The situation when, after opening the door or a pause in operation, the unit makes unusually loud sounds can cause alarm in any owner. Often this noise is accompanied by vibration of the case or strange clicks that were not previously observed. Understanding the nature of these sounds is the first step to preserving expensive equipment and peace of mind in the house.
A loud hum does not always indicate a breakdown, but sudden changes in the acoustic profile of a household appliance cannot be ignored. Modern models are equipped with efficient cooling systems that operate almost silently during normal operation. The appearance of extraneous noise can indicate both errors during installation and critical wear of internal components.
In this article we will analyze in detail the mechanics of the occurrence of sounds in various components of the refrigeration unit. You will learn how to distinguish the normal operation of the system from the harbingers of a serious accident. This will allow you to react in time and, perhaps, avoid costly repairs or replacement of the entire unit.
Physics of the process: why sound occurs at all
Any refrigerator is a complex thermodynamic system, the operation of which is based on the circulation of refrigerant. The main source of sound is compressor an electromechanical pump that compresses freon gas. At the moment of starting, the motor needs to overcome inertia and create the necessary pressure in the system, which is inevitably accompanied by vibration and a sound wave.
The intensity of the noise directly depends on the type of engine and the design of the compressor. Older models often used piston units, which by their nature are quite noisy reciprocating mechanisms. New inverter models operate smoothly, but even they can produce a specific high-frequency hum when reaching maximum speed.
The sound wave is transmitted from the engine to the metal case and tubes, which begin to resonate. If the resonant frequency matches the vibration frequency of the motor, a sound amplification effect occurs. That is why the correct positioning of the equipment and the condition of the shock absorbers play a critical role in acoustic comfort.
Inverter compressors, unlike classic ones, they do not turn off completely, but only reduce power. This means that the background hum can be present constantly, changing its tone depending on the load on the cooling system.
Normal operating sounds: what is not a breakdown
Before sounding the alarm and calling a technician, you must exclude standard operating sounds. Manufacturers of household appliances often indicate the permissible noise level in technical documentation, which usually ranges from 34 to 42 dB. However, to the ear, even normal sounds can be perceived as intrusive, especially at night.
One of the common phenomena is the sound of flowing liquid or gurgling. This is absolutely normal and indicates movement refrigerant along the capillary tube. After the compressor is turned off, the circulation process may continue for some time, creating a characteristic “rumbling” inside the chambers.
⚠️ Attention: If the gurgling is accompanied by a complete absence of cold or the formation of an ice coat in only one corner, this may indicate a freon leak or a clogged system. In normal mode, the sound of the liquid is quiet and not constant.
Periodic clicks emitted by thermostat or the starting relay are also considered normal. These elements act as electrical switches, opening and closing the compressor power circuit when the set temperature is reached. The clicking sound can be quite loud, especially in models with mechanical control.
Plastic cracking is another common “sound effect”. As the temperature inside the chamber changes cyclically, the plastic walls and shelves expand and contract. This process, called thermal deformation, causes a characteristic crackling sound that often frightens users of new refrigerators.
- 🔊 Uniform hum is a sign of a running motor, the intensity of which changes smoothly.
- 💧 Gurgling is the sound of freon movement, often heard immediately after the compressor stops.
- 🔌 Single click - activation of a thermal relay or thermostat at the beginning or end of the cycle.
- 🧊 Crackling of plastic - reaction of materials to temperature changes, typical of new models.
Installation errors: the most common cause of vibration
Service center statistics show that more than 40% of complaints about loud noise are not related to equipment malfunction, but to incorrect installation. If the refrigerator is not level, vibration from the operating compressor is transmitted to the floor and is amplified by the furniture body or the unit itself.
The first thing to check is the horizontality of the installation. Even a slight tilt can cause the refrigerator to “walk” or make a low-frequency hum. To make adjustments, use a building level and rotating supports at the bottom of the device.
☑️ Checking the installation of the refrigerator
The second critical factor is the distance to the walls and furniture. The rear condenser grille requires free space for air circulation. If the refrigerator is moved close to the wall, the vibration of the compressor is transmitted to the building structures, causing the walls or cabinets to hum.
It is also worth checking the contents of the refrigerator itself. Sometimes the source of rattling is bottles or cans that come into contact with each other or with shelves when vibrating. Simply laying out the food is enough to eliminate this external source of noise.
If the floor covering (for example, linoleum or laminate) is loose or has voids underneath, the vibration can increase many times over. In such cases, it is recommended to place special anti-vibration pads made of dense rubber under the legs.
Mechanical malfunctions of the compressor and suspension
If the installation is perfect and the products are laid out correctly, but the noise persists, the problem may lie in wear of the internal components. The most expensive and complex breakdown is related to the compressoritself. Over time, the motor shaft bearings wear out, which leads to a metallic knock or howling.
Inside the sealed compressor casing, the motor is suspended on special springs. These springs dampen vibrations during operation. If one of them bursts or comes off, hard contact between the metal parts occurs, which causes a loud clang and strong vibration of the case. Repairing such a malfunction often requires replacing the entire compressor.
⚠️ Attention: Operating a refrigerator with a broken compressor suspension spring is prohibited. Vibration can lead to breakage of tubes inside the casing and complete failure of the system.
Another reason for mechanical noise is wear or drying out of the rubber shock absorbers on which the motor is mounted. Over time, rubber loses its elasticity, hardens and ceases to perform its function. As a result, vibration is transmitted to the metal casing and body of the refrigerator.
