OPERATING METHOD FOR AN ELECTRIC HEATER

An operating method for an electric heater having at least one control unit with at least one temperature sensor measuring a reference temperature, and at least one heating element having a positive temperature coefficient mode above a critical temperature and a negative temperature coefficient mode below the critical temperature, may include heating a fluid passing the electric heater to an outlet temperature by the at least one heating element, and operating the electric heater in one of a normal mode or a protection mode. In the normal mode, the at least one heating element may be supplied with at least one of a direct current and a direct voltage. In the protection mode, electrical power supplied to the at least one heating element may be regulated by pulse width modulation. The electric heater may be operated in the normal mode if the reference temperature is less than or equal to the critical temperature, and in the protection mode if the reference temperature is greater than the critical temperature.