8 | Fuel material/-quantity
EN
Operating manual Heidi Back 2.0 945048
20
Please observe at all times the maximum specified amount to be laid, even when putting on more
wood! Otherwise your fire will not provide the desired efficiency - but above all considerable damage
may be caused to your appliance, to gaskets and material and to the flue gas duct.
The wood may only be burnt untreated. NEVER burn treated woods, not even wood processed with
natural substances or organic glazes. Wood waste does not belong in the stove!
Wood briquettes
Many people like wood briquettes as a fuel because they require less storage space than wood, can
be stocked or sold in small quantities and - at least at first glance - make less work than wood. Within
the scope of production, the quality of briquettes is consistent. Wood briquettes do not need to be
stored for a long time to be dried out. Due to the raw material (unrefined chips) and the production
process they have an already defined residual moisture.
If wood briquettes are designated as a suitable fuel, then this still only applies to this fuel, NOT for
coal-, paper-, bark- or other pressed items, such as pellets.
In spite of various standardizations and many advertising promises, there are also considerable differ-
ences in quality in wood briquettes. But even with good fuel quality, combustion behaviour is different
from that of unrefined log. And not every wood briquette burns equally well in every stove. Before you
decide on a particular variety and perhaps even store this up in larger quantities, you should extens-
ively test the wood briquettes under various draft conditions. Most suppliers keep “test packages” for
this purpose that can be purchased at preferential prices to test out and compare with one another the
various types offered.
TIP
When burning wood briquettes, the maximum quantity specified in these instructions must also be
observed. The quantity must not be exceeded.
As the wood is pressed and thus has little spatial volume for the same weight, modern heat-producing
appliances with a low placement quantity often have “little fire heaps” occur, leading one to wonder
whether a fire can burn at all with so little fuel. Nevertheless you must never exceed the maximum
placement, because that would cause damage. Many wood briquettes change during the temperature
increase when burning, by “opening up”. This should not worry you as it is normal. When inserting
wood briquettes make sure that this expansion as far as possible does not press not in the direction of
the window, as otherwise this will get very dirty.
In principle you should not insert wood briquettes as one piece, but rather break them at the layer
thicknesses, which are usually visible in slices, and place smaller pieces in the combustion chamber,
not in an interlocking manner, but randomly. This way you will ensure that the combustion air reaches
more burning material and flows around it better. Wood briquettes require a stronger air current, an
expert eye and perhaps a bit more patience, until you get the knack of it. Since less volume is available
(although the same mass, it takes less space up), the fire is generally smaller and does not burn so high
and vivaciously as when burning log. When wood briquettes alone are burnt, this therefore generally
leads to haziness in the combustion chamber, as well as on the stove window. Not all areas of the com-
bustion chamber have the same temperature applied to them as when unrefined wood is burnt, which
is why these deposits occur. It may be that with one variety of wood briquettes more deposits occur,
whereas with another variety none at all. This suggests trying out various varieties to determine the
suitable fuel for your heat-producing appliance. If you would really like to use wood briquettes, but
don’t get on quite well with them, then it may also help to mix the fuel. That means: Burn wood bri-
quettes and unrefined log in the mixture ratio that achieves a good burning result for your heat-produ-
cing appliance.
Wood briquettes must also be stored dry. In general it can be said that pressed items with a hole in the
middle usually burn better. Soft wood briquettes are to be preferred and are often more suitable than
hard wood briquettes.