Ferroli Sigma 30 FF 41-267-07 Installation And Servicing Instruction page 16

2.07.02 Two pipe flue system
1. Utilise the pipes and fittings flows resistance tables on the following pages and calculate the total flow resistance in
metres-air, by adding the flow resistances of the components in the whole air-flue system, based on their position
(vertical or horizontal, air inlet or flue outlet).
Please note that the same fitting, identified by a one code (i.e. 1 pipe diameter 80, code KWMA83A), can offer
different flow resistances if positioned as air inlet or flue outlet, if placed vertically or horizontally.
The flow resistance of the special two pipe flue-air adapters do not have to be included in the calculation as they
are already included in the maximum length calculation.
IMPORTANT: the pipes and fittings flow resistance (reduction) have been summarised on the following page. The
flow resistance values written refer only to Ferroli pipes and fittings.
2. Verify that the total flow resistance calculated is less or equal to 50 meter for Sigma 30 and 50 and 40 meter for
Sigma 40 and 60.
3. Choose the more suitable restrictor from table below.
Tab. 3
Total flow resistance
0 - 20 metres
20 - 30 metres
30 - 40 metres
40 - 50 metres
Example of calculation for wall inlet/outlet with 2 pipe system maximum total flue length: 40 metres
Tab. 5
Ref. Description
1 Connection for concentric pipe cod. KWMR52A
2 Air/Flue T separator cod. KWMA90U
3
Male - Female flue Ø 80 mm
4
5 Flue bend 80 mm
6 Air wall terminal outlet flue Ø80
7 Air wall terminal air Ø80
Total flow resistance 17,5 m:
use restrictor Ø41
16
Sigma 30
Ø36
Ø36
Ø39
Ø39
N° of Length
pieces reduction
1
1 already included
1
Horizontal
Air
Vertical
/
1
Horizontal
Flue
Vertical
5
1
1
1
Total
Sigma
Use restrictor:
Sigma 40
Ø36
Ø39
Ø39
not possible
6
/ /
1
/
2
5
2,5
5
2
17,5
7
Fig. 37
Sigma 50 Sigma 60
Ø41 Ø41
Ø41 Ø46
Ø46 Ø46
Ø46 not possible
4
1 m
Sigma 60
3
5
5 m
4
2
1