Fer FALCON II Installation, Servicing & User Instructions page 16

3.04 Top Outlet: Two Pipe Flue System
3.04.1 Two pipe connection
Two separate ducts Ø80 for air intake and flue gas
discharge can be directly connected to the boiler. mount
the separate outlet kit "1".
Connect flue duct to central hole Ø80 and air duct to left or right air intake hole Ø80. Insert blanking plate
"2" in remaining air intake.
A varied selection of accessories for two pipe systems are available from FER (ref. to page 17). Before installing
your system please check via calculation table at 3.04.2 you are not exceeding the maximum permissible
length for the appliance.
IMPORTANT:
Notes on two pipe system installation:
When using the two pipe system the flue discharge pipe must have a 25mm air gap when passing through combustible
materials. Where the flue discharge pipe passes through the airing space of an airing cupboard it must be protected by a
non combustible guard or expanded metal giving an annular air gap of at least 25mm.
Where the flue discharge pipe passes through a wall containing cavity insulation, a non combustible sleeve must be
fitted. Additionally a gap of 25mm between the sleeve and the insulation should be provided by cutting back the insulation
or packing loose fill bead insulation with mineral fibre. Where the flue pipe is run through an unheated roof space it
should be insulated with non combustible insulating material to prevent condensation. The flue pipe should be supported
at intervals of not more than 1.8m and the support should be preferably below a joint.
3.04.2 Two pipe flue system
To determine the maximum length of flue and air pipe permissible.
The calculation is based on a standard reference resistance of 1 metre of 80 mm horizontal air intake pipe. For every
configuration of the two-pipe system all components will have a resistance factor based upon this reference. (I.e. a 90
degree bend fitted in the flue line would attract a resistance factor equivalent to 2.5 Metres of horizontal 80mm pipe).
This is expressed as X metres. Each boiler will have a maximum equivalent length of flue/air pipe and this is shown in
the table as N metres. Therefore when calculating the proposed flue run the equivalent resistance of every length of pipe
and every bend, whether air intake or flue discharge is added together to give an actual total flue length. The final figure
calculated must not exceed the permitted maximum length (N metres) for each boiler type.
Calculation Routine
1. Identify all the components needed to complete the proposed flue/air pipe run.
2. Calculate the sum of all the equivalent lengths (see table at next page).
3. For boilers, which may require a flue restrictor, refer to table at page 13 (par. 3.02) to ascertain the correct
size and add this resistance to your total.
4. Check and verify that the total flue/air pipe length (flow resistance) does not exceed 50 mt. maximum
permitted for Falcon II.
IMPORTANT: Resistance factors apply to standard férroli components only.
16
FALCON II
Insert blanking plate 2
in remaining air intake
Fig. 18
2
Ø80 Ø80
FLUE AIR
1