The constant hum of the refrigerator is one of the most common household sounds, to which we are so accustomed that we stop noticing it. However, when the nature of the sound changes, an increasing hum or sharp vibrations appear, this immediately causes concern for any owner. Noisy operation of a household appliance often becomes the first sign that changes are occurring in the cooling system that require your attention.
Modern models of refrigeration equipment, whether quiet Liebherr or reliable Indesit, should not produce shrill or rattling sounds in normal mode. Understanding the physical nature of sound helps to distinguish an emergency situation from normal operation of equipment. In this article we will analyze in detail the mechanics of noise occurrence.
Before calling a specialist, it is important to carry out an initial diagnosis yourself. Often the cause is simple instability on the floor or adhered dust, and not a breakdown of an expensive unit. Strong vibration of the case when touched by hand more often indicates problems with the installation than a motor malfunction.
The physics of sound: how the compressor works and why it makes noise
The heart of any refrigerator is compressorwhich compresses the refrigerant and forces it to circulate through a system of tubes. It is this node that creates the main low-frequency hum that we hear. The principle of its operation is similar to the operation of a car piston engine: inside there are moving parts that, when moving, create vibration and sound waves.
In modern inverter models, such as Samsung or LG, the compressor operates smoothly, without sudden starts and stops, so their background noise is minimal. Old linear compressors turn on at full power, which causes a characteristic growing hum, which then abruptly ends when the desired temperature is reached.
It is important to understand that sound is transmitted not only through the air, but also through structures. If the body of the refrigerator touches a wall or furniture, vibration from the motor will be transmitted to them, increasing significantly. Resonance can turn a quiet hum into a deafening roar.
⚠️ Attention: If the hum is accompanied by a metallic clang, knocking or whistling, immediately unplug the appliance. These are signs of mechanical destruction of the internal parts of the compressor or jamming of the piston group.
In addition, it is worth considering the characteristics of the refrigerant. As freon passes through the capillary tube and expansion valve, a characteristic gurgling or hissing sound may occur. This a normal physical process changes in pressure and state of aggregation of a substance, which does not indicate a breakdown.
Natural causes of noise: when humming is normal
Not every sound emanating from the refrigerator is a sign of a malfunction. There are a number of natural processes that are accompanied by acoustic effects. For example, in models with a system No Frost a fan is constantly running, driving cold air through the chambers. Its uniform hum should be quiet and monotonous.
It is also worth considering the thermal expansion of materials. The plastic of the inner case and metal elements may crack slightly or make clicking noises when the temperature changes. This is especially noticeable immediately after turning on or off the compressor, when the temperature difference is maximum.
- 🔊 The quiet hum of the compressor - indicates that the motor is operating in normal mode, pumping up pressure.
- 💨 Fan noise - is typical for systems with forced air circulation (No Frost), the sound should be smooth, without whistling.
- 💧 Gurgling and overflowing —the sound of freon moving through the tubes, often heard immediately after the engine stops.
If you have recently placed new products in the chamber, especially in large volumes, the refrigerator will work more intensely and, accordingly, louder. This is the intensive freezingmode, which is necessary for quickly reducing the temperature of loaded products.
Installation problems: the most common cause of vibrations
Statistics from service centers show that more than half of the calls to technicians regarding the “breakdown” of the refrigerator are associated with improper installation. If the device is not level, its legs are not adjusted, or it is moved too close to the wall, vibration from the running motor is transmitted to the floor and walls.
Check the stability of the case. The refrigerator should not wobble when you lightly press the top corner. To make adjustments, use the screw supports on the lower front of the unit. They must be unscrewed so that the front part of the device is slightly higher than the back, ensuring a tight fit of the doors due to gravity.
☑️ Checking the correct installation
The gap between the back wall of the refrigerator and the wall of the room should be at least 5-10 centimeters. This is necessary for free air circulation around the condenser (grid at the back). If there is no gap, heat is not removed, the compressor overheats and begins to work with increased load, producing a louder hum.
Also check whether the internal shelves or dishes are touching the walls of the chamber. Sometimes it is enough to place the plate so that when it vibrates, it begins to rattle against glass or plastic, creating the illusion of equipment failure.
Technical faults: when it’s time to call a technician
If you are convinced that the refrigerator is level and nothing interferes with its operation, but the hum remains strong or changes tone, we may be talking about a technical fault. One of the common problems is wear of shock absorbers or rubber gaskets on which the compressor is mounted.
Over time, the rubber dries out and loses its elasticity. As a result, the metal housing of the motor begins to vibrate against the frame of the refrigerator. In such cases, the hum becomes metallic and rattling. Replacing gaskets is a simple and inexpensive procedure, available even for some models Bosch or Atlant.
A more serious problem is a malfunction of the electric motor itself. If the shaft bearings are worn out or a short circuit occurs in the winding, the sound becomes shrill and howling. In this case, compressor repair is often not economically feasible, and its complete replacement is required.
