When the refrigerator stops coping with its main task - cooling food, or, conversely, begins to turn the contents into an ice monolith, experienced technicians first advise checking the condition of the evaporator. In everyday life, this part is often simply called coil, although technically it is a complex system of tubes through which the refrigerant circulates. Understanding exactly where it is located in your particular unit is key to diagnosing a variety of problems, from insufficient cold to complete unit failure.
The location of this critical component directly depends on the type of defrosting system installed by the manufacturer. In modern models with the No Frost system and in classic “crying” refrigerators, the design will be radically different, which affects the accessibility of the element for visual inspection and repair. If you are planning on self-diagnosis, you need to clearly understand the architecture of your device so as not to damage fragile tubes when trying to find them.
In this article we will take a detailed look at where to look for a coil in various types of refrigeration equipment, what signs indicate its malfunction and why independent intervention can be dangerous without the appropriate knowledge. You will learn how to distinguish a condenser from an evaporator and what to do if you find a freon leak or mechanical damage to the tubes.
Design and purpose of the evaporator
The evaporator, or coil, is a system of tubes, usually made of aluminum or copper, that surround the freezer or refrigerator compartment. This is where the liquid refrigerant boils at low pressure, actively absorbing heat from the interior of the chamber. This physical process provides the very cold that keeps your food fresh. Without a working evaporator refrigerator, operation of the refrigerator is impossible in principle.
Depending on the model, the coil can be built directly into the wall of the case (foamed), which makes its replacement extremely labor-intensive, or it can be a separate removable radiator. Aluminum tubes are more susceptible to corrosion and mechanical damage, while copper ones are considered more durable, but are less common in budget segments of equipment.
Why does aluminum conduct cold better?
Aluminum has high thermal conductivity, which allows you to quickly remove heat from the chamber, but it is chemically active and easily oxidizes upon contact with moisture and air, forming a white coating.
It is important to understand the difference between an evaporator and a condenser. If the first is located inside or behind the back wall of the chamber and cools, then the second is a black grille at the back of the refrigerator, which, on the contrary, releases heat into the room. They should not be confused, since the symptoms of malfunctions are different.
Location in refrigerators with the No Frost system
In units equipped with the No Frost system, the coil is hidden from the user's eyes and is located behind the back panel in the freezer. Air is forced to circulate through this hidden radiator using a fan, distributed throughout the entire volume of the refrigerator. This means that you will not see frost on the products, but evaporator will become overgrown with ice, which periodically thaws thanks to the heater.
To access the coil in such models, you need to dismantle the rear plastic wall inside the freezer. It is often secured with hidden latches or screws covered with decorative plugs. After removing the panel, you will see an aluminum radiator, which is the heart of the cooling system. This is where problems most often arise with freon leakage or clogging of the capillary tube.
Also in this zone there is a defrost sensor and a heating element, which work in tandem with the coil. If the refrigerator is humming but not cooling, the problem may not be in the coil itself, but in the disruption of air circulation around it due to an ice coat.
Where to look for the coil in models with a drip system
In classic refrigerators with a drip defrosting system (or “weeping”), the design is simpler, but the location of the coil may vary. Most often, the evaporator is made in the form of an aluminum plate, which is also the rear wall of the fridge compartment. When the compressor is running, this wall becomes covered with frost, and when it stops, it melts, and water flows into the drainage hole.
In some older models or budget options, the coil can be brought out and secured to the outer rear wall of the housing, often under or next to the black compressor casing. In this case, it looks like a curved tube, sometimes covered with a layer of paint. The easiest way to find it in such models is to just move the refrigerator away from the wall.
If the evaporator is foamed inside the housing (hidden), then visually you will only see a smooth plastic or metal back wall inside the chamber. In such cases, diagnosis is carried out indirectly: by the presence of cold in the compressor and the absence of characteristic gurgling.
Hidden and open circuit: what is the difference
The distinction between a hidden and an open circuit is critical for repairs. The open circuit, as the name suggests, is accessible for visual inspection without compromising the integrity of the housing. This is typical for old Soviet refrigerators (for example ZIL, Biryusa early series) and some modern budget models. Repair here is possible by soldering without complex manipulations.
