Modern household appliances have become much quieter than their predecessors, but completely it cannot be silent. When there is a new model in the kitchen, any extraneous noise immediately catches the eye and causes alarm to the owner. Understanding the nature of acoustic phenomena inside the case will help you distinguish normal operation from a serious malfunction.
A refrigeration unit is a complex thermodynamic system in which physical processes constantly occur. Refrigerant circulationpressure drops, the operation of the compressor and thermostat are inevitably accompanied by a background sound. It is important to learn to distinguish between the monotonous hum of a working motor and alarming knocks that require the intervention of a technician.
In this article we will examine in detail the range of sounds that are considered normal for various types of equipment. You will find out why the refrigerator may crackle, gurgle or whistle, and in which cases it is necessary to urgently call service.
The nature of noise: how the compressor works
The main source of sound in the refrigerator is compressor, which is often called the “heart” of the system. It is he who builds up pressure and forces the refrigerant to circulate through the tubes. In modern inverter models, this process occurs smoothly, while older linear compressors operate in jerks, creating a characteristic sound profile.
A smooth, low-frequency hum is considered normal, which can intensify when starting or stopping the engine. Inverter compressors practically do not turn off, maintaining the temperature by changes in power, so their sound resembles a quiet hiss or hum that changes in tone.
- 🔊 A uniform low-frequency hum is a sign of stable operation of the motor.
- 🔊 A short-term increase in sound when turned on is a normal load on the start.
- 🔊 Quiet hissing in pauses - residual movement of freon in the system.
It is worth noting that the noise level directly depends on the quality of installation of the equipment. If the refrigerator is not level, vibration from the compressor is transmitted to the floor and walls, creating a resonating effect. Checking the legs and adjusting the level is the first thing to do when there are complaints about noise.
Refrigerant sounds: gurgling and overflowing
One of the most common questions users are affected by sounds reminiscent of water pouring or gurgling. Many people mistakenly believe that there should be nothing but gas inside the pipes, but this is not so. Refrigerant circulates through the system in two states: liquid and gaseous, which creates an acoustic effect.
The sounds of liquid “flowing” are most often heard immediately after the compressor stops or at the time of its startup. This is due to changes in pressure in the evaporator and condenser circuits. In No Frost systems these sounds can be heard even louder due to the design of the air ducts.
⚠️ Attention: If the gurgling sound is accompanied by strong heating of the side walls or the appearance of puddles under the refrigerator, this may indicate a freon leak or blockage capillary tube.
It is also worth considering that in modern models with a freshness zone or zero chamber, additional fans and dampers are used. Their work can add specific noises that are mistakenly attributed to the movement of freon.
Why do sounds increase at night?
At night, extraneous background noise in the apartment subsides, and the operation of equipment becomes more noticeable. In addition, voltage drops in the network at night may be smaller, which allows the compressor to operate in a more stable mode, but the sound does not disappear from this.
Thermal expansion: why the refrigerator cracks
Crackling, clicking and short series of sounds, similar to the blows of a plastic ruler, often frighten the owners of new equipment. However, in the vast majority of cases, this is an absolutely normal physical process known as thermal expansion. The inner walls of the chamber, plastic shelves and metal evaporator tubes constantly change their temperature. When cooled, materials contract, and when heated (during defrost or idle time), they expand. It is the friction of parts against each other during this movement that creates a characteristic crackling sound. thermal expansion.
The inner walls of the chamber, plastic shelves and metal evaporator tubes constantly change their temperature. When cooled, materials contract, and when heated (during defrost or idle time), they expand. It is the friction of the parts against each other during this movement that creates the characteristic crackling sound.
- 🌡️ Single loud clicks - the reaction of the plastic to a sudden change in temperature.
- 🌡️ Series of quiet crackling sounds - gradual expansion/contraction of the internal panels.
- 🌡️ The sound of “popping” is often heard in quick-freezing chambers.
This effect is especially pronounced in refrigerators with plastic inner lining of the chambers. Over time, when the material “gets used” to the heating and cooling cycles, the intensity of the cracking usually decreases, but does not disappear completely.
