Centrifugal chillers are used in medium- and large-sized buildings to provide comfort cooling. Many of them use the vapor compression refrigeration cycle, including centrifugal compressors and plate-and-frame or shell-and-tube heat exchangers, to produce chilled water that can be pumped to AHUs and FHUs located in different spaces throughout the building. At each AHU or FCU, the chilled water passes through a cooling coil while a fan blows air over the coil to produce cool air for the enclosed space. The chilled water then returns to the chiller unit, where it is re-cooled, and the process is repeated. Like other building systems, chiller systems require regular monitoring and maintenance in order to maintain their capacity and efficiency and avoid costly breakdowns and repairs. However, issues and breakdowns still occur. A good understanding of chiller design and operation is critical when troubleshooting a chiller system. This course discusses some common issues for centrifugal chillers and the troubleshooting steps and techniques that can be used to diagnose and determine the cause if a problem occurs.