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Technical documentation
Technical documentation
GAS CIRCUIT
The circuit consists of an atmospheric burner and a modulating type valve for gas combustion and
gas flow adjustment respectively.
- OPERATION
When the main coils (3) are energised, both inner valve shutters open, allowing the gas to flow
towards the burner.
The flow rate/outlet pressure is regulated by means of the gas valve stabiliser and the modulation
coil.
By means of the burner nozzles (7), the fuel is injected into the venturi pipes (ramps) inside which
the air-gas mix is obtained that is ignited by the spark from the ignition electrodes (5).
- MODULATING GAS VALVE
The gas valve (Honeywell VK 4105 or SIT 845) features two main coils and a third modulation coil
controlled by the adjustment board.
The maximum and minimum outlet pressure settings can be made on this valve (see gas
adjustments).
SIT 845
Main electrical coils (3)
Two coils of the ON-OFF type energised
(230V AC) by the board ignition circuit when
the burner has to be ignited.
In the case of the SIT 845 valve, the two coils
are electrically connected in parallel, while in
the case of the Honeywell VK 4105 valve,
these are connected in series and energised by
mains power rectified through a diode jumper
inside the connection connector (2).
Modulation coil (1)
Honeywell VK 4105
This is a low-voltage coil controlled by the
modulation circuit of the adjustment board.
This controls the gas valve stabiliser and
permits changing the outlet pressure in a way
proportionate to the signal that runs through it.
11
STNME ed 07/03
NIKE MINI
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