This may cause cracking of the surround back or marble.
4.3
Suitable flues and minimum flue sizes are as follows: -
It should be noted that, as with many appliances, sharp bends or horizontal runs in
metal flues at the top of the system can be a cause of problems in these types of
installation.
!
225mm x 225mm conventional brick flue.
!
175mm diameter lined brick or stone flue.
!
200mm diameter factory made insulated flue manufactured to BS4543.
!
175mm diameter flue pipe. See BS6461 Part 1 for suitable materials.
!
Single wall, twin wall or flexible flue liner with a minimum diameter of 125mm.
The materials to be used are stainless steel or aluminium as specified in BS715. The
liner must be sealed to the surrounding area above the fireplace opening and to the top
of the chimney. An approved terminal must be fitted.
!
A properly constructed precast concrete or clay flue system conforming to BS1289
or BS EN 1806. This system is only suitable if the conditions stated in section 4.2.4 are
met.
4.4
The flue must conform to BS 5440: Part 1 in design and installation.
The flue, measured from the bottom of the fireplace opening to the bottom of the
terminal, shall be not less than 3m in actual vertical height. When calculated in
accordance with BS 5440: Part 1 Annex A, the minimum
equivalent
height of the flue
shall be 2.0m of 125mm-dia. flue pipe.
4.5
The flue must not be used for any other appliance or application.
4.6
Any chimney damper or restrictor should be removed. If removal is not possible,
they must be secured in the open position.
4.7
If the appliance is intended to be installed to a chimney that was previously used
for solid fuel, the flue must be swept clean prior to installation. All flues should be
inspected for soundness and freedom from blockages.
4.8
If the fireplace opening is an underfloor draught type, it must be sealed to stop
any draughts.
4.9
The appliance must be mounted behind a non-combustible hearth (N.B.
conglomerate marble hearths are considered as non-combustible). The appliance can be
fitted to a purpose made proprietary class “O”-150°C surround. The hearth material
must be at least 12mm thick. The periphery of the hearth (or fender) should be at least
50mm above floor level to discourage the placing of carpets or rugs over it.
The surface of the hearth must be sufficiently flat to enable the bottom of the fascia and
the bottom front cover to be aligned horizontally. Any excessive unevenness (uneven
Page 10
INSTALLER GUIDE
©
Baxi Heating U.K. Limited 2007.
