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TECNIKA 28-35
USE AND INSTALLATION MANUAL
Chapter
4
page 17
Installing
Technical dept. - All rights reserved - Reproduction prohibited
4.3.
Connection to the flue pipe
For the connection of the flue outlet pipe, local and national regulations must be observed (see Standards
UNI 7129 and UNI 10683).
A flue pipe must comply with the following requirements:
It must be made of waterproof material resistant to the temperature of the smoke and related
condensation.
It must ensure sufficient mechanical resistance and weak heat conductivity.
It must be perfectly sealed, to avoid the cooling of the flue pipe itself.
It must be arranged as vertically as possible.
Chimneys both old and new, built without observing the above specifications, may be conveniently
recovered by "intubating" the chimney itself. This means a metal flue shall be inserted inside the
existing chimney and the space between the metal flue and the chimney shall be filled with suitable
insulation.
In order to prevent the wind from creating pressure areas around the chimney that prevail over the
rising force of the combustion gases, the outlet aperture must be positioned at least 0.4 metres
above any structure adjacent to the chimney itself (including the ridge of the roof) at least 8 metres
away.
The flue pipe must have a diameter of no less than the boiler union; for flue pipes with a square or
rectangular cross-section, the internal cross-section must be increased by 10% compared to the
boiler union.
The useful cross-section of the flue pipe can be calculated using the following formula:
S
= K x P/
√
H
S
ensuing section in cm
2
K
reduction coefficient:0.045 for wood
P
boiler output in kcal/h
H
height of the chimney in metres, measured from the flame axis to the outlet of the chimney into
the atmosphere. When sizing the flue pipe, please take into account the actual height of the
chimney in metres, measured from the flame axis t the top, decreased by:
0.50 m for every change in direction of the union duct between the boiler and the flue pipe
1.00 m for every metre of horizontal development of the union itself.
We recommend the sole use of outlet ducts which are suitable for the
type of fuel used. The supplier will not be held in any contractual and
non-contractual way liable for damage caused by installation and
usage errors and in any case due to failure to observe the instructions
provided by the manufacturer of the appliance.
The products of combustion of the boiler cannot be discharged in
collective flue ducts.
The correct installation of the flue duct is necessary to encourage the
normal flow of smoke from the combustion chamber to the outside in
the event of an electrical power failure.
Remember that a draught of 20 Pa must be guaranteed.
