States that since faulty of operation of HVAC system is detrimental to energy conservation, and maintenance experts are no longer able to detect faults due to the sophistication of current air handling units, automated fault detection and diagnosis is increasingly important. Summarizes the results of survey of typical faults in air handling systems and describes two methods of locating abrupt faults - an autoregressive exogenous (ARX) model and one based on an extended Kalman filter.

KEYWORDS: year 1996, Air conditioning, faults, detecting, calculating, air handling units