Gas Valve - Immergas VICTRIX 50 Manual

Technical Documentation
Air-gas circuit.
The circuit consists of a total pre-mix combustion system
comprising a fan (7), a pneumatic type gas valve (9), a Venturi
pipe (5) and a special cylindrical burner (4) that works inside
the condensation module.
Operation.
The fan (7) is controlled by the microprocessor driven p.c.b.
that varies speed according to the output required.
By means of this fan, combustion air is taken from the draught
diverter (3), which is in contact with outside and sent through
a duct where a Venturi pipe (5) is installed.
A positive pressure signal (P1) is located at the Venturi (5) inlet
and varies in a way directly proportional to the quantity of air
extracted by the fan (7) and which is detected by means of a
pressure point connected to the pneumatic gas valve (9).
The energising of the main valve coils causes both internal
shutters to open and the gas to flow through, whose outlet
pressure is regulated by the same pneumatic valve with a 1:1
ratio at pressure "P1".
Through nozzle (6), gas is injected at the inlet of the Venturi
pipe (5) where pre-mixing begins with the combustion air.
The resulting mix is ignited on the cylindrical burner surface
(4) by a spark of the ignition electrodes (10).
STV50 ed 09/08
Technical Documentation

Gas valve.

The gas valve features two main coils controlled by the inte-
grated board and a pneumatic control unit that modulates the
exiting gas pressure at a 1:1 ratio at pressure (P1) detected at
the Venturi pipe inlet.
The ratio between air and gas pressures (off-set) are set on this
valve (see gas regulations).
Electrical coils (4).
Two ON-OFF type coils that are powered by the integrated
board (24 V DC) when the burner has to be ignited.
They are connected in series and energised at a voltage of 24
V through a connector (3).
Pneumatic unit (2).
Outlet pressure can be varied with this unit at a 1:1 ratio at
pressure (P1) detected at the Venturi pipe inlet which is re-
turned to the valve through a silicone pipe (1).
Thanks to this system, the percentages in the air-gas mix remain
constant at optimum values on the entire modulation field thus
ensuring an almost constant combustion performance.
By means the off-set screw (2) the air-gas ratio can be adju-
sted.
This is only necessary if, after having analysed the flue,
incorrect combustion values are found (see air-gas ratio ad-
justment).
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VICTRIX 50 Rev. 002