ADI LT boiler – Technical manual
Page
12
8.1 ASSEMBLY OF GAS CONNECTION – AIR-GAS INLET
The ADI LT boiler includes an air-gas premix system of modulating combustion, composed of:
1
B
8-9
2
6
6b
6a
7
15
Pa
5
13
Pg
10
V.
Venturi operating as an air-gas mixer, ensuring combustion with a constant proportion of air/gas to
the premix burner, throughout its power modulation range.
The venturi produces a depression and drives the gas (G) towards the gas valve outlet (VV).
It operates as an additional safety: if there is no air inlet, there will be no gas admission.
VV.
The multiblock gas valve regulates the gas outlet pressure according to the pressure value in the
venturi.
Note: (13) in models LT 250 and higher: a coupling pipe between the multi-block gas valve and the venturi
measures the pressure drop before the mix. For lower models there is no pipe, the connection between the
multi-block gas valve and the venturi is internal.
M.
The power modulation is realized by varying the fan speed, which also produces a variation of
the air-gas mix flow entering into the burner (B).
Pg.
Minimum inlet pressure switch: adjusted at 15 mbar.
Pa.
Air pressure switch: safety of operation, in case of obstruction of the air inlet,
the motor-fan stops.
In Models ADI HT 105 to 200 these pieces form one only
global group: burner, burner-holder plate, motor-fan, venturi
and multi-block gas valve.
