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-Cracks in the chimney, badly sealed or dirty covers, air entering through
pipe joints, other devices connected to the chimney.... may affect chimney
draw negatively.
2.- Creosote formation and cleaning.
When wood burns slowly, it produces tar and other organic fumes that, when
combined with a damp atmosphere, form creosote.
Creosote fumes may condense if the chimney walls are cold. If it catches fire,
extremely tall fires may be caused.
Any accumulation of creosote must be eliminated.
As the accumulation of creosote depends on a number of variables, it is very difficult
to know when the chimney should be cleaned.
The safest way of ensuring that the chimney of your cooker is creosote free is by
performing a visual inspection.
Consequently, we recommend building installations that are easy to access.
3.- Options.
If you are going to build a chimney for your cooker, you have two alternatives:
a) Brickwork chimneys.
b) Metal chimneys.
Studies have reached the conclusion that there is no great difference in performance
between metal and brick-cement chimneys. You will have to choose one or the other.
Whenever possible, build your chimney inside the house; this will provide better draw,
lower creosote accumulation and a longer life.
The advantages of brick chimneys include:
a) Fumes cool off more slowly inside the chimney due to the mass of bricks and
tiles.
b) As bricks accumulate heat, the house keeps warm longer after the fire is put
out.
c) It can be built to the specific requirements of each person.
d) If well built, it will be more resistant to fire than metal chimneys.
Brick chimneys must be well lined to prevent the fumes from losing temperature.
They must be built with materials that support high temperatures and corrosion.
They may be round, square...., what matters is their size.
Brick-work chimneys must comply with the measurements indicated in the chapter on
TECHNICAL DATA.
