INSTALLER GUIDEPage 113.6.2 Any chimney damper or restrictor should be removed. If removal is not possible,they must be secured in the open position.3.7 Fireplace preparation.3.7.1 If the fireplace opening is an underfloor draught type, it must be sealed to stopany draughts.3.7.2 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.3.7.3 The front face of the fireplace should be reasonably flat over the area coveredby the convection box top and side flange seals toensure good sealing. These faces should be madegood if necessary. The fireplace floor should bereasonably flat to ensure that a good seal with theconvection box can be made.3.7.4 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 (See figure1). We suggest that the actual fascia is used as atemplate to mark the area for combustible claddingremoval and that this area is increased by at least2mm all round.3.7.5 If the fireplace opening is greater than theacceptable dimensions given in this guide, do notuse the back of a fire surround or marble to reduce the opening. This may causecracking of the surround back or marble.3.8 The hearth.The appliance must be mounted behind a non-combustible hearth unless theconditions of section 3.10.1.1 are met (N.B. conglomerate marble hearths areconsidered as non-combustible). The appliance can be fitted to a purpose madeproprietary class “O”-150°C surround. The hearth material must be at least 12mmthick. The periphery of the hearth (or fender) should be at least 50mm above floorlevel 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 frontsurround and the bottom front cover to be aligned horizontally. Any excessiveunevenness (uneven tiles, Cotswold stone, etc.) should be rectified.The appliance must not stand on combustible materials or carpets.© Baxi Heating U.K. Limited 2009.Figure 1. Removal of combustiblecladding (Fascia may differ fromthat shown).