5. FLUE
Essential requirements for a correct operation of the appliance:
•
the internal section must be preferably circular;
•
be thermally insulated and water-proof and produced with materials suitable to resist to heat, combustion
products and possible condensates;
•
not be throttled and show a vertical arrangement with deviations not greater than 45° ;
•
if already used, it must be clean;
•
observe the technical data of the instructions manual;
(1)
(2)
A+1/2A
(3)
(4)
Max.
A+1/2A
A
Should the flues have a square or rectangular section, internal edges must be rounded with a radius not lower than 20
mm. For the rectangular section, the maximum ratio between the sides must be ≤ 1.5.
A too small section causes a decrease of the draught. It is suggested a minimum height of 4 m.
The following features are forbidden and therefore they endanger the good operation of the appliance: asbestos
cement, galvanized steel, rough and porous internal surfaces. Picture 4 gives some examples of execution.
The minimum section must be 4 dm
than 200 mm, or 6.25 dm
The draught created by the flue must be sufficient, but not excessive.
A too big flue section can feature a too big volume to be heated and consequently cause difficulties in the operation of
the appliance; to avoid this, tube the flue along its whole height. A too small section causes a decrease of the draught.
The flue and the metallic pipe of connection must be properly spaced from any flammable materials or fuels
through a proper insulation or an air cavity.
It is forbidden to let plant piping or air feeding channels pass in the same flue. Moreover, it is forbidden to create
movable or fixed openings on the same for the connection of further other appliances.
1) Door for
cleaning
(1) Sportello
per
pulizia
(2) Representation of a correct flue with air-tight door
for the collection and discharge of solid unburnt
materials.
Picture 5
20
(1) AISI 316 steel flue with double chamber insulated with material resistant to 400° C. Efficiency
100% excellent.
(2) Refractory flue with insulated double chamber and external coating in lightweight concrete.
Efficiency 100% excellent.
(3) Traditional clay flue showing a square section with cavities. Efficiency 80% excellent.
(4) Avoid flues with rectangular internal section whose ratio differs from the drawing.
Efficiency 40% poor
2
(for example 20 x 20 cm) for appliances whose duct diameter is lower
2
(for example 25 x 25 cm) for appliances with diameter greater than 200 mm.
SI
YES
INSERTO 50 – 50
.
(1) The connection of more than one appliance to the
flue is not recommended.
Each appliance must have its own flue.
70 – 80 – 100
VERTICALE –
NO
Picture 6
6096801 - Rev.09 – EN
Picture 4