14
2000225013B
7 Flue Preparation
Diagram 7.1
Y
70
OUTSIDE
WALL
FACE
Diagram 7.2
STANDARD SIDE FLUE
9304
9313
REAR FLUE
DRILL AND
SCREW
BOILER MOUNTING
WALL
Diagram 7.3
SIDE FLUE EXTENSION
9305
DRILL AND
SCREW
7.1 Flue Length
All dimensions are in mm.
To determine flue length temporarily fit flue elbow to top of
boiler.
For rear or side flue, measure the distance from the outside wall
to the butt joint of the flue elbow fitted on top of the boiler. A
standard flue system will be suitable if the length measured ‘Y’
is less than 633mm, see diagrams 7.1 and 7.2.
If the measurement ‘Y’ exceeds 633mm then one or more
extension pipes are required.
When cutting the flue duct should be cut flush with the air duct.
7.2 Extension pipes
Refer to diagrams 7.3 and 7.4.
Note maximum permitted lengths
When extension pipes are required it should be noted that the
length of the air ducts which butt together are 960mm long and
this should be taken into account when calculating the length
that requires cutting.
For example:
Distance from outside wall to butt joint on the flue elbow ‘Y’ =
2700 mm.
Standard flue length = 633 mm.
Extension pipe length = 960 mm.
Length required of final extension pipe =
2700 - (633 + 960 + 960) = 147mm.
The length of the extension pipe in the above example to be cut
would be 147mm and would be measured from the end of the
air duct where the flue duct contains the ‘o-ring’ seal.
When cutting, the flue duct should be cut flush with the air duct
at the opposite end to where the flue duct contains the ‘o-ring’
seal.
The system is made up from a standard horizontal flue kit and
accessories. The accessories include flue extensions, bends
45
0
and 90
0
and fixing brackets.
The maximum permitted straight flue length is 10 metres plus
the standard horizontal flue. For each 90
0
or 45
0
x 2 bends fitted,
the maximum length must be reduced by 1 metre.
Note: 45
0
x 2 bends can replace 1 x 90
0
if necessary. When
using 90
0
bends any horizontal extension pipe should be
inclined by a minimum of 2.5
0
fall towards the boiler to facilitate
condense removal.
7.3 Flue Assembly
The flue assembly is a push fit design with securing collars.
Remove all burrs from cut pipes.
Diagram 7.5 shows the components supplied in the standard kit
and the flue adapter.
Having cut the air and flue ducts as described in sections 7.1-
7.2 assemble the flue as follows, the flue can be fitted externally
or entirely from inside.
Fit the rubber sealing collar behind the locating lugs on the flue
terminal, see diagram 7.5.
Push the flue assembly into the wall, externally or internally,
initially until the end of the assembly protrudes a short way from
the inside face of the wall. This will enable the inner rubber
sealing collar to be positioned and allow the flue duct to be
drawn back into the flue elbow after the boiler has been
mounted.
OUTER
RUBBER
COLLAR
