5. FLUE
Essential requirements for a correct operation of the device:
• 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;
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 device: asbestos cement, galvanized steel,
rough and porous internal surfaces. In
gives some examples of execution.
The minimum section must be 4 dm
2
(for example 20 x 20 cm) for devices whose duct diameter is lower than 200 mm or 6.25 dm
2
(for example 25 x 25 cm) for devices with diameter greater than 200 mm.
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 device; to avoid
this, tube the flue along its whole height. A too small section causes a decrease of the draught.
ATTENTION
: as far as concern the realisation of the flue connection and flammable materials please follow the requirements provided by
UNI 10683 standard. The flue 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 devices (
5.1. CHIMNEY CAP
The draught of the flue depends also on the suitability of the chimney cap.
Therefore, if it is handicraft constructed, the output section must be more than twice as big as the internal section of the flue.
Should it be necessary to exceed the ridge of the roof, the chimney cap must assure the discharge also in case of windy weather
(
Picture 5 at page 40 - Picture 6 at page 41
).
The chimney cap must meet the following requirements:
• have internal section equivalent to that of the stack.
• have a useful output section twice as big as the flue internal one.
• be manufactured in such a way as to prevent the penetration of rain, snow, and any other foreign body in the flue.
• be easily checkable, for any possible maintenance and cleaning operation
6. VENTILATION HOOD OR ADJACENT LOCAL
The product can distribute heated air by natural convection or forced convection by means of a centrifugal fan; therefore, during installation,
it is necessary to establish the type of ventilation or convection to be adopted:
A) NATURAL CONVECTION:
To ease the natural circulation of air (upward movement due to the heating of the same) in the external enclosure of the stack, it is
necessary to remove the underlying semi-blanks (see
By choosing this convection system, it is recommended not to install the electrical fan.
B ) FORCED CONVECTION:
By installing a centrifugal fan, it is possible to distribute hot air to adjacent rooms by means of ducts with a length up to 4 meters. In this
case, do not remove the underlying semi-blanks (see
The covering of each product is equipped with 4 outputs with a diameter of 150 mm for the connection of pipes resistant to heat.
a) Perform the drilling on the walls or on the existing hood to allow the passage and the application of the (fire-resistant) hoses with a
15 cm diameter equipped with related openings.
b) Fasten the pipes by means of clamps to the related collars and openings, after having removed the semi-blanks caps.
c) Each pipe must not exceed 2 m of length for natural ventilation and 4 m for forced ventilation, and has to be insulated with insulating
materials to avoid noise and dispersion of heat.
d) The openings have to be positioned at a height not lower than 2 m from the floor to avoid that hot air at output meets people.
Please
respect the distance of the convection openings according to the local construction norms;
e) The lengths of the canalization pipes must have the same length to avoid the distribution of differing quantities of air from each
output. ( (see
).
6.1. CONNECTION TO THE FLUE / AIR FOR COMBUSTION (external air intake)
The connection to the stack must be performed with stiff pipes in aluminized steel with a minimum thickness of 2 mm or in 316 stainless
steel with a minimum thickness of 1 mm.
It is FORBIDDEN to use metallic pipes or pipes in asbestos cement since they jeopardize the safety of the fitting itself, considering
that they are subject to tears or breaks resulting in leaks of smoke
.
The exhaust pipe must be air-tight fastened to the stack and can have a maximum inclination of 45°; this to avoid excessive deposits of
condensate produced in the initial start-up phases and/or the excessive gripping of soot and moreover it avoids the slowing down of the
17
