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With low outside temperatures, the water vapour
contained in the flue gas may condense and freeze
on the balanced flue.
This ice may fall from the
roof causing injuries or material losses.
Prevent
ice from falling through on-site measures, e.g. the
installation of a snow catcher grille.
If fire resistance
is not
required for the ceiling,
route the lines for the combustion air supply and
the flue gas from the top edge of the ceiling to the
roof skin inside a duct made from non-combustible,
rigid materials or inside a protective metal pipe
(mechanical protection). There is a risk of fires
spreading, if these requirements are ignored.
General notes
Particularly for safety reasons, use only original Wolf
components for concentric balanced flues and flues.
Where necessary, adapt the installation examples to the
relevant Building Regulations and requirements of your
country/region. Discuss any questions relating to the
installation, particularly regarding the inspection components
and ventilation apertures, prior to installation with your local
heating engineer/flue gas inspector.
Gas fired condensing boilers with a balanced flue
outlet above the roof may only be installed in attics
or in rooms, where the ceiling also forms the roof
or where only the roof construction is located above
the ceiling.
If the balanced flue crosses different floors, route
the pipes outside the boiler room inside a duct with
a fire resistance of at least 90 min., and in living
space of low height with a resistance of at least 30
min. Fire may spread if these instructions are not
observed.
The following applies to gas fired boilers with a balanced flue
above the roof, where only the roof structure lies above the
ceiling:
If fire resistance
is
required for the ceiling, the pipes
for combustion air supply and flue gas exhaustion
running between the top edge of the ceiling and the
roof skin must be run inside a liner that provides the
same fire resistance and is constructed from non-
combustible materials. There is a risk of transferring
fires, if these requirements are ignored.
Secure the balanced flue or flue outside ducts with
spacer pipe brackets with a minimum clearance of
50 cm from the flue outlet or upstream/downstream
of deviations to prevent the pipe joints being pulled
apart. Flue gas may escape, if this rule is not
observed. Furthermore, equipment damage may
result.
Design information
A clearance between the concentric balanced flue and
combustible materials or components is not required, as
no temperatures higher than 85 °C will occur at the rated
output.
If only a flue is installed, maintain the clearances specified by
DVGW/TRGI 2008 [or local regulations].
Balanced flues without ducts must not be routed
through other rooms, otherwise there would
be a risk of fire spreading, and no mechanical
protection would be provided.
The combustion air must not be drawn from
chimneys that used to carry flue gases from oil or
solid fuel boilers.
NB
