This project consist of the replacement of both the 20 and 60 ton refrigeration units and air handlers located in Mechanical Room 80 within the medical clinic. AHUs 4 and 6 are vertical DX AHU’s with external open type compressors and shell and tube, water-cooled condensers. Refrigerant piping is routed between components. Condenser water piping (from/to the cooling towers and pumps outside the mechanical room) is connected to the shell and tube condenser. Three-way valves at the condenser piping provide for head pressure control.