A modern household refrigerator is a complex mechanism that operates 24/7. Owners often notice that new equipment makes unfamiliar sounds that were absent from older models. Understanding the physics of processes helps to distinguish the normal operation of a unit from an incipient breakdown.
The sound background of operating equipment consists of many factors: motor vibration, movement of refrigerant through pipes and thermal expansion of materials. It is important to learn to differentiate these noises so as not to call a repairman for trifles and not miss a serious malfunction.
In this article we will analyze in detail the acoustic features of the operation of various refrigerator systems. You will learn to determine the nature of the malfunction by ear and understand when the intervention of a repair specialist is really necessary.
The physics of noise: why equipment sounds the way it does
The main source of sound in any refrigeration cabinet is compressor. This is the motor that compresses the refrigerant, causing it to circulate through the system. Old models used piston compressors, which created a characteristic hum and vibration of the housing.
Modern inverter models work on a different principle. They do not turn off completely, but only change the power of shaft rotation. Thanks to this inverter compressor it emits a smooth, barely noticeable hum, which is often confused with silence. However, even in such systems there are mechanical elements that can produce sounds.
The second important source of acoustic effects is the movement of freon. As the refrigerant changes from liquid to gas and back again, it passes through narrow capillaries and an expansion valve. This process is inevitably accompanied by gurgling and overflowing, which can be heard even through the thick walls of the chamber.
⚠️ Attention: If you have just installed the refrigerator, let it sit for several hours before turning it on. The oil in the compressor must drain into the crankcase, otherwise startup may be accompanied by a metallic knock and subsequent breakdown.
It is also worth considering the thermal expansion of materials. The plastic of the inner container and the metal tubes of the evaporator have different coefficients of expansion. With a sudden change in temperature, they can make a cracking noise, reminiscent of shots or clicks.
Normal sounds: what should not cause panic
Many users mistakenly believe that a working refrigerator should operate absolutely silently. This is a misconception. There are a number of sounds that indicate the correct operation of all systems of the unit.
First of all, this murmuring and gurgling. They occur when the refrigerant passes through the capillary tube and enters the evaporator. These sounds can be heard even after the compressor stops, as the pressure in the system gradually equalizes.
The second type of normal noise is clicks. They may sound when the engine is turned on or off. This triggers the start relay or thermostat. In models with the No Frost system, clicks are produced by a damper that regulates the supply of cold air into the chamber.
- 🔊 Uniform low-frequency hum of a running motor.
- 💧 Quiet pouring of liquid inside the housing after stopping the engine.
- 🧊 Plastic cracking during the first cooling of the chamber or after defrosting.
It is worth mentioning separately the sound of the operating fan in the systems No Frost. It creates a constant monotonous airflow noise. If the sound is smooth and does not change in tone, this is the normal operation of the blowing system.
Alarm signals: when to sound the alarm
There are sounds that clearly indicate the presence of a malfunction. Ignoring these signals can lead to costly repairs or complete replacement of the unit. It is important to react promptly.
The first warning sign is loud knocking or a clanging sound when starting the engine. This may indicate problems with the compressor suspension or wear on internal mechanical parts. If the sound resembles metal hitting metal, it is better to stop using it.
The second dangerous signal is a high-pitched whistle or hissing. This often indicates a refrigerant leak. Freon comes out under pressure through a microcrack, creating a characteristic acoustic effect. In this case, the refrigerator will stop freezing in the near future.
⚠️ Attention: A whistling sound may also indicate that the condenser tubes are touching the housing or each other. Vibration increases friction, which leads to the rapid formation of a fistula.
It is also worth paying attention to the humming, which does not stop even after reaching the set temperature. This indicates that thermostat does not open the circuit, and the compressor is working hard, trying to cool the already cold chamber.
| Sound type | Probable cause | Degree danger |
|---|---|---|
| Monotonous humming | Compressor operation | Normal |
| Gurgling of water | Freon movement | Normal |
| Loud metallic knock | Wear of engine mount | High |
| High-pitched whistle | Gas leak | Critical |
| Rubber creaking | Pipe friction | Average |
Acoustics features in No Frost systems
Refrigerators with the system automatic defrosting No Frost have a more complex design than drip counterparts. The presence of additional fans and heaters expands the range of sounds they produce.
The main source of noise here is evaporator fan. It may hum if ice has frozen on its blades, or if the bearings are dirty. The sound becomes shrill and annoying, especially at night.
Another specific sound is a crackling sound when the defrost heater is operating. The heating element heats up very quickly, and condensate, falling on a hot surface, instantly evaporates with a characteristic hissing sound. This is absolutely normal for the defrosting cycle.
