The situation when the refrigerator begins to make unusually loud sounds is familiar to many owners of household appliances. A quiet, barely noticeable hum is a normal operating process, but if motor starts to roar, growl or make intermittent sounds, this is a signal of a problem. Users are often frightened, believing that the unit is about to fail, but in most cases the reasons lie in small things that can be easily eliminated.
The noise can come from various components: from the compressoritself, the refrigerant circulation system, or even from incorrectly installed shelves. It is important to learn to distinguish the nature of the sound in order to understand whether an urgent call to the technician is required or a simple adjustment of the position of the housing is sufficient. In this article we will analyze in detail the physics of noise occurrence and methods for eliminating it.
Normal operating noise versus pathological hum
Modern refrigerators, especially models with the system No Frost, emit a number of sounds that are considered absolutely normal. This could be the quiet gurgling of freon, clicks of a thermostat, or the uniform low-frequency hum of a running engine. Decibels is a unit of sound measurement, and for household appliances the acceptable threshold is considered to be a level of up to 40 dB, which is comparable to a quiet conversation.
Pathological hum is often characterized by increasing volume or the appearance of new shades of sound. If the motor hums so much that it interferes with sleeping in the next room, or if knocking, grinding and vibration are added to the hum, transmitted to the furniture, this is an alarming symptom. Vibration can be caused not only by the engine, but also by the resonance of the case.
⚠️ Attention: If you notice that the motor hums continuously without turning off even after reaching the set temperature, this may indicate a freon leak or a thermostat malfunction.
The key diagnostic factor is frequency. Normal operation involves cycling: the motor turns on, cools the chamber, emits a steady hum and turns off. If the humming has become a constant companion, and the pauses have disappeared, it is necessary to conduct a deeper check of the technical condition of the unit.
The main reasons for the increased sound of the compressor
The compressor is the heart of the refrigerator, and it is it that creates the main acoustic pressure. One of the most common reasons for increased hum is wear or damage shock absorbers. These rubber elements dampen the vibration of the motor, and when they dry out or tear, the metal body of the motor begins to beat against the metal frame of the refrigerator. Shock absorbers The second common problem is incorrect operation (in models with forced air circulation). If ice freezes on the blades or dust gets into the bearing, the fan begins to hum and vibrate, transmitting the sound to the entire housing. It is also worth checking whether the fan is touching the wires or ice.
The second common problem is incorrect operation fan (in models with forced air circulation). If ice freezes on the blades or dust gets into the bearing, the fan begins to hum and vibrate, transmitting the sound to the entire housing. It is also worth checking whether the fan is touching wires or ice.
- 🔧 Wear of rubber shock absorbers under the compressor leads to direct transmission of vibration.
- ❄️ Ice on the evaporator or fan creates an imbalance and additional noise.
- 🔩 Loosening of the motor mounting bolts or the protective casing at the rear.
- 💨 Foreign objects entering the fan rotation zone.
Sometimes the reason lies in the refrigerant itself. If a plug forms in the system or circulation is disrupted, the motor is forced to work with increased load in order to push the freon. This causes a characteristic strained hum, which distinguishes an overloaded engine from a normally operating one.
The myth of two compressors
Many people think that two-compressor refrigerators are always noisier. In fact, each motor runs for less time, which often makes them quieter in terms of total operating time, although the peak noise may be higher.
The influence of installation and position of the refrigerator on acoustics
Often the answer to the question “why is the motor humming” lies not in the technology, but in how it is installed. Incorrect position of the housing leads to misalignment, due to which the doors may not fit tightly, and the compressor may operate in abnormal mode. Mirror causes displacement of the internal components and increased resonance.
It is important to provide a gap between the back wall of the refrigerator and the wall of the room. If the unit is moved too close, heat exchange is disrupted, the motor overheats and begins to work more intensely and noisily. The minimum distance should be at least 5-10 centimeters for free air circulation.
☑️ Checking the installation of the refrigerator
Resonance is another enemy of silence. If the refrigerator is on a hollow or uneven surface, or if its walls touch kitchen furniture, any operating sound is amplified significantly. Sometimes it is enough just to move the refrigerator a couple of centimeters from the cabinet so that the hum stops.
Diagnostics of faults by sound type
Experienced technicians can determine malfunction just by listening to the refrigerator. The nature of the sound gives a direct hint about which node requires attention. For example, a metallic clanging sound often indicates a problem with the compressor valves, while a monotonous whine may indicate electrical problems.
