A sudden increase in temperature in the refrigerator compartment or the formation of an ice crust on the back wall are alarming signals indicating problems with the cooling system. Most often, the culprit of such failures is evaporator, the key element of the circuit where the refrigerant boils, absorbing heat from the internal volume of the unit. Understanding the principle of its operation and the ability to diagnose malfunctions allows you to avoid an expensive call to a technician and extend the life of household appliances.
Repairing this unit requires not only technical skills, but also strict adherence to safety measures, since the work involves electricity and gas under pressure. In this article we will look at how to identify a breakdown, whether it is worth trying to fix it yourself or whether a complete replacement of the unit will be required. You will learn about the nuances of defrosting, searching for microcracks and the correct selection of components for various models of refrigerators.
Before taking active action, it is necessary to assess the scale of the disaster. If the refrigerator simply stops freezing, but the compressor runs silently and without overheating, it may be a freon leak or a clogged capillary tube. However, if you observe swelling of the rear wall or hear hissing, the problem lies directly in the heat exchanger. It is critically important to immediately disconnect the device from the power supplyto eliminate the risk of electric shock when contacting moisture or metal elements of the case.
Fault diagnosis evaporator
The first step to successful repair is to accurately determine the nature of the breakdown. Malfunctions can manifest themselves in different ways: from a complete lack of cold to periodic failures in the operation of the automation. Users often confuse an evaporator failure with a thermostat or start relay failure, so visual inspection and pressure testing are critical. If traces of oil are visible on the tubes, this is almost guaranteed to indicate a refrigerant leak.
Modern models of refrigerators, such as Indesit or Atlant, are often equipped with hidden evaporators, foamed in the walls of the case. In such cases, diagnosis is complicated, since visual access to the tubes is limited. You have to rely on indirect signs: a long compressor cycle, insufficient cooling or the appearance of condensation on the outer walls of the unit. For an accurate check, you will need a pressure gauge station and a vacuum pump.
Particular attention should be paid to the condition of the aluminum tubes. Aluminum is susceptible to corrosion and mechanical damage, especially if defrosted carelessly with a knife. Even a microscopic hole will cause gas to gradually escape from the system. If you find swelling of the plastic on the back wall of the freezer, this indicates that gas from a leak has accumulated between the insulation and the body.
⚠️ Attention: If during diagnosis you smell a strong chemical odor or see oily stains on the floor under the refrigerator, immediately ventilate the room. Although modern freons are less toxic, their concentration in a confined space is unacceptable.
For an initial assessment of the state of the system, you can use a simple survey that will help narrow down the range of possible causes:
Necessary tools and materials
High-quality repairs are impossible without properly selected tools. The set of equipment depends on the type of work expected: whether it is a simple replacement of a unit or complex soldering of aluminum tubes. To work with the cooling circuit, you will need specialized tools that are not always available in an ordinary household, but renting or purchasing them will pay off when you independently service the equipment.
The basis of the set consists of tools for working with copper and aluminum. Since evaporators are often made of aluminum and compressor connecting tubing is made of copper, you will need a quality solder and flux that can join these dissimilar metals. The use of ordinary rosin is unacceptable here, since it will not ensure a tight connection under pressure and vibration.
Below is a list of essentials without which you should not undertake repairs:
- 🔧 A set of wrenches and screwdrivers for dismantling panels and fastening the unit.
- 🔥 Gas burner with a cylinder (propane-butane or MAFF) for high-temperature soldering.
- 🌡️ Manometric manifold for filling and vacuuming the system.
- 🧪 Flux for aluminum soldering and solder (for example, HTS-2000 or Castolin 192FBK).
- 🧹 Nitrogen or dry air for purging and checking tightness (pressure testing).
It is worth mentioning separately about personal protective equipment. Working with open flames and chemicals requires gloves, safety glasses and a respirator. Flux fumes can be corrosive, and accidental contact of hot solder with your skin will cause serious burns. Also have a fire extinguisher with you, since the design of the refrigerator contains a lot of plastic and foam materials.
