46
925.224.3 - EN
INSTRUCTIONS PERTAINING TO THE INSTALLER
… SEPARATED FLUE-AIR DUCTING
This type of ducting allows to disengage exhaust flue gases both outside the building and into single flue ducts.
Comburant air may be drawn in at a different site from where the flue terminal is located.
The splitting kit consists of a flue duct adaptor (100/80) and of an air duct adaptor.
For the air duct adaptor fit the screws and seals previously removed from the cap.
The restrictor must be removed in the following cases
(*) The first 90° bend is not included in the maximum available length.
The 90° bend allows to connect the boiler to flue-air ducting regardless of direction as it can be rotated by 360°. It can
moreover be used as a supplementary bend to be coupled with the duct or with a 45° bend.
• A 90° bend reduces the total duct length by 0.5 metre.
• A 45° bend reduces the total duct length by 0.25 metre.
Split flue air control adjustment
The adjustment of this control is required
to optimise performance and combustion
parameters. The air suction coupling can
be rotated to adjust excess air according
to the total length of the flue and intake
ducts for the combustion air.
Turn this control to increase or decrease
excess combustion air (figure 9):
To improve optimisation a combu-
stion product analyser can be used to
measure the CO
2
contents of the flue
at maximum heat output, gradually
adjusting air to obtain the CO
2
reading
in the table below, if the analysis shows
a lower value.
To properly install this device, also refer
to the technical data accompanying the
fitting.
Figure 9
0604/2301/CG1776
Flue duct adaptor
Seal
Air suction coupling
adjust
Index
Opening
Boiler
model
(L1+L2)
Air suction
copupling
position
Flue
RESTRICTOR
A
CO2 %
G20
G31
240 Fi
1.240 Fi
0 ÷ 4
3
Yes
6,4
7,3
4 ÷ 15
1
No
15 ÷ 25
2
25 ÷ 40
3
280 Fi
310 Fi
1.310 Fi
0 ÷ 2
1
No
7,4
8,4
2 ÷ 8
2
8 ÷ 25
3
