Failure of a compressor is often the most expensive and complex repair that the owner of a household appliance may encounter. It is this unit that is the heart of the system, ensuring the circulation of the refrigerant and creating the necessary pressure to cool the chambers. When the refrigerator stops freezing or starts to work intermittently, the issue of replacing the main unit comes to the fore, requiring a careful approach and technical knowledge.
Many people mistakenly believe that it is enough to simply buy a motor of the same brand as the refrigerator itself, but the reality is much more complicated. Performance, overall dimensions and the type of refrigerant can differ radically even within the same model line of different years of manufacture. The wrong choice will lead to the fact that the equipment either will not start or will work inefficiently, consuming a huge amount of electricity.
In this article we will analyze in detail all the nuances of selection so that you can make an informed decision. We will look at markings, engine types and hidden parameters that are often ignored by beginners. A properly selected unit will extend the life of your refrigerator for many years, returning it to factory efficiency.
Diagnostics and causes of failure
Before looking for a replacement, you need to make sure that the problem lies in the compressor, and not in the thermostat or freon leak. Often, symptoms of motor failure, such as lack of cold or constant operation, can be caused by other system malfunctions. Accurate diagnostics will save your budget from unnecessary expenses on the purchase of an expensive unit.
Pay attention to the nature of the sound of the operating unit. If you hear a loud metallic knocking, clanging or humming noise that ends abruptly with a click of the relay, this is a sure sign of mechanical failure of the internal parts or jamming of the piston group. In such cases, motor-compressor must be replaced, since it is practically beyond repair.
It is also worth checking the electrical part. If the motor windings “ring” to the housing or between each other have a resistance close to zero or infinity, it means that an electrical breakdown has occurred. Interturn short circuit often leads to the activation of a thermal relay and the impossibility of starting.
⚠️ Attention: Before any During diagnostics, be sure to disconnect the refrigerator from the power supply. Working with live electrical circuits is life-threatening and can lead to electric shock.
Sometimes the compressor turns out to be working, but does not start due to problems with the start-up relay. This is a small part that fits onto the motor contacts. If it burns out, a new motor is not needed - just replace the relay. However, if the old motor hums but does not start even with a new relay, or does not make any sounds when power is applied, then replacement is inevitable.
Basic parameters for choosing a replacement
Selecting an analogue is not just a search for the brand name on the label. There are a number of critical technical specifications that must be met or within acceptable tolerances. The first step is to read the information from the nameplate located on the body of the old unit. It indicates the model, voltage, shaft speed and, most importantly, the cooling capacity.
Cooling capacity measured in kcal/h or Watts and shows how much heat the compressor is capable of removing per unit of time. If you install a lower power motor, the refrigerator will not be able to reach the desired temperature, and the motor will wear out, trying to compensate for the lack of performance. This will lead to rapid overheating and repeated breakdown.
The second important parameter is the type of refrigerant. Modern refrigerators run on R600a (isobutane) or R134a freons. These refrigerants require different compressor oils: mineral oil for older models or synthetic oil (POE) for newer ones. It is strictly forbidden to mix oils or use a compressor designed for one type of freon with another refrigerant.
Overall dimensions and seating positions also play a key role. Compressors come in different shapes and sizes, and if the new unit does not fit into the normal place on the refrigerator frame or touches the body, it will be impossible to install it without complex modifications to the structure. Measure the height, width and length of the old motor in advance.
Types of compressors and their features
There are several types of compressor units on the household appliances market, and each of them has its own design features. Understanding the difference between them will help you avoid mistakes when purchasing. Most often, piston compressors are used in home refrigerators, but there are other options.
The most common type is piston compressor. In it, the refrigerant is compressed due to the reciprocating movement of the piston in the cylinder. They are reliable, repairable (at least theoretically) and relatively cheap. However, they create vibration and noise, since they have many moving parts.
A more modern option is inverter compressor. Unlike conventional ones, it does not turn off completely, but smoothly changes the shaft rotation speed, maintaining the temperature. Such motors are quieter, more economical and more durable, but are much more expensive and sensitive to voltage changes in the network. It is impossible to replace a conventional compressor with an inverter one without altering the control system.
⚠️ Attention: Installing an inverter compressor instead of a conventional linear one requires replacing the electronic control module. Without flashing or replacing the board, the refrigerator will not work.
There are also rotary compressors, where compression occurs due to the rotation of the rotor. They are more compact and quieter than piston ones, but are less common in household refrigerators, mainly in small-sized models or in No Frost systems of recent years. When selecting, it is important to take into account that rotary models often have a lower starting torque.
Is it possible to replace R134a with R600a?
Theoretically, it is possible, but this requires a complete flushing of the system, replacing the oil with mineral oil and installing a new filter-drier. Simply replacing the compressor without altering the circuit will lead to mixing of oils and the formation of acids, which will kill the new engine in a few months.
Decoding markings and model codes
Each manufacturer uses its own coding system, but the general principles are often similar. To choose the right analogue, you need to be able to read the markings. Usually it consists of an alphanumeric set, where the type of refrigerant, cylinder volume and design are encrypted.
Let's consider popular markings using the example of compressors Danfoss (Secop) and Atlant. At Danfoss, the first two letters often indicate the area of application and type of refrigerant: NL - low temperature for R134a, TL - for R600a. The numbers indicate the volume of the cylinder in cubic centimeters. Atlant's markings are even simpler: the first numbers indicate the cooling capacity, and the letter at the end indicates the type of freon (H - R134a, 1 - R12, 6 - R600a).
