Patent ID: 8269513

Claim:
A method for monitoring an electrical heating apparatus having a plurality of electrical heating elements fed by an alternating current, the method comprising: arranging a sensor to jointly measure a measured value associated with each of the electrical heating elements, wherein the measured value associated with each of the electrical heating elements depends upon a resistance or inductance of the respective electrical heating element; connecting the sensor to a monitoring device; measuring an actual measured value associated with each of the electrical heating elements, wherein the measured value associated with each of the electrical heating elements depends upon a resistance or inductance of the respective electrical heating element, the measurement being performed by sampling of the actual measured value during a measurement period, wherein the measurement period corresponds to a half-wave of the alternating current, and wherein energization of at least one heating element during is suspended during the measurement; comparing the actual measured value to a predetermined comparison value; and determining if a fault exists based on the comparison between the actual measured value and the predetermined comparison value.