Why Is My Fridge Evaporator Coil Freezing Up?

Modern fridge models come equipped with automatic defrost systems that inhibit ice build-up on the evaporator coils.

When we open the fridge to take something out, hot, humid air from outside the fridge replaces the cold air inside. This hot air condenses and frosts over the evaporator coil. Excessive ice build-up will hinder the evaporator fan from circulating cold air to other parts of the fridge. The defrost system clears out this frost.

However, suppose any component of the defrost system is faulty or inoperative. The result is frosted over evaporator coils which inhibit the fridge from cooling correctly, thus increasing electrical costs. 

If your evaporator coils are freezing up, then this article is just for you. Read below the four most common reasons and solutions for frosted evaporator coils.

1. Defective Defrost Heater

The defrost heater periodically turns on throughout the day to prevent any ice build-up on the evaporator coil. The defrost heater works like a small bulb and heats the coils to remove frost that may have formed on them. The frost melts into water and moves out of the appliance through a duct.

If the defrost heater malfunctions or does not melt the ice build-up, the coils would freeze up.

To see if the defrost heater is faulty, use a multimeter. Test the component for continuity. If the defrost heater fails to establish continuity, replace it with a new one.

2. Faulty Defrost Thermostat

Another common reason why the evaporator coil in a fridge keeps frosting over is a faulty defrost thermostat.

The function of a defrost thermostat is to monitor the temperature of the evaporator coils. The thermostat only allows the defrost heater to start working if it senses that the coils are cold enough for a defrost cycle to initiate. Although the preset temperature may differ from model to model, a general average is for the coils to be below 30 degrees Fahrenheit. If the defrost thermostat malfunctions, it will not detect the temperature correctly, resulting in the heater not turning on when needed. In that case, the coils would freeze over.

As you would for the defrost heater, test the thermostat for continuity with the help of a multimeter. If the component does not establish continuity, replace it.

3. Inoperative Defrost Timer

The defrost heater and the compressor do not turn on simultaneously as a safety measure during the defrost cycle. The job of the defrost timer is to repeatedly turn on the defrost heater throughout the day to melt any frost accumulated over the coils.

For the defrost heater to start operating, the defrost timer has to be in the defrost cycle. If the defrost timer incorrectly advances into the cycle, the heater will not run. If the defrost timer is inoperative and fails to initiate the heater, the coils would freeze over, and the fridge would eventually stop cooling.

To check if the component is functioning correctly, use a screwdriver or your hand to turn the timer slowly until you hear an audible click. This should turn off the compressor and the evaporator fans. If the problem is the timer and not the heater or the defrost thermostat, the heater should start to heat up.

If the defrost cycle initiates after manually manipulating the defrost timer, it means that it has gone bad. Replace with a new defrost timer, and that should fix your problem.

4. Torn Door Gasket

You can locate the evaporator coil at the back of the freezer compartment. You can use a screwdriver to undo the back wall of the freezer, which acts as the top cover for the coil. When the freezer door is opened and closed, the door gasket completely seals the compartment to stop humid air from making its way into the freezer.

If the door gasket has frayed over the years or doesn't seal the door tight enough, the humid air can get inside the freezer and settle on the evaporator coils. When that happens, the moisture in the hot air condenses and freezes over, creating icy insulation over the coil. In addition, the continuous leakage into the freezer compartment due to a torn door gasket inhibits the cooling ability of the appliance. It freezes the coils over too quickly for the defrost cycle to keep up the heating process.

To determine if the gasket is shutting the door completely, you can perform a reasonably straightforward test. All you need is a dollar bill. Close the freezer door over the dollar bill and try to pull it out. If the dollar bill stays stuck and you cannot pull it out easily, your door gasket is not allowing any leakage. However, if the bill slips and slides, it indicates that the gasket is worn and needs replacement.

Note: Make sure to test with the dollar bill all around the door gasket.

How to Manually Remove Frost Evaporator Coils in a Fridge: For Older Models

For an older fridge model, if frost builds up on the evaporator coil and the freezer compartment, you will have to resort to manual defrosting.

The first thing that you will have to do is empty your fridge and freezer compartments. Next, take everything out. This includes all the ice cube trays, baskets, and food. Place them outside or in coolers as necessary.

Ensure that you have placed dry towels under the fridge and the door to soak up all the water as the frost melts. Then, make sure the thermostat is all the way down to zero and unplug the appliance. Finally, crack the doors a bit for both the fridge and freezer compartments - this will allow hot air to circulate through them more efficiently.

As the frost melts, use a soft cloth or towel to gently clean the insides of the freezer and dry off the coils. Once done, plug in the fridge and set the thermostat to the required temperature. If you have the 0 - 7 settings, you should go for either 3 or 4.

Use a thermometer to test if the fridge has cooled down to 42 degrees Fahrenheit or a lower temperature. If yes, put all the perishable items back inside.

Conclusion

The reasons mentioned above are most likely why your evaporator coil is freezing up. Reading through these potential problems and applying the suggested solutions should rectify the issue for you. In case part replacement is not something you can do on your own, call a technician or a maintenance specialist to do the job for you. If your appliance is still under warranty, you can also request service from the manufacturer.

Frequently Asked Questions

How do I know if my fridge is low on Freon?

Unplug the fridge, ensuring the temperature control is at zero. Next, uncover the evaporator - you can locate it near the evaporator fan. Turn the fridge back on and set the thermostat to your desired temperature. Close the door and let the fridge run for a while. Check if there is any frost build-up on the evaporator. If not, then your fridge is either low on Freon or suffering from a clogged system.

How to reset the compressor on a fridge?

Disconnect the fridge’s power cord from the wall. You will find it at the back of the appliance. Allow the fridge a few minutes to dissipate any electrical charge. Ensure that both the fridge and freezer compartment controls are "OFF" or on "0," and plug the power cord back into the wall. Set the temperature controls back to your desired settings. Allow your appliance at least one full day to come up to a stable temperature.

Why does my fridge keep making a clicking noise?

The three most likely reasons why your fridge makes a clicking noise are as follows:

If your fridge isn’t cooling well and keeps making a clicking sound every few minutes, dirty condenser coils are the most common reason. Cleaning the coils to remove any debris or dirt is often a great first step to troubleshooting this issue.

A faulty start relay can also cause a clicking noise and cause your fridge to stop working properly. The cooling it could provide, if any, would not be enough to prevent your food from going bad. Check for continuity and replace the part if it fails the test.

If your fridge is cooling, but you can hear a clicking noise, the reason is most likely a broken defrost timer. Replace it with a new timer.

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