Kalfire W Series Installation And User Manual page 18

Method when using openings
If you do not want to use grills, openings at the top and base of
the surround (chimneybreast) are also sufficient. For through put
openings, see Table 2. These openings serve the same function as
the gratings and supply and extract the convection air. We advise
you, to place tubes or hoses on the outlet openings. This makes
the convection system (just a little) more powerful and the heat is
guided more easily to the openings.
If you do not use the recommended convection set, this
may damage the fireplace by overheating. The result may
be soiled walls and ceilings in the room. There is always a
risk of discolouration to walls and ceilings, but this risk can
be considerably reduced, by correctly ventilating the room.
Mount the grills at a distance of at least 30 cm from the
ceiling or wall. Ensure there are no flammable materials
closer than 30 cm next to and 50 cm above the gratings.
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Heat storage/radiation system
If installing a heat storage/radiation system, the external
elements surrounding the fire must be made of materials that
are resistant to high temperatures and capable of drawing
in and releasing heat. Heat distribution plates, in chamotte
fireclay or similar materials, are adapted for this type of use. Any
constructed elements surrounding the fireplace insert, such as
the ceiling, floor and walls, need to be insulated. The insulation
should be 10 cm thick for combustible materials and 6 cm thick for
non-combustible materials. The wall behind the insulation should
be made of stone, brick, chalk or porous concrete at least 12.5 cm
in thickness. A gap should be left between the fireplace insert and
the external elements, allowing the air in this space to heat up and
then be transferred via the surface materials.
It is possible to combine the fireplace's hot air outlets with the
heat storage/radiation system in the installation. The standards
that apply to heat-storage fires must be respected for this type of
combined installation in order to comply with fire regulations.
In heat storage/radiation installations, the convection hood
should remain mounted on the Kalfire W.
The maximum wood amount (indicated in kg/hour) must
be respected to avoid overheating the installation. See the
table on page 42 of this Manual.