Failure diagnosing apparatus for combustion systems

An apparatus 9 for diagnosing failures in the combustion system to be installed in the regenerator of an absorption chiller is adapted to automatically prepare quantitative diagnosis data from a plurality of items of measurement data. The apparatus comprises an abnormality degree calculating circuit 2 for calculating degrees of abnormality serving as indexes for discriminating failures, from different items of data obtained by a combustion system control unit 1, a binary conversion circuit 4 for converting the abnormality degrees obtained from the circuit 2 to binary data representing "normal" or "abnormal," a condition judging circuit 5 for discriminating types of states of failures from the binary data by driving a diagnosis knowledge base 7, and a diagnosis data calculating circuit 6 for calculating diagnosis data from the abnormality degrees and types of failure states by driving the base 7.