The situation when refrigerator suddenly begins to make unusual sounds or increases the hum can unbalance any owner. The quiet hum characteristic of the motor is replaced by an obsessive noise that interferes with rest and causes concern for the safety of food. It is important to understand that not every sound indicates a breakdown, but sudden changes in the acoustic profile of the equipment cannot be ignored.
Primary diagnostics allows you to identify source of the problem without calling a technician. Often the reason lies in improper installation, vibration of the case or the operating features of the No Frost system. In this article, we will analyze the main reasons why the refrigerator is humming and determine in which cases professional intervention is required.
Modern units, such as LG, Atlant or Boschhave their own design features. If the hum is accompanied by vibration of the floor or rattling of the cabinet walls, in 80% of cases this can be solved by adjusting the support legs. Let's look at all possible scenarios in detail.
Normal operating noise versus alarm signals
The first thing to do is to understand the nature of the sound. A working refrigerator does not operate silently; its operation is accompanied by a certain background hum. This is due to the circulation of refrigerant through the pipes and the operation of electrical components. If you hear a uniform, quiet hum, which either subsides or intensifies, most likely everything is in order with your equipment.
The alarm should be sounded if the nature of the sound changes to intermittent, whistling or reminiscent of rolling stones. Compressor —the heart of the refrigeration system—can make different sounds depending on the load. However, a sharp knock when turning the engine on or off indicates wear of the starting relay or problems with the fastening of the unit itself.
Particular attention should be paid to models with the system No Frost. A fan is constantly running in them to circulate cold air. His humming is normal. But if the fan begins to crack or whistle, this means that ice has formed on its blades or the bearings have worn out.
⚠️ Attention: If the hum is accompanied by a lack of cold in the chambers, immediately unplug the device. Operating a faulty compressor can lead to its complete combustion and costly repairs.
Casing vibration and improper installation
The most common, but common cause of noise is improper installation. If the refrigerator is not level or touches the back wall of furniture, a pipe or a wall, the vibration from the running motor is transmitted to these surfaces, increasing significantly. This creates a resonance effect, which is perceived as a loud hum.
Check the position of the support legs. They must be unscrewed so that the body is stable and does not wobble when pressed lightly. Often, users forget to remove the shipping gaskets from the compressor or set the level incorrectly, which leads to constant rattling.
Make sure that there is a gap of at least 5-10 centimeters between the back wall of the refrigerator and the kitchen wall. This is necessary not only to reduce noise, but also for the normal operation of the capacitor. Close contact with furniture can also cause panels to hum.
☑️ Installation diagnostics
Sometimes shelves or bottles standing on the door hum. Carry out a simple test: alternately hold the shelves and the objects inside with your hand. If the noise disappears, the problem is solved, you just need to arrange the containers more tightly or place rubber gaskets under the shelves.
Problems with the compressor and start relay
If the installation is corrected, but the refrigerator continues to hum, the reason may lie in compressor. This is the most expensive and important unit. A loud, bassy hum that turns into a growl often indicates that the motor is working at the limit of its capabilities or has mechanical wear.
A frequent problem is the failure of the starting relay. This small element is responsible for starting the engine. If it is faulty, the compressor may hum but not start, or make a loud clicking noise before turning on. In older models, the relays may hum on their own due to vibration of the coil.
It is also worth checking the compressor mounts. Over time, the rubber shock absorbers dry out or tear, and the metal motor housing begins to vibrate against the frame of the refrigerator. In this case, the hum will be accompanied by strong vibration of the entire body.
How to test the compressor by ear?
Put your hand on the side wall of the refrigerator. If you feel a strong, rhythmic vibration accompanied by a humming noise, there is most likely a problem with the motor mounting or wear. If there is no vibration, but there is a hum, check the refrigerant.
Replacing a compressor is a complex process that requires evacuation of the system and charging with freon. You cannot undertake this procedure on your own without equipment; you need to call a specialist.
Refrigerant circulation and sounds in the pipes
The movement of freon through the pipe system is often accompanied by sounds that users mistake for a malfunction. Gurgling, gurgling, quiet hissing or pouring of liquid are absolutely normal physical processes. The refrigerant changes from liquid to gaseous and back, which creates acoustic effects.
However, if you hear a loud hissing sound, similar to gas coming out of the cylinder, this may indicate a freon leak. In this case, the refrigerator may hum constantly, trying to gain temperature, but it will be bad to cool. A leak is often accompanied by swelling of the walls or the appearance of oily spots.
A clogged capillary tube also changes the character of the sound. The system is overloaded and the noise becomes louder. In such cases, professional cleaning of the system and replacement of the filter-drier are required.
| Sound type | Probable cause | Danger |
|---|---|---|
| Burbling, gurgling | Movement freon | Normal |
| Loud hissing | Refrigerant leak | High |
| Smooth humming | Work compressor | Normal |
| Whistling or howling | Fan malfunction | Average |
It is important to distinguish sounds in different operating modes. When you turn it on for the first time or after defrosting, the refrigerator may hum louder than usual as the system returns to operating mode. If after a few hours the sound does not return to normal, you should be wary.
