Flue System - Keston 30C Installation And Servicing Instructions

9

FLUE SYSTEM

Note. When installing a replacement boiler a new flue
system must be used. Do not re-use the existing boiler flue
installation.
DESIGN
Individual air supply and flue outlet pipes are used as
standard, although a concentric flue kit is available as an
optional extra.
The material used for flue outlet &/or air inlet must be
muPVC (PVC-C) to BS 5255 and/or BSEN 1566-1 and BSEN
1329 of an internal diameter of 51mm. (i.e. nominal 50mm
diameter muPVC solvent weld waste pipe).
Marley muPVC (PVC-C) Solvent Weld Waste System
(50mm) and Polypipe System 2000 muPVC (PVC-C) solvent
weld waste (50mm) are the only systems approved for this
application.
The following pipes and fittings are approved:
Polypipe System 2000 muPVC solvent Weld Waste System (50mm)
Poly Pipe Code
MU 301 4m length muPVC wastepipe 5/225
MU 313 50mm x 45 deg muPVC obtuse bend
MU 314 50mm x 92.5 deg muPVC swept bend
MU 310 50mm muPVC straigh coupling
MU 316 50mm x 92.5 deg muPVC swept pipe
Marley muPVC solvent Weld Waste System (50mm)
Marley Code
KP 304 50mm x 4m double spigot pipe
KP32 50mm x 45 deg bend
KSC3 50mm straight coupling
KB3 50mm x 88.5 deg bend
KT3 50mm swept tee
Both the 50mm flue outlet
terminal and the 50mm air inlet
terminal are supplied with the
twin flue box (pack 2b) and are
illustrated in Fig. 1 and must be
used in ALL installations. (Both
terminals are identical).
When the flue and air terminals are
located within 500mm of each other
ensure that the air terminal is
pointing towards the ground using
a 90º bend and one of the 100mm
sections of pipe provided within
pack 2a.
Keston 30C -
Installation and Servicing
INSTALLATION
MAXIMUM LENGTHS
The maximum lengths of both air inlet pipe and flue outlet pipe,
when no bends are used, are as detailed in fig.2b.
However, each bend used has an equivalent length that must be
deducted from the maximum straight length stated in fig. 2b.
Knuckle bends must not be fitted.
A 92.5º swept elbow is equivalent to 1.0m straight length. A 45º
bend is equivalent to 0.5m straight length.
It is possible to have variable flue and air lengths as detailed
below.
Fig. 2b
Example (assuming 50mm muPVC flue and air pipework)
Air inlet uses two 92.5º swept elbows. Hence, maximum length
permissible (i.e. a+b in fig. 2a) = 22m - 1m - 1m = 20m.
Flue outlet uses one 92.5º swept elbow. Hence, maximum
length permissible (i.e. c+d in fig. 2a)= 22m - 1m = 21m).
But maximum total flue and air intake must not exceed 19m in
the examples above.
Boiler Output Vs Flue Length
Due to the resistance presented by extended flue length a slight
reduction in maximum boiler output will occur where combined
flue and air lengths in excess of 16.0m (50mm muPVC) are
Fig.1
used. In such cases the boiler output will be reduced by 1.0%
per additional metre.
Fig.2a
FLUE
d
c
KESTON 30C
Maximum Combined Flue & Air Intake Lengths
Air Inlet
Flue Outlet
Total Flue & Air Intake
(does not include allowance for elbow on top of boiler)
AIR
b
a
Flue Box
21m
21m
22m
17