Preparing the refrigerator for repair
The preparation stage is often ignored by beginners, which leads to spoilage of food, damage to the floor covering and difficulties in accessing components. Proper organization of your workspace is the key to success. Before starting work, the refrigerator must be completely defrosted, even if you plan to change only the electrical part, since moisture may get on the contacts or tools.
The defrosting process takes from 10 to 24 hours, depending on the thickness of the ice. It is strictly not recommended to speed up this process with a hairdryer or boiling water, since a sharp temperature change can damage the plastic and seals. After the ice has melted, you must thoroughly wipe all surfaces and allow the unit to dry. Only after this can you begin dismantling.
For ease of operation, follow these steps:
- ❄️ Completely defrost the refrigerator and remove water from the drain pan.
- 🔌 Disconnect the power cord from the outlet and move the unit away from the wall.
- 📦 Remove all shelves, drawers and containers to free access to the back wall.
- 🧼 Wipe the internal surfaces with a dry rag to remove any remaining moisture.
☑️ Preparing to dismantle the evaporator
If your refrigerator belongs to the system No Frost, preparation will be more difficult. You'll have to remove the plastic panel in the freezer, which is often held in place by hidden latches and screws underneath the plugs. You need to act carefully so as not to break the fragile plastic in the cold. In some models, for example LG or Samsung, access to the evaporator may require partial disassembly of the housing from the outside.
Technology for replacing and repairing the evaporator
The repair process itself is divided into two main ways: restoring the tightness of the old evaporator or its complete replacement. The first option is only possible if you have accurate leak detection equipment and aluminum soldering skills. The second option is more reliable and often less labor-intensive, especially if the old heat exchanger is heavily corroded.
When replacing, it is necessary to select an analogue that is as close as possible in geometric dimensions and heat exchange area. Using an evaporator from a different model may lead to incorrect operation of the refrigerator: the compressor will work with overload or will not be able to reach the desired temperature. If there is no exact analogue, you can install a universal aluminum evaporator, selecting it according to the volume of the chamber.
The table below will help compare the main characteristics of evaporators for different types of refrigerators:
| Refrigerator type | Evaporator material | Location | Difficulty of replacement |
|---|---|---|---|
| Single chamber | Aluminium/Steel | Inside the chamber (open) | Low |
| Two-chamber (Crying) | Aluminium | Behind the back wall (hidden) | High |
| No Frost | Aluminium/Copper | In the freezer compartment | Medium |
| Side-by-Side | Combined | Individual circuits | High |
The process of soldering aluminum tubes requires special skill. The joint must be cleaned to a shine, apply flux and heat evenly with a torch. The solder should melt from the heat of the tube, not from the flame of the torch. It is important not to overheat the soldering area, otherwise the aluminum may leak, forming a through hole. After cooling, the seam should be cleaned of flux residues, as it is chemically active and can cause corrosion.
Evacuating and charging with refrigerant
After installing a new evaporator or sealing the old one, air and moisture remain in the system, which are strictly unacceptable. The air increases the condensation pressure, increasing the load on the compressor, and the moisture freezes in the capillary tube, forming an ice plug that blocks the circulation of freon. Therefore, the evacuation stage is mandatory.
To remove air, a vacuum pump is used, connected through a pressure manifold to the service connection of the compressor. The pumping process should last at least 30-40 minutes until a residual pressure close to absolute vacuum is achieved. Only after making sure that the system is tight (the pressure gauge needle should not rise after turning off the pump) can you begin refueling.
Refilling is carried out strictly according to the weight indicated on the technical sticker of the refrigerator (usually on the inner wall or back). The use of cylinders without scales is unacceptable, since underfilling or overfilling of freon will lead to ineffective operation or breakdown of the compressor. The type of refrigerant (R600a, R134a) must also strictly comply with the marking.
