The situation when the refrigerator began to humis familiar to many owners of household appliances. Just yesterday the unit worked quietly and unnoticed, but today it emits an obsessive hum that interferes with sleep at night or is simply annoying during the daytime. Understanding the nature of this sound is the first step to solving the problem, be it a simple rearrangement of furniture or a complex repair.
The noise can be caused by many factors: from a banal misalignment of the case to serious malfunctions in the system refrigerant circulation. It is important to learn to distinguish between normal operating sounds and abnormal ones, since ignoring the latter can lead to failure of expensive components and damage to products.
In this article we will analyze in detail all the possible causes of hum, methods for self-diagnosis, and situations where you can’t do without calling a technician. Correct diagnostics will help save your budget and extend the service life of your refrigeration equipment.
Physics of the process: why noise occurs at all
Any working mechanism makes sounds, and the refrigerator is no exception. The main source of noise is traditionally considered to be compressor the “heart” of the refrigerator, which compresses the refrigerant and forces it to circulate through the system. Modern models use inverter compressors, which operate quieter and smoother, but even they can produce a characteristic low-frequency hum.
In addition to the motor, sounds can occur when freon moves through the tubes. This may be gurgling, hissing or whistling. Users often confuse these sounds with a breakdown, although in most cases it is the normal operation thermostat and heat dissipation system. However, if the nature of the sound has changed sharply, become louder or extraneous vibrations have appeared, this is a signal of an imbalance in the system.
⚠️ Attention: If the hum is accompanied by a strong burning smell, smoke or strong heating of the rear wall, immediately disconnect the device from the power supply. Operation of faulty equipment can lead to a fire.
It is also worth considering the acoustic properties of the room. An empty kitchen with tiled floors and smooth walls acts as a resonator, amplifying any sounds. The addition of furniture, curtains or carpets can dramatically change the perception of noise, even if the refrigerator itself is operating as usual.
External factors: vibration of the case and incorrect installation
Before opening the technical compartment or calling a technician, it is necessary to exclude the simplest reasons. Often the answer to the question “why is the refrigerator humming” lies in incorrect installation. If the case touches a wall, furniture or objects on a shelf, vibration from the running compressor is transmitted to them, causing resonance and strong hum.
Check the distance to the walls. The operating instructions for most brands, such as Indesit or LG, require a gap of at least 5-10 cm on all sides for free air circulation. The lack of clearance not only increases the noise, but also forces compressor to work with overload, which reduces its resource.
The second important aspect is the horizontal installation. If the legs of the refrigerator are not adjusted correctly, the body will warp and the compressor will begin to vibrate more than usual. To check, use a building level or a regular glass of water placed on the lid of the unit.
☑️ Diagnostics of refrigerator installation
Particular attention should be paid to the floor. If the surface is uneven or slippery, the refrigerator may move slightly when the motor is running, creating a rattling noise. In such cases, special anti-vibration pads can be placed under the legs to dampen vibrations.
Diagnostics of the compressor and start relay
If external factors are excluded, most likely the source of the noise is inside the technical compartment. The compressor is the noisiest component. Over time, the engine bearings wear out, play appears, and the engine begins to hum louder, sometimes with a metallic tint. This is a sign that the resource unit is coming to an end.
Another common reason is a malfunction of the starting relay. This small element is responsible for starting the engine. If it is damaged or the contacts have oxidized, the compressor may hum but not start, or may start with a loud clicking and humming sound. In such cases, the relay must be replaced, which is a relatively inexpensive procedure.
It is also worth checking the fastening of the compressor itself to the frame of the refrigerator. Sometimes bolts or rubber shock absorbers become loose, and the motor begins to beat around the frame during operation. This creates a very strong, low-frequency hum and vibration of the entire case.
| Noise type | Probable cause | Difficulty of repair | Required actions |
|---|---|---|---|
| Uniform hum | Normal operation or bearing wear | Average | Checking the installation, replacing the compressor |
| Hum with clicks | Faulty start relay | Low | Replacing the relay |
| Metal knocking | Loose motor mounts | Low | Tightening the bolts, replacing shock absorbers |
| Intermittent hum | Problems with the thermostat or wiring | Average | Electrical diagnostics |
Perform this operation yourself without special equipment impossible and dangerous.
Problems with the defrosting system and fan
In system refrigerators No Frost the fan is responsible for circulating cold air. If ice accumulates on its blades or moisture gets into the bearing, a characteristic noise, crackling or buzzing appears. Often this sound intensifies precisely at the moment when the door is closed and the blowing system is running.
