Abstract: A heat exchanger assembly for a refrigeration system is disclosed. The assembly is a single vessel construction having an evaporator, condenser and flash subcooler. A plate inside the shell separates the evaporator from the condenser and the flash subcooler, and a partition inside the vessel separates the condenser from the flash subcooler. Removable orifice means in the partition control flow of refrigerant into the subcooler from the condenser. Removable solid pipe plugs in the shell of the vessel provide access to the orifice means so that, if desired, an individual orifice means may be removed and replaced with another, different sized orifice means.