Baxi 746 Installer's Manual page 8

A properly constructed precast flue
!
conforming to B.S 1289 or BS EN 1806.
A flue pipe with a minimum diameter
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of 127mm. See B.S 6461 Part 1 for
suitable
materials. Metal flue pipes must comply
with B.S 715.
3.3.1 The minimum effective height of
the flue must be 3m.
3.3.2 The flue must be clear of any
obstruction and its base must be clear of
debris.
3.3.3 The flue must be completely sealed
so that combustion products do not come
into contact with combustible materials
outside the chimney.
3.3.4 The flue must serve only one
fireplace.
3.4 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.
3.5 The flue must not be used for any other appliance or application.
3.6 Any chimney dampers or restrictors should be removed. If removal is not
possible they must be fixed in the open position.
3.7 If the appliance is intended to be installed to a chimney, which 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.
3.8 If the fireplace opening is an underfloor draught type, it must be sealed to stop
any draughts.
3.9 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
INSTALLER GUIDE
Figure 3. Pre-cast fireplace
Page 8