Technical data

25
Chimney size
Ensure the cross section of the chimney complies with the
diagram and table below.
Fire resistance
The materials used for the construction of the chimney
must be fire resistant in compliance with the figures
stated below.
Preparing the chimney
•
The chimney must be swept if it has been previously used
for an appliance burning a fuel other than gas
•
It is recommended that the chimney be swept before
installation of the flexible flue
•
Any damper or restrictor plate in the chimney must be
removed. If it is not possible to remove the sliding damper
it must be fixed permanently in the open position
•
Any holes in the chimney must be sealed
•
The existing chimney pot and flaunching must be removed
•
The catchment space (void below the point of flue
connection) must be checked to ensure it complies with
the flue to be installed
•
All debris must be cleared from the catchment space
c
dia. d
Chimney size (mm)
‘c’ min ‘c’ max ‘dia. d’ min ‘dia. d’ max
130 300 146 300
Type of building Fire resistance
Single storey 30 minutes
Multi-storey 90 minutes
Calculating the effective flue length
Appliance Max. flue length Max. flue length
vertical (L
v
max) horizontal (L
h
max)
FS 30CDi 12m 3m
FS 42CDi 12m 3m
80/125mm bend Effective length (m)
90º 2
45º 1
To calculate the effective flue length:
•
Check the flue path and consider the following:
– number of 90° and 45° bends required outside
the chimney
– number of bends in the flexible liner
•
Deduct the effective length of each bend from the
maximum horizontal flue length of 3m
•
Deduct the effective lengths of each bend from the
maximum vertical flue length (L
v
max) of 12m.
Example of effective flue length calculation
This example shows the use of the flexible flue kit without
additional extensions or bends.
Bend in 80mm flexible liner Effective length (m)
45º 1.5
Horizontal effective flue length
(no extensions or bends) L
h
≤ L
h
max ?
L
h
= 1m L
h
max = 3m Yes
Vertical effective flue length
(with 2 x 45º bends) L
v
L
v
max = 12m - 2 x 45º bends = 3m = (12 - 3) 9m
45º bends
L
v
L
h
Calculating the effective flue length