20
8.0 Flue Options
© Baxi Heating UK Ltd 2007
8.1
Horizontal Flue Systems
1. The Main System HE can be fitted with either
horizontal, vertical or twin flue systems as illustrated.
2. The standard flue is suitable only for horizontal
applications.
3. Maximum permissible equivalent flue lengths are:-
Horizontal Concentric
(18 model)
5m
(24 model)
4m
(28 model)
3m
4. Any additional “in line” bends in the flue system must
be taken into consideration. Their equivalent lengths
are:-
Concentric Pipes:
135° bend
0.5 metres
93° bend
1.0 metres
Twin Flue Pipe
135° bend
0.25 metres
91.5° bend
0.50 metres
The elbow supplied with the standard horizontal flue is
not included in any equivalent length calculations
6. The illustrations opposite show examples of
maximum equivalent lengths.
NOTE: Flue length is measured from point X to Y
as shown.
Horizontal
Flues
Y
X
Plume Displacement Kit 60 /100 Ø
1M Extensions, 45° & 93° bends are
also available - see Section 9.0
NOTE:
Horizontal flue pipes should always be installed with at least a 1.5° fall
from the terminal to allow condensate to run back to the boiler.
Y
X
This bend is equivalent to
1 metre
Total equivalent length (upto 3m) =
A+B+C+2x90°Bends
B
A
C
This bend is equivalent to
1 metre
