If you heard a strange sound, smelled burning or noticed that your refrigerator has stopped freezing, the first thing that comes to mind is to check the condition of the motor. Compressor is the heart of any refrigeration unit, and the safety of your equipment depends on its proper operation products. However, before you panic or call a technician, it is useful to know exactly what this unit looks like and where to look for it.
In this article we will examine in detail the appearance of various types of compressors, their location in modern and old models of refrigerators, and also consider what visual signs may indicate a breakdown. Understanding what a working and faulty motor looks likewill help you make the right decision on further actions.
Location of the compressor: where to look for the main unit
In the vast majority of household refrigerators, be it classic models Atlant or modern LG i Samsung, the compressor is located in the lower rear part of the case. This is a specially designated niche, which is often covered with a metal or plastic cover to protect against dust and mechanical damage, as well as to reduce noise levels.
To see the device, you will most likely have to move the refrigerator away from the wall and remove the back panel. In some designer models, access may be limited, but the principle remains the same: heavy black cylinder always located at the bottom, since it is the most massive element of the structure. It is where the copper tubes coming from the evaporator inside the chamber meet.
⚠️ Attention: Before removing the protective panel or any interference with the electrical equipment, be sure to disconnect the refrigerator from the electrical outlet. Even when turned off, a residual voltage may remain in the start relay capacitors, which is dangerous to humans.
Sometimes users confuse a compressor with a condenser (grid at the back) or a filter drier. If you see a vibrating black cylinder connected to a system of tubes, you have found what you were looking for.
Appearance of a classic piston compressor
The most common type of engine, which can be found in 90% of refrigerators produced over the past 30 years, is a hermetic piston compressor. Visually, it is black metal cylinder or a barrel painted with special heat-resistant enamel. The surface may be smooth or have a slight texture, but the color is almost always black, which helps to better dissipate heat.
On the body of such a device you can notice several characteristic elements. On top or on the side there is a contact group covered with a plastic box (starting and protective relay). An electrical cable departs from this group, which is connected to the general network of the refrigerator. It is through this unit that current is supplied to start the engine.
Three copper tubes are welded to the metal body. Two of them are usually located closer to each other and lead into the housing (suction), and one is separate (discharge). When the refrigerator is operating, the discharge tube can become very hot, so touch it during operation strongly not recommended. The diameter of these tubes varies, but they are always made of copper or copper-plated steel.
The manufacturer's logo (Danfoss, Secop, Embraco) and a technical plate with characteristics: voltage, refrigerant, cylinder volume and production date are often stamped on the side wall of the cylinder. This information is critical when selecting a replacement part. The engine model is always indicated in alphanumeric code format, for example NL9G or FR80NB.
Inverter compressors: differences in appearance
With the development of technology in premium refrigerators, such as Siemens or Bosch, all Inverter compressors are more common. Externally, they may differ little from the classic models - they are also a sealed black cylinder. However, if you look closely, you will notice the absence of a massive starting relay on the case, since the motor is controlled by an electronic board.
The main visual difference often lies in the markings. The nameplate of the inverter motor will necessarily contain the word Inverter or the corresponding logo. Also, such engines tend to be quieter and have a more complex suspension system inside the housing, which, however, is not visible from the outside. They are attached directly to the frame of the refrigerator through special damper bushings.
Inverter models may have a slightly different shape - more flattened or, conversely, elongated, depending on the manufacturer. For example, in refrigerators LG with technology Linear Inverter the compressor may look like a rectangular block moving back and forth, which fundamentally distinguishes it from the round “barrels” of its piston counterparts.
⚠️ Attention: Inverter compressors are sensitive to voltage drops. If you are replacing an old refrigerator with a new one with an inverter, make sure that your wiring in the house is grounded, otherwise the electronics may fail.
It is worth noting that it is difficult to visually distinguish a working inverter compressor from a faulty one without special equipment. However, if traces of oil leaks are visible on the housing at the places where the tubes are welded, this is a sure sign of depressurization of the system, requiring immediate intervention by specialists.
Why are inverter compressors more expensive?
Inverter motors contain rare-earth magnets and a complex electronic control board, which increases their cost. However, they consume less electricity and last longer due to the absence of constant starting loads.
