Ferroli F24
13
3.02 Restrictor
For boiler operation, the restrictor supplied with the unit must be mounted following the instructions below.
Determine the correct size of flue restrictor required. Before inserting the flue gas duct in the boiler, check that
the restrictor fitted is correct and that it is correctly positioned (see fig. 14).
Ø
Fig. 14
CHOICE OF RESTRICTOR:
RESTRICTOR FOR TWO PIPE SYSTEM
Total flow resistance
of flue system
Use
restrictor
size
minimum
maximum
mm
0 m
13 m
45
13 m
23 m
47
23 m
38 m
50
38 m
48 m
No restrictor
• With concentric systems:
- Choose correct restrictor from table below.
• With 2 pipe system:
- Calculate the total flow resistance of the air and
flue pipes in metres (cap. 3.04.2)
- utilise the table shown below to choose the more
suitable restrictor for the flow resistance calculated
RESTRICTOR FOR CONCENTRIC SYSTEM
Flue lenght up to:
Use
restrictor
size
Ccncentric
60 / 100
1 bend + 1 meter
50 mm
1 bend + 3 meters No restrictor
Ccncentric
80 / 125
1 bend + 3 meters
45 mm
1 bend + 4 meters
50 mm
1 bend + 5 meters No restrictor
N.B.: the diameter of the hole is
stamped on the restrictor
No restrictor is required for
back outlet fl ue