⚠️ Attention: Do not try to disassemble the sealed circuit yourself or change the compressor without special equipment and a license. This requires evacuation of the system and charging with freon under pressure.
Another reason for noise in No Frost refrigerators is a fan malfunction. If ice has frozen on its blades or the bushing bearings have worn out, a characteristic crackling or hum appears, which intensifies when the door is opened (since many fans only work when the door is closed).
Comparison of noise levels and diagnostics by sound
To understand how loud your device is, it is useful to know the standard values. Modern energy efficiency standards require manufacturers to reduce noise levels. However, different types of equipment sound differently.
| Sound type | Probable cause | Degree of danger | Action required |
|---|---|---|---|
| Uniform low hum | Normal operation of the compressor | Safe | No need to do anything |
| Rattling of the housing | Touching furniture, uneven floor | Safe | Align, move away |
| Metal clanging | Destruction of compressor valves | Critical | Turn off, call a technician |
| Fan whistling or crackling | Ice ingress, bushing wear | Medium | Defrosting, cleaning |
Pay attention to the cyclical nature of the sound. The normal operating cycle implies: turning on the motor (increasing hum) - operation (smooth sound) - turning off (fading and gurgling). If the engine hums continuously without turning off for hours, this is a sign of a freon leak or a leak in the circuit.
In models with inverter control the sound may be barely audible, but if it suddenly becomes louder, this may indicate a failure in the electronic control module, which is sending incorrect commands to the engine.
Why can a new refrigerator hum louder than an old one?
New models often have more powerful compressors to comply with environmental standards (elimination of old freons), which can increase the noise level. In addition, the lack of production in new mechanisms sometimes makes the sound louder until the parts are worn in.
Do-it-yourself noise reduction methods
If the refrigerator is technically working, but the noise level is still annoying, you can resort to additional sound insulation measures. First of all, make sure that the refrigerator is not placed in a niche that acts as a resonator. The sound wave, reflected from the walls of the niche, intensifies.
Check the fastenings of the internal elements. Sometimes the plastic fasteners on shelves or drawers can become loose. Tighten the screws or use small pieces of foam where the plastic touches the metal to prevent rattling.
- 🔧 Tightening the fasteners —check all visible bolts and screws on the body and inside the chambers.
- 🧊 Removing ice —carry out a complete defrost (at least 24 hours), to remove ice from the fan and pipes.
- 🔊 Soundproofing walls —if the refrigerator is located against the wall, you can stick sound-absorbing material on the wall behind it.
It is important to regularly clean the rear grille of the condenser from dust. A grate clogged with dust impairs heat transfer, forcing the compressor to work longer and more intensely, which inevitably leads to an increase in the level of noise produced.
When professional repairs are needed
There are a number of symptoms in which independent actions are useless or dangerous. If, after defrosting and leveling the floor, the hum does not stop, and the temperature in the chambers no longer remains at the desired level, the problem lies deep inside the system.
The technicians diagnose the condition refrigerant and the tightness of the circuit. Freon leakage is a common reason why the compressor runs “idle”, trying to build up pressure, and because of this it makes a lot of noise. This can be visually noticed by swelling or, conversely, wrinkling of the evaporator inside the chamber.
⚠️ Attention: If you smell burnt wiring or plastic when the refrigerator is operating, immediately unplug the cord from the outlet. This may be a sign of an interturn short circuit in the motor winding.
A specialist’s help is also needed if the compressor needs to be replaced. This is a complex process that includes cutting pipes, soldering new connections, installing a filter drier, evacuating the system and charging a strictly defined amount of refrigerant.
Why does the refrigerator hum only at night?
At night, the overall level of background noise in the apartment decreases, and even the standard hum of the compressor becomes more noticeable. In addition, the power supply voltage often drops at night, which can cause transformers to hum or engine performance to change. Also at night, neighbors work more quietly, and sound passes through the walls better.
Is it possible to lubricate the compressor so that it does not hum?
It is impossible to lubricate the refrigerator compressor from the outside, since it is a sealed welded block. Internal lubricant is filled at the factory. If you hear friction noise inside, this means wear of the mechanical parts, and lubrication will no longer help - the unit needs to be replaced.
Does the amount of products affect the noise level?
Yes, it does. A fully loaded refrigerator maintains its temperature better and the compressor turns on less often. However, if the food is too dense and blocks the air flow (in No Frost), the fan may begin to hum more due to increased resistance to air flow.
Does the old refrigerator hum louder than the new one?
Usually yes. Over time, rubber shock absorbers wear out, backlashes appear in mechanisms, and rubbing parts become dirty. New models are often designed with acoustic comfort in mind and have improved sound insulation of the housing.
What to do if there is a buzzing sound after defrosting?
After defrosting, water may remain in the system. Let the refrigerator run empty for 2-3 hours. If the hum does not go away, it is possible that water has got into the electrical part or has frozen on the fan blades, which requires repeated drying or checking.