5.2 Initial startup
5.2.1 Permitted fuels
Firewood
Firewood up to max. 55 cm long.
Water content (w) greater than 15% (equivalent to wood moisture u > 17%)
Water content (w) less than 25% (equivalent to wood moisture u < 33%)
EU:
Fuel as per EN ISO 17225 – Part 5: Firewood class A2 / D15 L50
Additional for
Germany:
Fuel class 4 (§3 of the First Federal Emissions Protection Ordinance
(BimSchV) in the last amended version)
▪ Use wind-exposed areas where possible for storage (e.g. store at edge of forest instead
of in forest)
▪ Walls of buildings facing the sun are ideal
▪ Create a dry underlay, where possible with air access (line with round timber, pallets,
etc.)
▪ stack split wood and store in such a way that it is protected from the elements
▪ If possible, stock fuel for the day in a warm place (e.g. in boiler room) (pre-heats the
fuel!)
Storage time dependent upon water content
Wood type
Water content
15 – 25%
less than 15
%
Storage in heated and ventilated room
(approx. 20°C)
Soft wood (e.g.
spruce)
approx.
6 months
from 1 year
Hardwood (e.g.
beech)
1 – 1.5 years
from 2 years
Outdoor storage (protected from
elements, exposed to wind)
Soft wood (e.g.
spruce)
2 summers
from 2 years
Hardwood (e.g.
beech)
3 summers
from 3 years
Freshly cut wood has an approximate water content of 50 to 60%. As the above table
shows, the water content of the firewood decreases the longer the wood is stored
depending on how dry and warm the storage location is. The ideal water content of
firewood is between 15 and 25%. If the water content falls below 15%, we recommend
you adjust the combustion control to the fuel.
Water content
Note on standards
Tips for
storing wood
Start-up
5
Initial startup
Installation Instructions S3 Turbo | M1081217_en
59
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