9
2000225005B
3 Flue and Ventilation
Important Notes
The flue must be installed in accordance with the rules in force
in the countries of destination.
The flue must be in accordance with the current issue of
BS5440 Part 1.
The Chimney Flue Adapter Kit (Pt. No. 2000461993) socket is
designed to take flue pipes to the current issue of BS567. If a
flue pipe to BS715 is to be used, an adapter must be fitted to the
boiler flue socket.
The flue must be at least equivalent to 1m vertical.
The maximum flue length must not exceed 15m vertical.
Due to the Sedbuk D efficiency of the Hideaway FF if the flue
length exceeds the following ;
40C FF - 5m, 50C FF - 6m, 60C FF - 7m
then provision must be made to ensure that the condensate
products are drained away and that the flue liner is of the
appropriate specification. We would recommend that one of the
following flue liners should be used or an equivalent specification:
Ritevent - Chimflex LW or SB
Selkirk - Selflex TS or TSE
An existing liner must be changed if there is any doubt that it will
not operate safely throughout the life of any new appliance.
A drain point is incorporated on the chimney flue adapter to
which a drain pipe can be connected, refer to section 4.10.
3.1 Flue Guidelines
The flue should be kept as short as possible. Horizontal or very
shallow runs of the flue should be avoided as they encourage
local cooling.
Always choose a flue route which will cause the least cooling of
the flue.
There should be a vertical rise of at least 600mm (2ft) before
using a bend. 90
o
elbows should not be used.
The existing flue may not be completely sound. Therefore, to
prevent the possibility of leakage, additional sealing MUST be
carried out between the base of the chimney and the flue liner.
The end of the flue liner at the chimney top must be adequately
sealed and clamped, using proprietary fittings suitable for the
flue liner used, see diagram 3.1.
The flue should, preferably, end above ridge height but at the
least above the eaves of a pitched roof. Use a certificated
terminal.
If the flue is passed through or near any combustible material it
should be installed in accordance with the current issue of
BS5440 Part 1.3. If in doubt seek advice from the local gas
undertaking or Hepworth Heating Ltd.
3.2 Existing Chimney
An existing brick chimney must be thoroughly swept and all
debris cleared away before lining.
Remove any damper or register plate. Alternatively it may be
locked in the fully open position.
A flexible flue liner is preferred but a rigid liner may be used, with
connection to the boiler flue socket made with a short vertical
piece of flexible liner, see diagram 3.2.
The sealing plate also prevents debris falling and gives the flue
better insulation, reducing the possibility of condensation, see
diagram 3.1.
Check the system efficiency before installing the boiler.
Diagram 3.2
9915
APPROVED
SEAL
FLEXIBLE
LINER
BOILER
RIGID
FLUE
LINER
Diagram 3.1
9914
SEALING AND
CLAMPING
PLATE
AIR
SPACE
150mm (6in) plug of Mineral Wool or similar
600mm
SEALING
PLATE
3.3 New Chimney
A newly built chimney can be lined with a moisture resistant
lining, such as salt glazed pipe, of an appropriate diameter as
specified in the Building Regulations.
In the case of a salt glazed lined flue, it is recommended that a
short vertical length of flue pipe, preferably flexible metallic be
used. Fix and seal it to the boiler flue socket and make good with
an approved seal.
If a flue and false chimney breast are to be constructed all
openings for pipework to upper floors etc. must be sealed.
If a specially built compartment is constructed for the boiler, it
must conform to the requirements of the current issue of
BS5440 Part 1 and BS5871.