MCZ Omega '05 - Manual (Page 17)

PELLET STOVES Chapter 2
INSTALLATION AND USE MANUAL page
16
Theoretical notes for installation Technical service – Rights reserved MCZ S.p.A. – Reproduction prohibited
EN
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It is compulsory to check that an anti-wind chimney has been installed,
in accordance with current standards.
This type of connection ensures the evacuation of the
fumes even in the event of a temporary power cut.
2.10. OPERATING ABNORMALITIES DUE TO FLUE
DRAUGHT PROBLEMS
Of all the meteorological and geographical factors which affect the
operation of a flue pipe (rain, fog, snow, altitude a.s.l., exposure to
sun, exposure to cardinal points, etc.) the wind is undoubtedly the most
important one. In fact, apart form the thermal difference caused by
the temperature difference inside and outside the chimney, there is
another kind of pressure difference: the dynamic pressure caused by
the wind. Updrafts always increase the depression and hence draft.
Horizontal wind increases draught if the chimney has been properly
installed. A downdraft always decreases the depression, at times
inverting it.
Besides the direction and force of the wind, the position of the flue and
the cowl with respect to the roof of the building and the surrounding
landscape is important.
The wind also indirectly affects the operation of the fireplace, creating
high and low pressure areas not only outside but also inside dwellings.
In rooms directly exposed to the wind (2) a high pressure area may be
created which may favour the draught of stoves and fireplaces, but
which may be contrasted by high external pressure if the chimney is
exposed to the wind (1). On the contrary, in rooms opposite to the
direction of the wind (3) there may be a dynamic low pressure area
which competes with the natural thermal depression in the fireplace,
which may however at times be compensated by placing the smoke
duct on the side opposite from the wind (4)
IMPORTANT !
The operation of the pellet stove is noticeably
sensitive to the conformation and position of the flue
which is adopted.
Hazardous conditions can only be overcome by
suitable setting-up of the stove carried out by
qualified MCZ personnel.
Least favorable position Most favorable position
WIND
Down draft
Pressure area Depression area
45° down draft at 8m/sec. High
pressare of 17 Pa
Horizontal wind 8m/sec.
Depression of 30 Pa
1
2 3
4
1-2 = High pressure area
3-4 = Low pressure area
WIND