Figure 6-40. - Storage type of water cooler.

method of installation. Water cooler cabinets have a sheet metal housing attached to a steel framework. The condenser and hermetic compressor are located in the housing base, and the evaporator is located in the cabinet depending on its type of evaporator, but normally under the drain basin. Most water coolers use a heat exchanger or precooler, which precools the fresh water line to the evaporator, reducing cooling requirements for the evaporator. A thermostat, which is manually set and adjusted, is located in the cooler housing close to the evaporator.

Automatic ice machines, similar to the units shown in figures 6-41 and 6-42, are often used in galleys, barracks, gymnasiums, and other public areas. Ice machines are self-contained, automatic machines, ranging from a small unit producing 50 pounds of ice per day to a commercial unit producing 2,400 pounds of ice per day. The primary difference in the design of these machines is the evaporator. They automatically control water feed to the evaporator, freeze the water in an ice cube mold, heat the mold and empty the ice into a storage bin, and shut down when the storage bin is full. Floats and solenoids control water flow, and switches operate the storing action when ice is made. Electrical heating elements, hot water, hot gas defrosting, or mechanical devices remove the ice from the freezing surfaces depending on the unit. Figures 6-43 and 6-44 show the freezing and defrost cycle of a typical ice cube machine. In recent years, many companies have begun to manufacture their units to use HFC R-404a refrigerant instead of HCFC R-22.

Figure 6-41. - Flake or chipped-ice machine.