24
Connecting to the stack
The stack plays a vital role in efficient operation of the system.
It must meet the following requirements:
• It must be made of waterproof material that is resistant to the
temperature of the flue gas and any condensate formed.
• It must have sufficient mechanical resistance and low thermal
conductivity.
• It must be perfectly airtight.
• It must be as vertical as possible and the terminal must have a
chimney cap that guarantees efficient and constant discharge of
the products of combustion.
• The diameter of the stack must not be less than the diameter at
the start of the boiler flue; for square or rectangular stacks, the
inside cross section must be 10% greater than that at the point of
connection to the draught diverter.
• Starting from the boiler, the coupling must have a vertical
section of a length that is no less than twice the diameter before
entry in the stack.
Direct discharge outside
Natural draught boilers can discharge the products of combustion
straight into the atmosphere by means of a pipe through the
perimetral wall of the building to which a draught terminal is
connected.
The discharge pipe must also comply with the following
requirements:
• the sub-horizontal part inside the building must be reduced to
a minimum (no more than 1000 mm);
• there must not be more than 2 changes in direction;
• it must be connected to a single boiler;
• the section passing through the wall must be protected by a duct that is closed at the inside end and open towards the outside;
• the final section must have a draught terminal fitted onto it and project from the building by the equivalent of at least 2 diameters;
• the draught terminal must be at least 1.5 metres above the discharge pipe fitting on the boiler (see fig. 11).
3.2.7. Air/flue gas system for forced draught boilers (BTFS)
The boiler is equipped with an automatic-reset safety device that prevents flue gas from entering the boiler room.
If the system malfunctions, this device shuts the boiler down (see 1.5.3.).
The safety device must never be tampered with or deactivated.
If the boiler shuts down repeatedly, the air intake and flue gas discharge pipes need to be checked by an Authorized
Service Centre or a qualified person as they may be blocked or unsuitable.
The manufacturer declines all liability for damage caused by wrong installation or use of the boiler, modifications or failure to
comply with the manufacturer’s instructions and installation standards.
450
7
50
Ø 130,8
229
7 mm
221
534
372
DIMENSIONS FOR CONNECTING THE FLUE GAS PIPE
FOR NATURAL DRAUGHT BOILERS
fig. 10
2 Ø min.
2 Ø min.
1,5 m min.
1,5 m min.
Ø
Ø
2
Ø
2
Ø
1 m max.
1 m max.
Pendenza
min. 3 %
Pendenza
min. 3 %
> 3
Ø
>
3
Ø
fig. 11
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