Flue; Chimney Cap; Connection To The Flue; Air For Combustion - La Nordica WF25 DsA Manual Del Usuario

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
The minimum section must be 4 dm
dm (for example 25 x 25 cm) for devices with diameter greater than 200 mm.
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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

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 - Picture 6).
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

CONNECTION TO THE FLUE

The connection to the stack must be performed with stiff pipes in steel comply with all current Standards and Regulations and to those
envisioned by the law.
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 smokes at output.
The failed tightness of the connection can cause the malfunction of the device.
The internal diameter of the connection pipe must be equal to the external diameter of the smokes stub pipe of the device. This is
assured by the pipes complying with DIN 1298.
For a better working of the appliance, it is suggested to have a flue draught of 17-20 Pascal (=1.7-2 mm of column of water).
The measurement has always to be carried out with hot device (rated thermal performance).
When the depression exceeds 20 Pa (=2 mm of column of water), it is necessary to reduce the same by installing an additional
draught regulator (butterfly valve) on the exhaust pipe or in the chimney, according to the regulations in force.
IMPORTANT: When using metallic pipes, they must be insulated with proper materials (coatings in insulating
fibers resistant up to 600°C) in order to avoid deterioration of walls or of the counter-hood.

AIR FOR COMBUSTION

It is necessary to ventilate continuously the space included between the upper part, the sides of the device and the deflector of the
fire-proofing material of the hood.
For this reason, it is necessary to foresee an intake of air from the bottom (intake of fresh air) and a high output (output of hot
air). The spaces foreseen for the circulation of air indicated in
Picture 3 gives some examples of execution.
(for example 20 x 20 cm) for devices whose duct diameter is lower than 200 mm or 6.25
2
Picture 7
Top: Minimum opening 800 cm
Base: Minimum opening 600 cm
ENgLIsH
(Picture
- Picture 14 represent the minimum requirements:
2
2
4).
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