Specifications
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8.4 FLUE GAS EXHAUST SYSTEM.
ACK2 boilers are B
23
type appliance so the flue gases must be connected to an
adequate draught chimney, without any flue gas leakage to the boiler room.
Chimney design must be according to local codes. Chimney inside diameter, height,
material, thermal insulation, strength shall be according the flue gas specifications
and shall not cause dangerous high pressures.
0 to -0.3 mbar vacuum shall be observed at the flue gas exit of boiler.
Some informative diagrams are given for quick reference in annex
Effective chimney height is the height difference between boiler flue gas exit and
chimney end.
Flue gas ducts between boiler and chimney shall not be longer then ¼ of the
effective height but anyhow it shall not be longer then 7 m and shall not be shorter
then 0.6 m. There can be maximum two 90° elbow (avoid sharp turns)
Flue gas ducts shall not have any downward slope. It is advised to have 10° slope
upwards and enter the chimney with an angle of 45°.
8.5 BOILER WATER AND MAKE UP WATER FOR HOT WATER BOILERS
According to EN 12953-10:2003 (Shell boilers: Requirements for feed water and
boiler water quality.
Parameter Unit Make up Boiler Water Boiler water
Operating pressure Bar Total range
Appearance
-
Clear, free from suspended solids, no stable foam
Direct conductivity at 25 °C
μS/cm
< 1500
pH value at 25 °C - >7.0 9.0 to 11,5
a
Total hardness (Ca + Mg)
mmol/l
< 0,05
Iron concentration
mg/l
< 0,2
Composite alkalinity
mmol/l
-
<5
Oil/grease concentration
mg/l
<1
-
Organic substances
(as TOC)
- See footnote
b
a
If non-ferrous materials are present in the system, e.g
.
aluminum, they may require
lower pH value and direct conductivity, however, the protection of the boiler has
priority.
b
Organic substances are generally a mixture of several different compounds. The
composition of such mixtures and the behavior of their individual components under the
conditions of boiler operation are difficult to predict. Organic substances may be
decomposed to form carbonic acid or other acidic decomposition products which increase
the acid conductivity and cause corrosion or deposits. They also may lead to foaming
and/or priming which shall be kept as low as possible.