As the final phase of a three phase research project launched by ASHRAE TC 7.5-Smart Building Systems, this research aimed to: 1) evaluate the effectiveness of three fault detection and diagnostics (FDD) methods for centrifugal chillers online in laboratory and field environments; and (2) identify a specification for one or more algorithms that can be incorporated within commercial FDD products or embedded into the control systems onboard the chiller to monitor the health of the chiller's operation. Based on a comprehensive understanding of the chiller system, cause of the faults, impact of the faults, and associated implementation cost considerations, several decoupling features for (1) reduced condenser water flow, (2) reduced evaporator water flow, (3) refrigerant low charge, (4) refrigerant overcharge, (5) condenser fouling and (6) non-condensable gas in the refrigerant fault were developed. The performance of the proposed decoupling features were tested and evaluated with the steady-state laboratory data from ASHRAE 1043-RP. The validation results showed that the couplings among the different centrifugal chiller faults can be fully or partially broken by the proposed decoupling features. Three FDD methods were identified and tested in a laboratory test environment. The test data sources included the historical data of the 1043-RP, additional test data, and multiple simultaneous faults test data. Based on the evaluation methodology provided by 1275-RP, the overall FDD performance of the three FDD methods was evaluated and compared. The capability of the three methods of detecting multiple simultaneous faults was evaluated and discussed. Based on the laboratory tests results, two of the three methods were identified for the subsequent field implement and evaluation.