3.8.3
Slope
‘Horizontal' flue outlet pipework MUST slope at
least 2 degrees (35 mm per metre run) downwards
towards the boiler. Pipework can be vertical. Only
swept elbows can be used.
Air inlet pipework can be truly horizontal or vertical,
or sloping in a downward direction towards the
boiler but in this case rain, etc., must be prevented
from entering the pipe.
There must be no troughs in any of the
pipework, whether it be air inlet or flue outlet.
Due the low temperature of the flue gases further
condensate will form within the flue system. Drain
points, with suitable traps, must therefore be
incorporated within the flue system at the base of
vertical flue sections in excess of 6m, for 50mm
muPVC pipe flue systems. These additional
condensate drains must be run to discharge as
detailed in section 3.11. Such drain points can be
formed using standard muPVC fittings. Refer to the example in Figure 3.8.3.
3.8.4
Terminations
Air inlet terminals must be facing horizontally or downwards to prevent entry of rain into
the terminal and positioned to ensure only fresh air is drawn into the boiler. The air
terminal must be located outside of the building.
Drawing of combustion air directly from a ventilated boiler room invalidates the heat
exchanger warranty.
The flue outlet terminal is designed to face outwards but can, if desired, be adapted to
face in any direction BUT must not be directed in the region of the air inlet. The flue
terminal and air inlet terminal can be located on different, but not opposing wall faces.
The two terminals are subject to the requirements of BS 5440 Pt 1 for clearances from
features of the building although some can be decreased to the values indicated.
The Keston C36 Combi and C36P Combi, as with any condensing boiler, will
generate a condensate “plume” from the flue terminal in all weather conditions.
Consideration must therefore be given to the effect of this “plume” when selecting
a location for the flue terminal. It is the responsibility of the installer to ensure the
selected terminal location does not cause nuisance.
300
300
L Horizontally from terminal on same wall.
1,500
1,500
K Vertically from terminal on same wall.
100
1,200
J From opening in a car port.(not recommended)
1,200
1,200
I
From terminal facing a terminal.
100
600
H From surface facing a terminal *
100
200
G Above ground or balcony or roof.
50
200
F From internal or external corner.
50
75
E From vertical drain or soil pipes.
50
200
D Below balconies or car port roof.
50
200
C Below eaves.
75
75
B Below gutters, soil pipes, drain pipes.
50
300
A Below or beside openable window, air brick,
etc.
Air
Inlet
Flue
Terminal
Dimensions (mm)
WD388/0/2004 Chapter 3 : Boiler Location
The Keston C36 Combi & C36P Combi Boilers
Installation & Servicing Instructions
Page : 17
6 in min.
Figure 2.8.3 :
Flue Condensate Drain
Point Example
Tee Fitting
To Boiler
T
o
T
e
rm
in
a
l
