Wolf CGB-75 Assembly And Operating Instructions Manual page 43

General notes
Particularly for safety reasons, use only original Wolf
components for concentric balanced flues and for
conventional 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 of inspection covers and ventilation apertures with
your local flue gas inspector.
At 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 the balanced flue crosses different floors,
route the pipes outside the installation room
inside a duct with a fire resistance of at least
90 min., and in low residential buildings with a
resistance of at least 30 min. Fire may spread if
these instructions are not observed.
Gas 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.
The following applies to gas 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
expulsion 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 fire spreading if
these requirements are ignored.
3062555_201507
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 in
accordance with local regulations.
If fire resistance is not required, route the pipes
for combustion air supply and flue gas expulsion
between the top edge of the ceiling and 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 fire
spreading if these requirements are ignored.
Balanced flues without ducts must not be routed
through other installation rooms, as there is a
risk of fire spreading, and mechanical protection
is not ensured.
The combustion air must not be drawn from
NB
chimneys that used to carry flue gases from oil
or solid fuel boilers.
Secure the balanced flue or flue outside ducts
with spacer brackets with a minimum clearance
of 50 cm from the flue outlet or upstream/
downstream of diverters to prevent the pipe
joints being pulled apart. If this is not observed,
there is a danger of poisoning caused by
escaping flue gas. Furthermore, equipment
damage may result.
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