Suddenly appearing or increasing The hum of the refrigerator compartment can unsettle any apartment owner. Equipment that has worked silently for years suddenly begins to hum, gurgle, or make alarming knocking noises. This is not just acoustic discomfort, but also a signal that changes have occurred in the operation of the unit that require attention.
The first thing to do when detecting extraneous sounds is to evaluate their nature. Monotonous hum often differs from an intermittent knocking or high-frequency whistle. Understanding the difference between the operating noise of the compressor and abnormal vibrations will allow you to make the right decision: try to fix the problem yourself or call a specialist.
In this article we will analyze in detail the physics of the processes inside the refrigeration cabinet. You will learn which components can become the source of sound, how to distinguish normal operation of the system from a breakdown, and when ignoring a symptom can lead to expensive repairs.
Natural sounds of a working refrigerator
Modern models of household appliances, be it Indesit, LG or Atlantcannot work in absolute silence. The main source of sound is compressorwhich compresses the refrigerant and pumps it through the pipe system. When the engine is started or during its active operation, a background hum is acceptable, the level of which usually does not exceed 40 dB.
In addition to engine operation, physical processes are constantly occurring in the freon circulation system. The liquid refrigerant, passing through the capillary tube and evaporator, boils and turns into gas. This process is accompanied by a characteristic gurgling or overflow, which can be heard even after the compressor is turned off. This is absolutely normal and indicates correct circulation of the substance.
⚠️ Attention: If you have just defrosted the refrigerator or loaded a large amount of warm food into it, the intensity of the sounds may temporarily increase. The system will operate in enhanced mode until the set temperature is reached.
It is also worth considering the thermal expansion of materials. The plastic of the inner case and metal elements may become slightly deformed when the temperature changes, producing quiet clicks or crackling sounds. Typically, such sounds occur when the unit is turned on or off and do not pose a threat.
Installation errors as a cause of vibration
One of the most common reasons why the refrigerator began to make a lot of noise or vibrate is incorrect installation. If the body of the equipment touches the walls of the kitchen unit or does not stand level, the vibration from the running motor is transmitted to the building structures, amplifying many times over.
Check the horizontal installation. To do this, use a building level or simply try to shake the unit. If it is unstable, the height of the front supports must be adjusted. Most models are provided for this adjusting feet, which can be turned manually or using a key.
- 🔧 Make sure that there is a gap of at least 5-10 cm between the back wall of the refrigerator and the kitchen wall for free air circulation.
- 🔧 Check whether pipes or other objects are touching the body of the refrigerator, creating resonance.
- 🔧 Make sure that nothing is vibrating inside the chambers: bottles, dishes or loose shelves can rattle in response to the motor.
Often users forget to remove shipping bolts or backings, which secure the compressor during transportation. If these elements are left in place, they will transmit vibration to the chassis, creating a strong rumble. It is also worth checking whether the refrigerator is on a slippery floor without rubber bearings.
☑️ Installation diagnostics
Foreign objects and rattling of parts
Sometimes the source of noise is not in the depths of the unit, but in plain sight. Vibration can be transmitted to objects standing next to the refrigerator or on its top panel. Heavy pots, jars of pickles, or decorative items may resonate with the frequency of the compressor.
Inside chambers, the source of sound is often glass shelves or plastic containers. If they do not fit tightly to the guides or have cracks, they will make an unpleasant ringing noise. Particular attention should be paid to egg trays and door shelves, which are most often subject to mechanical stress.
To diagnose this type of noise, try pressing your hand on various surfaces of the operating refrigerator. If the sound disappears when you press the door, shelf or top cover, then you have found the source of the rattling noise. In some cases, it is necessary to place a piece of foam rubber or rubber under the vibrating part.
Hidden sources of noise
Sometimes the refrigerator handle itself can rattle if its fastening is loose. Also check if small objects (coins, caps) have fallen behind the rear radiator grille.
Problems with the compressor and motor
If external factors and installation errors are excluded, and the hum becomes loud, metallic or intermittent, the problem may lie in the heart of the refrigerator - the compressor. Wear of the motor shaft bearings leads to the appearance of a characteristic howl or hum, which intensifies over time.
Another serious reason is turn-to-turn short circuit in the windings of the electric motor. In this case, the refrigerator may hum but not start, or it may start for a couple of seconds and go silent again with a click from the thermal relay. This condition requires immediate intervention from a technician, as the motor may burn out completely.
| Sound type | Probable cause | Danger level |
|---|---|---|
| Smooth low hum | Normal operation of the compressor | Safe |
| Metal clanging at start | Wear of motor mounts | Average |
| Loud humming without cooling | Compressor malfunction | High |
| Intermittent knocking | Refrigerant has entered the cylinder | High |
It is important to note that inverter compressors that are installed in modern models Samsung i Boschoperate on a different principle. They do not turn off completely, but only change power, so their operation may be accompanied by a constant low hum, which should not frighten the owner.
