4.7 Fireplace preparation.4.7.1 If the fireplace opening is an underfloor draught type, it must be sealed to stopany draughts.4.7.2 The fireplace floor should be reasonably flat to ensure that the convection boxcan be installed without it rocking and so that a good seal can be made at the bottomfront of the box.4.7.3 The front face of the fireplace should be reasonably flat over the area coveredby the convection box top and side flange seals to ensure good sealing. These facesshould be made good if necessary.4.7.4 If the appliance is to be fitted against a wallwith combustible cladding, the cladding must beremoved from the area covered by the fascia. Thecladding must also not touch the fascia (Seefigure 2). We suggest that the actual fascia isused as a template to mark the area forcombustible cladding removal and that this areais increased by at least 2mm all round.4.7.5 If the fireplace opening is greater than theacceptable dimensions given in this guide, do notuse the back of a fire surround or marble toreduce the opening. This may cause cracking ofthe surround back or marble.4.8 The hearth and back panel.The appliance must be mounted behind a non-combustible hearth unless the conditions ofsection 4.10.1.1 are met (N.B. conglomeratemarble hearths are considered as non-combustible). The appliance can be fitted to apurpose made proprietary class “O”-150°C surround. The hearth material must be atleast 12mm thick. The periphery of the hearth (or fender) should be at least 50mmabove floor level to discourage the placing of carpets or rugs over it.The appliance must not stand on combustible materials or carpets.Page 13© Baxi Heating U.K. Limited 2010.INSTALLER GUIDEFigure 2 (Fascia may differ fromthat shown).