The hidden circuit, or foamed evaporator, is integrated directly into the heat-insulating layer of the case. The tubes are laid between the inner plastic box and the outer metal casing, after which the space is filled with polyurethane foam. In this case, finding the location of the leak is extremely difficult, and replacement requires either installing an external “weeping” evaporator or labor-intensive opening of the housing.
You can determine the type of circuit by the thickness of the chamber walls. If the back wall inside the refrigerator is thin and caves in when pressed, most likely the coil is located outside or in a separate unit. If the wall is hard and thick, the circuit is probably foamed.
| Characteristics | Open circuit | Hidden (foamed) circuit |
|---|---|---|
| Location | Outside the case or inside on view | Inside thermal insulation of walls |
| Maintainability | High, easy to solder | Low, requires installation of a new radiator |
| Risk of corrosion | High (contact with air) | Low (no oxygen access) |
| Repair cost | Low | High |
Symptoms of malfunction coil
You can understand that the coil is out of order by a number of indirect signs. The most obvious is that the refrigerator runs without interruption, the compressor hums continuously, but the cold does not accumulate. This may indicate a refrigerant leak a microcrack in the evaporator tube.
Another symptom is the appearance of oily spots under the refrigerator or at the location of the coil. Since freon circulates along with compressor oil, oil leaking out almost guaranteed means depressurization of the circuit. You can also notice a characteristic white or greenish coating on aluminum tubes - oxidation of the metal at the leak site.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately unplug the device. This may indicate a short circuit or overheating due to impaired refrigerant circulation.
In No Frost systems, a sign of problems with the evaporator may be the growth of a “coat” of ice inside the freezer, even if the system is working properly. This indicates that the freon does not boil evenly along the entire length of the tube, or the tightness of the system is broken.
☑️ Evaporator diagnostics
Is it possible to replace the coil yourself
Replacing the coil is a complex technical process that requires special equipment: a vacuum pump, a pressure gauge station, a torch and, of course, soldering skills. Even if you find the leak and seal it, there will be air and moisture in the system, which, when in contact with freon, form acid that kills the compressor in a matter of months.
In addition, you need to know exactly the type and amount of refrigerant required for your model (R134a, R600a etc.). Filling by eye will lead to either insufficient cooling or water hammer in the compressor. Therefore, independent replacement is recommended only for open circuits in older models if you have experience.
In modern refrigerators with a foamed circuit, craftsmen often do not change the original evaporator, but install a hinged one. This looks less aesthetically pleasing (an additional radiator appears inside the chamber), but allows you to restore the functionality of the unit without compromising the factory thermal insulation.
⚠️ Attention: Work with refrigerants requires a license in a number of countries. In addition, improper disposal of freon is harmful to the environment. Always contact certified specialists.
Prevention and care of the cooling system
In order for the coil to serve for a long time, it is important to follow the operating rules. The main rule for open loop systems is to avoid mechanical damage. When defrosting, never use sharp objects to chip ice. Allow the ice to melt naturally or use a hairdryer at minimum power, directing the air stream carefully.
Regularly wipe the back wall of the refrigerator (if it is open) from dust and dirt. Dust deposits act as a heat insulator, interfering with efficient heat transfer, which causes the compressor to work overload. For cleaning, use a soft brush or a vacuum cleaner with a narrow nozzle.
Watch the door seal. If it passes warm, moist air, excess ice will form on the evaporator, which, when defrosted, can cause corrosion of the aluminum tubes due to prolonged contact with water.
Frequently asked questions (FAQ)
Why does the refrigerator not turn on or knock out plugs after replacing the coil?
Most likely, the insulation of the wires was broken during soldering or a short circuit occurred in the compressor circuit. It is also possible for moisture to get into the electrical part. Diagnostics by an electrician is required.
Is it possible to use the refrigerator if the coil is slightly damaged?
No, you cannot operate the device with a damaged circuit. The refrigerant will come out, the compressor will run idle and overheat, and moisture will get inside the system, which will lead to complete failure.
How to distinguish a condenser from an evaporator?
The condenser is always located outside (at the back of the refrigerator), it is hot and black. The evaporator is located inside or behind the inner wall, it is cold and often covered with frost or aluminum foil.
How much does it cost to replace the coil in a service center?
The cost depends on the model and type of circuit. Open circuit replacement is cheaper. Replacing a foamed evaporator with the installation of a mounted one can cost up to 50-70% of the price of a new refrigerator.