In some cases, the cause of the hum is the weakening of the fastening bolts of the compressor itself to the frame of the refrigerator. Regular vibration during operation can gradually weaken the connections. Tightening these bolts often allows you to restore silence without replacing parts.
A critical sign of mechanical failure is a metallic ringing or knocking noise that increases as the engine warms up and does not stop after it stops (inertial knock).
Problems with the No Frost system and fans
Owners of modern refrigerators with the system No Frost often encounter specific noises associated with the operation of fans. Unlike a drip system, here air is forced to circulate through the chambers, which requires additional moving parts.
The main cause of noise in such models is fan freezing. If the defrost system is not working properly, ice will build up on the fan blades or on the evaporator. The blades begin to touch the ice crust, producing a crackling or humming sound, similar to the operation of a propeller.
The bearings of the fan itself can also be a source of sound. With prolonged use, the lubricant in them dries out, and the shaft begins to rotate with difficulty, creating a monotonous hum or whistle. Replacing a fan is a simple procedure, but requires disassembling the internal panel of the refrigerator.
| Sound type | Probable cause | Characteristic symptoms | Difficulty of repair |
|---|---|---|---|
| Crackling/Knocking | Ice on the blades | The sound appears periodically, subsides after defrosting | Low (defrosting) |
| Hum/Howl | Fan bearing wear | Constant high-pitched sound during operation | Medium (replacement) |
| Whistling | Dirty air ducts | Sound changes when loading products | Low (cleaning) |
| Clicks | Plastic deformation | Audible when temperature changes | Not required |
To diagnose a problem with a fan, it is often enough to listen to where exactly the sound is coming from. If the noise is localized in the upper part of the freezer or behind the back wall, the likelihood of a malfunction of the fan or defrost system is very high.
Hydraulic hammers and problems with refrigerant
Sometimes when turned on, you can hear a sharp, single knock or a series of blows, after which the refrigerator begins to operate normally. This phenomenon is known as "water hammer". It occurs when liquid refrigerant or oil enters the compressor cylinder along with gaseous freon.
Liquid, unlike gas, is not compressed. When you try to compress it with a piston, a sharp surge in pressure and a characteristic knock occurs. Frequent water hammers destroy the valve group of the compressor and can lead to its failure. The reasons may be a malfunction of the thermostat or overfilling the system with freon.
Is it possible to ignore water hammer?
Frequent water hammer cannot be ignored. Although isolated occurrences may be acceptable under certain conditions (for example, after a long period of inactivity), regular shocks indicate a problem with refrigerant circulation. This leads to destruction of the piston group and expensive repairs.
Another problem associated with the refrigerant is a clogged capillary tube. If a plug from oil or moisture oxidation products forms in the circulation system, the compressor has to work with increased load, trying to push the gas. This causes a strong, intense hum and overheating of the engine.
It is difficult to diagnose these problems at home, since they require a manifold and special equipment to measure the pressure in the system. If you hear strong knocks when starting, it is better not to risk it and contact a specialist.
When you need to call a technician: critical signs
There are a number of symptoms in which further operation of the refrigerator becomes dangerous or leads to complete destruction of the device. If you notice that the noise is accompanied by other alarming signs, you should not hesitate.
First of all, pay attention to the temperature. If the refrigerator hums louder than usual, but has stopped freezing or, conversely, freezes too much, turning food into ice, this is a sign of a failure in the control system or a freon leak. The compressor can work continuously, trying to compensate for the loss of cold, which causes increased noise.
The smell of burning or scorched wiring combined with humming is a signal to immediately disconnect the device from the network. This may indicate an interturn short circuit in the motor windings or overheating of the starting relay. Continued activation may result in a fire.
⚠️ Attention: If after defrosting the refrigerator within 24 hours the noise does not disappear and the temperature does not return, independent repairs are prohibited. The intervention of a certified specialist with a vacuum pump and a charging station is required.
Also a reason to call a technician is when the compressor tries to start, makes a click and a beep, but after a few seconds it stalls, and the cycle repeats. This indicates a faulty start relay or compressor wedge.
In conclusion, it is worth noting that paying close attention to the “soundscape” of your refrigerator allows you to identify problems at an early stage. Regular maintenance, proper installation and timely defrosting will prolong the life of the appliance and maintain silence in your kitchen.
Frequently asked questions (FAQ)
Why is a new refrigerator noisier than the old one?
Modern refrigerators often have greater compressor power for faster cooling and compliance with environmental standards energy efficiency. In addition, new models with the system No Frost add noise from fans. However, if the noise exceeds 45 dB, this may be a defect.
Can a refrigerator hum due to power surges?
Yes, unstable voltage in the network causes the compressor to operate abnormally, which can cause humming, vibration and overheating of the windings. In such cases, it is recommended to use a voltage stabilizer.
How long should the compressor operate normally?
The operating time of the compressor depends on the load of the chambers and the room temperature. Typically the operating cycle ranges from 10 to 30 minutes, followed by a pause. If the refrigerator works without a break for days and makes a lot of noise, this is a malfunction.
Is squeaking dangerous when the refrigerator is operating?
A high-frequency squeak most often comes from an electronics unit (transformer) or a choke whistle. If the squeak is quiet, it may be normal. A loud whistle may indicate a freon leak through microcracks or a fan malfunction.
Is it necessary to lubricate the refrigerator if it squeaks?
Self-lubrication of the moving parts of the compressor is prohibited, since it is sealed. The door (hinges) can make a creaking sound - you can lubricate them. If the creaking comes from the motor, the components need to be replaced.