Ventilation and No Frost system
In refrigerators with a system No Frost the main source of noise, in addition to the compressor, is the fan. It is located in the freezer (or behind the back wall) and circulates air. If you hear a humming noise that comes and goes, it may be the fan cycling.
The problem occurs when ice builds up on the fan blades or on the evaporator. The blades begin to touch the ice, making a cracking sound, grinding or increasing the noise. This often happens due to a loose door or a malfunction of the defrost sensor.
Another reason is wear of the fan motor bearings. Over time, the lubricant dries out and the bushings begin to make noise. In this case, the fan requires replacement or lubrication (although modern models are usually replaced entirely).
Do not forget that in dual-compressor models two motors can operate simultaneously, which creates a total background noise. This is not a breakdown, but only a design feature.
Influence of temperature and operating mode
The intensity of the hum directly depends on the operating mode of the refrigerator. If you have just loaded a large amount of warm food, compressor will operate at maximum power to cool the chamber. In this mode, the noise can be much louder than usual.
In the summer, when the room temperature is high, it is more difficult for the refrigerator to release heat to the environment. The condenser (grid at the back) heats up and the motor runs longer and more intensely. This is a physiological norm, but it can irritate residents.
Check the temperature settings. If the thermostat is turned up to maximum (very low temperature), the refrigerator will hum almost without interruption. Try setting the average value, usually 3-4 degrees Celsius in the main chamber.
⚠️ Attention: Do not place the refrigerator next to heat sources (stove, radiator, window on the sunny side). This forces the compressor to work in extreme mode, accelerating wear and increasing the noise level.
It is also worth checking the tightness of the sealing rubber on the doors. If the rubber is worn out or dirty, the cold goes away, the temperature sensor detects the heating and turns on the motor. Constant work without pauses is a sure way to loud buzzing and breakdown.
When you need to call a specialist
Despite the possibility of self-diagnosis, there are situations when you cannot do without a specialist. If you have checked the installation, made sure the integrity of the fan and normalized the load, and the refrigerator continues to hum with a vengeance, the problem is within the system.
Symptoms requiring repair: constant operation without shutting down, lack of cold when the engine is running, a burning smell, strong shocks when starting. In these cases, delay can lead to a complete replacement of the compressor, which is up to 70% of the cost of a new refrigerator.
The technician will measure the pressure in the system, check the current consumption of the motor windings and carry out troubleshooting. Only professional equipment allows you to accurately determine whether refilling with freon or replacing the motor is necessary.
Noise prevention and care of equipment
In order for the refrigerator to enjoy silence for as long as possible, it is important to properly care for it. Regular defrosting (for drip systems) prevents the build-up of excess ice, which can cause cracking and buzzing noises. Wipe the seals and keep the back of the condenser clean.
Check the stability of the legs every six months. The floor may sag or the legs may become loose due to vibration. A simple adjustment will restore silence. Also check that small objects (coins, buttons) have not fallen behind the back panel or under the bottom of the refrigerator.
Do not overload the shelves. Heavy objects that are not stable may begin to vibrate in response to the motor's operation. Correct loading of the chambers is the key not only to silence, but also to proper air circulation.
⚠️ Attention: Never wash a refrigerator that is plugged in. Water that gets onto electrical contacts or into ventilation can cause a short circuit and cause not only noise, but also a fire.
Following simple operating rules will extend the life of your equipment. Remember that a new refrigerator can “break in” for several days, making different sounds. But if the noise increases over time, this is a signal to action.
Why does the refrigerator hum immediately after turning on?
At the moment of startup, the compressor experiences maximum load in order to start the circulation of the refrigerant. At this time, the start relay clicks and the motor begins to hum. If after 1-2 minutes the sound becomes smooth and quiet, this is absolutely normal. If the humming is accompanied by strong vibration or does not stop, check the fastenings.
Can an old refrigerator hum louder than a new one?
Yes, over time, the compressor shock absorbers wear out, plastic elements dry out, and the fan becomes dirty. Old models of refrigerators (Indesit, Stinol 90s) are structurally noisier than modern inverter models. However, a sharp increase in noise in old appliances often indicates a nearing end-of-life component.
What to do if only the freezer is humming?
Most likely, the problem is in the system fan No Frost, which is located exactly there. Frozen ice on the blades or a worn fan motor bearing causes the sound. Try defrosting the refrigerator completely (for 24 hours with the doors open). If the noise returns, the fan needs to be replaced.
Does the fullness of the refrigerator affect the noise level?
An empty refrigerator may hum louder due to the resonance of the internal shelves and the lack of sound absorption by food. Full shelves dampen vibration. However, if the food touches the back wall or lies too tightly, disrupting circulation, the motor will work harder and noisier.