Fer FALCON II Installation, Servicing & User Instructions page 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. 13).
Holes Ø : 47 50 52
Choice of restrictor:
• With concentric pipes:
• With 2 pipe system:
FALCON II
Fig. 13
- up to 1m long + one bend, use the 52 mm restrictor.
- for flue lengths over 1 metre, use no restrictor.
- 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
N.B.: the diameter of the hole is stamped on
the restrictor
Boiler is fitted with Ø47 restrictor as
standard
13