How Chimneys Work - hergom CRETA Instructions For Installation, Maintenance And Use

After some years you can change the type of fuel but once the chimney has
been built it is not easy to change its position.
The following information will help you to decide if you want to use the
existing chimney or if you want to construct a new chimney.
This information will help you take the correct decision
1. – How chimneys work
A basic understanding of how chimneys work will help you to get the best
out of your Crete stove.
A chimney is:
a) To safely take smoke and gases away from the house.
b) To provide enough draft in the stove for the fire to stay alight.
What is draft?
The tendency of hot air to rise creates a draft.
When the stove is lit hot air goes up the chimney and out through the
chimney top. The chimney flue heats up and maintains the draft. The draft will not
work at full efficiency until the stove and the chimney are hot.
The placement, the size and the height of the chimney affect the draft.
The following points must be taken into consideration:
- Chimneys situated inside the house keep hot so the draft is greater.
- The size of the chimney advised by the manufacturer will maintain a good
draft.
- The height of the chimney affects the draft:
The chimney must be at least one metre higher than the highest part of the
roof.
Other factors which affect the draft are:
- In houses which are very well internally insulated, with no drafts, as no air
enters the premises this impedes the draft. This is corrected by seeing that air from
the outside gets to the STOVE.
- High trees and/or buildings close to the dwelling impede the draft.
- Wind speed. Generally continuous, high winds increase the draft, but
stormy winds reduce the draft.
- The outside temperature. The colder it is outside the better the draft.
- Air pressure. On rainy, damp or foggy days the draft is generally poor.
- The temperature of the fire. The hotter the fire the stronger the draft.
- Cracks in the chimney, a poorly sealed or dirty door, if air is getting in
through the joins in the pipes, or through another piece of equipment connected to
the chimney etc. could mean that the draft is insufficient.
2. – Formation of soot and its cleaning.
- It is recommended that you clean your chimney stack at least once a year.
Higher chimney better draft.
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