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External balanced flue
(Green system)
Where it is not practical to use a low
level (Yellow system) or internal high
level/vertical (White system) balanced
flue, the boiler can be fitted with an
external vertical/high level flue (Green
system).
See Figure 9-9.
The Starter kit fits to the boiler in the
same way as a low level balanced flue
(Yellow system) and the external Tee
allows the connection of a twin wall
insulated flue pipe and a combustion
air inlet - providing a room sealed flue
system.
The external system can terminate at
either high level or vertically (above roof
level) as required.
See Figure 9-9.
The minimum dimensions for locating the
terminal from building features (windows,
doors, etc.) are shown in Figure 9-10.
The terminal must be positioned so
as to avoid products of combustion
accumulating in stagnant pockets
around the buildings or entering into
buildings. Care should be taken that the
plume from condensed flue gases does
not cause a nuisance.
The components listed on the following
page for the external flue (Green system)
components are available from Grant
UK.
Flue System and
Air Supply
Figure 9-8:
Red system balanced flue (15/21 and 15/26 only)
Boiler
Outer plastic liner
Terminal
Terminal upstand
Top plate
Support clamp
Rigid/flexible adaptor
Starter section
Telescopic flue (lower)
Telescopic flue (upper)
Locking band for
adjustable joint section
Connector
Plastic locking band
Locking band
Locking band
Elbow, extension
and adjustable extension
from 'White' system
Flexible inner
stainless steel liner
The flue liner
is directional
(see Section 9.4)
Note:
