Figure 16-3 is a general diagram of the main parts of an R-12 refrigeration system. The primary components of the system are the TXV, the evaporator, the compressor, the condenser, and the receiver. Additional equip-ment required to complete the plant includes piping, pressure gauges, thermometers, var-ious types of control switches and control valves, strainers, relief valves, sight-flow in-dicators, dehydrators, and refrigerant charging connections.

Figure 16-2.-The high-pressure side of an R-12 refrigeration installation aboard ship.

Figure 16-3.-Diagram of an R-12 refrigeration system.

In this chapter, we will discuss the R-12 system as though it had only one evaporator, one compressor, and one condenser. You should realize, however, that a refrigeration system may (and usually will) include more than one evaporator. It may also include an additional compressor and other condenser units. We will discuss the main components and their functions.