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your stove at the level of combustion and draft. Always confirm that the depression
one meter above the recuperator is at least 12Pa.
b) Installing an air intake duct. A 100mm diameter pipe can be connected to the air
control damper inlet and channeled to the outside of the house. The length of this
pipe should be as short as possible and it should be ensured that the airflow is not
blocked and that the air current measured at one meter above the unit is 12Pa or
higher.
6.1. Circulation of air and flue gases
6.1.1. Theoretical notions for the installation of chimneys
There are some factors that you should consider in the installation of your chimney and
that can cause significant changes in the depression created in your chimney and
consequently in the smoke draw that you will have in your equipment.
Generally, the combustion created in your recuperator greatly increases the temperature
at the beginning of your chimney, compared to the outside ambient temperature. This fact
causes inside your chimney a low pressure (next to the recuperator), which combined with
a higher pressure in the air outside the chimney generates the force that causes a natural
movement of gases through the chimney pipe, which we call natural extraction or chimney
effect, and which also causes air entry necessary for combustion inside the recuperator.
The higher the height of your chimney, the greater the difference in pressures and
therefore the greater the natural extraction or chimney effect
This effect is based on a physical calculation that leads us to indicate that the minimum
height of the chimneys, in relation to an average altitude of the terrain, the differences in
average ambient temperatures and the average operating temperatures of the
recuperators, should not be less than 4 meters. However, this measure is not binding, and
there will be chimneys working well with less height and others with higher height working
worse. The reasons for this phenomenon must be understood in order to set up efficient
chimneys. In addition to the normal geographical factors (altitude, sun exposure,
direction) and atmosphere (rain, fog, snow) that influence the drawing of a chimney and
its depression, or even the ability to extract the fumes from the recuperator, there is still
a decisive factor in many cases that must be taken into account – the WIND.
In fact, the prevailing wind (which often depends on the morphology of the land and the
areas of implantation of the houses) can cause very 12 relevant changes to the depression
created in a chimney, that is, a wind with a predominantly updraft, causes an increase of
depression in the chimney and this justifies better runs. On the contrary, a predominantly
