8
3.4
FLUE SYSTEM
The flue system must be installed in accordance with BS 5854, BS 6644, IM/11.
For horizontal flues ensure the flue assembly slopes downwards towards the boiler by a minimum of 25 - 30 mm per
metre of flue.
It is recommended that horizontal and vertical flue assemblies should be supported approximately every 1.5 m with access
provided to the joints.
Alpha CD90S and CD115S boilers leave the factory with 'B23' type flue configuration (open chamber and forced draught -
single flue pipe). To change the configuration to 'C' type (sealed chamber and forced draught - concentric flue pipe),
remove the 80 mm dia. adapter, the bracket and gasket from the top of the boiler and fit the concentric flue adaptor, see
Section 4.5.
Note: 1.
Under no circumstances must the flue length (including allowances for extra bends) exceed the maximum flue
lengths stated for each type of flue.
2.
Failure to use the correct Alpha flue components with the boiler will invalidate the boilers CE approval, guarantee
and may be unsafe.
Seals for flue elements -
If lubrication of components (already performed by the manufacturer) is not sufficient, remove
the residual lubricant using a dry cloth, then to ease fitting apply a small amount of common or industrial talc to the seal.
Ensure that the seals are correctly located in the elbows and extensions as shown in Fig. 4.
Alpha CD90S/115S - General Boiler Information
Fig. 4
Seal
Seal
Flue components are available as follows:-
Open flue - 80 mm dia. single pipe
Horizontal terminal kit 80 mm dia. (includes 1 m straight with terminal, one 90° bend and two collars)
Vertical terminal kit 80 mm dia.
Extension pipe 1 m x 80 mm dia.
90° bend 80 mm dia.
45° bend 80 mm dia.
Concentric flue - 80/125 mm dia.
Horizontal terminal kit 80/125 mm dia. (includes 1 m straight with terminal, one 90° bend, two collars and adaptor)
Vertical terminal kit 80/125 mm dia. (includes adaptor)
Extension kit 1 m x 80/125 mm dia.
90° bend 80/125 mm dia.
45° bend 80/125 mm dia.