Ventilation and No Frost system
Refrigerators equipped with a No Frost or “Full No Frost” system have one or more fans in their design. They ensure the circulation of cold air through the chambers, preventing the formation of ice on the walls. The operation of the fan creates a constant background noise, different from the hum of the compressor.
A smooth whistling or rustling sound is considered normal, the tonality of which can vary depending on the speed of rotation of the blades. In some models, the fan turns on periodically, together with the compressor, in others it works in its own mode.
If you hear extraneous sounds, such as grinding, beating or an intermittent hum, this may indicate a problem. Most often, the cause is ice freezing on the blades or wear of the fan motor bearings.
| Sound type | Probable cause | Normal or breakdown |
|---|---|---|
| Uniform hum | Fan motor operation | Normal |
| Periodic humming | Air circulation through the channels | Normal |
| Rattling or beating | Object hit or ice frozen | Attention required |
| Complete lack of sound | Fan motor malfunction | Failure (no cold) |
It is important to keep the air channels clean. Clogged vents may create a whistling sound due to increased resistance to air flow. Regularly check whether the ventilation sieves in the rear part of the chamber are not blocked.
Specific sounds during defrosting
Modern refrigerators automatically switch to evaporator defrost mode. At this moment, the compressor stops and turns on Defrosting heating element. The process of heating the ice is also accompanied by sound effects that should not cause concern.
Often you can hear hissing or the sound of dripping water. This melt water flows into a drainage tray located above the compressor. As water evaporates from the hot surface of the motor, it creates a characteristic hissing sound that can last for several minutes.
⚠️ Attention: If the dripping sound is too loud and constant, check the drain hole. Its clogging can lead to water leaking into the chamber or onto the floor.
Also at the end of defrosting, when the heating element turns off, a distinct click may be heard. This activates the thermostat or relay, breaking the heater circuit. Such clicks are normal and indicate the correct operation of the automation.
☑️ Diagnostics of sounds during defrosting
When noise becomes a problem: alarms
Despite the variety of normal sounds, there are clear signs of malfunction. If you hear metallic clanging, loud knocking, high-pitched whistling, or vibration radiating through your furniture, you cannot ignore it. Such symptoms often indicate mechanical damage or wear of components.
Particular attention should be paid to situations where the nature of the sound has changed dramatically. If the usual quiet hum is replaced by a loud rumble, and the cooling inside the chamber has stopped, the compressor has probably failed or the pipes have broken.
- 🛑 Loud metallic knock - destruction of the compressor suspension or the entry of a foreign object.
- 🛑 A high-pitched whistle - freon leaking through microcracks.
- 🛑 Rattling of the case - loosening of fastening bolts or contact with furniture.
If such symptoms appear, it is recommended to immediately disconnect the device from the network and conduct a visual inspection. If external causes (for example, touching the cabinet wall) are not found, it is better to contact specialists for diagnostics.
Can a refrigerator hum due to power surges?
Yes, unstable voltage in the network can cause a humming of the transformer or incorrect operation of the starting relay, which leads to a change in the sound profile of the compressor.
FAQ: Frequently Asked Questions
Why is the new refrigerator noisier than the old one?
New models often have more powerful compressors to quickly reach the set temperature. In addition, in older refrigerators, noise could be masked by a layer of dust and dirt, and also dull the owner’s hearing over time. If the noise does not exceed the 40 dB stated in the passport, this is normal.
Is it normal for the refrigerator to click when it is not working?
Yes, this is absolutely normal. Clicking sounds when turned off are most often caused by thermal expansion of the materials of the case and internal shelves, which continue to respond to changes in ambient temperature.
How to reduce the hum of a refrigerator?
Make sure that the refrigerator is level and does not touch walls or furniture. Check to see if items on the shelves inside are vibrating. It is also recommended to move the equipment away from the wall at least 5-10 cm for normal air circulation.
Is the sound of bursting bubbles dangerous?
The sound of bursting bubbles is usually associated with the movement of freon and is the norm. However, if this sound is accompanied by a complete lack of cold, this may indicate a critical decrease in the level of refrigerant in the system.