42
Calculation of chimney when firing with wood
Data
Aduro 12
Aduro 15 Lux
Flue temperature at [20°C]
279
395
Chimney draft at testing power [mbar]/[Pa]
0.12/12
0.12 / 12
Flue gas mass flow [g/s]
4.11
5.4
4.1 Inadequate draft in the chimney
If you experience poor draft in the stove after the installation, please make sure that there is nothing in the
chimney to restrict the smoke and that no nearby buildings or trees affect the winds around the chimney.
If the chimney is too short, leaks, or is inadequately insulated, there may be problems with the chimney draft
(let the chimney sweep assess this). The draft should be sufficient during the ignition phase when the
stove/chimney is cold to provide a clean combustion and prevent smoke leakage. Therefore, we recommend
a chimney draft around 5 Pa in the ignition phase.
Once the ignition is a success, and the smoke temperature is rising, it is important that the chimney draft
reaches a stable area around 18-25 Pa in operation (1 hour after ignition) when the chimney/stove is hot.
The draft in the area of 18-25 Pa when the stove is hot is essential in order to achieve an optimum and clean
combustion. Therefore, we recommend that you measure the chimney draft when the chimney is cold and
when it is hot after 1 hour in operation.
In practice, the chimney draft will differ
– especially in cold condition. Therefore, the best indication of the
chimney draft is to measure the draft when it is hot. If the chimney sweep judges the draft to be sufficient, but
you still have problems lighting a fire, try extending the ignition phase by using more thin pieces of kindling
and 1-2 firelighters, so that the chimney gets thoroughly warm. The chimney will not draw at optimum effect
until it is warm. When a layer of embers has been formed, add 2-3 dry logs.
If it is impossible to establish a sufficient natural chimney draft, you can mount a smoke exhauster, e.g.
4.2 Chimney and smoke
If you experience smoke coming out of the stove or the start section of the smoke pipe, it could be due to
certain weather conditions. On stormy or cold winter days, or if the chimney has not been used in a while, a
cold plug can be created in the chimney, meaning the natural draft will be at its minimum.
If the chimney is cold and cold plugs are created, you may experience smoke leaks during the ignition
phase. In this situation there can be more smoke than usually in the combustion chamber, and some of it
might leak out of the stove. Therefore, if you have a cold chimney that has not been used for a while, we
recommend that you use some wood sticks to heat the chimney and eliminate the cold plug.
