4.4 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.
4.5 Maintaining Wood Fires
4.5.1 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 wood fire. 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.

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Installation and Operation Manual - Osburn 3500
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 three, and preferably more,
pieces on the fire at a time 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 wood fire’s loading door while the wood is
flaming. This is an advantage because there is more chance that smoke will leak from the wood
fire when the door is opened as a full fire is burning. This is especially true if the flue connector
has 90 degree elbows and if the flue system runs up the outside wall of the house.
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.
4.5.2 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 wood fire is relatively cool, but there is still
some flue system draft to draw the ash dust into the wood fire and prevent it from coming into the room.
After ashes have been removed from the wood fire 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 shall not be placed in this container.
NEVER STORE ASHES INDOORS OR IN A NON-METALIC CONTAINER OR ON A WOODEN DECK.
4.5.3 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.

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4.5.4 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 flue system so it can produce strong, steady draft for the rest of the cycle.
Although it is important to fire each new load hot, do not allow the fire to burn at full intensity
for more than a few minutes.
DO NOT LEAVE THE WOOD FIRE UNATTENDED WHILE A NEW LOAD IS BEING FIRED HOT.
When you burn a new load of wood hot to heat up the wood, the wood fire and the flue system,
the result will be a surge of heat from the wood fire. 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.
4.5.5 Turning down the Air Supply
As you reduce the air supply to the fire, two important things
happen. First, the firing rate slows down to spread the heat energy
in the fuel over a longer period of time. Second, the flow rate of
exhaust through the wood fire and flue slows down, which gives
more time for the transfer of heat from the exhaust. You will notice
that as you reduce the air setting, the flames slow down. This is
your indication that the wood fire is burning at its peak efficiency.
If the flames get small and almost disappear when you turn down
the air, you have turned down the air too early, or your firewood is
wetter than it should be. With good fuel and correct air control use,
the flames should slow down, but should stay large and steady,
even as the air supply is reduced.
4.6 Building different fires for different needs
Using the air control is not the only way to match the wood fire’s heat output to the heat demand.
Your house will need far less heat in April than in July to be kept at a comfortable temperature.
If you fill the firebox full in fall weather, you will either overheat the space or turn the wood fire
down so much that the fire will be smoky and inefficient. Here are some suggestions for building
fires to match different heat demand.