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9.2 Conventional Flue Systems
Under no circumstances can Grant
VORTEX Pro boilers be installed
with existing flue systems. Only flue
systems and components suitable for
wet flues should be used.
Failure to install the correct type
of flue system will invalidate the
warranty.
Grant condensing boilers have high
operating efficiencies and low flue gas
temperatures. Care must be taken to ensure
the flue system is suitable for the very low
flue gas temperatures and condensate in
the flue gases.
Suitable conventional flue systems are
available from Grant UK.
The flue must terminate in a down
draught free area, i.e. at least 600 mm
above the point of exit through the roof
or preferably above the ridge level.
The condensate may be allowed to run
back into the boiler. A condensate drain
at the base of the flue system is not
required.
The high level flue terminal must be at
least 600 mm from any opening into
the building, and 600 mm above any
vertical structure or wall less than a
horizontal distance of 750 mm from
the terminal.
If an existing chimney is to be used,
it must be lined with a smooth bore
stainless steel liner suitable for use with
oil fired condensing boilers. The top and
bottom of the annular space must be
sealed.
Grant recommends the use of the
Grant 'Orange' flue system, specifically
designed for the VORTEx range of
condensing boilers.
The internal flue and liner diameter for all
models up to 46 kW output must be 100
mm (4 in) and for the 46/58 and 58/70
models 125 mm (5 in).
The maximum vertical height (from the
top of the boiler to the terminal) for the
'Orange' system is 19 metres.
The Grant Orange system flexible
stainless steel liner is directional. The
arrows marked on the 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.
If a rigid flue is used externally,
it must
be of the twin-wall type incorporating
seals at all joints, constructed with a
stainless steel inner skin and be suitably
insulated and weatherproofed. The
internal flue diameter for a rigid flue
for all models - up to and including the
58/70 - is 100 mm (4 in). Use the larger
'200' size of 'Green' system components
as listed in Figure 9-9.
Grant recommends the use of the
Grant 'Green' and 'Orange' flue system
components for this application. Refer to
Section 1.2 for details.
As no flue adaptor is supplied with the
boiler, in order to correctly connect
the hybrid system, it will be necessary
to purchase the Grant CF adaptor kit
(Ref. CFA15/70).
If required, it is possible to use the
white painted single-wall straight flue
extensions, adjustable extensions and
elbows from the Grant 'Orange' system
for the internal
section of the flue system,
see Figure 9-4. These components can
be fitted between the boiler connector
and flue adaptor. The flue adaptor, to
which the external twin-wall 'Green'
flue components are connected, can
therefore be situated just before the flue
system passes through the wall.
Grant 'Orange' system single-wall
flue components must not be used
externally.
The maximum vertical height (from the
top of the boiler to the terminal) for the
100 mm diameter hybrid 'Green/Yellow'
system is 8 metres.
Grant 'Green' twin-wall flue is
recommended for externally run flues to
reduce the possibility of the condensate
freezing in the flue.
No part of any flue system should be
made of an asbestos material; aluminium
must not be used in any part of the flue.
Only stainless steel flue components
should be used.
If the draught conditions are satisfactory,
the flue should terminate with a standard
cowl.
Refer to the locally applicable Building
Regulations, BS 5410:1 and OFTEC
Installation Requirements (OFTEC
Technical Books 2 and 4) for further
guidance on conventional flue systems.
It is important to ensure that the flue
system is sealed and that condensate
cannot escape. Up to 1.5 l/h of
condensate can be produced in a
conventional flue system.
Only use flue systems suitable for oil
fired condensing boilers.
Do not use fire cement. The use of
high temperature silicone sealants is
recommended.
To comply with the requirements of
the Building Regulations Approved
Document J - conventional flue systems
must have a flue data plate. A suitable
data plate is supplied with the Grant
Orange flue system and should be
displayed next to the boiler or flue.
Flue System and
Air Supply
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CAUTION
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