Sudden silence in the kitchen or, conversely, an unusually loud hum of operating equipment often becomes the first signals that something has happened changes. The compressor is the heart of any refrigerator, be it old refrigeration unit changes have occurred. The compressor is the heart of any refrigerator, be it an old one Atlant or modern Liebherr. It is on its uninterrupted operation that it depends on whether the products will remain fresh or whether they will have to throw away supplies.
Understanding exactly which components can fail helps the owner not to panic ahead of time and to correctly assess the situation before the technician arrives. Many problems appear long before the engine stops completely, requiring only careful attention to the sounds and operation cycles of the device.
In this article we will analyze in detail the internal structure of the motor, typical failure scenarios and methods of their initial diagnosis. You will learn why increased pressure in the circuit is a common cause of emergency stops and how to distinguish natural wear and tear from a critical malfunction.
Design and principle of operation of the compressor
To understand what exactly breaks, you need to imagine how this mechanism works. Most household refrigerators use hermetically sealed piston compressors, where the electric motor and compressor part are located in the same steel housing. When voltage is applied, the rotor begins to rotate, setting in motion the piston group, which compresses the refrigerant and pushes it through the system.
Inside the housing there is also oil, which is necessary for lubricating rubbing parts and removing heat. The most important element is the starting relay, which supplies an impulse to the motor windings to start. If any of these components does not work correctly, the entire cooling cycle is disrupted.
Modern models are often equipped with inverter engines that operate without constant switching on and off, smoothly regulating power. This reduces the load on the mechanical parts, but makes the electronic filling more vulnerable to power surges in the network.
⚠️ Attention: Opening the sealed compressor housing at home is impossible without special equipment and subsequent vacuum charging of the system. All diagnostics described below are carried out without breaking the tightness!
Electrical faults of the motor windings
One of the most common causes of failure is damage to the electrical part. The compressor motor has two main windings: starting and working. Over time, the insulation of the wires may dry out or melt due to overheating, which leads to a short circuit.
If this happens turn-to-turn short circuit, the engine may hum, but not start, or knock out the circuit breaker in the apartment panel. You can check the integrity of the windings using a multimeter by ringing the terminals on the housing. Lack of resistance or, conversely, too low readings indicate a burnt-out winding.
The thermal protection built into the motor housing also often fails. It is designed to open the circuit during critical heating, but if it “sticks” in the open state, the compressor simply will not receive power. In some cases, replacing the external start relay solves the problem if the engine itself is intact.
Mechanical wear of the piston group
The mechanical part is subjected to enormous loads, working for years without a break. Pistons, connecting rods and shafts rub against each other, and even in the presence of oil, there comes a time when the clearances increase beyond permissible limits. This leads to a drop in performance.
A symptom of wear is often a situation when the compressor works constantly, but temperature in the chambers does not drop to the required values. The motor hums smoothly, but does not create the necessary pressure in the system. This is called “does not hold compression.”
In advanced cases, a so-called “knock” may occur. If the compressor is knocking, this often means that the shaft bearings are broken or the piston group is loose. It is impossible not to hear such a sound - it resembles a metallic clang or rhythmic beats.
Why can’t you ignore the knocking?
If you leave a knocking compressor running, metal shavings will quickly spread throughout the entire refrigerator system, clog the capillary tube and filter drier. Repairs in this case will cost 2-3 times more.
Problems with the starting relay and capacitor
Often the motor itself is fine, but there is nothing to start it. The start relay is a small plastic block that fits over the contacts of the compressor. Inside it there is a coil or posistor that switches the windings. With frequent power surges or simply from old age, this element burns out.
A sign of a relay malfunction is a characteristic click when trying to start, followed by a hum and shutdown after a few seconds. The thermal protection is triggered and the cycle repeats. Replacing a relay is one of the simplest and cheapest repair procedures.
