The situation when the refrigerator is knockingcan unbalance any owner of household appliances. Sudden impacts, rhythmic clicking or loud clicks that interrupt the silence in the apartment are often the first signal that something is wrong with the unit. However, do not panic ahead of time: the noise can be caused either by a banal unevenness of the installation or by a serious malfunction of the internal mechanisms.
Understanding the nature of sounds is the key to quickly solving the problem. In some cases, it is enough to simply adjust the position of the case so that compressor stops hitting the cabinet walls. In other situations, knocking indicates wear motor suspension or problems with the defrost system. Ignoring these signals can lead to expensive repairs or complete replacement of an expensive unit.
In this article we will analyze in detail all the possible causes of knocking, diagnose the main components and tell you in which cases you can handle it yourself, and when it is better to call technician. If the knocking is accompanied by a lack of cold or the appearance of a puddle under the unit, operation must be stopped immediately.
Natural sounds of the compressor and defrost system
Before sounding the alarm, you must learn to distinguish normal operating sounds from signs of breakdown. Modern refrigerators, especially models with the No Frostsystem, make specific sounds during their operation. For example, the characteristic “gurgling” or flow of liquid is the movement of the refrigerant through the tubes of the evaporator and condenser. A periodic click when the motor is turned on or off is the normal operation of the starting relay. Also, in models with automatic defrosting, a cracking sound or even a loud knock, reminiscent of a gunshot, may be heard. This occurs due to thermal expansion and contraction of plastic parts, as well as due to breaking off pieces of ice falling on the heater. refrigerant through the evaporator and condenser tubes.
A periodic click when the motor turns on or off is normal operation of the starting relay. Also, in models with automatic defrosting, a cracking sound or even a loud knock, reminiscent of a gunshot, may be heard. This occurs due to thermal expansion and contraction of plastic parts, as well as breaking off pieces of ice falling on the heater.
If you hear these sounds regularly and they are not accompanied by other symptoms (heating of the case, lack of cold), then the equipment is working properly. However, if the nature of the sound has changed, become louder or a metallic clang appears, you should listen more carefully.
- 🔊 Quiet humming — normal operation of the motor.
- 💧 Gurgling —freon circulation in the circuit.
- ⏱️ Rare clicks - operation of a thermostat or relay.
It is important to note that the noise level depends on the brand and model of the device. Some brands, such as Liebherr or Boschare famous for their quiet operation, while others may hum a little louder due to design features.
Installation problems and body vibration
The most common and easily fixed reason why a refrigerator knocking or buzzing - this is an incorrect installation. If the body is not level, a resonance occurs, which increases the vibration of the worker compressor. As a result, the unit begins to rattle, and over time it may shift and begin to hit furniture or a wall.
Check whether the legs of the refrigerator are firmly attached to the floor. It often happens that one of the supports hangs in the air, which creates a misalignment. It is also worth checking the distance to the back wall and side cabinets: if the refrigerator touches them, the vibration will be transmitted to the furniture, creating the effect of increased knocking.
⚠️ Attention: Do not move the refrigerator close to the wall. For normal air circulation around the condenser grill, it is necessary to leave a gap of at least 5-7 cm, otherwise the motor will overheat and run louder.
To fix the problem, you will need a building level. Place it on the lid of the refrigerator and, by rotating the adjusting feet, achieve a horizontal position. If the floor is slippery (for example, tiles), you can place special anti-vibration pads or a piece of rubber under the legs.
Faulty suspension and compressor mounting
If everything is in order with the installation, but the refrigerator continues to knock, the problem most likely lies internally. The compressor is the heart of the unit, and it is mounted on special shock absorbers (springs, rubber bushings or bolts). Over time, these elements wear out, dry out or break.
When depreciation is broken, the motor begins to vibrate during operation and hit the metal cabinet body or frame. This creates a loud, ringing knock that can be clearly heard throughout the entire apartment. This is especially pronounced when the engine starts, when vibrations are maximum.
In some models, compressors are mounted rigidly, and knocking may occur due to loosening of the mounting bolts. If you have skills in repairing household appliances, you can remove the back cover and visually assess the condition of the fasteners. However, remember that this will require disconnecting the device from the network and possibly removing the compressor.
☑️ Diagnostics of compressor mounts
Replacing shock absorbers is a simple procedure, but requires care. It is important to choose the right parts, as there are no universal solutions. For older models Indesit or Atlant often require specific springs, which can be found in service centers.
Knock in the No Frost system: fan and ice
In refrigerators with the system No Frost The source of the knocking is often the fan located in the freezer. Its job is to circulate cold air. If ice has formed on the fan blades or on the walls of the evaporator, the blades begin to touch the ice, producing a characteristic cracking or knocking sound.
