5 Vitolig 100
The rated boiler output will only be
achieved with dry firewood (25 %
moisture content). Firewood of poor
quality or with a high moisture content
reduce the rated output and the length
of combustion.
Logs should ideally be 30 to 33 cm long.
Approx. 44 % more softwood is
required for the equivalent energy yield
as for hardwood.
57
5.3 Fuel
Split logs
Calorific value of firewood subject to its water content
Wood condition
Water content (w)
Calorific value (Hu)
Freshly cut
50 60%
2.0 kWh/kg
Dried over a summer season
25 35%
3.4 kWh/kg
Dried for several years
15 25%
4.0 kWh/kg
Comparison between softwood and hardwood
Calorific value
with a water
content of
w = 20%
Raw density
Energy/m
3
Softwood (e.g. common spruce)
4.1 kWh/kg
0.43 kg/dm
3
1.763 kWh
Hardwood (e.g. beech)
3.9 kWh/kg
0.65 kg/dm
3
2.535 kWh
5.4 Flue gas connection
Chimney
A chimney corresponding to regulations
and appropriate for the rated boiler
output is a pre−requisite for an efficient
operation. The chimney should be
gas−tight and be completely rendered/
plastered. Observe DIN 4705 or
DIN 18160. The system requires a draught
of 0.17 mbar (1.7 mm WS). We
recommend the installation of a draught
restrictor to ensure a constant draught. It
will regulate the chimney draught to an
optimum value for Vitolig 100. This
ensures even combustion, standby losses
are reduced and condensation inside the
chimney will be prevented. This leads to
reduced energy consumption and lower
costs.
Flue pipe
Provide a clean−out cover in the flue pipe;
the flue pipe should be rising towards the
chimney.
5822241 GB
