A lintel may be required above the recess for the convection box. If in doubt, seek
expert building advice before commencing to cut the recess.
8.2.1 Fitting a lintel.
Whenever a lintel is required to
support the recess in the inner leaf
of a brick/blockwork building,
follow the method outlined below
(See figure 8).
!
The lintel should be either steel
(Catnic) or reinforced precast
concrete. It should be 750mm
long x 75mm deep x inner leaf
thickness.
!
The opening should be, as near
as possible, centrally below a joint
in the inner leaf block.
!
Cut out the opening for the
lintel.
!
Where cutting through masonry, drill pilot holes and then cut out the slot using a
mechanical cutter. This will minimise damage to the surrounding structure.
!
Insert the lintel. Bed the lintel on mortar. Don’t dry bed. Slate pin to ensure the lintel
and structure above is secure and safe.
!
Make the opening below the lintel by removing the masonry and clearing debris. If
the cavity has loose fill (e.g. granular) insulation material, pack the edges of the opening
with Rockwool as you proceed to hold back the insulating material.
8.2.2 Preparing a wall cavity.
!
The wall cavity must not be bridged other than by the flue unit. The appliance case
must not project into the cavity between the inner and outer walls by more than 10mm.
!
The cavity should be sealed where the opening has been cut. We recommend filling
fully across the cavity with Rockwool or equivalent to at least 100mm above and each
side of the recess opening (See figure 9).
!
An alternative to rockwool
above
the opening is to seal across the top of the cavity
with superlux board or equivalent. The board should slope downward to the back so that
any moisture will be channelled to the outside (See figure 9).
Page 18
INSTALLER GUIDE
©
Baxi Heating U.K. Limited 2007.
Figure 8. Lintel installation