This problem often occurs if the tightness of the door seal is broken or if the door has been used for a long time, leaving it open. Moisture gets inside, freezes and interferes with the fan's operation. The cause may also be wear on the bearing of the fan itself, which begins to hum and knock when rotating.
To eliminate ice, it is often enough to completely defrost the refrigerator. Leave the unit turned off for 10-12 hours (preferably a day) with the doors open. During this time, the ice will melt and the fan will be able to rotate freely again.
| Symptom | Probable cause | Solution method |
|---|---|---|
| Crackling noise in the freezer | Ice on fan | Defrost 12+ hours |
| Humming + knocking | Fan bearing wear | Fan replacement |
| Intermittent knocking | A piece of ice in the air duct | Cleaning the duct |
| Vibration of the case | The fan touches the wall | Editing the fastening |
If after defrosting the knocking returned after a few days, which means that the problem is not a one-time frost, but a malfunction of the defrost system (heating element, timer, sensor), which does not have time to melt the formed frost.
Hydraulic hammer and problems with the refrigerant
A more serious reason for the knocking is the so-called water hammer. This phenomenon occurs when liquid refrigerant (freon) along with oil enters the compressor cylinder. Normally, only gaseous freon should enter the compressor. The liquid, being incompressible, causes a sharp impact of the piston, which is heard as a loud knock or clang.
The reasons for water hammer can be different: an excess of freon in the system, a clogged capillary tube, or a malfunction of the compressor itself, which does not have time to evaporate the oil. This condition is dangerous for the motor and can cause it to jam.
⚠️ Attention: If you hear loud knocks inside the motor, similar to the operation of a hammer drill, immediately turn off the refrigerator. Further operation in this mode will quickly damage the compressor.
It is difficult to diagnose this problem yourself, since it requires measuring the pressure in the system and checking the amount of refrigerant. Here you need the help of a qualified technician with a manometric manifold.
Is it possible to add freon yourself?
Refilling freon yourself without evacuating the system and replacing the filter-drier will lead to moisture and air getting into the circuit. This will cause the formation of ice plugs, corrosion and rapid failure of the compressor. Professional equipment is required.
Foreign objects and shelf contents
Before disassembling the equipment, exclude the simplest reasons. Often the source of knocking is objects located inside or behind the refrigerator. The vibration from the running motor is transmitted to the shelves, and if there are glass jars or bottles on them, they may touch each other or the walls, creating a ringing sound.
Also check the area behind the refrigerator. There may be forgotten things lying around, packaging or tools that begin to rattle when vibrated. Pay special attention to the condensation tray located above the compressor: if it is moved, it will knock on the housing.
Try to remove all the food and remove the shelves, then turn on the empty refrigerator. If the knocking noise disappears, then the reason was in the contents. Arrange foods so that they do not touch each other or the walls of the chamber.
When you need to call a specialist
Not all breakdowns can be repaired with your own hands. If you have checked the installation, defrosted it, removed unnecessary items, but The refrigerator is knocking it still most likely requires professional repair. This is especially true when the knocking is accompanied by other alarming symptoms.
A technician is needed if a compressor malfunction is suspected (wear of valves, liners), problems with the defrost system in No Frost models, or a refrigerant leak. An attempt to replace the compressor yourself without special equipment (vacuum pump, burner, pressure gauges) is doomed to failure.
It is also worth contacting service if the refrigerator is new and under warranty. Independent opening of seals or repairs will lead to loss of the manufacturer's warranty.
Why did the old refrigerator start knocking more than before?
Over time, all mechanical parts wear out. Rubber shock absorbers dry out and lose elasticity, fan bearings break, and the gaps between parts in the compressor increase. In addition, the housing fasteners may have become loose. If the refrigerator is more than 10 years old, increased noise is a natural process of aging equipment.
Is knocking dangerous for food in the refrigerator?
Knock itself does not directly affect the quality of food. However, if the knocking noise is caused by a malfunction of the compressor or defrost system, this may lead to temperature disturbances. In this case, food may begin to spoil faster. Monitor the temperature in the chambers.
Can an inverter compressor knock?
Inverter compressors (Digital Inverter, Linear Compressor) work quieter and smoother than conventional ones, since they do not turn off completely, but only change power. However, they can also make sounds: a hum, a high-frequency squeak, or rare clicks. A loud knock is uncharacteristic for them and indicates a breakdown.
What to do if the knocking appeared immediately after purchase?
If the new refrigerator makes loud noises, check that all shipping bolts and film have been removed. Make sure it is leveled correctly. If the problem persists, do not try to repair it yourself - contact the store for a replacement or warranty repair, as this may be a manufacturing defect.