Installation manual

PRE-INSTALLATION
8 716 115 519a (2009/03)10
4.5 CALCULATING THE EFFECTIVE FLUE LENGTH
To calculate the effective flue length:
B Check the flue path and consider the following:
– number of 90° and 45° elbows required outside
the chimney
– number of bends in the flexible liner
B Deduct the effective length of each elbow from the
maximum horizontal flue length of 3m.
B Deduct the effective lengths of each bend from the
maximum vertical flue length (L
v
max) of 12m.
Fig. 4 Maximum flue length
EXAMPLE OF EFFECTIVE FLUE LENGTH CALCULATION (FOR FIGURE 4)
This example shows the use of the flexible flue kit
without additional extensions or elbows.
appliance
variant
max flue length
vertical
(L
v
max)
max flue length
horizontal
(L
h
max)
FS 30CDi 12m 3m
FS 42CDi 12m 3m
Table 10: Maximum flue length
80/125 mm elbow Effective length (m)
90° 2m
45° 1m
Table 11: Elbow equivalent lengths
Bend in 80mm flexible liner Effective length (m)
45° 1.5m
Table 12: Bend equivalent lengths
Horizontal effective flue length
(no extensions or elbows)
L
h
≤ L
h
max ?
L
h
= 1m L
h
max = 3m OK
Tab. 13: Example: horizontal flue length
Vertical effective flue length
(with 2x 45° bends)
L
v
?
L
v
max
= 12m
-
2x 45° bend
= 3m
=
9m
Tab. 14: Example: vertical flue length