29
Therefore, it is essential that it is made perfectly and that it is subjected to maintenance operations in order to keep it in good condition
(many of the claims due to malfunctioning reasons refer exclusively to a bad draft). The chimney can be made of masonry or metallic pipe
compound.
It is necessary to comply with the following requirements for the proper operation of the stove:
•
The interior section must be perfectly circular.
•
It must be thermally insulated along its entire length in order to prevent condensation (the smoke is liquefied by heat shock) and even
more if the installation is outside the house.
•
If we use metallic pipe for the installation outside the house, it is compulsory to use thermal insulated pipe. It consist of two concentric
pipes and, between them, there is a thermal insulator. Moreover, we will avoid condensation problems.
•
It should not have bottlenecks (enlargements or reductions) and it must be vertical with deviations not higher that 45º.
•
Do not use horizontal sections.
•
If it has been used previously, it must be clean.
•
Respect the technical data of the instructions manual.
** For the fitter
The optimum draft for the stoves vary between 12+/-2 Pa (1.0–1.4 mm water column). We recommend checking the technical information of
the product.
A lower value causes a bad combustion causing carbonic deposits and excessive smoke generation, having leaks and, even worse, an
increase of the temperature that could damage the structural components of the stove, while a higher value leads to a too rapid combustion
with the heat dispersion through the flue.
Materials that are prohibited for the chimney and, therefore, damage the proper functioning of the equipment are: fibre cement, galvanized
steel (at least in the first few meters) and rough and porous interior surfaces.
drawing D46
shows some examples of solution.
D46
(1) Stainless steel AISI 316 chimney with double insulated
chamber and material resistant up to 400°C.
Efficiency
100% optimum.
(2) Traditional clay chimney with square section and
holes.
Efficiency 80% optimum.
(3) Chimney with refractory material and double
insulated chamber and exterior coating made of
lightweight concrete.
Efficiency 100% optimum.
(4) Avoid chimneys with rectangular interior section
different to the one of the drawing.
Efficiency 40% poor.
Not recommended
D47
All stoves that send smoke to the exterior should have their own chimney.
Never use the same chimney for several equipments at the
same time (see drawing D47).
The minimum diameter must be 4 dm2 (for example, 20 x 20 cm) for
stoves with a diameter below 200 mm or 6.25 dm2 (for example, 25 x 25
cm) for equipments with a diameter higher than 200 mm.
A big section of the chimney (for example, diameter of the pipe superior
to the one recommended) may results in a volume too large to be heated
and, therefore, it can cause difficulties for the proper operation of the
equipment. In order to avoid this problem, it is necessary to enclose
the chimney in its entire length. However, a small section (for example,
diameter of the pipe inferior to the one recommended) may cause a
reduction of the draft.
INSTALLATION, OPERATING AND SERVICING INSTRUCTIONS
STOVES
EN
