Osburn 3500, Installation And Operation Manual

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Page 23 Installation and Operation Manual - 1700
ENGLISH
On the other hand, too much air can make the fire uncontrollable, creating very high temperatures in
the unit as well as in the chimney and seriously damaging them. A reddish glow on the unit and on the
chimney components indicates overheating. Excessive temperatures can cause a chimney fire.
5.7 Fire Types
Using the air intake control is not the only way to match the appliance heat output to the desired
temperature in the house. A house will need far less heating in October than in January to
maintain a comfortable temperature. Filling the firebox full in fall weather will overheat the space.
Otherwise, the combustion rate will have to be reduced to a minimum and the fire will be smoky
and inefficient. Here are some suggestions for building fires suitable for different heating needs.
5.7.1 Flash Fire
To build a small fire that will produce a low heat output, use small pieces of firewood and load
them crisscross in the firebox. The pieces should only be 3» to 4» in diameter. After raking the
coals, lay two pieces parallel to each other diagonally in the firebox and lay two more across
them in the other direction. Open the air control fully and only reduce the air after the wood
is fully flaming. This kind of fire is good for mild weather and should provide enough heat for
up to four hours. Small fires like this are a good time to use softer wood species and avoid
overheating the house.
5.7.2 Long Lasting Fire
For a fire that will last up to eight hours but will not produce intense heat, use soft wood and
place the logs compactly in the firebox. Before reducing the air intake, the load will have to burn
at full heat for long enough for charring the surface of the logs. The flame must be bright before
letting the fire burn by itself.
5.7.3 High Output Fires
When heating needs are high during cold weather, the fire should burn steadily and brightly. This
is the time to use larger pieces of hardwood. Place the biggest pieces at the back of the firebox
and place the rest of the pieces compactly. A densely built fire like this will produce the longest
combustion this stove is capable of.
Special attention must be paid when building fires like this since if the air intake is reduced too
quickly, the fire could smoulder. The wood must be flaming brightly before leaving the fire to
burn.
5.7.4 Burn Cycle Time
The burn cycle time is the period between loading wood on a coal bed and the consumption of
that wood back to a coal bed of the same size. The flaming phase of the fire lasts for roughly
the first half of the burn cycle and the second half is the coal bed phase during which there is
little or no flame. The burning time expected from this stove, including both phases, will vary
depending on a number of things, such as:
− firebox size,
− the amount of wood loaded,
− the species of wood,
− the wood moisture content,
− the size of the space to be heated,
− the climate zone where the house is, and
− the time of the year.