Chapter 6 Basic Refrigeration Systems 101 Copyright Goodheart-Willcox Co., Inc. 2 Emerson Electric Co. Figure 6-15. The direction of refrigerant vapor flow is indicated on this suction line filter-drier. Note the service connections on each side of the filter. These are convenient for connecting gauges for taking pressure measurements. Liquid receiver Electrical wiring box Pressure motor control Liquid receiver service valve Discharge service valve Suction service valve Suction line service valve Accumulator Tecumseh Products Company Some commercial refrigeration condensing units have nearly all the basic components of an HVACR system in one convenient location. This arrangement promotes ease of service and installation.