In circuits with capacitor starting, the capacitor itself may dry out or swell. It stores energy for the initial jerk of the engine. Without it, the motor only hums quietly, trying to move, but cannot gain momentum.
⚠️ Attention: Before replacing the relay, be sure to unplug the refrigerator! Even after switching off, a residual charge may remain in the capacitors, which can cause an electric shock.
Compressor jamming: causes and symptoms
The most unpleasant diagnosis that the owner can hear is “the compressor is jammed.” This means that the mechanical parts inside the HDA are tightly stuck and cannot move. The reasons can be different: from lack of oil to solid particles getting into the cylinder.
When you try to start in this state, the engine emits a strong, strained hum, and then sharply clicks and goes silent. This triggers the thermal protection relay. If you immediately turn it on again, the situation will repeat. Long-term attempts to “swing” a jammed motor can lead to burnout of the windings.
Sometimes craftsmen use a method of increasing the voltage or use a special transformer to try to break it, but this does not always help and carries risks. In most cases, when a wedge occurs, a complete replacement of the unit is required.
☑️ Diagnostics before calling a technician
The influence of refrigerant and oil on engine operation
Although the refrigerant (freon) circulates through the system, its condition directly affects the compressor load. If there is a leak in the system and there is little freon, the compressor begins to idle. This leads to overheating, since the gas also cools the engine when passing through it.
The reverse situation is hydraulic shock. If liquid refrigerant or oil in large quantities enters the compressor instead of gaseous freon, the piston cannot compress the liquid. This causes a sharp shock that can break the valves or connecting rod.
The quality of the oil is also critical. Over time, it oxidizes, loses its lubricating properties and turns into a thick mass. This increases friction and wear of parts. Inverter models use synthetic oils that cannot be mixed with mineral oils.
| Symptom | Probable cause | Sound character |
|---|---|---|
| Buzzes, but does not start | The winding is jammed or burnt out | A steady hum, then a click |
| Clicks and is silent | Faulty starting relay | Frequent clicks every few seconds |
| Strong knocking/clanging | Broken bearings or piston | Metal clanging inside the housing |
| Works without stopping | Freon leakage or wear piston | Smooth but continuous hum |
How to extend the life of a refrigerator compressor
The service life of the engine is set by the manufacturer, but operating conditions play a huge role. First of all, this is the temperature regime in the room. If the refrigerator is located near a radiator or in direct sun, the motor is forced to work with increased load to remove heat.
It is also important to keep the condenser grid at the back clean. Dust and animal hair act as a thermal insulator, interfering with cooling. Regular vacuuming of the rear wall (with the device turned off) helps the motor operate normally.
You should not load a large amount of warm food into the chambers at once. A sharp jump in temperature forces the compressor to work at its limit for a long time, which accelerates wear of the oil and mechanics.
⚠️ Attention: Specifications and maintenance requirements may vary depending on the model and year of manufacture. Always check the official manufacturer's instructions for your specific device.
Frequently asked questions (FAQ)
You can Is it possible to repair the compressor yourself?
You can replace the start relay or clean the contacts yourself if you have electrical skills. However, repairing internal mechanics or replacing windings requires factory conditions, a vacuum pump and welding, so they cannot be done at home.
Why is the compressor hot to the touch?
Heating to 70-90 degrees Celsius for the rear of the compressor is the normal operating temperature. The alarm should be sounded if the body is so hot that it is impossible to touch it, or if it is hot, but the refrigerator does not freeze.
How long does a compressor last on average?
The average service life of modern compressors is from 10 to 15 years, provided there is a stable voltage in the network and proper operation. Inverter models theoretically last longer due to the absence of constant starting loads.
Is it dangerous to breathe fumes from a burnt compressor?
When the windings burn, acrid smoke with the smell of burnt insulation can be released. Although freon is inert in a working circuit, if the gasket breaks and the oil burns, the mixture of gases can be toxic. It is recommended to ventilate the room.