4148 (RP-883) -- Small-Scale On-Line Diagnostics for an HVAC System PDF

This paper describes an automated fault detection and diagnosis scheme for HVAC equipment, the Real-Time Diagnostic System (RTDS). The principles of operation of the RTDS are outlined, a computer implementation of the RTDS is described, and results of applying the RTDS to HVAC laboratory data are presented. The tests indicated that application of this inference system to the diagnosis of mixing box failures yields encouraging results. Although misdiagnosis of failure conditions is more frequent than the authors might like, false alarms are uncommon. The tests also show that training a diagnostic model on one mixing box and using the model on the other mixing boxes yields good results.