25
Standard Horizontal Flue
10 Standard Flue - Length, Preparation and Installation
Diagram 10.11
14007
14006
10.6 Flue Length
The maximum permissible horizontal ue length is 8 metres
plus the ue terminal assembly, this can be achieved by use
of the accessories, see diagram 10.13.
However should additional 87.5º or 2 x 45º elbows be used
then the length MUST be reduced by 1metre.
The diagram 10.11 shows the length achievable by using the
kit A2043400.
When extension pipes are used the ue system must be
designed to have a continuous fall to the boiler of at least 2.5º
44mm/metre to allow condensate to run back into the boiler
and out via the condensate drain.
The ue can be installed from inside the building, when
access to the outside wall face is not practicable.
Multiple Boiler Chimney Flue Length
The ue length must be calculated and installed according to
the relevant standards EN 13384-1 and 2 (C43 ue systems
only) with reference to the table below and the manufacturers
instructions supplied.
The appliance maximum ue length must be included when
calculating the overall design of the ue system.
NOTE: The horizontal ue terminal must be removed, see
diagram 10.12.
MODEL 18sx 30sx
Exhaust mass rate (g/s)
At Min Thermal
Load (40C°/30°C)
4.26 4.26
At Max Thermal
Load (80C°/60°C)
8.24 13.95
Exhaust temperature (ºC)
At Min Thermal
Load (40C°/30°C)
33.2 33.2
At Max Thermal
Load (80C°/60°C)
63.0 87.4