MCZ Athos HYDRO 14 kW - Manual (Page 11)

PELLET STOVES Chapter 2
INSTALLATION AND USE MANUAL page
11
Theoretical notions for installation Technical service - Rights reserved MCZ S.p.A. - Reproduction prohibited
2. THEORETICAL NOTIONS FOR INSTALLATION
2.1. PELLETS
Wood pellets are manufactured by hot-extruding compressed sawdust
which is produced during the working of natural dried wood. The
compactness of the material comes from the lignin which is contained
in the wood itself, and allows the production of pellets without the use
of glues or binders.
The market offers different types of pellet with characteristics which
vary depending on what mixture of woods is used. The diameter varies
between 6 mm and 8 mm, with a standard length in the range 5 mm to
30 mm. Good quality pellets have a density which varies between 550
kg/m 3 to over 700 kg/m 3 , with a moisture content which varies from
5% to 8% by weight.
With the aim of guaranteeing the stated rate of fuel
consumption per hour and ensuring optimum combustion, MCZ
has devised a patented method which allows the identification
and cataloguing of any type of pellet with a 6 mm and 8 mm
diameter, in terms of its specific gravity and particle size.
By using the special PelletBox® and following the procedure set out in
the paragraph on lighting the stove, the user can determine the correct
settings for configuring the stove.
Besides being an ecological fuel (exploiting timber residues to the
maximum and achieving cleaner combustion than is possible with fossil
fuels), pellets also have technical advantages. While good-quality
timber has a calorific power of 4.4 kW/kg (with 15% moisture, after
about 18 months' seasoning), the equivalent figure for pellets is 5.3
kW/kg.
To ensure good combustion, the pellets must be stored in an area that
is free of humidity and protected from dirt. The pellets are usually
supplied in 15 kg. sacks, so storing them is very convenient.
Good quality pellets ensure good combustion, thus lowering the
emission of harmful agents into the atmosphere.
The poorer the quality of the fuel, the more
frequently will intervention be necessary for cleaning
the internal parts, such as the grate and the
combustion chamber.
The pellets must be produced from pure wood which has not been
treated chemically.
The standards DIN 51731 and ONORM M 7135 certify a high-quality
pellet with the following characteristics:
9 Calorific power: 5.3 kW/kg
9 Density: 700 kg/m 3
9 Water content: max 8% of weight
9 Percentage of ashes: max 1% of weight
Figure 1 - Pellet fuel
Figure 2 - PelletBox®
Figure 3 - Sack of fuel, 15 kg