Hergom H-01 Instrucciones Para La Instalación, Uso Y Mantenimiento página 29

Other factors also affect chimney draw:
- High trees and/or buildings near the house also have a negative
effect on chimney draw.
- Wind speed. Usually, sustained strong winds increase chimney
draw but stormy winds have a negative effect.
- External temperature. The colder it is outside, the greater the
chimney effect.
- Atmospheric pressure. The chimney effect is usually poor on
rainy, damp or stormy days.
- Intensity of the fire. The hotter the fire, the stronger the chimney
effect.
- Cracks in the chimney, badly sealed or dirty door, air entering
through pipe joints, other devices connected to the chimney.... may
affect chimney draw negatively.
4.1.2 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 hearth is creosote free is by performing a
visual inspection. Consequently, we recommend building installations that
are easy to access.
4.1.3 Options.
If you are going to build a chimney for the HEARTH, 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.
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