eta PE-K 35, Руководство по установке

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11 PE-K installation 35 to 90 kW
2012-02
Chimney Dimensioning, requirements
Obsolete regulations require
the wrong chimney
Laws and regulations demand a fl ue system that is
moisture-resistant for oil and gas and one that is
resistant to soot fi res for solid fuels.
Wood is a solid fuel. But in the lower output range,
the temperature of the fl ue gas can be under
100°C
and condensates can be deposited in the chimney.
So the chimney must be moisture-resistant, "against
regulations". Whoever builds a chimney resistant
to soot fi res can then look on helplessly as the
condensate destroys the chimney wall.
Soot fi res are possible in natural-draught boilers or
wood-burning stoves regulated by throttling the
air supply. When the wood fi re is at full intensity
and the boiler temperature has been reached,
a thermostat closes the air fl ap. That stops the
combustion, but since the combustion chamber
temperature doesn't fall, the wood continues to
gasify. Uncombusted wood gas condenses to tar in
the chimney; the tar can be ignited by sparks from
the fi re.
With modern lambda-controlled wood boilers, such
a soot fi re is nearly impossible since the control
system reduces the wood gasifi cation and not the
air. In modern lambda-controlled pellet boilers,
the control system shuts down the fi re by stopping
the pellet supply without closing off the air supply.
So there is no lack of air and no fl ammable tar in
the chimney. The low exhaust temperatures of a
modern boiler also provide no ignition source for a
soot fi re. With a modern and properly maintained
wood boiler, there is no danger to chimneys from
soot fi res.
Moisture-resistant W3G fl ue systems
Since 2005 there are W3G chimneys (classifi ed
according to the German DIN 18160), which are
resistant to both moisture and soot fi res. These
chimneys are approved for all fuels. Most of these
W3G chimneys have ceramic inner pipes, which
have a signifi cantly longer service life than metal
chimneys due to their acid resistance.
Small chimney diameter required
Please note that for partial-load operation with fl ue
gas temperature of only
100°C , the large chimney
cross sections that were previously typical for solid
fuel are no longer optimal. If the cross section is too
large, the fl ue gas is no longer certain to rise from
the chimney opening and may fl ow along the roof
and sink to the windows of the living quarters.
INSERT TABLE!
Normally no defl agration damper
The boiler is designed with safety routines in the
control system to prevent defl agrations, so no
defl agration damper (also often called a blowback
fl ap) is required if the connecting pipe is short and
ascends to the chimney. If a defl agration damper is
needed at high points before descending sections
or at the beginning of a long horizontal section
(L > 30 x D), it must be situated so that people are
not endangered by a defl agration.
Dimensioning, requirements
Height
above
boiler
room
floor
Chimney diameter in cm
(required minimum diameter)
35 kW 50 kW 70 kW 90 kW
6 m 20 cm 20 cm* 22 cm 22 cm
7 m 18 (16) cm 20 cm 22 cm 22 cm
8 m 18 (15) cm 18 (16) cm 22 cm 22 cm
9 m 18 (15) cm 18 (15) cm 20 (18) cm 20 (18) cm
10 m 16 (14) cm 18 (15) cm 20 (18) cm 20 (18) cm
11 m 16 (14) cm 18 (15) cm 20 (18) cm 20 (18) cm
12 m 16 (14) cm 18 (15) cm 20 (18) cm 20 (18) cm
Values on grey background:
Connection from boiler to chimney with
same cross-section as chimney.
*) For boiler outputs over 30 kW and low chimney
heights, a chimney joint tilted 45° can help achieve
the required draught of 5 Pa at full load with
acceptable cross-sections (a size smaller than indi-
cated in the table).