When dry wood is burned in a wood-burning stove the following
process occurs (over a period of approx. 1 hour):
- After lighting up the log dries out and heats up.
- After drying the temperature of the wood rises so much (to
approx. 150 - 200° C) that it is con-verted into volatile gases and
charcoal.
- As the wood is gasifed a certain portion of the gases produced
burn and are converted into car-bon dioxide and water. During this
phase the temperature rises to around 600 - 800° C, and a plentiful
supply of air is required. If the air supply is accidentally
reduced, the flames will be smothered, but this will not stop the
conversion of the wood into gas. The unburned gas will then flow
out into the chimney, causing a nuisance outdoors and build up of
tarry soot.
- Next the charcoal will burn, which requires very little air
supply. Finally, new wood must be laid on the glowing charcoal
cinders.
Warning
It is extremely important to ensure that you do not overheat your
stove, as this can cause irreparable damage. This kind of damage is
not covered by the warranty.
Extremely high combustion temperatures can occur when using very
dry fuel, such as:
- Kiln-dried wood
- Coke
- High-energy coke
- Compressed fuel
- Pallet wood
INCORRECT WOOD BURNING
Too much air supplied to the combustion process causes an
uncontrollable fire that will heat the en-tire stove very rapidly
to an extremely high temperature. This can happen if you fire
with
- an open ashpan
- open air vent in weather conditions that produce an extra-strong
draught in the chimney.
Never fill the stove completely with wood. It is better to heat
a stove up slowly, like a car. This will prevent cracked
tiles/soapstone, damage to welds and annealing of the iron.
Overfilling the firebox also substantially reduces the useful life
of the vermiculite panels, as cracks are more easily caused.
Never ignite the fire at the top. Start slowly with a "normal"
fire from the bottom, as any former Scout will know!
A LITTLE TECHNICAL INFORMATION ON WOOD
BURNING
1 kilo of dry wood is made up of 20% water, with the remaining 80%
divided into 60% gas and 20% charcoal. The 60% gas only contains
around half the energy content of the wood, while the 20% charcoal
con-tains the other half.
To achieve optimum combustion, the temperature must reach 600 -
800° C *. It is best to stoke fre-quently using small quantities of
wood. If too much wood is laid on a layer of embers, the air
sup-plied will not be sufficient to attain the required
temperature, and the gases will disappear out through the chimney
unburned. So, it is vital to supply air to the fire immediately
after adding fuel, so there are flames in the firebox, and the
gases burn. (See the operating instructions for your stove model
for further guidance.)
REMEMBER THAT THREE LOGS WILL BURN JUST AS QUICKLY AS
ONE
The quantity of firewood determines the heat emission - the more
heat you require, the more wood you should add at each new
stoking.
TYPES OF FUEL AND HEATING VALUES
Stoves from Jydepejsen are designed and approved for burning
wood.
Combustion involves conversion of the fuel from solid form into
gases, water vapour and charcoal. The heating value is an
expression of the content of combustible gases - stated in kcal/kg.
All wood has roughly the same heating value per kilogram. The
lighter the wood, the more that must be used to achieve the same
heating value as with a heavier species of wood.
As mentioned, air-dried wood contains around 20% water,
corresponding to a heating value of ap-prox. 4 kWh/kg equivalent to
approx. 3440 kcal/kg (1kW = 860 kcal.)
* Source: Technological Institute, Denmark
Warning!
NEVER use impregnated wood, painted wood, laminated plastic,
plywood, chipboard, refuse, milk cartons, printed matter or
similar. Use of such materials will invalidate your warranty, as
they may emit toxic, corrosive and hazardous fumes when burned.
They may also cause a build-up of the toxic gas dioxin, which is
damaging to the stove and the environment.
FUEL
Recently-felled wood contains 60-70% water and must therefore be
seasoned before it can be used in a wood-burning stove. It must be
sawn, chopped and air dried, and must contain no more than approx.
25% water before use. This equates to the wood being left in the
open for approx. 1 year - covered only to protect against rain.
It is very important to always use pure, dry wood. Damp wood
requires a lot of air for combustion, as extra energy in the form
of heat is needed to dry it out. Heat emission is therefore
minimal. It also causes sooting up of the chimney, with a risk of
tarry soot and chimney fire.