Wolf COB Installation Instructions And Technical Manual page 54

General notes
Particularly for safety reasons, use only original Wolf
components for flues and concentric balanced flue
systems.
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.
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 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 fire
spreading if these requirements are ignored.
If fire resistance is not required, route the pipes
for combustion air supply and flue gas exhaustion
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.
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31. Design information
A clearance between the concentric balanced flue and
combustible materials or components is not required, as
temperatures are limited to 85 °C at the rated boiler output.
If only a flue is installed, maintain the clearances specified
by DVGW/TRGI 86/96 [or local regulations].
Connection to the balanced flue
The clear cross-section of flues must be able to be inspected.
Therefore, install an inspection and/or test aperture inside the
boiler room; agree suitable arrangements with your local flue
gas inspector.
Flue cascade
Flue cascades are only suitable in balanced flue operation.
They must be designed to EN 13984-1.
Flue gas temperature limiter
The electronic flue gas temperature limiter switches the oil
condensing boiler off when the flue gas temperature exceeds
120 °C.
The boiler restarts when the reset button is pressed.
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 chimneys
NB
that used to carry flue gases from oil or solid fuel
boilers.
Ducts which were previously connected to an oil
NB
or solid fuel boiler must be thoroughly cleaned
by the flue gas inspector. There must be no dust,
sulphur or soot residues left on the inner surface of
the chimney. If this is not possible, use a separate
ventilation supply. If the combustion air is drawn in
via the cleaned duct, the prior use can cause odours
in the boiler room.
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.
To prevent flue gas escaping, a flue cascade is only
permitted with a tested flue gas damper.
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