⚠️ Attention: Refrigerant R600a (isobutane) is explosive. Work with it should be carried out only in a well-ventilated area, away from open flame sources. It is prohibited to create a spark near equipment working with this gas.
After refueling, it is necessary to solder the filling tube and check the operation of the unit in test mode. The compressor should turn on, gain speed and turn off when the set temperature is reached. The condenser (the grille at the back) should be warm to the touch, and the evaporator should be uniformly cold over the entire area.
Typical mistakes in self-repair
DIY Repair of refrigerators is full of pitfalls, which novice craftsmen often learn about too late. One of the most common mistakes is trying to solder an aluminum evaporator with ordinary tin-lead solder. Such a connection will not withstand pressure and vibration, and the leak will resume after a few days or weeks.
Another common mistake is ignoring the vacuum procedure. Some “masters” simply bleed off the remaining gas and immediately fill in a new one, believing that the air will “go somewhere”. As a result, after a month, the refrigerator stops freezing due to an ice plug in the capillary, and repairs have to start all over again, but with replacing the compressor and filter-drier.
List of actions that can fatally damage equipment:
- 🚫 Using open fire near plastic panels without protection (heat-reflecting screen).
- 🚫 Refilling "by eye" or by pressure, and not by weights.
- 🚫 Leaving the system open to the air for a long time (moisture absorption).
- 🚫 Using aggressive solvents to clean the inner surface of the tubes.
It is also worth mentioning the erroneous opinion that any aluminum evaporator will do as a replacement for the standard one. The difference in the length of the tube and the heat exchange area can be up to 30%, which is critical for automation. If you are not sure about the parameters, it is better to find an original spare part or consult a specialist.
Prevention and extension of service life
In order for the evaporator to serve for a long time after repair, it is necessary to follow the operating rules. The main reason for the failure of aluminum heat exchangers is mechanical damage when clearing ice. Never use a knife, screwdriver or other sharp object to chip ice. Defrost the refrigerator regularly, avoiding the formation of a thick ice crust.
It is also important to monitor the condition of the rubber seals on the doors. If they allow warm air to pass through, the humidity in the chamber increases and the evaporator becomes covered with snow faster. The compressor is forced to work longer, which increases wear on all system components. Regular washing and checking the fit of the door will help avoid these problems.
In addition, you should pay attention to the installation level of the refrigerator. If the unit is distorted, the oil in the compressor may not return to the crankcase, and the circulation of the refrigerant will be disrupted. Use a spirit level to check the level and adjust the legs of the refrigerator. Proper ventilation around the cabinet is also important for effective heat transfer.
Following these simple rules will allow your refrigerator to operate efficiently for many years. Remember that prevention is always cheaper and easier than complex repairs with the replacement of expensive components. If you notice the first signs of a malfunction, do not delay diagnostics.
Is it possible to seal a hole in the refrigerator evaporator?
You cannot seal it with ordinary glue or tape - it will not withstand pressure and temperature. There are special two-component compounds for repairing radiators, but they are considered a temporary measure. A reliable solution is only soldering with a special solder for aluminum or replacing the evaporator.
How much does it cost to replace an evaporator in the service?
The price consists of the cost of the spare part (from 2000 to 6000 rubles) and the work of a specialist (from 3000 to 5000 rubles), plus the cost of refilling freon. The total amount can vary from 5,000 to 12,000 rubles depending on the refrigerator model and region.
Why is the back wall of the freezer swollen?
This is a sure sign of freon leakage from the foamed evaporator. The gas escaping under pressure delaminates the insulation and plastic. Repair in this case is complicated: it requires either installing an external “crying” evaporator, or re-foaming and replacing the circuit, which is often not economically feasible.
Is it necessary to change the filter drier during repairs?
Yes, definitely. The filter drier is disposable. When the circuit is opened, it absorbs moisture from the air and loses its properties. If you leave the old filter, the system will quickly become clogged with ice or acid, which will lead to compressor failure.