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© Baxi Heating UK Ltd 2010
Boiler Performance
Total thermal output is 12 kW with 3.8 to 10.4 kW available for controlled space
heating/domestic hot water production.
The difference of 1.6 kW is accounted for by heat radiated directly into the room, unless the
supplied shield is fitted in which case it will reduce this to 1.1 kW and increase the maximum
output to10.9 kW.
This must be taken in to account when designing the central heating system and in
particular when siting the appliance.
Preparatory Work and Safety Checks - IMPORTANT WARNING
This boiler must not be installed into a chimney that serves any other heating appliance.
There must not be an extractor or ceiling/paddle fan fitted in the same room as the boiler as
this can effect the safe operation of the appliance.
A Carbon monoxide sensor which complies with BS EN50291-1: 2001 must be fitted in the
same room as the appliance and positioned as outlined in the Building Regulations Part J.
Either mains or battery powered models may be used.
Consult the HETAS web site – www.hetas.co.uk for suitable models.
Further guidance on the installation of carbon monoxide alarms is available in
BS EN 50292:2002 and from the manufacturers’ instructions. Provision of an alarm should
not be regarded as a substitute for the correct installation and regular servicing.
Chimney
The chimney must be swept at least twice a year, one of which should be during the annual
service, preferably at the beginning of the Heating season. .
In order for the boiler to perform satisfactorily the chimney height must be sufficient to
ensure an adequate draught of approximately -15 Pa so as to clear the products of
combustion and prevent smoke emission into the room.
NOTE:
A chimney height of not less than 4.5 metres measured vertically from the outlet
of the boiler to the top of the chimney should be satisfactory.
The outlet from the chimney should be above the roof of the building in accordance with
the provisions of Building Regulations Approved Document J.
Connection to Chimney
The appliance is supplied with a 125mm flue gas connector that allows connection to either
a suitably lined masonry chimney or a prefabricated factory made insulated metal chimney in
accordance with the instructions.
It will be neccessary to fit an adaptor to the flue gas connector for chimney diameters
greater than 125mm. Maximum diameter is 150mm.
Because the boiler operates at high efficiencies, the temperature of the flue gases is at times
lower than conventional solid fuel appliances. Although it is not classed as a condensing
appliance, the low flue gas temperature results in condensation occurring within the flue. Any
chimney flue system must therefore be able to withstand the effects of condensate and
operate under wet conditions (designation letter W). In addition it should be soot fire
resistant and able to withstand the corrosive effects of flue products generated by solid fuels
(Designation G and 3 respectively). If installation is into an existing masonry chimney then it
will require re-lining with a liner meeting the specification described above. Existing concrete
or clay lined chimneys are NOT suitable for this boiler and must be lined as described above.
All installations must be in accordance with Building Regulations Approved Document J. For
suitable flue manufactures please refer to the HETAS web site as above.
Any existing chimney must be clear of obstruction and have been swept clean immediately
before installation of the lining system.
If there is suitable liner already installed ensure any
existing draught stabiliser is removed or sealed. If there is any doubt about the liner suitability
it should be replaced.
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.
Under no circumstances should a flexible liner designed solely for use with gas fires be
used with a solid fuel burning appliance.
A single wall metal fluepipe is suitable for connecting the boiler to the chimney but is not
suitable for use as the complete chimney.
Any bend in the chimney or connecting fluepipe should not exceed 45°.
90° bends should NOT be used.
Flex Flue
Masonry
Chimney
Prefabricated
Metal Flue
Flexible
Connection
0 - 30°
45°
1m
Max
Insulate Flue
3m
Max
125mm Dia
Adaptor