Flue System and
Air Supply
37
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.
The minimum dimensions for locating
the terminal from building features
(windows, doors, etc.) are shown in
Figure 9-11.
If the flue terminal is fitted less than 2
metres above a surface to which people
have access, the terminal must be
protected by a guard. The guard must
be fitted centrally over the flue terminal
and securely fixed to the wall.
The low level balanced flue (Yellow
system) is supplied with a stainless steel
guard. This must be fitted in all
circumstances to prevent objects from
entering the flue outlet.
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.
Figure 9-10 shows the external flue
(Green system) components that are
available from Grant UK.
Typical Flue
System
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 (Ref. ELB K2145/90).
No more than a maximum of four
elbows should be used per system.
Figure 9-10: External balanced flue
(Green system)
Vertical terminal kit
GTV90 (15 - 26 kW)
GTV200 (26 - 70 kW)
45° elbow kit
GE45/90 (15 - 26 kW)
GE45/200 (26 - 70 kW)
High level terminal kit
GTH90 (15 - 26 kW)
GTH200 (26 - 70 kW)
Extended wall bracket
Extension kits
Starter kit
GK90 (15 - 26 kW)
GK200 (26 - 70 kW)
GK90S - Short(15 - 26 kW)
GK200S - Short (26 - 70 kW)
Wall bracket
Locking band
Green System Components
Item - for models up Part No. Combi Part No. Combi
to 26 kW output 21e and 26e 36e
Starter kit - standard GK90 GK200
Starter kit - short GK90S GK200S
150mm extension GX150/90 GX150/200
250mm extension GX250/90 GX250/200
450mm extension GX450/90 GX450/200
950mm extension GX950/90 GX950/200
195-270mm adjustable extension GXA250/90 GXA250/200
45º elbow GE45/90 GE45/200
High level terminal GTH90 GTH200
Vertical terminal GTV90 GTV200
Wall bracket - standard GWB90 GWB200
Wall bracket - extended GEB90 GEB200
Air intake
Do not
obstruct
Figure 9-9: Red system balanced flue
Terminal
Terminal
upstand
Outer plastic
liner
Support clamp
Top
plate
Inner
stainless
steel liner
Telescopic
flue (upper)
Locking band
for adjustable
joint section
Boiler
Starter
section
Locking
band
Telescopic
flue (lower)
Connector
Rigid/flexible
adaptor
Plastic locking
band
Locking
band
Liner is
directional
See Note
on p36