Metal-Fach SD DUO BIO 16, Technical And Operational Documentation

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METAL-FACH Heating Technology
33
Connection of boiler to chimney
(Installer)
Smoke ducts
The purpose of flue pipes is to reliably carry exhaust fumes to the outside and to draw in air for fuel
combustion. The chimney draught required for this depends on:
●
the temperature difference between hot flue gases and cold air,
●
the effective height of the chimney,
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a chimney section not less than 20 x 20 cm,
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the execution of the chimney (as smooth internal surfaces as possible) and the tightness of the joints.
The effective height of the chimney is the height difference between the highest hearth and the exit of the
chimney. The effective height of individual chimneys must be at least 4m and common chimneys for solid and
liquid fuels at least 5m. The height difference between two fireplaces must not be greater than 6.5m. In the case
of sloping roofs, the chimneys should terminate at the ridge (the highest point of the roof), in an area of free
wind flow. This avoids draught disturbance. The position of the building in relation to other buildings must
always be taken into account.
Chimney selection
In most cases an approximate method or selection according to the chimney manufacturer's diagrams is
sufficient for selecting the chimney. In special cases (unfavourable pressure and temperature relations, large
flue gas volume) chimneys are calculated according to the binding norm. Low outlet flue gas temperature at
nominal boiler output can cause emission of damp flue gases, soot deposition, insufficient chimney draught.
This can lead to dampness and corrosion of brick chimneys. It is recommended to use a chimney insert:
●
For new buildings, a ceramic flue system resistant to condensation, thermally insulated and with a
condenser is recommended,
●
In existing buildings, it is advisable to upgrade the brick chimney by using a stainless steel chimney
system (designed for solid fuel boilers) single or double wall.
Flue
The boiler is connected to the chimney by a flue pipe and a flue pipe. Flue pipes are pipes and fittings that are
laid in rooms. Smoke ducts meet fire safety requirements for chimneys and are often made of the same
material as the main chimney. Smoke ducts should be made of non-combustible products. Smoke ducts or
casing should meet the requirements specified in the Polish Standard for fire testing of small chimneys. An
enclosure made of 12 cm thick solid brick, built on cement-lime mortar, with external plaster or pointing, is
acceptable. Joints should be as short as possible and laid with an elevation to the chimney to avoid heat loss and
additional resistance. They must not be routed to other floors. Flue pipes should not be laid in rooms where
fireplaces cannot be fitted, nor should they be placed in walls or ceilings. In order to protect the chimney against
dampness and draught limitation, acid resistant or ceramic chimney liners should be used, with condensate
drainage to the drainage grating. A distance of at least 6 m should be kept between the chimney and the nearest
edge of a tree crown.