Another common problem is a malfunction of the defrost system. If the defrost heating element burns out or the timer fails, a “coat” of ice builds up on the evaporator. The fan begins to touch these ice build-ups with its blades, which causes a loud cracking and buzzing noise. Visually, this can be seen by the snow on the back wall of the freezer.
How to check the fan without disassembling?
Try to localize the sound. If the hum comes from the top of the freezer and changes when the door is opened (in many models the fan turns off when the door is open), the problem is most likely this or ice on the evaporator.
To eliminate this problem, it is often necessary to completely defrost the refrigerator within 10-12 hours. If after switching on the noise disappeared, but returned a week later, then the defrosting system is faulty and requires repair by a specialist.
⚠️ Attention: Do not try to chip the ice with a knife or sharp objects. Damage to the evaporator tubes will lead to freon leakage and costly repairs.
Hydraulic shocks and movement of refrigerant
Sometimes users hear sounds reminiscent of water pouring or gurgling. This is the sound of moving through the tubes refrigerant. In normal mode it is quiet and almost inaudible. However, if the refrigerator has just been defrosted or it has been turned off for a long time, the sound may be louder due to the mixing of freon and oil.
If the gurgling is accompanied by a strong hum and the refrigerator does not freeze well, this may indicate a clogged capillary tube or the presence of air in the system. In such cases, the pressure in the circuit changes, and the compressor is forced to work in extreme mode, trying to push through the plug.
It is also worth mentioning the so-called “hydraulic shocks”. If moisture gets into the system (which is rare, but possible with poor repairs), it can freeze in narrow places, creating plugs. As the refrigerant passes through them, it makes whistling or hissing sounds.
Only a technician can diagnose the condition of the refrigerant and the pressure in the system using a pressure gauge station. It is strictly not recommended to get into the gas circulation system on your own.
When you need to call a specialist: critical symptoms
There are a number of symptoms in which independent repair is not only useless, but also dangerous. If the refrigerator is humming and it does not turn off for hours, and the temperature in the chambers does not drop below +10°C, this is a sign of a serious compressor failure or freon leak.
Another alarming signal is the appearance of oil under the refrigerator or on the condenser tubes. This indicates a depressurization of the system. You should also be wary if the humming is accompanied by heating of the side walls to a state where they cannot be touched.
In cases where it is necessary to replace the motor, refill with freon or complex repairs of the No Frost system, it is better to contact an authorized service center. Professionals have access to original spare parts and guarantee the quality of the work performed.
Do not forget that modern refrigerators are complex electronic devices. An attempt at repair without the appropriate knowledge can lead to damage to the electronic control module, the cost of which is a significant part of the price of a new device.
Prevention and care of the refrigerator
In order for your refrigerator to serve for a long time and work quietly, it is necessary to regularly carry out preventive measures. The most important thing is to prevent a thick crust of ice from forming in the freezer, even in models with manual defrosting. A layer of ice of more than 5 mm impairs heat transfer and makes the compressor work harder.
Check the door seals regularly. If they become dry or dirty, the door does not close tightly, warm air gets inside, and the unit is forced to work without interruption, which increases wear and noise. Wipe the seals with a soft cloth and check their fit.
It is also important to keep the condenser (the grill at the back of the refrigerator) clean. Dust and animal hair, accumulating on the tubes, impair heat transfer, which leads to overheating of the compressor and increased noise. It is recommended to vacuum the rear panel once every six months.
☑️ Noise prevention plan
Is it normal for the refrigerator to hum when you first turn it on?
Yes, this is normal. When first starting up or after a long period of inactivity, the compressor may run longer and louder than usual until the required temperature is reached and the pressure in the system is stabilized. This usually takes from 2 to 6 hours.
Why does an old refrigerator hum louder than a new one?
Over time, the mechanical parts of the compressor wear out, the rubber shock absorbers dry out, and the fasteners weaken. In addition, older models are simply less technologically advanced and do not have modern sound insulation, so their operating noise is initially higher.
Is it possible to lubricate a humming compressor?
No, modern compressors are sealed units. They are filled with lubricant at the factory and are designed for their entire service life. An attempt to drill a hole for oil will lead to immediate breakdown of the unit and leakage of freon.
Does the amount of food in the refrigerator affect the noise level?
Indirectly - yes. A full refrigerator holds the temperature better, and the compressor turns on less often, but not for long. An empty refrigerator heats up faster, causing the motor to turn on more often. However, a sudden change in sound is usually associated not with loading, but with the technical condition.
What to do if a buzzing sound appears after defrosting?
If a new sound appears after defrosting, let the refrigerator operate for several hours. There may be some water or oil left in the system that needs to be distributed. If the noise does not go away and is accompanied by poor cooling, call a technician.