Unexpected hum, whistle or intermittent howl from the refrigerator can unsettle any owner. It is especially annoying when the system technology No Frost, designed to give silence and comfort, begins to make sounds reminiscent of an airplane taking off or a dripping faucet. Extraneous noise - this is not just discomfort, but also a signal that changes have occurred in the operation of the unit that require attention.
Before you panic and look for a service number, you need to conduct an initial diagnosis. Often the reason lies in trivial things: incorrect installation or temporary operating mode. However, in a system No Frost, which is more complex than a conventional drip system, there are more sources of sound: these are fans, a complex defrosting system, and refrigerant circulation.
In this article we will analyze in detail all possible scenarios. We will divide them into standard (normal) and emergency sounds so that you can accurately understand whether your refrigerator needs the help of a technician or whether it is enough to simply move it a couple of centimeters.
Normal sounds: when humming is the norm
Modern refrigerators are complex electromechanical devices. Unlike old Soviet models, which simply hummed monotonously, modern units produce a wide range of sounds. Operating noise includes the sound of a running compressor, the movement of refrigerant through the tubes and the operation of fans.
It is especially important to understand the principle of operation of the system No Frost. In such models there are always fans that forcibly circulate cold air inside the chambers. The evaporator fan in the No Frost system can make a characteristic whistling sound if an ice crust has formed on the blades, touching the housing. This is not always a breakdown, often it is a defrosting stage or a design feature.
It is also worth considering the operating phases of the compressor. When starting, the motor-compressor always makes a louder sound, which gradually fades away. If your refrigerator makes a noise that appears and disappears, most likely the appliance is operating in normal temperature maintenance mode. a smooth low-frequency humwhich appears and disappears, most likely the equipment is operating in normal temperature maintenance mode.
Remember that new models may sound different than the ones you are used to. Inverter compressors, for example, are quieter, but can produce a high-frequency hum that can only be heard in the stillness of the night.
Installation problems: resonance and vibration
One of the most common reasons why the refrigerator began to hum more than usual is a violation of the installation rules. Vibration from a running compressor is transmitted to the housing, and then to the floor and walls. If the device is not level, resonance occurs, which greatly enhances the acoustic effect.
Check the distance to the walls. For normal air circulation and to prevent overheating (which also causes noise), it is necessary to leave a gap. If the refrigerator is moved close to a wall or furniture, the hum may be reflected and intensified, creating a “barrel” effect.
⚠️ Attention: Make sure that the rear wall of the refrigerator does not touch the heating pipe or other communications. Vibration can be transmitted through pipes to the entire apartment, creating the illusion of a breakdown of the unit itself.
Another important aspect is the transportation bolts. Although refrigerators have fewer of them than washing machines, some models have retaining elements for the compressor or internal components. If they are not removed, vibration will be colossal.
☑️ Checking the installation of the refrigerator
Faults in the compressor and start relay
The heart of the refrigerator is the compressor. If it begins to hum unusually loudly, ring metallic or make sounds similar to the operation of a tractor, this is an alarming signal. Wear of the motor leads to the fact that the internal mechanisms lose lubrication or the geometry of the piston group is disrupted.
Often the problem lies not in the motor itself, but in the start relay. This device is responsible for starting the engine. If the relay is faulty, the compressor may hum but not start, or may start with a loud clicking and humming sound. In such cases electric horn is interrupted by a protective shutdown.
The table below shows the main symptoms of a compressor group malfunction:
| Symptom | Probable cause | Required actions |
|---|---|---|
| Loud metallic clanging | Destruction of the engine suspension | Replacement of shock absorbers or compressor |
| Humming without starting | Malfunction starting relay | Diagnostics and replacement of relay |
| Increasing howl | Wear of bearings or piston | Urgent repair or replacement of unit |
| Intermittent hum | Power surges or relays | Checking the electrical network and relays |
If you notice that the compressor has become hotter than usual and is making noise constant hum, do not try to operate the refrigerator further. This can lead to complete failure of the unit and expensive repairs with replacement of the filter-drier and refilling of freon.
Fan in the No Frost system: whirring and crackling
In refrigerators with the system No Frost fans are responsible for air circulation. Usually there are two of them: one in the freezer, the other (not always) in the refrigerator compartment. They are often the source of whistling, howling or crackling.
Over time, fan bearings wear out. The lubricant dries out in them, and play appears. As a result, the fan begins to hum or vibrate. This is especially audible when you open the door: in many models, when the door is opened, the fan should stop, and if the sound disappears, the problem is definitely in it.
Another common cause of noise in the system No Frost is ice freezing on the blades. If the defrost system is not working properly, ice builds up on the evaporator and traps the fan. The blades begin to touch the ice crust, producing a characteristic crackling or buzzing sound.
How to check the fan without disassembling?
Open the refrigerator door. Find the button (or magnetic sensor) that signals the door is closed (usually it is recessed into the body). Press it with your finger, simulating the closing of a door. If after 1-2 minutes (delay time in some models) the hum stops or changes, the problem is in the fan or icing of the evaporator.
