Instructions
29
NO SV
1.9 Draught
If smoke comes out of the stove when the re door is opened, it will be due to the poor
draught in the chimney. This type of stove requires at least 12 pa. of chimney draught to
achieve satisfactory combustion, and to prevent smoke from escaping. Smoke may, ho-
wever, escape in any event, if the stove door is opened during very vigorous burning, so
this should be avoided. The ue gas temperature at the rated output is 283°C relative to
20°C.
If in doubt, you may want to get your chimney sweep to measure the draught in the
chimney.
Draught
The draught in the chimney is the result of the dierence between the high tem-
perature in the chimney and the cooler temperature outside. Other factors that
determine whether enough negative pressure can be produced to create a draught
include the length and insulation of the chimney, and wind and weather conditions.
The draught will be reduced when:
- The temperature dierence is too low, e.g. in connection with a poorly insulated
chimney. If the chimney is cold, it may help to light (burn up) a rolled-up news-
paper in the chimney’s cleaning door.
- The outside temperature is too high, for example during the summer.
- There is no wind.
- The chimney is not tall enough, with the result that it sits in the lee of the roof
surface or tall trees. These conditions are also associated with the greatest risk
of smoke coming back down the chimney.
- Air is entering the chimney in undesired places, e.g. through cracked joints or
leaks in the cleaning door or the ue pipe.
- Unsealed, unused replaces are connected to the chimney.
- The ue pipe and chimney are clogged up with soot, due to inadequate cleaning.
- The house is too tightly sealed (please see the section on Fresh air supply).
- Too little air is getting in.
A good draught is achieved when:
- T here is a big dierence between the temperature in the chimney and outside
during ring, i.e. when the need for heating is greatest.
- T he weather is clear and there is a good wind.
- T he chimney is of the proper height, i.e. at least 4 metres above the stove, and
clearof the spine of the roof.