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If there is no existing chimney then any new system must be to the designation described above
and in accordance with Building Regulations Approved Document J.
A single wall metal fluepipe is suitable for connecting the boiler to the chimney but is not
suitable for use as the complete chimney. The chimney and connecting fluepipe must have a
minimum diameter of 150 mm and its dimension should be not less than the size of the outlet
socket of the boiler.
Any bend in the chimney or connecting fluepipe should not exceed 45
°
. 90
°
bends should not
be used.
Combustible material should not be located where the heat dissipating through the walls of
fireplaces or flues could ignite it. Therefore when installing the boiler in the presence of
combustible materials due account must be taken of the guidance on the separation of
combustible material given in Building Regulations Approved Document J and also in these
boiler instructions.
If it is found that there is excessive draught in the chimney then a draught stabiliser should be
fitted in the chimney above the chimney above the flue pipe connection. Fitting of a draught
stabiliser will affect the requirement for the permanent air supply into the room in which the
boiler is fitted in accordance with Approved Document J (see also combustion air supply).
Adequate provision e.g. easily accessible soot door or doors must be provided for sweeping the
chimney and connecting fluepipe.
Hearth
The hearth should be able to accommodate the weight of the boiler and its chimney if the
chimney is not independently supported. The weight of the boiler is indicated in the brochure.
The boiler should preferably be installed on a non-combustible hearth of a size and construction
that is in accordance with the provisions of the current Building Regulations Approved
Document J.
The clearance distances to combustible material beneath, surrounding or upon the hearth and
walls adjacent to the hearth should comply with the guidance on the separation of combustible
material given in Building Regulations Approved Document J and also in these boiler
instructions.
If the boiler is to be installed on a combustible floor surface, it must be covered with a non-
combustible material at least 12mm thick, in accordance with Building Regulations Approved
Document J, to a distance of 30 cm in front of the boiler and 15 cm to each side measuring from
the door of the combustion chamber.
Combustion air supply
In order for the boiler to perform efficiently and safely there must be an adequate air supply into
the room in which the boiler is installed to provide combustion air. The provision of air supply to
the boiler must be in accordance with current Building Regulations Approved Document J. An
opening window is not appropriate for this purpose.
