How Does a Refrigerator Keep Food Cold?

Fred's Appliance
July 13, 2020
Refrigerator Repair

In today’s world is it possible to live without a refrigerator? Sure, if you share an island with the Emperor Penguins in Antarctica or live with the Eskimo’s in Alaska. While it is possible to live without a refrigerator, for most people, it is undesirable. Of course, refrigerator repair would be a thing in the past, but is it possible to keep food from spoiling without the aid of refrigeration?

What is a Refrigerator

A refrigerator is nothing more than a tall rectangular box stuffed with insulation between the inner and outer walls replete with a number of integrated components designed to keep food items in the freezer, rock-hard-frozen, while food and beverages stored in the refrigerator compartment are meant to remain cold until such a time as when you need to use them.

The process of refrigeration functions with a power source, compressor, two different types of coils, a fan to control airflow, a temperature control via a thermostat, a control board, and a defrost mechanism to prevent ice build-up.

Even the most expensive and highly rated refrigerator in the world will not last forever. But if you treat your refrigerator with tender-loving-care, do some basic maintenance, such as keeping the coils free from dust, debris, and animal fur, it should bring you cool comfort for 15-20 years.

Refrigerators are intended to keep your food and beverages cold. But how do you diagnose a refrigerator that fails to keep things cold? The following points explain the basic tenets of refrigeration that should aid you in your endeavor to accurately diagnose why your refrigerator no longer keeps anything cold and/or frozen.

Principles of Refrigeration

How does refrigeration work?

  • The compressor turns the refrigerant into a gas which is pumped into the condenser coils
  • The condenser coils convert and condense the gas into a hot liquid that travels through a small capillary tube to the evaporator coils
  • Condenser coils are designed to disperse the heated temperature as the hot liquid moves through them
  • As the refrigerant — which is now a hot liquid — enters the evaporator coils, it expands into a gas which causes the evaporator coils to become cold
  • The gas then returns through the coils and back to the compressor
  • The compressor converts the gas back to a liquid where the cooling cycle repeats itself
  • This process is known as refrigeration and is what removes heat from inside the refrigerator

On most models the condenser coils are located near or at the bottom of the refrigerator. And to make things even more unmanageable, in most homes the refrigerator is placed in an alcove indented into a kitchen wall. The location for refrigerators in most kitchens presents a logistical challenge to keep the condenser coils free from dust and debris.

Pro Tip 1

If the refrigerator is not cooling properly, unplug it from its power source, and inspect the condenser coils for dirt, dust, and debris. Remove the grille to gain access to the coils. Use a refrigerator coil brush to clean away impediments. Sweep and vacuum remaining debris. Plug the refrigerator back into its power source. Wait a few minutes or as long as needed to determine if the refrigerator is cooling after this very simple repair.

Please note that condenser coils should be cleaned in this manner every 3-4 months.

Pro Tip 2

If cleaning the condenser coils does not correct the cooling problem, plug the refrigerator back into its power source. Inspect the evaporator coils. If the cooling system is functioning according to how it was designed, you should see a static frosty appearance present on all evaporator coils. Some coils may have frost present, while others have no frost at all. If this is what you see, the system is either blocked or leaking.

If your inspection yields this diagnosis, any further repairs should be referred to a qualified professional appliance technician.

Temperature Control

Temperature control seems like a likely place to begin, as there are several things that could go wrong. The most likely part to fail in this process would be the thermostat. But hold on before you replace the thermostat as it could be something else related to the thermostat.

  • First check the refrigerator and freezer temperature setting. Temperature should be set to 35 degrees Fahrenheit (1.67 °C) and the freezer set at 0 degrees or lower
  • Temperature is managed by its control panel
  • The control could be a switch that works in conjunction with its sensors
  • Because one size does not fit all, most models allow separate controls for the refrigerator and freezer
  • Once desired temperatures are achieved, the voltage to the system is turned off
  • Note that the temperature may fluctuate throughout the cooling cycle

Pro Tip 3

If food stored in the refrigerator is beginning to freeze, check the damper door and determine if it is stuck open. If the refrigerator is not cooling, but the freezer is functioning, the damper door might be stuck closed. It is definitely an airflow issue and suggestive of a malfunctioning evaporator fan. The blade may be broke or the fan assembly might need to be replaced.

Air Flow

Air flow is vital to keep your food cold. How does that work?

  • A condenser fan pulls air in from outside the refrigerator
  • It then sends the air over the condenser and returns the air back through the grille cover
  • While that process is taking place, another fan draws air from inside the refrigerator and back to the freezer
  • Air passes over the evap coils and removes heat from inside the refrigerator and freezer
  • The air then returns to the refrigerator and repeats the cycle over and over
  • Many models are equipped with a damper door that controls the amount of air to be released from the freezer 
  • The damper is regulated by some type of control mechanism or if needed can be controlled by you

Pro Tip 4

Please do not keep maxing out the temperature control as this could cause the air in the refrigerator to eventually freeze food you don’t want to be frozen. And ultimately render the thermostat control ineffective all together entirely.

Please feel free to reach out to us if you need help with this or any other appliance repair you might be struggling with. 

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