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9 CONCENTRIC FLUE SYSTEM
The concentric flue system is composed of an inner flue and
an outer flue. These flues have been set up concentrically so
the combustion gases will be discharged via the internal flue
while the fresh combustion air is supplied via the gap between
the inner and outer flues.
9.1 Components of the concentric
flue system
Different connections are possible using the concentric flue
system. These are:
Through the roof face and through the exterior wall
The pathway used for this system can be laid in different ways,
but there are a few important conditions:
•
The total allowed vertical flue length must not exceed
9 metres (the sum of the flue length and calculation lengths
for the bends).
•
90° bends have a 2-metre horizontal calculation length.
•
45° bends have a 1-metre horizontal calculation length.
•
The outlet can be installed at any point on the roof face or
exterior wall (supply and discharge in an identical pressure
area), but must meet applicable regulations.
•
Flue pathways must not be insulated.
NOTE
Ensure the restriction plate is mounted in the correct
manner, as indicated in these instructions.
The correct restriction plate will provide the unit with the
most optimal efficiency, flame image and combustion.
Mounting an incorrectly placed restriction plate may cause
malfunction of the unit.
9.2 Indirect/direct façade connection
if applicable
See Chapter 8
The outlet may also be installed above the exhaust in the
wall, taking any hindrance to the surrounding area into
consideration, in accordance with national, regional, local
standards and regulations.
NOTE
Ensure wind pressure on the outlet is not excessive,
such as in locations with a balcony, flat roof, corners and
very narrow alleys, etc., as this can negatively affect the
performance of the unit.
•
Make a recess in the façade of around 155mm when
using Ø100-150 flues (keep an extra space of 50mm in
a refractory façade around the outer tube) and fit the façade
pass-through with the wall plate on the inside of the wall.
The wall plate of the exterior façade pass-through must be
sealed sufficiently against the wall on the outside to avoid
moisture and/or flue gas leaks leaking into the living space.
We recommend our clearance box use as a direct façade
pass-through through a refractory façade.
•
The flue should be encased if necessary. Even if the flue
is to be installed along non-refractory materials, sufficient
fire-resistant measures must be taken.
•
Determine the position of the unit and outlet and begin
construction of the flue with the connection on the
unit, paying attention to the direction of installation and
connecting the elements by means of clamp strips.
•
The fitted pipe can be used between the bends or when
connecting to the unit. If necessary, use wall brackets
to support the flue.
Mounting using the roof pass-through option
•
The flue outlet can be located at any random place on the
roof face (supply and exhaust in identical pressure areas)
and must meet the applicable rules and regulations.
•
A roofing sheet for a flat roof or a roofing sheet lead for
sloping tiled roofs can be used for a watertight duct. Use
various bends for the slope, if required. The recess in the
roof decking should be 5cm larger all around to ensure
sufficient fire resistance.
•
One needs to take into account the regulation regarding
fire resistance between rooms (See national, regional, local
standards and regulations). A casing of fireproof material
(for example, 12mm Promatect fire-resistant plate) should
be applied up to 25mm from the outer flue.
•
Determine the position of the unit and the outlet and begin
the construction of the flue with the connection on the unit
(always 1 metre vertical first) pay attention to the direction
of installation. The inner flue must be installed for draining
purposes. Connect the elements using the clamping straps.
Ensure all connections are gastight.
•
A fitted pipe can be used between the bends or when making
the connection to the unit and/or the roof pass-through. Use
2 wall brackets to support the flue on each floor.
9.3 Installation instructions regarding
existing flues
See Appendix 2
Instructions
The flue gas exhaust system falls within category: C91 and
must be built in accordance with national rules and regulations
and the instructions of the manufacturer, as specified in the
documentation and installation instructions.
This means, among other things, that the chimney pass-
through must not be smaller than 150mm round/square,
but no larger than 200mm, and not ventilated by grilles, etc.
In the case of larger chimney pass-throughs, a flexible hose of
around 150 mm may possibly be used in combination with a
flexible hose of around 100mm, as described below. For other
situations, consult your supplier/manufacturer.
9.4 Parts
Check all parts for damage before commencing the
installation. For the conversion of a brick flue to concentric
flue, connected to CC flue system, you need the components
described in Appendix 2.
NOTE
The renovation kit consists of parts:
4
Interior mounting plate
5
Sliding element
8
Chimney mounting plate
