Chilled water system can be considered as one of the critical systems in commercial buildings. One of its major components is addressed here, which is chiller system. The related faults of the said system normally make negative impact on its performance and accordingly reducing its life cycle. Addressing these faults by finding them while operating the buildings is recommended to make an efficient maintenance program. So, in this research, a quality engineering mechanism to address or to find these faults is proposed. Two tailed t-test is used as part of the proposed methodology. A case study of a building that contains five chillers is presented. During a particular period of time, the performance of one of that chillers has been found substantial for inspection. The proposed method has shown a significant outcome for the users at the said building from engineering management point of view.