How Does My Refrigerator Work?
How Refrigerators Work
All frost-free refrigerators operate on the same principles. It is a closed system that is controlled by the use of timers and controls.
- The way it works is that refrigerant is compressed into a liquid in a closed system and is sent to the freezer through a tube where it is allowed to expand back into a gas state. When it expands, it actually absorbs heat.
- Then it is sent through a tube back to the compressor where it is compressed into a liquid again, giving off a lot of heat.
- There are coils in two places. The coils located in the freezer compartment behind a panel or wall are called the evaporator coils. The coils located near the compressor which are located on the bottom or back of the refrigerator are called the condenser coils.
That is the basic idea of how it works, the refrigerant cycles in and out of the refrigerator, absorbing and releasing heat. This cycle operates on a continuous loop to keep the refrigerator at a constant temperature.
Understanding Your Refrigerator's Controls
The refrigerator would get too cold if it ran all the time. It needs to turn off when it is cold enough and turn back on when things start warming up.
The on-off function is controlled with a device called a cold control. This is a device that uses an adjustable thermostat to sense the temperature inside the unit, turn off when it is cold enough, and turn back on when the temperature rises. The adjustable part of the thermostat is controlled with a dial that is usually located inside the refrigerator. The numbers normally range from 0 (off) to 9 (coldest). Some may have fewer numbers, and some have more, but the largest number is the coldest setting.
Most refrigerators also have another dial that is normally labeled AIR or FREEZER and has letters or numbers that indicate level of coldness. Usually the letters are A, B, and C, where A = warmest, B = normal, and C = coldest. If it is labeled with numbers, it most likely is 1 to 5, 1 to 7, or 1 to 9 with 1 being the warmest setting and the largest number being the coldest. This control has a link to a door or slide that opens and closes to allow more or less air from the freezer to circulate into the refrigerator section. This control does not actually control the cold— it controls the air that circulates between the freezer and the refrigerator.
Fortunately, most manufacturers label the two controls with a suggested normal setting. With a new refrigerator, the recommended settings are the place to start.
If you have a refrigerator that has been working fine for the past couple of years and now the temperatures are not low enough, adjusting the controls may help temporarily, but a change in the operation of the refrigerator is an indication that the unit may be developing problems.
Important: Wait 24 hours after changing one of the controls. It takes this much time for the temperature to completely adjust to the new settings. Always follow safety procedures when working on a refrigerator (but you do not need to unplug the refrigerator to change the control settings).
Frost-Free Defrost Cycle
Most frost-free refrigerators have a defrost cycle that is timed and uses a heater to melt the frost on the evaporator coil in the wall (usually the back wall) of the freezer compartment. Yes, several times a day, a heater comes on and warms up the coils in the freezer to melt any frost that might build up. The temperature in the wall of the freezer is limited to somewhere between 45 and 65 degrees. When the temperature reaches the correct temperature, the heater is turned off by the defrost thermostat which is a simple on/off switch set to turn off at a specified temperature.
For the defrost cycle, there is a timer that turns the refrigerator off from 2 to 4 times a day for about 20 minutes each time. The frost that is melted produces a small amount of water that is drained through a tube that goes from the floor of the freezer to a small pan near the compressor. The condenser fan blows hot air over the pan holding this warm water to evaporate it away.
Do-it-yourself repairs on a refrigerator should be limited to all the systems outside of the sealed system. The sealed system (consisting of the compressor, condenser coils, and the evaporator coils) should only be serviced by authorized technicians.
I would say that most of the problems with a refrigerator are related to other devices and controls. Armed with information, it is possible to fix most problems.
To summarize, the refrigerator is a complete system that operates a complex set of tasks on a timed and temperature sensitive schedule. It actually is a pretty amazing machine. If you take care of it, you will have many years of use.