The refrigerator is one of the most important household appliances in every home, ensuring the safety of food for a long time. Many users take its operation for granted, noticing the presence of the equipment only when it becomes too warm inside or, conversely, ice begins to freeze. However, behind the stable microclimate in the refrigerator and freezer chambers there is a complex engineering system, the heart of which is compressor. Without this unit, circulation of the refrigerant would be impossible, and the cooling process would not start at all.
Understanding the operating principle of this mechanism helps not only to better understand the characteristics of the equipment when purchasing, but also to notice the first signs of a malfunction in time. Often the service life of the entire unit depends on the condition of the engine. In this article we will analyze in detail what role this element plays, how different types of drives differ and why it is called the “heart” of the refrigerator.
The main function of the compressor in the cooling system
The main task of the compressor is to create and maintain the necessary pressure in the refrigerant circulation system. In simple words, it works like a pump that forces freon to move through the pipes. In the evaporator located inside the chamber, the refrigerant boils at low temperatures, taking heat from the food. Then, in a gaseous state, it enters the compressor, where it is compression and a sharp increase in temperature occurs.
After compression, the hot gas under high pressure is pushed into the condenser (usually a grate on the back wall), where it cools and turns into a liquid. This cycle is repeated continuously until the temperature inside the chambers reaches the set values. It is the compressor that provides the pressure difference, without which freon would not be able to change its state of aggregation and effectively remove heat.
⚠️ Attention: If you hear that the compressor is humming, but does not start, or starts and immediately stalls, do not under any circumstances try to forcefully turn it on. This can lead to burnout of the motor winding or failure of the start relay.
It is important to understand that the efficiency of the entire refrigerator directly depends on the performance of this unit. If the compressor power is incorrectly selected for the volume of the chambers and thermal insulation, the equipment will work with overload. This will lead to increased energy consumption and accelerated wear of parts.
Design and operating principle of the engine
Structurally, a household compressor is a sealed metal a casing containing the electric motor and the compression mechanism itself. Such tightness is necessary to prevent leaks of refrigerant and oil, which lubricates the rubbing parts. The engine shaft is connected to a crank mechanism, which converts rotational motion into translational motion of the piston.
The compression process occurs in the cylinder. When the piston moves down, the pressure drops and freon gas is sucked into the cylinder through the inlet valve. As the piston moves upward, the valve closes, the gas is compressed, and when the pressure exceeds the pressure in the discharge line, the exhaust valve opens. The gas is pushed into the condenser. This cycle is repeated dozens of times per second.
- 🔌 Electric motor: drives the shaft, consuming electricity from the network.
- ⚙️ Crank mechanism: converts shaft rotation into piston movement.
- 💨 Valve group: regulates the direction of movement of the refrigerant, preventing reverse flow.
- 🛢️ Oil system: provides lubrication of rubbing surfaces and sealing of gaps.
Modern models are often equipped with additional protection and control systems. For example, a thermal relay turns off the motor when it overheats, and a starting relay helps overcome inertia when starting. In models with inverter control a complex electronic board is responsible for the operation of the engine, which smoothly regulates the rotation speed, unlike classic models that operate in the “on-off” mode.
Why is the compressor hot?
During the process of gas compression, a significant amount of thermal energy is released. In addition, the electric motor itself heats up due to the passage of current through the windings. The normal operating temperature of the case can reach 70-90 degrees Celsius, so slight heat on the back wall or in the motor area is a normal situation.
Types of compressors: linear and inverter
On the household appliances market you can find various types of motors, each of which has its own operating characteristics. Traditional linear (or piston) compressors operate on a start-stop principle. The thermostat detects the increase in temperature in the chamber and gives the command to start. The motor runs at full power until the temperature drops, after which it stops. This causes characteristic clicks and noise drops.
Inverter models are a more modern solution. In them, the engine does not turn off completely, but only reduces the speed to a minimum to maintain temperature. This avoids peak loads on the power grid during startup and provides a more stable temperature regime. The absence of constant starts and stops significantly extends the life of the mechanism.
There are also linear inverter compressors that combine the simplicity of a linear type design with smooth power control. They do not have some of the disadvantages of classic piston systems, such as vibration, but remain quite reliable. The choice between these types often depends on the budget and energy efficiency requirements.
When choosing equipment, you should pay attention to the warranty period. Manufacturers often provide extended warranties specifically for inverter compressors (up to 10 years or more), which indicates their confidence in the durability of these components. However, it is worth remembering that the electronics of inverters are more sensitive to voltage surges in the network.
Comparative characteristics of compressor types
To better understand the differences and decide which unit may be preferable in a given situation, it is useful to consider their parameters in comparison. The differences concern not only the principle of operation, but also the impact on user comfort.
| Parameter | Linear (Start-Stop) | Inverter | Linear-inverter |
|---|---|---|---|
| Operating principle | Cyclic switching on at full power | Smooth change in rotation speed | Smooth change in piston stroke |
| Noise level | High (clicks relay, hum at start) | Low (monotonous quiet hum) | Very low |
| Energy consumption | Standard or increased | Economical (class A++ and above) | Economical |
| Wear of parts | High due to starting currents | Minimum (no starting modes) | Low |
| Grid sensitivity | Average | High (stabilizer needed) | High |
The table shows that technological progress is shifting the balance towards inverter systems. They are quieter, more economical and more careful with products, since the temperature in the chambers fluctuates within 0.5 degrees, while in classic models the spread can reach 2-3 degrees.
