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4.7
AIR FLUE DUCT INSTALLATION
4.7.1
PREPARING THE AIR/FLUE DUCTS
20
MEASURING THE EXACT FLUE LENGTH
21
AIR/FLUE DUCT ASSEMBLY
If the wall thickness is less than 800mm (31 in) the air/flue duct
may be fitted without access to the external wall providing that the
optional wall liner is used. (This is necessary to seal any cavity and
to allow the sealing ring to pass through from inside but still open
and provide an adequate seal). The wall liner is a tube diameter
130mm with a wall thickness of 0.8mm.
a)
Measure the required flue length as shown in Figure 20. Refer
to section 2.5 to determine whether any extension kits are
required. Installations using only the standard ducts or
standard ducts with straight extensions are described in this
section. Installation instructions for all other flue systems are
described in the supplements at the rear of this booklet.
b)
Fit the external sealing ring to the terminal assembly and
assemble the air/flue ducts as shown in Figure 21. The
standard duct is always used at the entry / exit to the boiler,
and the sliding (telescopic) terminal is always slid into the end
of the standard or extension duct (where appropriate).
c)
Achieve the correct flue length using Figure 22 as a guide.
Note that the flue length is measured to the inside of the
external wall sealing ring. In most cases it will be possible to
achieve the required flue length without cutting the ducts,
however where necessary the plain ends of the extension ducts
may be cut.
Never cut the swaged end
, and always
ensure that the cut is square and free of burrs or debris. The
minimum overlap of the telescopic section is 50mm (2 in).
d)
Assemble the flue using Figure 23 as a guide. It is important
that the steps are carried out in the order stated in Figure 23.
When securing the ducts in position always drill two 3.3 mm
diameter holes in each extension air duct joint and use the self
tapping screws provided to secure each joint.
NOTE IT IS ESSENTIAL THAT THE TERMINAL IS FITTED THE
CORRECT WAY UP See Fig 21 (i.e. rainshield at the top).
•
•
STANDARD DUCT
Fits Outside Elbow
•
EXTENSION DUCT(S)
Fits Over Duct
•
STANDARD
TERMINAL
Fits Inside Duct
•
EXTERNAL SEALING
RING
•
TOP
FAN OUTLET
EXTERNAL
Dia. 60mm
•
TOTAL FLUE LENGTH FROM
FLUE OUTLET CENTRE TO
OUTSIDE WALL FACE:
= LENGTH
L
WALL
L
•
•
•
•
15
Ensure the “O” ring
(fitted in the flanged
end of the flue elbow
only) is located correctly.
