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ENGLISH RAIS - manual for SIRA & SIRA SOAPSTONE
19
ENGLISH RAIS - manual for SIRA & SIRA SOAPSTONE
Operating instructions
Please note that HETAS Approval only covers the use of wood in the stove
and approval does not cover the use of other fuels either alone or mixed with
other fuels, nor does it cover instructions for the use of other fuels.
Fuel
The stove is designed and approved in accordance with EN 13240 and NS 3058 for stok-
ing split, dried firewood. The firewood must have a water content of 15-22% and its
maximum length should be the length of the combustion chamber minus 50-60 mm.
Stoking with wet firewood causes both soot, environmental pollution and bad fuel
economy. Freshly cut wood contains approx. 50-70% water and is thoroughly unsuitable
for stoking. Count a minimum 1 year of storage time for newly cut wood before using.
Wood with a diameter of more than 100 mm should be split. Regardless of wood size, it
should always have at least one surface area free of bark.
We do not recommend stoking with painted, laminated or impregnated wood, wood with
a synthetic surface, painted refuse wood, chipboard, plywood, domestic waste, paper bri-
quettes and pit coal, as this will produce malodorous smoke, which could be poisonous.
When firing with the above-mentioned items and amounts larger than those recommend-
ed, the stove is subjected to a larger amount of heat, which results in a higher chimney
temperature and lower efficiency. This can result in the stove and chimney becoming dam-
aged and would void the warranty.
The calorific value of the firewood is closely connected to the moisture level of the
firewood. Moist firewood has a low heat value. The more water the wood contains, the
more energy it takes for this water to vaporise, resulting in this energy being lost.
ONLY USE RECOMMENDED FUELS
The following table shows the calorific value of different types of wood, which have been
stored for 2 years, and which have a residual moisture of 15-17%.
Wood
Kg dry wood pr. m
3
compared to beech/oak
Hornbeam
640
110%
Beech and oak
580
100%
Ash
570
98%
Maple
540
93%
Birch
510
88%
Mountain pine
480
83%
Fir
390
67%
Poplar
380
65%
1 kg of wood yields the same heat energy irrespective of wood type. 1 kg beech merely
takes up less space than 1 kg of fir.
Drying and storage
Drying wood takes time: proper air drying takes approx. 2 years.
Here are some tips:
Store the wood sawn, split and stacked in an airy, sunny place, which is protected against
rain (the south side of the house is particularly suitable).
Store the firewood stacks at a hand’s breadth apart, as this ensures that the air flowing
through takes the moisture with it. Avoid covering the firewood stacks with plastic, as
this prevents the moisture from escaping. It is a good idea to bring the firewood into the
house 2-3 days before you need it.