Typical malfunctions and their symptoms
Despite the reliability of modern engines, they are not immune to breakdowns. The most common problem is failure of the starting relay or motor windings. If the compressor hums but does not start, or starts for a few seconds and clicks when it turns off, this is a sure sign of an electrical problem or a mechanical jam.
Another alarming symptom is continuous operation without shutting off. If the refrigerator hums for days, does not gain temperature and there is no frost on the walls (or, conversely, everything is frozen), this may indicate a freon leak or loss of power by compression. In this case, the motor tries to compensate for the lack of cold, working for wear.
- 🔊 Knock and vibration: may indicate broken bearings or loose casing fastenings.
- 🔥 Overheating: if the engine casing is hot to the point where it is impossible to touch, this may indicate interturn short circuit.
- ❄️ Lack of cold: with the engine running, often indicates a clogged capillary tube or valve malfunction.
⚠️ Attention: Independent replacement of the compressor requires special equipment (vacuum pump, burner, pressure gauges) and skills in working with refrigerants. Without sealing the system and vacuuming the pipeline, the refrigerator will not work correctly.
Diagnostics should begin by checking the voltage in the network and the integrity of the starting relay. Often, replacing an inexpensive relay solves the “non-start” problem, allowing you to save the main unit. If the problem is inside the sealed casing, qualified repairs with replacement of the unit are required.
The influence of operating conditions on service life
The service life of the compressor directly depends on the conditions under which it has to work. One of the main enemies is overheating. If the refrigerator is installed close to the wall, without clearance for condenser ventilation, or is standing next to the radiator and stove, the cooling system is overloaded. The motor is forced to work longer and more often to compensate for external heating.
Frequently opening the door and loading warm products also forces the compressor to work intensively. Sudden temperature changes inside the chambers require active production of cold. In addition, contamination of the heat exchanger (grid at the back) with dust and animal hair impairs heat transfer, which also leads to overheating.
It is important to follow the installation rules specified in the instructions specific model. Typically, a distance from the walls of at least 5-10 cm is required. Regular removal of dust from the back panel (with the device turned off) will help maintain the efficiency of heat transfer.
☑️ Checking the operating conditions
Following these simple rules can significantly extend the life of the “heart” of your refrigerator. Stable operating conditions reduce the number of switching cycles and the intensity of work, which in the long run saves money on repairs and electricity.
Is it possible to repair or replace a compressor
The issue of repair often arises before equipment owners when the old motor fails. Hermetic compressors used in residential refrigerators are technically considered unrepairable in a home environment. Their body is sealed, and opening requires industrial equipment for subsequent sealing.
However, there are services on the market that offer the service of “overhauling” or replacing valves, but such measures are temporary. The most reliable solution is to completely replace the unit with a new one. In this case, it is necessary to select an analogue with identical characteristics: power, refrigerant, oil type and dimensions.
The replacement process includes:
- Draining the old oil and dismantling the faulty unit.
- Installation of a new compressor and filter-drier.
- Soldering copper tubes in a nitrogen environment (to prevent oxidation).
- Evacuation of the system to remove moisture and air.
- Filling with the exact amount of refrigerant by weight.
The cost of such a procedure often makes up a significant part of the price of a new refrigerator, especially when it comes to modern ones models. Therefore, it is economically feasible to change the compressor in high-quality models of the middle and high price segment, where the rest of the unit (casing, shelves, electronics) is in excellent condition.
How long does a compressor last?
The average service life of a modern compressor is 10-15 years. Inverter models can operate for up to 20 years or more, provided there is a stable voltage in the network and proper operation.
Conclusion
The compressor is the key element that ensures the operation of the refrigerator. It is responsible for the circulation of refrigerant, creating conditions for cooling products. Understanding its structure, the differences between linear and inverter models, as well as knowledge of the signs of malfunctions will help you better operate the equipment and respond to problems in a timely manner.
Care, proper installation and regular cleaning can significantly extend the life of this expensive unit. If you notice changes in the operation of the motor, do not ignore them, as early diagnosis can save the refrigerator from serious repairs.
Why does the compressor work constantly and does not turn off?
This can happen for several reasons: the door is open, warm products are loaded, the seal is damaged, freon leaks or the thermostat has failed. Also, the cause may be contamination of the condenser at the back of the refrigerator.
Is it normal that the compressor gets very hot?
Yes, during operation the compressor heats up to 70-90 degrees. This is fine. However, if it is heated to such an extent that it smokes or smells of scorched insulation, it is necessary to urgently disconnect the device from the network.
Is it possible to replace a conventional compressor with an inverter one?
Theoretically it is possible, but technically difficult and expensive. This requires replacing not only the motor, but also the electronic control board, since they are incompatible with each other. It is easier and cheaper to replace with a similar type.
How to extend the life of the compressor?
Do not place the refrigerator near the radiator, leave gaps for ventilation, do not load hot foods, defrost regularly (if there is no No Frost) and keep the rear grill clean.
What to do if the compressor hums, but does not start?
Immediately unplug the refrigerator from the outlet. Let it sit for 15-20 minutes. If, when you turn it on again, the situation repeats (humming and clicking), call a technician. Independent attempts to “unwind” the shaft can lead to final failure.