Abstract: The invention relates to a water heating device, comprising a burner (20) and a flame current measuring device (100) for measuring a flame current, which measuring device comprises two electrodes and a voltage source (14), wherein each of the poles (18, 19) of the voltage source is connected to one of the electrodes. The water heating device further comprises a heat exchanger (40) which is electrically insulated relative to the burner. The burner and the heat exchanger here form the electrodes of the flame current measuring device. The heat exchanger functioning as electrode can be earthed (41). The measured flame current can be used to determine the excess air factor of the combustion. The water heating device can further comprise an air/fuel controller for controlling the air/fuel ratio, wherein the air/fuel controller uses the determined excess air factor to control the air/fuel ratio. The invention also relates to a method for measuring a flame current in a flame.

Abstract: The invention relates to a water heating device, comprising a burner (20) and a flame current measuring device (100) for measuring a flame current, which measuring device comprises two electrodes and a voltage source (14), wherein each of the poles (18, 19) of the voltage source is connected to one of the electrodes. The water heating device further comprises a heat exchanger (40) which is electrically insulated relative to the burner. The burner and the heat exchanger here form the electrodes of the flame current measuring device. The heat exchanger functioning as electrode can be earthed (41). The measured flame current can be used to determine the excess air factor of the combustion. The water heating device can further comprise an air/fuel controller for controlling the air/fuel ratio, wherein the air/fuel controller uses the determined excess air factor to control the air/fuel ratio. The invention also relates to a method for measuring a flame current in a flame.