Installation manual

INSTALLATION
8 716 115 519a (2009/03)22
5.8 EXTENSIONS AND ELBOWS
The examples opposite show the dimensions for:
• a 90° elbow and the tee piece connected together
• two 45° elbows connected together
To calculate the effective flue length:
B Identify the number of 90° and 45° elbows required.
B Deduct the effective length of each elbow from the
maximum horizontal flue length of 3m.
Fig. 32 Elbow measurements
To reduce the length of a flue extension:
B Mark the flue extension to the required distance,
measuring from the socket end as shown in fig. 33.
B Cut the flue extension square, taking care not to
damage the tubes.
B Remove any burrs and chamfer the outer edges of the
tubes to prevent seal damage.
Fig. 33 Cutting a flue extension
Fig. 34 Horizontal flue inclination
Connecting flue bends increases the
effective flue length and allowance must be
made for the different connectors.
80/125 mm elbow Effective length (m)
90° 2m
45° 1m
Table 15: Elbow equivalent lengths
180m
Only straight flue extensions may be cut.
B Do not modify flue elbows or the
tee piece.
The flue pipe must not be closer than 25mm
to any combustible material.
The tee piece has a built-in angle of 3°.
All horizontal sections of the flue must rise
by 3° or at least 52mm for each metre away
from the appliance as shown opposite.
This is to ensure the condensate flows back
into the appliance.