Kostrzewa Mini Bio Luxury 12kW, User Manual, Page: 47 / 212

47
Mini Bio Luxury 12; 21kW
User Manual – EN 10.17
Leader in pellet boilers
4. Design guidelines
e. Flue system installation guidelines
THE FLUE SYSTEM MUST CONFORM TO THE RELEVANT
STANDARDS AND REGULATIONS.
The flue system removes flue gas from the boiler room to the atmosphere.
The flue system creates draught determined by:
•
temperature gradient between the flue gas temperature and the
ambient temperature (difference in density and pressure)
• flue length
• flue shape (bends, inclination, draught breaker etc.)
• flue cross section
• flue diameter (flue diameter must correspond to the boiler’s flue
connector diameter)
• flue internal surface roughness
• flue flow capacity
• flue gas tightness (seals, grouts etc.)
• flue thermal insulation
• changes in ambient conditions (temperature, pressure fluctuations due
to the air flow, roof shape, flue location in relation to building envelope
components etc.)
The diameter of the duct connecting the boiler with the flue must correspond
to the diameter of the boiler’s flue connector. Do not use any reducing couplings
of the boiler’s flue connector or the flue. Any transition between the flue and
the duct may include a tee with a correct combination of diameters. The flue
design must guarantee that the flue gas temperature at the entire flue length
to the outlet is higher than the dew point of the flue gas from the boiler
(dry operation). The flue and the smoke ducts must be fitted with drains or
inspection holes with sealed doors and in case of wet flue gas also with a
condensate drain valve.
Guidelines:
• in the lower range of EEI Pellets 12 power, the flue gas temperature may
fall below 100°C, the boilers must be connected to the moisture resistant
flues (acid proof liners - steel sheet, vitrified clay recommended); if the
boiler is not connected to the moisture resistant flue, perform required
calculations or use the existing flue data;
• the connection between the boiler’s flue connector and the flue must be
insulated and as short as possible, slightly upwards without sharp bends
and a minimum number of bends.
• the smallest diameter or cross section of a natural draught flue and
a smoke duct must be at least 0.14 m, whereas the smallest diameter
must be at least 0.12 m if steel liners are used;
• horizontal flue duct length must not exceed the effective flue
height or 7 metres
Tip:
Connect the flue ducts without any loads and stresses
•
seal the flue duct
• the flue must be opened upwards and lead horizontally at least 1 metre
over the roof surface (with a rain cap)
• flue diameter must be selected in accordance with the flue liner
manufacturer’s requirements
• estimate cross sectional area of a circular flue is calculated using
Redtenbacher’s equation:
A = 0,026 [cm
2
]
where:
A
= flue cross section area [cm 2 ];
Q
= boiler heat output [W];
h
= flue height [m];
CAUTION!
THE INSTALLED FLUE SYSTEM REQUIRES COMMISSIONING
AND INSPECTION OF THE FOLLOWING:
· FLOW CAPACITY
· GAS TIGHTNESS
· DRAUGHT
• CORRECT FLUE GAS SYSTEM CONNECTIONS
AND CONFORMITY WITH THE DESIGN
• STANDARD HEIGHT ABOVE THE ROOF
• MEETING ENVIRONMENTAL PROTECTION STANDARD REQUIREMENTS
• INSTALLATION CONFORMITY WITH THE DESIGN
AND AS-BUILT DOCUMENTATION
• VALID CERTIFICATES FOR STRUCTURAL, INSULATION
AND MOUNTING MATERIALS USED FOR INSTALLATION
The device has to be commissioned by authorized personnel with a report.
Q
k
[W]
√h [m]