Heating At Low Thermal Output (During Transitional Seasons); Emptying The Ash Drawer; The Combustion Process; Drying Phase - HASE Luno B.13 Mode D'emploi

16. Heating at Low Thermal Output
(during Transitional Seasons)
You can vary the thermal output of your Luno by adjusting the
quantity of fuel used.
NOTE!
Do not attempt to slow down the combustion
by reducing the air supply. When heating with
wood, this can result in an incomplete burning
process and pose the risk of an explosive like
combustion of the accumulated wood gases
(deflagration).

17. Emptying the Ash Drawer

As a safety precaution, please make sure that you only dispose
of ashes once they are cold. While the ash collects during the
fire, the lid (fig. 6/1) is located under the ash drawer
(fig. 6/2).
The ash drawer contains the mineral components of the wood
(approx. 1%) as combustion residues.
Remove both the ash drawer and the lid located underneath it.
Make sure the ash does not pile up all the way to the bottom
of the fire box. Slide the lid onto the ash drawer so that it is
closed; this prevents ashes from flying around, which in turn
means your home stays clean (fig. 7).
Fig. 6
Fig. 7

18. The Combustion Process

EA piece of wood burns in three phases. In a wood fire, ho-
wever, these processes occur both consecutively and simul-
taneously.

18.1 Drying Phase

The moisture still remaining in the air-dried wood (approx.
15 - 20%) is evaporated. This takes place at temperatures of
approx. 100°C. For the evaporation to occur, the wood must
be supplied with heat during the warming up phase; this is
achieved by using small wood logs.

18.2 Degasification Phase

At temperatures between 100°C and 150°C, the contents of
the wood start - slowly at first – to disintegrate and gasify and
the wood begins its thermal decomposition. At temperatures
above 150°C, the gas development accelerates. The proporti-
2 on of volatile components makes up around 80% of the wood
substance. The actual combustion begins at a temperature of
1
about 225°C (ignition temperature) with the ignition of the
resultant gases and the release of heat. There must be an ade-
quate supply of oxygen available for this purpose. The peak
of the combustion process is reached at approx. 300°C. The
reaction process is now so rapid that the largest amount of
heat is released at this point; flames can reach temperatures
of up to 1100°C.
1

18.3 Burn-off Phase

2
Glowing charcoal embers remain after the volatile compon-
ents have been burned off. These burn slowly, almost without
flames, at a temperature of approx. 800°C.
Crucial to a clean and efficient combustion process is a com-
63