Abstract: Systems and methods are provided for evaluating performance of a heat exchanger, such as a condenser, using rules-based logic. A plurality of sensors can measure various operating properties of the heat exchanger and transmit corresponding measurement information to a controller. The controller can (i) evaluate the measurement information for a plurality of rules in which each rule considers an operating parameter of the heat exchanger that is based on the measurement information to provide a set of operating values; compare the set of operating values to a rules matrix in which each of a plurality of possible diagnoses for the heat exchanger are associated with a corresponding set of predetermined values from a set of the plurality of rules; and (iii) based on the comparison, determine at least one likely diagnosis for the heat exchanger from among the plurality of possible diagnoses.