Connecting To A Brick Chimney; Connecting To A Steel Chimney; Draught - Morso 8800 Instructions For Installation And Use Manual

1.7 Connecting to a brick chimney

Brick a flue bushing securely into the wall, and insert the flue pipe into it. The pipe must
not extend into the actual chimney opening, but only to the inside of the chimney aperture.
The joints between the stove/pipe and pipe/wall bushing must be sealed with the glass
tape provided. It is not normally necessary to seal between any pipe joints.
If the flue pipe transitions from horizontal to vertical, it is a good idea to install it with a
gentle bend so as to avoid any loss of draught.
The flue pipe must be dimensioned in accordance with national and local regulations.
Morsø recommends, however, that flue pipes be made of 2 mm sheet steel, as this will ex-
tend the service life.

1.8 Connecting to a steel chimney

If your installation involves taking the chimney straight up and through the ceiling, you
must comply with National, Local Building Regulations or flue manufacturers instructions
concerning clearances to combustible materials such as walls, floor joists and ceilings. The
joint between the stove flue collar and the stovepipe must also be sealed using the glass fi-
bre rope provided. It is important that the insulated flue system is properly supported both
at ceiling level and at roof level.
THE STOVE MUST NOT BEAR THE WEIGHT OF THE CHIMNEY SYSTEM (See chimney
manufacturer's instructions). Excessive weight on the stove will inhibit expansion and could
lead to damage of the stove top. Damage caused to the stove in this way would not be cov-
ered by the manufacturers guarantee.
If a chimney fire should occur as a result of incorrect operation of the stove or prolonged
use of wet fuel, close the vents completely and contact the fire brigade.
Be aware of the following:
Discuss the cleaning options with your chimney sweep.
If there is insufficient draught in the chimney, it may be a good idea to install
the flue pipe straight up, so as to minimise smoke migration in the actual com-
bustion chamber.
Avoid having any more bends than necessary, and limit the length of the flue
pipe so as not to reduce the draught.
Fresh air supply
A wood-burning stove requires air for combustion. As a result, firing a wood-
burning stove will help to create a healthy climate in your house. If the house
is very tightly sealed, and particularly if there is a cooker hood or ventilation
system in the house, it may be necessary to install an air grate in the room in
which the wood-burning stove is installed. Otherwise there may not be enough
draught in the chimney, which may result in the stove not being able to burn
properly, and smoke may come out of the stove when the fire door is opened.
If it is necessary to install air grates, they must be positioned so that they can-
not be obstructed.
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1.9 Draught

If smoke comes out of the stove when the fire 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, how-
ever, escape in any event, if the stove door is opened during very vigorous burning, so this
should be avoided.
The flue gas temperature at the rated output is 256°C relative to 20°C.
If in doubt, you may want to get your chimney sweep to measure the draught in the chim-
ney.
Draught
The draught in the chimney is the result of the difference between the high
temperature 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 difference 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 flue pipe.
- Unsealed, unused fireplaces are connected to the chimney.
- The flue 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:
- There is a big difference between the temperature in the chimney and outside
during firing, i.e. when the need for heating is greatest.
- The weather is clear and there is a good wind.
- The chimney is of the proper height, i.e. at least 4 metres above the stove, and
clear of the spine of the roof.
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