Evaluating The Combustion Quality; Wood Moisture Content And Calorific Value; Storing And Drying Wood; Cleaning And Maintenance - HASE SENDAI 175 Operating Instructions Manual

Only use small pieces of wood to light the fire.
They burn faster than large logs and as a result, the
temperature required for complete combustion is
reached more quickly.
For continuous heating, adding smaller quantities
of wood more frequently is more efficient and more
ecological.

13. Evaluating the Combustion Quality

The following characteristics can help you evaluate
the quality of the combustion:
- Colour and composition of the ash:
If the combustion process is clean and
efficient, the result is a fine white ash.
Dark colouration indicates that the ash
contains charcoal residue; in this case,
the burn-off phase was incomplete.
- The colour of the flue gases emitted at
the chimney pot:
Here, the following applies: the more
invisible the flue gases exiting the chim-
ney, the better the combustion quality.
During the transitional seasons (spring/autumn),
outdoor temperatures above 16°C can impair the
chimney draught. If a draught cannot be created at
these temperatures by rapidly burning paper or thin
wood shavings (quick fire), you should refrain from
lighting the stove.
14. Wood Moisture Content and Calorific
Value
Rule of thumb: the more damp the wood, the lower
the calorific value.
The calorific value of the wood depends largely on
the wood moisture content. The more moisture the
wood contains, the more energy expended to evap-
orate it during the combustion phase; this energy is
then lost. The more damp the wood, the lower its
calorific value.
An example: freshly cut wood has a moisture con-
tent of approx. 50% and a calorific value of around
2.3 kWh/kg; in contrast, wood which has been ef-
ficiently air-dried has a moisture content of approx.
15% and a calorific value of around 4.3 kWh/kg.
Accordingly, if you burn very moist wood, you will
have about half the thermal output with the same
quantity of wood. Furthermore, burning moist wood
results in substantial soot build-up on the fire box
window. Moreover, when moist wood is burned, the
resultant water vapour can condense in the flue pipe
or chimney, which can lead to a build up of shiny
soot on the chimney or chimney creosote. Chimney
creosote can cause unpleasant odours and dam-
age brick chimneys, while shiny soot poses a fire
hazard (chimney fire). In addition, if the wood has a
high moisture content, the combustion temperature
decreases, which prevents complete combustion of
all the wood components and causes considerable
environmental pollution.
You can use a wood moisture meter to determine
the residual moisture content of your firewood.

15. Storing and Drying Wood

Wood needs time to dry. If stored properly, it will air-
dry in approx. 2 to 3 years.
Saw, split, and store the wood ready for use; this
ensures rapid drying because smaller pieces of
wood dry better than larger, uncut logs.
Stack and store your wood logs in a ventilated lo-
cation that is as sunny as possible, ideally facing
south, and ensure that the wood is protected from
rain.
Leave a hand's width between the individual piles of
wood so that air can flow between them and carry
away any escaping moisture.
Do not cover your wood stacks with plastic sheeting
or tarpaulins; otherwise the moisture cannot es-
cape.
Do not stack fresh wood in a cellar or basement,
since it will rot rather than dry due to the lack of
airflow.
Only store already dried wood in dry and well-venti-
lated cellar or basement rooms.

16. Cleaning and Maintenance

16.1 Steel Cladding

Hase stoves are coated with a heat-resistant open
pore lacquer that provides only limited corrosion
protection; accordingly, a rust film may develop in
some cases.
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