Below is a table of correspondence between some popular models and their characteristics, which will help you navigate the variety of options:
| Model compressor | Refrigerant type | Cooling capacity (W) | Cylinder volume (cm³) |
|---|---|---|---|
| Secop NL10F | R134a | 105 | 7.9 |
| Secop TL57K | R600a | 65 | 5.7 |
| Atlant 100NK | R134a | 105 | 8.7 |
| Atlant 80NB | R600a | 80 | 6.2 |
| Embraco EMTG80HBR | R600a | 95 | 7.5 |
When looking for analogues from other manufacturers (for example, replacing Atlant with Embraco or Danfoss), focus primarily on cooling capacity. Deviation within ±5-10% is allowed. If you install a more powerful compressor, the system may not have time to transfer heat through the condenser, which will lead to an increase in pressure and an emergency shutdown.
Oil compatibility and system requirements
One of the most critical points that is often forgotten is the compatibility of lubricants. Compressors operate in a closed circuit, and oil circulates along with freon throughout the system. If you change the type of compressor or type of freon, you must take into account the chemical compatibility of the oils.
For freon R12 and R134a (in older systems), mineral oils or alkylbenzene oils were often used. Modern R134a and especially R600a require synthetic polyester oils (POE). These oils are hygroscopic, that is, they actively absorb moisture from the air, which leads to the formation of acids and destruction of the engine windings.
- 🛢️ Mineral oils - used in old refrigerators with R12, do not mix with synthetics.
- 💧 Polyester oils (POE) - standard for R134a and R600a, require careful evacuation of the system.
- ⚗️ Mixing - are strictly prohibited, leads to sedimentation and capillary blockage.
If you are changing the compressor from R134a to R600a (or vice versa), simply replacing the motor is not enough. It is necessary to completely flush the system with solvent, purge with nitrogen and replace the filter drier. The filter is a disposable element that absorbs moisture and oil breakdown products. Installing an old filter on a new compressor is guaranteed to cause failure in a short time.
⚠️ Attention: An open flask of polyester oil (POE) can absorb a critical amount of moisture from the air in just 15-20 minutes. Do not keep the system open longer than necessary.
Installation and startup instructions
The process of replacing a compressor requires not only correct selection, but also compliance with installation technology. This is a job for a trained craftsman with special tools: a torch, a pressure gauge station and a vacuum pump. You can’t just “screw on” a new motor by soldering it.
The first step is always dismantling the old unit and removing the sealed tubes. This is followed by thorough flushing of the circuit if there was a motor malfunction (especially if it burned out). Soot and combustion products of the windings scatter throughout the entire system and must be removed, otherwise they will clog the new compressor.
☑️ Checklist before soldering
When soldering the tubes, it is important not to overheat them. The burner flame should be directed so that the joint is heated, and not the tube itself along its entire length. Excessive heating causes the formation of oxides inside the tube, which subsequently fall off and clog the capillary tube. Use nitrogen purge during soldering to prevent oxidation of copper from the inside.
After installing all elements, the system is soldered and connected to a vacuum pump. Vacuuming is a mandatory step to remove air and moisture. The evacuation time depends on the pump power and the length of the circuit, but is usually at least 15-20 minutes until a pressure of less than 200 microns is achieved.
Only after creating a vacuum is the refrigerant charged. The amount of freon must strictly correspond to the data on the refrigerator nameplate. A lack of freon will lead to poor cooling, and an excess will lead to liquid hydraulic shock in the compressor, which will instantly disable it.
Is it necessary to add oil to the system?
Usually new compressors are already filled with oil in the required quantity. You only need to add oil if you have replaced the condenser or evaporator with a longer one, or if there is a lot of old oil left in the system during flushing. Excess oil is just as harmful as its lack.
Frequently asked questions (FAQ)
Is it possible to install a more powerful compressor, for example, from a two-chamber refrigerator to a single-chamber one?
Technically, you can start it, but you shouldn’t do this. A more powerful motor will operate in a short cycle (on and off frequently), which is harmful to the start relay and windings. In addition, it may not have time to cool, since the refrigerator condenser is designed for a lower thermal load.
Why does the new compressor get hotter than the old one?
A slight increase in the temperature of the body of the new compressor is normal, especially in the first hours of operation, while the system is getting into operation. However, if it is impossible to touch the bottom of the case (temperature above 90-100°C), this may indicate a lack of freon, the presence of air in the system, or improper operation of the thermostat.
Where can I find an original compressor for an old refrigerator?
Original spare parts for models older than 7-10 years are often discontinued. In such cases, you need to look for universal analogues from market leaders such as Secop (Danfoss), Embraco, Aspera or Atlant. The main thing is the coincidence of the characteristics, and not the logo on the case.
You can hear metal ringing inside the compressor when shaking - is this a defect?
No, this is not a defect. Inside the hermetic casing, the compressor is suspended by springs. When shaking an unsecured unit, a characteristic metallic clang is heard. This is a design feature that dampens vibrations during operation. You need to check the compressor for functionality only after installation and connection.
Which compressor is quieter: Atlant or Danfoss?
On average, Secop compressors (formerly Danfoss) are considered quieter and more reliable, especially the series with low noise levels. However, modern Atlant models also have good performance. The noise level often depends not only on the motor itself, but also on the quality of its attachment to the refrigerator frame and the condition of the rubber shock absorbers.