described case of a power cut dangerous situations can be avoided for that reason at least one of the electric control terminals of the solenoid valve 4 is connected to a first valve switch 17 a that is in the here shown example arranged in the main switching unit 14 and switches a current from a power source 12 for example the power source 12 can be a battery or can be connected to the in house mains supply to provide the energy necessary to energize the solenoid valve 4 the power source 12 can energize the solenoid once the main valve 16 is manually opened and the spark module 15 generates an electric current for the at least one igniter 10 to ignite the gas at the gas burner the solenoid is kept energized during the entire time the gas burner is in operation and is disconnected from the power source 12 when the main valve 16 at the main switching unit 15 is closed in case that a change in the conductivity across the spark gap of the igniter 10 is sensed which is indicative of the absence of a flame the current from the power source 12 can be immediately interrupted to shut off the electric current to the solenoid valve 4 as described above with reference to fig2 a and 2 b.