Keston K170 Installation And Servicing Instructions page 15

WD51/2/1997 Chapter 2 - Boiler Connections
2.8.3 Slope
Figure 2.8.2 : Flue & Air Maximum Length Example
'Horizontal' flue outlet pipework MUST slope at least 5 degrees (80 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. If a 80 mm per meter slope is not possible, contact
Keston Boilers Technical Department for further guidance.
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 2m.
These additional condensate
drains must be run to
discharge as detailed in
section 2.11. Such drain points
can be formed using standard
muPVC fittings. Refer to the
example in Figure 2.8.3.
2.8.4 Terminations
Air inlet terminals must be
facing upwards 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 will invalidate the heat exchanger warranty. The air intake terminal must
face upwards to prevent entry of rain into the air intake pipework.
The flue outlet terminal is designed to face outwards but can, if desired, be
Installation & Servicing Instructions
FLUE
d
c
Keston
To Boiler
The Keston 170 Condensing Boiler
AIR
b
a
Figure 2.8.3 :
Flue Condensate Drain
Point Example
50mm Tee Fitting
6 in min.
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