Chapter 25 Installation and Troubleshooting of Domestic Refrigerators and Freezers 649 Copyright Goodheart-Willcox Co., Inc. 8 • The condensing unit runs more often than normal. • The outside surface of the refrigerator feels colder than normal. In a freezer compartment, the condensed mois- ture will form ice in the insulation. The symptoms will be the same as in a refrigerator. If this condition contin- ues, enough ice will soon build up to cause the sides of the cabinet to buckle. The leak in the cabinet shell must be located and completely sealed. Most freezers provide a small opening through the inner lining. This connects the insulated area with the inside of the freezer cabinet. The temperature inside the freezer is much lower than the insulation tem- perature. Therefore, any moisture will tend to escape through this small opening. It will then condense on the evaporator surface. 25.2.5 Ice Maker Problems An ice maker requires the proper functioning and timing of all its components. If an ice maker is not functioning properly, check the following: • Make sure the ice maker has been properly installed and is properly connected to water and electric power. • Make sure the freezer compartment is at the proper temperature. Check the temperature of the mold to determine if it is above 15°F (–9.5°C). If the freeze temperature is above 15°F, it is not cold enough to close the ice maker thermostat. • Make sure that several ice making cycles have been completed and the ice maker is in the freezing cycle. • Make sure the ice maker thermostat is a single- throw switch wired in series with the mold heater. • Make sure the ejector blades make two revolutions per cycle and that ice is not stored on the blades after harvest. • Make sure the water valve solenoid is wired in series with the mold heater. 25.2.6 Unusual Noises Audible noises in the refrigerator may be caused by vibrations. The following are common sources of unusual noises: • Loose baffles or ducts. • Tubing touching something that vibrates. • Listing (leaning to one side) of the condensing unit, caused by an uneven floor. • Fan and motor vibration. • Loose components or panels. • Loose articles on the shelves. • Shelves not seated properly on the supports. An ultrasonic leak detector can be used to isolate many noises. Ultrasonic refers to sound at a frequency above the human hearing range. Sounds generated by leaks or other defects can be located with this tool, which helps the technician identify and diagnose problems in the system, Figure 25-8. Noise originating from the compressor unit may indicate that it is laboring too hard. To determine this, test the electrical load with a clamp-on ammeter. An overloaded compressor unit can sometimes be identi- fied by its starting behavior. Three seconds to operate the relay is an average time. A slower start indicates an overload. Parabola Sensor horn Headphone volume switch Coarse sensitivity switch Battery power indicator On/off switch and fine sensitivity adjustment LED display Amprobe Figure 25-8. An ultrasonic leak detector can be used to locate the source of leaks and other noises.