Hase Ottawa - Manual (Page 39)

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In addition, some stove models also use tertiary air,
which is usually drawn up the back of the fire box.
Depending on whether they are designed for burning
wood or for burning both wood and lignite (brown
coal), the stove models have either one or two
combustion air control elements. For information
on setting and regulating the combustion air control
elements, please see Part 1 of the operating instruc-
tions.
WARNING!
Burning wood when the primary air slider
is opened too wide poses the risk of over-
heating the stove (forge fire effect).
The secondary air flow may not be comple-
tely closed while the stove is in operation.
If there is not a sufficient air supply, there
is a risk that the flue gases will not burn
completely (smouldering fire), that soot
will build up on the fire box window, or that
the amassed wood gases will burn explo-
sively (overfiring/deflagration).
NOTE!
When the stove is not in use, the airflow
slider(s) should remain completely closed
to avoid heat loss due to the unintentional
throughflow of cold air.
9. The Right Fuel
Only fuels which generate low quantities of smoke
may be burned in stoves. For your stove, natural, un-
treated logs, including the adhering bark and wood
briquettes according to DIN EN 14961 or equivalent,
can be used as fuel. Depending on the stove model,
charcoal briquettes can be used as well (see Opera-
ting Instructions Part I).
For the most attractive stove fire, use beech wood
logs. If other types of wood are used, such as oak,
birch, pine or larch, we recommend adding beech
wood for picturesque dancing flames. Brushwood and
small pieces of wood are good kindling materials.
Highly resinous coniferous wood (e.g. spruce, pine,
fir) tends to emit flying sparks and leaves behind a
fine layer of flue ash that can swirl up when the fire
box door is opened.
The firewood should be stored for at least two years
to achieve the required maximum residual moisture
content of 20 %.
CAUTION!
If the wood used as fuel is too moist, wa-
ter vapour can condense and damage the
stove. In addition, it will reduce the thermal
output.
CAUTION!
Burning, e.g.:
- damp or moist wood (residual
moisture content over 20 %),
- varnished, laminated, treated, or
plastic-coated wood,
- wood treated with wood preservatives,
- household waste,
- paper briquettes (contains pollutants
such as cadmium, lead, zinc), or
- any flammable fluids (including me-
thanol and ethanol) as well as any fuel
pastes or gels is not permitted.
ENVIRONMENT!
Combustion of the materials listed above
not only gives off unpleasant odours, but
also generates emissions that damage the
environment and are harmful to health.
Combustion of non-permitted fuels cons-
titutes a violation of the German Federal
Immission Control Act.
Improper fuels and their combustion resi-
dues can be detrimental to the functioning
and service life of the stove and chimney.
10. The Combustion Process
A piece of wood burns in three phases. In a wood
fire, however, these processes occur both consecu-
tively and simultaneously.
10.1 Drying Phase
The moisture still remaining in the air-dried wood
(approx. 15 - 20%) is evaporated. This takes place
at temperatures of approx. 100°C. For the evapora-
tion to occur, the wood must be supplied with heat
during the warming up phase; this is achieved by
using small wood logs.