8
Fig. 6 Wall Cover Plate
Fig.5 Combustible Clasdding Removal
Fig. 4 Wall Drilling
5.2
Place the template against the wall. Make sure that the
centre of the flue hole is not less than the minimum shown in figure
4.
5.3
Pierce the centre of the screw fixing holes and the flue hole
and mark the positions on the wall.
Remove the template.
5.4
Cut the hole for the flue unit. Make sure that it is straight
and level. Though a hammer and chisel can be used, using a core
drill is by far the quickest and simplest method for normal
brickwork.
5.5
Core Drilling
5.5.1
Drill a pilot hole through the wall. Inspect the hole to
ensure that it is in the brickwork and not in mortar. If it is in
mortar, it is advisable to reposition the hole approximately 25mm
away (making sure that the minimum side clearances and height are
complied with). Remember to reposition the screw fixing holes.
5.5.2
Drill the flue hole with a 6in. (152mm) core drill. Where
practical, it is recommended that the hole is drilled from
inside the building to about half the wall depth with the
remainder drilled from outside. This ensures that the
edges of the hole are clean on both sides.
5.6
Hammer & Chisel Cutting
5.6.1
Mark a 152mm (6in) diameter circle for the flue
hole. Chisel out the area marked.
5.6.2
It may be necessary to make good both the
internal and external wall faces. To achieve a neat finish
and to make any future removal of the flue unit easier, it
is recommended that a cardboard cylinder is formed
around the flue unit and inserted in the hole while
making good. Remove the cardboard cylinder after
making good.
5.7
Recheck the screw fixing holes relative to the
flue hole.
5.8
Drill the four fixing holes to a minimum depth
of 42mm using a 7mm diameter masonry drill.
5.9
Insert the four wall plugs supplied.
5.10
Remove any combustible wall cladding material
from the area shown in figure 5.
5.11
Leaving a Hole, Building under
Construction
It will be convenient to use a non-corrosive metal tube
160mm diameter built into the wall at the correct position
for the flue unit.
5.12
Combustible Walls (Wood, Fibreboard,
Plasterboard etc.)
Building regulations require that the inlet and outlet ducts
and terminal bust not be closer than 25mm to combustible
material.
5.12.1
Mark out and cut a hole 202mm diameter through
the combustible part of the wall. A 152mm diameter hole
can be cut through non-combustible parts of the wall (see
figure 6).
5.12.2
Cover the hole with a square sheet steel plate
500mm x 235mm with a 152mm diameter hole cut out of
the centre (see figure 6). The steel should be not less than
1.5mm thick. Fix with suitable screws and plugs.
5.12.3
Where the whole wall is of combustible material, a
non-corrosive plate 455mm x 455mm with a 152mm
diameter hole in the centre must be fitted to the outer wall.
The hole through the wall should be lined with a non-corrosive metal tube 202mm diameter.
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