Installing Flue And Air Pipes - Keston 50 - GC Installation And Servicing Instructions

WD50/2/1997
Combustion air filters are fitted to the Keston condensing boilers as standard. This
filter must be examined at least once every year, and more often in particularly
dusty and dirty areas.
The combustion air filter will prevent plugging of the burner caused by dirt being trapped
in the burner's outer mesh. The filter element supplied with the boiler is obtainable from
Keston Boilers or its distributors.
3.4

INSTALLING FLUE AND AIR PIPES

Remember the flue pipe must slope downwards back towards the boiler and this is best
achieved using 92.5
a
b
3.4.1
3.4.2
3.4.3
Installation & Servicing Instructions
Chapter 3 : Installation
o
bends.
From the two connections on the boiler, mark the positions of the two holes for
the flue and air pipes on the wall(s) or ceiling. To allow access to drill the holes it
may be necessary to temporarily remove the boiler. If the boiler stays put then it
is imperative that the front panel and top access plate are replaced and the two
plastic pipes capped off whilst drilling. Under no circumstances must debris from
the wall or cut pipes be allowed to enter the appliance or the plastic pipework.
Drill the two holes in the wall/ceiling, preferably using a core drill.
Diameter of holes.
i) Allowance must be made for
socketed lengths if these are
to be passed through the
holes :
du = unsocketted
diameter
= 43 mm
ds = socketed
diameter
= 50 mm
ii) For 'horizontal' runs of flue
pipe the holes must either be
oversized or cut at a 5
(the latter may be difficult on
long holes).
Oversizing
For every 1m length of run, L, the minimum diameter of the horizontal hole, D,
must be du + 10 mm or ds + 10 mm respectively, assuming the pipe touches the
wall at points T otherwise D will have to be increased by clearance from T. See
Section 3.4.3 - Examples.
Examples
a. Wall Depth
Unsocketted pipe
Diameter hole D
Page : 19
The Keston 50, 60 & 80 Condensing Boilers
T
D
o
slope
Flue Pipe
L = 750 mm
du = 43 mm
= 43+{(
= 43+7.5
= 50.5 mm
L
750
/ )X10}
1000
T