Water heater

Abstract

The invention relates to a water heater comprising first (2) and second (3) electric heating devices for heating water; an electric control device (8) for controlling the total output of the electric heating devices; and a control device. The second electric heating device has a greater power than the first electric heating device. The controller combines the output patterns of the second electric heating device, which are 0%, approximately 50%, and 100% of its full power, with the output patterns of the first electric heating device, which reduces the predetermined percentage in the AC half-waves at a zero cutoff point from its full 100% power. The controller also determines the combination of one of the output models of the first electric heating device and one of the output models of the second electric heating device based on the target magnitude of the total output of the electric heating devices as established by the power control unit.