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With low outside temperatures, the water vapour
contained in the flue gas may condense on the
balanced flue and freeze.
This ice may fall from
the roof, causing personal injuries or material
losses.
Prevent ice from falling by taking on-site
measures, e.g. installing a snow guard.
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 in a shaft made from non-combustible, rigid
materials or in a protective metal pipe (mechanical
protection). There is a risk of fire spreading if these
requirements are not observed.
General information
For reasons of operational safety, use only original Wolf
components for concentric balanced flues and standard
flues.
Where necessary, adapt the installation examples to the
relevant building regulations and requirements in your
country/region. Any questions relating to the installation,
particularly regarding the inspection components and
ventilation apertures should be raised with your local flue gas
inspector prior to installation.
Gas condensing boilers with a balanced flue
with roof outlet 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 shaft
with at least 90 min fire resistance. In low-rise
residential buildings (building category 1 to 2) a
minimum of 30 min fire resistance is required. Fire
may spread if these instructions are not observed.
The following applies to gas boilers with a balanced flue
routed 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 must
be equipped with a casing in the area between
the top edge of the ceiling and the roof skin. The
casing must provide the same fire resistance as the
ceiling and must be made from non-combustible
materials. There is a risk of fire spreading if these
requirements are not observed.
Outside the shaft, secure the balanced flue or
standard flue with spacer brackets. These must be
provided at a minimum 50 cm from the appliance
connection and upstream/downstream of
diversions, to prevent the pipe joints being pulled
apart. Flue gas may escape if these instructions
are not observed. Furthermore, equipment
damage may result.
No clearance is required between the concentric balanced
flue and combustible materials or components, as no
temperatures higher than 85 °C will occur at the rated output.
If only a standard flue is installed, maintain the clearances
specified by DVGW/TRGI 2008 [or local regulations].
Balanced flue systems without shaft 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
chimneys previously used to carry flue gases from
oil or solid fuel boilers.
Please note
31. Technical information, balanced flue
If the gas condensing boiler is installed with a balanced flue
routed over an external wall (type C13x), the rated boiler
output in heating mode must be reduced to below 11 kW (for
appropriate measures, see chapter "Matching the maximum
output").
