shown in fig2 the activator may also comprise a control device 60 that acts on the switch 61 when a predetermined time equal to or greater than the time necessary for the incandescent element 1 to reach the gas combustion temperature has elapsed the switch 61 allowing the activation coil 42 to be powered this guarantees that the valve 3 opens when the incandescent element 1 has reached the gas combustion temperature the control device 60 acts on the switch 61 preferably by means of an activation pulse the switch 61 allowing the activation coil 42 to be powered only during the activation pulse given that the additional coil 41 may keep the valve open by itself in addition if the incandescent element 1 breaks down for example the additional coil 41 is no longer powered and as power is prevented from reaching the activation coil 42 the valve 3 closes so as to not allow the passage of gas to the burner 5 the control device 60 may also generate for example at least one additional pulse for the purposes of safety to ensure that the valve 3 has opened in the embodiments of fig1 2 and 4 instead of a control device 60 and a triac the activator may comprise for example a temperature sensor not shown in the figures that activates the switch 61 when it.