Table: Comparison of characteristics of different types of compressors
To better navigate the variety of devices, let's summarize the main visual and technical differences in a single table. This will help you quickly identify the type of motor in your refrigerator.
| Characteristics | Classic piston | Inverter | Linear (LG) |
|---|---|---|---|
| Shape body | Cylinder (barrel) | Cylinder or block | Rectangular block |
| Location | Back bottom | Rear below or built-in | Rear below |
| Presence of relay | Yes (on the body) | No (in electronics) | No (in electronics) |
| Noise level | Audible start/stop | Quiet, even operation | Very quiet |
| Marking | Model code (eg SC15CL) | The word Inverter | Linear Inverter logo |
The table shows that the main external difference is the shape and the presence of external hinged elements. Classic models are more repairable in terms of replacing the starting relay, while in inverter and linear models, diagnostics require connecting a tester to an electronic board.
When purchasing spare parts or searching for analogues, rely specifically on the model indicated in the characteristics table. Even if externally the compressor Zelmer looks exactly the same as Electrolux, their internal characteristics (torque, type of refrigerant, type of oil) can differ radically.
Visual signs of a malfunction: what should alert you
Knowing what it looks like the compressor is in working order, anomalies are easy to notice. The first warning sign is a change in the color of the case. If the black barrel is covered with a yellowish or brown coating, this may indicate overheating or an oil leak. Oil stains around the tubes or on the floor under the refrigerator is a critical sign of depressurization.
Pay attention to the condition of the copper tubes. If you see a greenish coating (oxidation) or, worse, cracks and creases, the system requires repair. Also, a sign of a malfunction may be swelling of the start relay housing or melting of the plastic elements of the contact group, which indicates an electrical problem.
☑️ Diagnostics of appearance
Another important point is vibration. A healthy compressor vibrates evenly and predictably. If you observe a strong, "jerky" vibration, or hear a metallic clanging, knocking or buzzing sound that was not there before, this indicates wear on internal mechanical parts, such as bearings or piston group.
⚠️ Attention: Never attempt to weld copper tubing or open the sealed compressor casing yourself. This requires special equipment, skills and is life-threatening due to the high pressure and toxicity of the refrigerant.
If you notice that the compressor is running non-stop (humming constantly), and the temperature in the chamber does not drop, this may indicate a loss of performance or a freon leak. Visually, the motor may look intact, but its “behavior” indicates a problem.
Connection diagram and contact group structure
For those who want to delve into technical details, it is useful to know what the electrical connection looks like. After removing the protective plastic cover (if there is one), you will see a block with three contacts. These are the connection points for the motor windings: starting, working and common. A starting relay is suitable for them, which visually resembles a smaller black or white cylinder placed on the contacts.
In modern models, instead of an electromagnetic relay, there may be a positor (starting element), which looks like a small tablet or disk inside a plastic case. Its task is to briefly supply current to the starting winding to spin up the motor shaft. If this element is crumbled or blackened, the compressor will not start, although the motor itself may be fine.
The wires going to the compressor usually have heat-resistant insulation. If you see that the insulation of the wires is cracked, melted or exposed, you cannot operate the refrigerator - this is a direct threat of fire. In such cases, replacement of the wiring and, possibly, the starting device itself is required.
When inspecting the contact group, also check the thermal relay (protective), which is often combined with a starting device. It looks like a metal tablet with a bimetallic plate inside. Its function is to break the circuit when the windings overheat. If it is “broken,” the compressor may hum, but not start, or work without protection, which will quickly lead to combustion.
FAQ: Frequently asked questions about compressors
Is it possible to replace the compressor in the refrigerator yourself?
Theoretically, replace the “barrel” itself it is possible, but this requires a vacuum pump, a pressure gauge station, a burner and skills in working with refrigerants. Without this, it is impossible to refill the system and seal the tubes efficiently. You can replace only the start relay yourself.
Why is the compressor hot, but the refrigerator does not freeze?
This is a classic sign of a freon leak or a clogged capillary system. The motor runs idle, trying to pump gas that is not in the system, or overcoming a blockage, so it overheats, but does not produce cold.
How many years does a compressor last on average?
The average service life of modern piston compressors is 10-15 years. Inverter models with stable network voltage can last up to 20 years or more. The period greatly depends on the operating conditions and the quality of installation.
Is it dangerous to breathe vapors from a leaking compressor?
Yes, it is dangerous. Modern refrigerants (freons) themselves may not be toxic in small doses, but upon contact with open fire they form phosgene, a chemical warfare agent. In addition, the oil from the compressor is harmful to the skin and respiratory tract.
Is it possible to paint a compressor if the paint has peeled off?
You cannot paint a compressor with regular paint, as it can peel off from heating or cause overheating, disrupting heat transfer. If aesthetics are important, you can use special heat-resistant enamels for engines, but only after the unit has been completely turned off and cooled.