To fix the problem, it is often necessary to completely defrost the refrigerator within 24 hours. If after turning on the sound returns, it means that fan replacement or repair of the defrost system (heating element, timer or sensor) will be required.
Foreign objects and vibration of internal components
Sometimes the source of noise is trivially simple - a foreign object. A bottle placed against the back wall may resonate with the vibration of the compressor. A glass shelf that is not fully inserted into the grooves begins to rattle. Vibration transmitted throughout the body, intensifying in empty chambers.
Check whether the condenser tubes (usually black, on the back wall) are not touching each other or the body. During operation, the compressor swings the tubes, and if they touch, a metallic ringing or buzzing occurs. Gently push them apart with your hand (only when the refrigerator is cold and turned off!).
It is also worth inspecting the water collection tray, which is located above the compressor. If it is misaligned or has debris floating in it, it may rattle. In some models No Frost plastic parts of the inner lining may come off and vibrate from the air flow.
Refrigerant and sounds of freon circulation
Sounds made by the refrigerant itself often frighten owners, but they are usually safe. Murbling, gurgling, overflowing is a normal phenomenon, especially immediately after the compressor is turned off. Freon changes from a liquid state to a gaseous state and continues to move through the tubes.
However, if you hear a loud hissing or whistling sound, similar to gas escaping, this may indicate a leak. In the system No Frost freon leakage often occurs at the sealing point of the evaporator tubes, hidden behind a plastic panel.
If the sounds are accompanied by a lack of cold or slight frost formation, you need to call a technician to look for a leak and refilling the system. It is impossible to eliminate a freon leak on your own; special equipment and skills are required.
⚠️ Attention: Freon used in modern refrigerators is odorless and colorless, but some types can be flammable or toxic in high concentrations. Do not try to solder the tubes yourself or open the circuit without knowledge of chemical safety.
Diagnostics: step-by-step algorithm of actions
In order not to guess on the coffee grounds, act systematically. Eliminate simple causes first, then move on to complex ones. Do not rush to disassemble the unit if you are not confident in your abilities.
The first step should always be defrosting. Even if there is visually no ice, it may be inside the evaporator channel. Complete defrosting (minimum 24 hours with doors open) eliminates 50% of problems with sounds in the system No Frost.
If defrosting does not help, audit the installation and external factors. And only after this should you think about calling a technician to diagnose internal components: compressor, fans or electronics.
When you need to urgently call a technician
Not all noise can be eliminated with your own hands. There are situations where delay threatens complete loss of products and costly repairs. If you hear loud grinding metal on metal inside the compressor, this is a sign of its imminent destruction.
A combination of noise and burning smell is also an alarming signal. This may indicate overheating of the wiring, melted insulation, or problems with the start relay. In such cases, the refrigerator must be immediately disconnected from the network.
A technician will be required if, after defrosting and checking the installation, the hum does not stop, and the temperature in the chambers no longer corresponds to the specified parameters. Professional diagnostics using pressure gauges and testers will allow you to accurately determine the malfunction.
Is it worth repairing an old refrigerator?
If the refrigerator is more than 10-12 years old and the compressor needs to be replaced, it is often more economically feasible to buy new equipment. Repairing an old unit can cost up to 70% of its residual value, and the resource of other components (seals, plastic) can also be exhausted.
Why does the refrigerator hum only at night?
At night, the overall noise level in the apartment decreases, and you begin to hear the normal sounds of the unit, which during the day are masked by household noise. In addition, at night the voltage in the network may stabilize or, conversely, jump, which affects the operation of the compressor. Also at night, the fast freezing mode turns on more often if you opened the door in the evening.
Is it possible to lubricate the refrigerator fan yourself?
Theoretically, it is possible if you remove the fan and find suitable oil for the plastic bearings. However, in practice this is a temporary measure. The bearing is already worn out, and lubrication will help for a short time. It is recommended replace the fan entirely, since new parts are inexpensive and guarantee silence for a long time.
Is it dangerous if the refrigerator hums, but freezes?
If the temperature in the chambers is normal, direct There is no danger to the food right now. However, a constant hum indicates increased load on the nodes. This can lead to accelerated wear on the compressor. It is better to schedule diagnostics so as not to be left without a refrigerator at the most inopportune moment.
How to distinguish the sound of a compressor from the sound of a fan?
The compressor emits a low-frequency, deep hum, which can be felt even by the body if you lean against the side of the refrigerator. The fan produces a higher-pitched, whistling or rustling sound that is localized inside the chamber. To check the fan, open the door: the compressor will continue to hum, and the fan (in most models) should stop.
Does overcrowding the refrigerator affect the noise level?
Yes, it does. If products lie close to the rear wall, they block the air circulation channels in the system No Frost. The fan has to work harder, overcoming resistance, which increases the noise. In addition, loose objects can rattle from vibration.