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An Expert Rule Set For Fault Detection In Air-Handling Units



J House, H Vaezi-Nejad


This paper presents an expert rule set for air-handling units (AHUs) and examines the performance of the rule set using simulation and field data. APAR (air-handling unit performance assessment rules), the software implementation of the rule set, is first applied to fault-free and faulty simulation data. As expected, the ability of APAR to detect faults is influenced by the severity of the fault and the operating conditions. Results obtained through the analysis of field data with APAR demonstrate the importance of considering control performance problems. APAR successfully identified fault situations caused by what appeared to be an outdoor air damper stuck in the open position and a manual override of the control signal to the mixing box dampers. The expert rule set consists of simple rules that can successfully identify some fairly obvious AHU operation problems that are often hidden by compensating conditions or overlooked by operators overwhelmed by raw data.
ASHRAE Transactions
107 Part 1


air handling, classification, control, economizer, field study, maintenance, monitoring


House, J. and Vaezi-Nejad, H. (2001), An Expert Rule Set For Fault Detection In Air-Handling Units, ASHRAE Transactions (Accessed April 24, 2024)
Created January 1, 2001, Updated February 19, 2017