How A Refrigerator Works In Layman’s Language
Refrigerators help preserve food and keep temperatures cold by removing heat from the inside of the appliance. To accomplish this, a refrigerator uses a sealed system that pumps refrigerant by a set of coils. The system includes a compressor, a pump which compresses the refrigerant in gas form into the condenser coils, where the gas is condensed into a hot liquid. The condenser coils dissipate the heat as the liquid travels by them. Over time these coils can collect dust, dirt and hair, which prevents the coils from properly dissipating the heat. If you notice that the refrigerator is not cooling properly, the condenser coils may need to be cleaned. Once the refrigerant has passed by the condenser coils and the capillary tube, it travels to the evaporator coils, which are located in the freezer. As the refrigerant liquid enters these coils, it expands into a gas, which makes the coils cold. The gas flows by the coils to a suction line attached to the compressor. The compressor converts the gas back into a liquid and the cooling cycle continues. You can determine if there is a cooling problem with this system by observing the evaporator coils while the evaporator is running. If the system is operating properly, there should be a consistent frost pattern on all of the evaporator coils. If only one or two rows contain frost and the rest do not, it is likely that the sealed system has developed a restriction or a leak. Be aware that any repairs to the system must be performed by a licensed technician.
The temperature within the refrigerator should be between 35 and 40 degrees Fahrenheit (2 – 4 degrees Celsius). The temperature in the freezer should be should be 0 degrees Fahrenheit (-18 degrees Celsius) or lower. The temperature is regulated by the refrigerator control. Depending on the form, the control may be a thermostat switch and sensing bulb assembly or an electronic control board that works with one or more sensors. Be aware that some models with have a separate control for the freezer. To cool both the refrigerator and freezer, the control allows voltage to travel to the start relay and compressor in addition as to the condenser fan motor and to the evaporator fan motor. Once the proper temperatures are reached, the control shuts off the voltage to the cooling system. Bear in mind that it is normal for the temperature to vary throughout this cycle.
Air flow is vital for refrigerators to work properly. To cool the condenser wire, the condenser fan draws in air from the front of the appliance, sends it by the condenser itself and then circulates the air back out the grill. At the same time, the evaporator fan draws air from the refrigerator into the freezer. The air passes by the evaporator coils, which remove the heat from the air. The air then circulates back into the refrigerator continuing the cycle. Most models with have a damper door to control the air flow from the freezer to the refrigerator. This damper may be automatically controlled by a temperature control or manually controlled by the user. If the food or beverages in the refrigerator compartments start to freeze, the damper door could be stuck open. If the refrigerator will not cool properly, but the freezer appears to be working, the door could be stuck closed, or the evaporator fan may have failed and will need to be replaced.
As we mentioned earlier, the evaporator coils collect frost as the air from the refrigerator passes by them. Since frost build-up can cause airflow problems, coils required regular defrosting. Older models needed to be defrosted manually, but most of today’s models use an automatic defrost system. The basic elements in this system are the defrost heater, the defrost thermostat and the defrost control. Depending on the form, the control may be a defrost timer or a defrost control board. A defrost timer turns the heater on for about 25 minutes 2 or 3 times a day to prevent the evaporator coils from frosting over. A defrost control board will also turn the heater on regularly but will control it more efficiently. If the control, thermostat or heater fail, the evaporator coils will likely frost over, causing poor cooling in the refrigerator. You can test both the thermostat and heater for continuity to determine if a continuous electrical path is present. If both the thermostat and heater test positive for continuity, it is likely that the control is defective and will need to be replaced.
I hope that this article has helped you to understand the inner workings of your refrigerator a little more and will permit you to keep it in good running order.