TEMPRA 24
16
Fig. 16
Ø80
Ø80
AIR
FLUE
1
2
3.04 Top Outlet: Two Pipe Flue System
3.04.1 Two pipe connection
Two separate ducts Ø80 for air intake and fl ue gas discharge can
be directly connected to the boiler. For converson to top outlet
(see 3.05) mount the separate outlet kit 1
Insert blanking plate 2
in remaining air intake
Connect fl ue 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 number of accessories for two pipe systems are available from Ferroli (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.
Notes on two pipe system installation:
When using the two pipe system the fl ue discharge pipe must have a 25mm air gap when passing through
combustible materials.
Where the fl ue 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 fl ue discharge pipe passes through a wall containing cavity insulation, a non combustible sleeve must
be fi tted. Additionally a gap of 25mm between the sleeve and the insulation should be provided by cutting back
the insulation or packing loose fi ll bead insulation with mineral fi bre.
Where the fl ue pipe is run through an unheated roof space it should be insulated with non combustible insulating
material to prevent condensation. The fl ue 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
• Calculating maximum permissible flue length.
The calculation method is based on a standard reference parameter (1 metre of horizontal air fl ue 80 diameter
80) for the maximum length permissible for all the pipes + fi ttings fl ow resistance coeffi cient. In other words, for
all components and pipes in the different installation confi gurations (vertical or horizontal, air or fl ue, etc.) and
for all the fi ttings, a fl ow resistance (reduction) equivalent to
x
metre of horizontal air induction pipe is indicated.
For every boiler model a maximum pipe length is provided, expressed in
n
metres of horizontal air pipe. In
this way, to calculate the length of a proposed 2 pipe air-fl ue system, add the fl ow resistance (reduction) in
equivalent metres-air for every component and fi tting present in the system, and check that the total is less than
the maximum length permissible for the boiler model.
IMPORTANT: the pipes and fittings flow resistance (reduction) have been summarised on the following
pages. The flow resistance values written refer only to Ferroli pipes and fittings.
Calculation routine
1.
Utilise the pipes and fi ttings fl ows resistance tables on the following pages and calculate the total fl ow
resistance in metres-air, by adding the fl ow resistances of the components in the whole air-fl ue system, based
on their position (vertical or horizontal, air inlet or fl ue outlet).
Please note that the same fi tting, identifi ed by a one code (i.e. 1 pipe diameter 80, code KWMA83A), can offer
different fl ow resistances if positioned as air inlet or fl ue outlet, if placed vertically or horizontally.
The fl ow resistance of the special two pipe fl ue-air adapters do not have to be included in the calculation as
they are already included in the maximum length calculation.
2.
For the restrictors, please refer to cap. 3.02 to determinate the correct restrictor.
3.
Check that the total fl ow resistance calculated is less or equal to 48 metre, the maximum permissible
for Tempra 24.