No Frost system malfunctions
Refrigerators with the No Frost system are equipped with additional fans that circulate cold air inside the chambers. If you hear whistling, howling or wind noise, the problem most likely lies there. Over time, the fan bearings wear out, or ice builds up on its blades.
The build-up of a snow coat on the evaporator or fan is a common cause of noise. This may occur due to a malfunction of the defrost heating element, timer or thermostat. Ice interferes with the rotation of the impeller, and it begins to touch the walls of the plastic box, making a cracking noise.
- ❄️ Try to defrost the refrigerator completely (for 24 hours) - if the noise disappears, then the problem was in the ice.
- ❄️ Check whether the fan is warped due to the destruction of the plastic fastenings.
- ❄️ Make sure that no foreign objects (foil, labels) have gotten into the air ducts.
If after defrosting the sound returns after a few days, it means that the defrosting system is not working correctly and diagnostics of electronic components or replacement of the heating element is required. Ignoring this problem will lead to the complete accumulation of ice on the evaporator and the cessation of cooling.
Hydraulic hammer and problems with freon
One of the most frightening sounds is a loud knock, similar to a hammer hitting metal, that occurs when the compressor starts or stops. This phenomenon is called water hammer. It occurs when liquid freon or oil enters the compressor cylinder, where there should only be gas.
The reasons can be different: from an excess of oil in the system to a temperature violation (for example, if you put a hot pan in the chamber, causing a sudden boiling of the refrigerant). Water hammer is also possible if the compressor valves are faulty.
⚠️ Attention: Regular water hammer destroys the valve group and piston system of the compressor. If you hear such knocks constantly, the service life of the motor is sharply reduced.
In addition, if a microcrack has formed in the system and freon begins to flow out, the compressor may work with increased load, trying to compensate for the loss of pressure. This is accompanied by a change in the tonality of the sound of the engine and often by overheating of the motor housing.
Is it possible to add freon?
You cannot do this yourself. Special equipment is required to evacuate the system and accurately fill by weight. Simply “adding” gas without looking for a leak will not solve the problem.
When you need to call a technician
Not all noise can be eliminated with your own hands. If you have checked the installation, removed unnecessary items and defrosted the unit, but the sound remains, a professional repair is most likely required. It is especially important not to delay if the noise is accompanied by other symptoms.
There are a number of signs in which independent repair is not only useless, but also dangerous. Opening a sealed circuit or attempting to repair the electrical part without qualifications can lead to electric shock or permanent breakdown of the equipment.
- 🛑 The compressor hums, but does not start, the relay clicks are heard.
- 🛑 There is a smell of burning or burning plastic.
- 🛑 The refrigerator has stopped freezing or is freezing too much.
- 🛑 Oily spots have appeared on the floor under the appliances (oil coming out of the compressor).
The specialist will carry out diagnostics using pressure gauges and testers, pinpoint the faulty unit and replace it. In some cases, for example, when a compressor fails, repairs may not be economically feasible, and it is easier to purchase new equipment.
Why does the refrigerator make a loud bang after turning off?
A loud pop or click immediately after stopping the engine is often caused by a change in pressure in the system. When there is a sudden change in pressure, the walls of the tubes or the compressor housing can make such a sound. If this happens once and rarely, this is normal. If it slams frequently, the start relay may be faulty.
Can an old refrigerator be quieter than a new one?
As a rule, no. Over time, bearings wear out, rubber shock absorbers dry out, and the equipment begins to make more noise. However, new models with larger compressors may be noisier than the old Soviet ones, but they are more energy efficient. Silence depends on the energy efficiency class and the type of compressor.
Is it dangerous if the refrigerator hums, but freezes well?
If the cooling is normal, most likely there is no threat to the food. However, an increased hum indicates an increased load on the nodes. This can lead to premature wear of the compressor. It is recommended to carry out preventive maintenance: check the installation and cleanliness of the condenser at the back.
How to reduce the noise of a refrigerator with your own hands?
In addition to adjusting the legs, you can place a special vibration-isolating mat under the compressor (if there is access) or replace the rubber washers on the motor mounts. Pasting the inner walls of the chambers with soundproofing material also helps, but this requires disassembly and can disrupt heat transfer.