Unit installation

Page 18
© Baxi Heating U.K. Limited 2010.
 Cover the hole with a square sheet
steel plate 500mm x 235mm with a
152mm diameter hole cut out of the
centre (See figure 9). The steel should
be not less than 1.5mm thick. Fix with
suitable screws and plugs.
 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.
Cut the Flue Hole -Timber Frame
Buildings
Drill the pilot hole and hole in the outer wall as section 7.5.
 Since the flue will pass through combustible material in the inner leaf of the wall, a
non-combustible sleeve 203mm (8in.) diameter will be required round the flue (See
figure 8).
 Cut a hole through the inner leaf to accommodate a non-combustible sleeve
203mm (8in.) outside diameter. To minimise the effect of breaking through the vapour
control layer (VCL), if possible, cut the hole approximately 10mm undersize so that
the sleeve will be forced through the layer. A recommended technique for cutting the
inner leaf is shown in figure 9.
 Fit the non-combustible sleeve to the inner leaf. The sleeve must extend to be at
least flush with the breather membrane / timber sheathing but must not protrude more
than 10mm into the cavity.
 The annular gap between the flue unit and the sleeve must be sealed to prevent
air heat and moisture passing along it.
INSTALLER GUIDE
Figure 9. Wall cover plate.