Section 9: Flue System and Air Supply
Page 35
! NOTE !
If the flexible liners must pass around an offset inside
the chimney, deduct two metres of straight flue length to
compensate for this.
The Grant Red system flexible stainless steel liner is directional.
The arrows marked on the inner liner MUST be pointing vertically
upwards, following the direction of the flue gases. Failure to
comply with this instruction could lead to a leakage of condensate
from the flue liner.
Flue extensions cannot be cut, use adjustable extensions where
required.
Three types of locking band are supplied with the kit, as follows
(Refer to Figure 9-9):
•
Type 1.
A white painted band - for connecting the white
painted flue sections that butt together, i.e. the joints with the
starter section and the rigid/flexible adaptor.
! NOTE !
Two of this type of locking band are supplied in the kit.
Refer to Figure 9-9.
A single locking band of this type is supplied with every
additional elbow, extension kit or adjustable extension kit
used.
•
Type 2.
A white painted band - to cover the sliding joint on
the white painted adjustable (telescopic) section.
! NOTE !
The locking band for the adjustable section is labelled for
easy identification.
A single locking band of this type is supplied with every
additional adjustable extension kit used.
•
Type 3.
An unpainted stainless steel band - to secure the
outer of the two stainless steel flue liners to the white painted
rigid/flexible adaptor.
The flue kit includes a Black coated terminal with upstand and is
designed to be fixed (using the screws provided) to the top of a
masonry chimney.
The flue system may be offset using 45° elbows (product code:
ELBK2145/90 models up to 26 kW output).
No more than a maximum of four elbows should be used per
system.
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 9-10.
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 9-10.
The minimum dimensions for locating the terminal from building
features (windows, doors, etc.) are shown in Figure 9-13.
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.
FLEXIBLE VERTICAL BALANCED FLUE (RED
SYSTEM)
Boiler
Flexible outer stainless steel 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
(Type 2)
Connector
Stainless Steel
Locking band
(Type 3)
Locking band
(Type 1)
Locking band
(Type 1)
Elbow, extension
and adjustable extension
from 'White' system
Flexible inner
stainless steel liner
The inner flue
liner is directional
(see Section 9.4)
Note:
Figure 9-9:
Red system balanced flue
This is a flexible vertical balanced flue system (for the 21 and 26
models only) designed to be fitted inside an existing masonry
chimney. See Figure 9-9.
It basically consists of three sections:
•
Concentric white painted flue pipe connected to the boiler.
•
The vertical concentric flexible flue consists of a flexible
stainless steel inner flue liner (directional) inside a flexible
stainless steel outer flue liner.
•
Terminal assembly for chimney top mounting.
The flue pipe seals are factory fitted and must be lubricated with
the lubricant supplied before assembly.
The Red system is supplied as a separate kit. Flue extensions
and 45° elbows from the White system may be used to extend the
flue between the boiler and the flexible section of the system.
The maximum vertical straight length of flue, from the top of the
boiler to the top of the terminal, is 20 metres – using no more than
four 45° elbows. Deduct 1 metre of straight flue length for every
elbow used.