Why does the fan begin to make noise over time?
During operation, microparticles of food and dust enter the chamber. Over time, they stick to the fan axis, disrupting the balance. In addition, the lubricant in the bearings dries out, which leads to dry friction and squeaking.
It is important to ensure that food does not touch the back wall of the chamber. In systems No Frost there are air duct openings. If a bag of food sticks to the grill, the fan will begin to work with increased load and make a loud whistle.
Diagnostics of faults by the nature of the sound
An experienced technician can determine the breakdown by simply approaching the refrigerator. You, too, can carry out initial diagnostics by carefully listening to the operation of the unit. This will help you more accurately describe the problem when you call a specialist.
If you hear intermittent clicks, and the engine does not start, most likely the starting relay is faulty. It tries to start the compressor, but the current does not pass, and the relay opens the circuit with a characteristic sound. Frequent clicks indicate that the motor “does not pull.”
A loud hum with vibration that is transmitted to the floor may indicate a problem with the shock absorbers. The compressor is mounted on springs or rubber feet. If they are worn out or burst, the vibration is transmitted directly to the body and floor.
- 🛠️ Check that the refrigerator is not touching the wall or furniture.
- 🛠️ Make sure that the transport bolts on the compressor have been removed (for new models).
- 🛠️ Inspect the rear grille for contact with the tubes.
It is also worth checking the installation level. If the refrigerator is not level, the door may not fit tightly and the compressor may work misaligned. This creates noise and stress on the nodes.
☑️ Primary diagnosis of noise
The influence of installation and placement on the noise level
Often the cause of increased noise is not a breakdown, but incorrect installation. A refrigerator is a technique that requires free space for air circulation and vibration damping.
The distance to walls and furniture should be at least 5-10 cm. If the refrigerator is moved close, the vibration of the body is transmitted to building structures, which begin to resonate, increasing the hum significantly. This creates a “drum” effect.
The condition of the floor is also important. On soft surfaces (linoleum, carpet), the legs may sink, disrupting the balance. On hard surfaces (tiles, laminate), vibration is transmitted best. Using anti-vibration pads under the feet can significantly reduce the noise level.
⚠️ Attention: Never install the refrigerator near heat sources (radiators, ovens). This forces the compressor to operate at maximum power, which increases noise and shortens service life.
Check the contents of the shelves. Glass bottles or dishes touching each other due to vibration can create ringing. It is enough to simply move objects apart or place a rug under them to eliminate extraneous sound.
Prevention and care of speaker systems
To ensure that your refrigerator enjoys silence for as long as possible, it is necessary to regularly carry out preventive measures. They are simple, but effective for maintaining technical condition.
Regular defrosting (for drip systems) and cleaning the rear condenser grill from dust is mandatory. The layer of dust acts as a heat insulator, causing the compressor to run longer and louder. You need to vacuum the grille at least once every six months.
Monitor the condition of the door seals. If they are worn out, warm air enters the chamber and the frequency of compressor starts increases. The more often it turns on, the greater the chance of hearing the sounds of startup and operation.
If you notice a change in the background sound, do not wait for a final breakdown. Early diagnosis allows you to replace cheap parts (bushings, gaskets, relays) before you need to replace an expensive compressor.
Why does a refrigerator make the sound of a bursting bubble?
This sound is characteristic of the process of expansion and contraction of the plastic of the inner cabinet as the temperature changes. This can also be the sound of refrigerant passing through bottlenecks in the pipes. If the sound is rare and quiet, this is normal.
Is it normal for the refrigerator to hum immediately after purchase?
In the first days of operation, new equipment may sound louder due to the grinding in of parts. However, if the humming turns into roaring or knocking, this is a sign of a defect. Let the equipment work for 2-3 days, but watch the sound dynamics.
Can the noise level depend on the amount of food?
Yes, a full refrigerator is quieter. The products act as an acoustic load and a heat accumulator, smoothing out temperature changes and reducing the frequency of compressor starts. An empty unit turns on more often.
What to do if the refrigerator starts to crack after defrosting?
Cracking after defrosting is usually associated with the thermal expansion of plastic that has been very cooled. If the cracking does not stop for several hours and is accompanied by a refusal to freeze, an ice plug may have formed in the system.
Does the voltage in the network affect the sounds of the refrigerator?
Low voltage in the network can lead to a humming sound of the compressor and difficult starting. The engine tries to start, hums, but cannot gain momentum. In such cases, it is recommended to use a voltage stabilizer.