User manual

Version: 10/09 Page 10
Types of fuel and heating values
Combustion involves conversion of the fuel from solid form into gases, water vapor 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.
Type of wood Dry wood - Lbs./ft3 (Kg/m3) Compare to Beech
Beech and oak 36.2 (580) 100%
Ash 35.6 (570) 98%
Maple 33.7 (540) 93%
Birch 31.8 (510) 88%
Mountain pine 30.0 (480) 83%
Fir 24.3 (390) 67%
Poplar 23.7 (380) 65%
As mentioned, air-dried wood contains around 20% water, corresponding to a heating value of approx. 4
kWh/kg equivalent to approx. 3440 kcal/kg (1kW = 860 kcal).
Warning! NEVER burn treated/painted wood, laminated plastic, plywood,
chipboard, refuse, milk cartons, printed matter or similar. Use of such materials
will invalidate your warranty, as this 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 cut,
split 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 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.
When wood is burned slowly, it produces tar and other organic vapors,
which combine with expelled moisture to form creosote. The creosote
vapors condense in the relatively cool chimney flue of a slow-burning fire.
As a result, creosote residue accumulates on the flue lining. When
ignited, this creosote makes an extremely hot fire.
The chimney and chimney connector should be inspected at least once
every two months during the heating season to determine if a creosote
buildup has occurred. If creosote has accumulated, it should be removed
to reduce the risk of a chimney fire.