hergom Nansa Instruction Manual page 4

This information will help you make the correct decision
1.- How chimneys work
A basic knowledge of the dynamics of chimneys will help you make the most of your
Nansa cooker.
Chimneys:
a) Safely evacuate smoke and gasses from the house.
b) Provide sufficient draw in the hearth to keep the fire alive
.
What is the "chimney draw"?
The tendency air has to rise generates the chimney effect.
When a cooker is lit, hot air rises through the chimney. The chimney flue heats up and
keeps it drawing. Until the cooker and the chimney are hot enough, the chimney effect
will not work properly.
The chimney effect depends on the location, size and height of the chimney.
The following must be taken into consideration:
- Chimneys located inside a house keep warm and, therefore, chimney draw is
greater.
- The chimney size recommended by the manufacturer will provide a good
chimney effect.
- The height of a chimney affects how it draws:
The chimney must project at least one metre over the highest part of the roof.
Other factors also affect chimney draw:
- Houses that have very good internal insulation, free from draughts, provide
inadequate draw as no air enters the building. This can be corrected by
allowing external air to reach the cooker.
- 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.
greater height => better chimney effect
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