The following table helps classify sounds and their likely causes. This will help you more accurately describe the problem to the technician or understand whether you can handle it yourself.
| Sound type | Probable cause | Urgency of repair |
|---|---|---|
| Smooth humming | Normal operation or resonance housing | Not required |
| Knock and clanging | The compressor is loose or the valve is faulty | Medium |
| Whistling or hissing | Freon leak or problem with the fan | High |
| Intermittent hum | Start relay malfunction | High |
Particular attention should be paid to the sound of “gurgling” or “transfusion”. In most cases, this is the normal flow of refrigerant through the pipes. However, if these sounds become very loud and are accompanied by a lack of cold, this is a sign of depressurization of the system.
Starting Relay and Electrical Problems
The starting relay is a small but critical element that supplies current to the motor windings to start it. If the relay is faulty, the engine may attempt to start, make a short, powerful beep, and click, but will not start. This condition is called “operation on a stuck rotor.”
Signs of electrical failure are often accompanied by heating of the compressor housing. If you put your hand on the rear grille (carefully, it may be hot) and you feel that the motor is hot, but there is no sound of operation or it is intermittent, the problem is most likely in the windings. starting relay without experience can lead to a short circuit or final failure of the compressor. starting device or windings.
⚠️ Attention: Attempting to replace the start relay yourself without experience can lead to a short circuit or permanent failure of the compressor.
It is also worth checking the integrity of the electrical cable and socket. Poor contact can cause humming and sparking, which is a fire hazard. Make sure that the plug sits tightly in the socket, and that the wire is not frayed and has no traces of melting.
Vibration and resonance: how to eliminate rattling
Sometimes the motor itself works properly, but creates a “rattling bucket” effect due to the vibration of the tubes. The copper tubes through which freon circulates may come into contact with each other or with the walls of the housing. When the engine is running, they begin to vibrate and produce an unpleasant metallic rattle.
To fix this problem, you need to remove the back panel and visually inspect the location of the tubes. If you notice points of contact, you need to carefully separate them with your hands (only if you are confident in your abilities and the refrigerator is turned off!).
- 🛑 Unplug the refrigerator before any manipulations with the tubes.
- 👐 Carefully bend the tubes so that the gap between them is at least 5 mm.
- 🔨 Check whether the compressor itself is loose on the frame and tighten the bolts.
Another source of resonance is internal shelves and objects inside. Empty glass shelves or loose bottles may vibrate as the motor operates. Try to fill the space or arrange the products more closely to prevent the dishes from rattling.
When you need to call a specialist
There are a number of situations when independent repair is not easy impractical, but also dangerous. If you have determined that it is the internal mechanics of the compressor that are humming (you can hear the knocking of valves inside the pressurized unit), then only replacing the unit can help. Opening a sealed compressor housing at home is impossible.
Also, professional help is needed in case of a refrigerant leak. Freon is a gas that requires special equipment for refilling. If you hear hissing and see oily stains on the floor or on the pipes at the back, you can’t hesitate.
Modern refrigerators with inverter compressors have a complex electronic control board. If this is the problem, then without diagnostic equipment and knowledge of electronics it will not be possible to find the fault. In such cases, it is better not to experiment so as not to aggravate the situation.
Compressor service life
The average service life of a modern compressor is 10-15 years. If your refrigerator is more than 20 years old, repairing the compressor may not be economically feasible.
Why did the refrigerator begin to hum immediately after defrosting?
Often after defrosting, water gets into the tray above the compressor or onto the electrical contacts, causing short-term noise or crackling. Also, a sudden change in temperature could cause the plastic to shrink/expand, which gives a cracking effect. If the humming does not stop after a day, check whether the fan is frozen.
Is it possible to lubricate the refrigerator motor if it is humming?
It is strictly forbidden to lubricate the operating components of the compressor or electric motor with household oils. This will lead to damage to the rubber seals and failure of the equipment. Lubrication is possible only in fan bearings, and then with special compounds.
Does an old refrigerator hum louder than a new one?
Yes, old models with conventional compressors and without sound insulation are always louder than modern analogues. In addition, over years of operation, shock absorbers wear out and fasteners become loose, which increases the noise.
What to do if it hums only at night?
At night, the overall noise level in the apartment drops, and the operation of the refrigerator becomes more noticeable. Also, at night the mains voltage may be lower, which forces the motor to work harder. Check the tight fit of the door - perhaps the noise is masked during the day, but at night the gap makes itself felt.