PRITY 2CF, Technical Description And Operation Instructions

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2. If there are fireproof bricks in the firebox, they must maintain their natural
colour in yellow - brown, not in black.
3. With dried logs and sufficient primary air an immediate kindling must be
achieved on each new refuelling.
4. The glass ceramics of the door (if there is any) must remain clean.
5. The gases going out of the top of the chimney must be transparent or white.
The grey smoke indicates that there is smouldering or ba d burning.
V. Chimney
The chimney is intended to draw the combustion products out of the fireplace and
to throw them away in the atmosphere beyond (outside the limits of) the abode.
The upward draught or the “pulling” of the chimney is a result of the combination
between its height and the difference in the temperatures of the flue gases and the air
outside. The column of hot flue gases in the chimney has smaller weight than the
equivalent column cold air outside, so that the pressure in the lower end in the warm
chimney is smaller than the atmospheric (air) pressure outside. This quite small
difference in the pressures creates the draught.
The lower draught is a prerequisite for difficult kindling or returning of flue gases,
and it is overcome through quick kindling and burning of dry, thin and fast - burning
sticks and paper. After kindling of the fire and warming up the chimney, its draught
increases. For economical regime and high efficiency after the warming up of the
chimney, the draught must be decreased to 5 - 10Pa, so that there may be no return of
the flue gases (smoking) with a closed door.
VI. The main causes of insufficient draught are the following:

layering of soot inside the chimney, which decreases its diameter and increases
the resistance of the rising flue gases;

a cracked wall of the chimney or a loose rosette;

loose smoke pipes, or pipes pushed deeply in the chimney, as in this way they
decrease the diameter or plug up the chimney;

The use of a single chimney with a small draught by several stoves on the same
level (in close proximity);

Smoking also appears when the weather outside has suddenly got warmer - the
warm gases from the kindling of the fire can't escape through the cold chimney.
In this case a bigger amount of quickly burning sticks and paper is used. The same
effect takes place while attempting to kindle a fire on the first (ground) floor,
provided the same or an adjacent chimney is already being used by a fireplace
on the top floor;

when the ceiling is not air - tight or there are open windows on an upper floor,
the effect «staircase - chimney» takes place, creating a reverse draught;

w hen a chimney is located in an area of overpressure caused by a wind.