A constant hum, an irritating hum or a sharp crackling sound is exactly what owners of refrigeration equipment face when the equipment stops working silently. Ideally, modern refrigerator should function almost imperceptibly to the ear, creating only a background, barely audible sound of a running motor. However, when the noise level increases sharply, it not only interferes with comfortable living in the apartment, but also often serves as the first alarm signal about problems within the system.
You should not ignore the changed nature of the operation of the equipment, since a banal sound may hide a serious breakdown of expensive components. Before calling a technician or panicking, it is necessary to conduct an initial diagnosis. In this article, we will analyze in detail why the refrigerator is constantly humming, what causes it casing vibration and how to distinguish normal operation of the equipment from an emergency situation.
There are many factors that affect acoustic comfort: from improper installation to compressor wear. Understanding the physics of the process will help you quickly isolate the problem. Sometimes it is enough just to correct the leg, but in other cases it will be necessary replacement of the refrigerant or repair of the very heart of the unit.
Natural sounds of operation: normal or pathological?
The first thing you need to do when you hear a hum is to determine whether the sound is a sign of a malfunction. Many models, especially those equipped No Frost system, produce specific sounds during normal operation. Air circulation, periodic turning on of fans and the movement of refrigerant through the tubes create an acoustic background, which can vary depending on the model and age of the equipment.
It is worth knowing that inverter compressors work on a different principle than their linear counterparts. They do not turn off completely, but only change power, so a quiet, monotonous hum for them is an absolutely normal state. If your refrigerator began to hum louder than usual immediately after purchase, perhaps you are simply not accustomed to the sounds of new equipment that has not yet “got used to it.”
⚠️ Attention: If the hum is accompanied by a periodic click and subsequent silence (the unit does not start), this may indicate a faulty start relay. In this case, it is dangerous to operate the device.
To understand what noise level is normal for your device, refer to the technical data sheet. The documentation always indicates noise level in dB. Exceeding the values declared by the manufacturer by more than 10-15 dB is already considered a deviation.
Problems with installation and alignment of the case
The most commonplace, but common reason why a refrigerator constantly hums lies in its incorrect location. If the unit is not level, it occurs vibration resonance. The compressor inevitably vibrates during operation, and if this vibration is transmitted to the floor or walls through a skewed housing, a quiet hum turns into a loud roar.
Check the horizontal installation. Even a slight repainting can cause the doors to fit poorly and the body to resonate. To fix the problem, use adjustable supports, which are usually located in the front lower part of the unit.
- 🔧 Take a building level and check the position of the refrigerator in two planes.
- 🔧 Tighten the front legs so that the body slightly “falls” back (this will ensure that the doors close tightly).
- 🔧 Make sure that that between the back wall of the refrigerator and the kitchen wall there is a gap of at least 5-7 cm for ventilation.
It is also worth checking whether the vibrating parts of the case are touching other objects. Sometimes it is enough to move the refrigerator a couple of centimeters to eliminate contact with furniture or pipesthat can amplify the sound.
Vibration and contact with foreign objects
Often the source of irritating sound is not internal mechanisms, but external factors. During operation, foreign objects may get into the space between the compressor and the rear wall, as well as into the lower compartment. These could be forgotten rags, food packaging, or even children's toys.
If an object touches a vibrating compressor or pipes, it begins to rattle. Also, the source of noise can be bottles or cans standing on the door shelf or in close proximity to the walls. When the motor is running, they begin to resonate and create a constant ringing or humming.
Pay special attention to the space behind the refrigerator. If the unit is located close to a wall, vibration can be transmitted to it, causing the wall itself or cabinets standing nearby to hum. In old houses with thin partitions, this effect can be very strong.
How to check for foreign objects?
Unplug the refrigerator, move it away from the wall and carefully inspect the space around the compressor (the black “barrel” at the bottom back). Remove all unnecessary things, including dust and cobwebs, which can also create noise when blowing.
Malfunctions of the compressor and start relay
If everything is in order with the installation and external objects, the reason why the refrigerator is constantly humming most likely lies in the “heart” of the unit - the compressor. This is the main source of noise. Over time, motor parts wear out, bearings lose lubrication, which leads to increased hum and the appearance of a metallic clang.
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 may run rough, making loud clicking and humming noises. In such cases, it is often necessary replacement of the starting device.
There is also the problem of “water hammer” inside the compressor, when refrigerant or oil enters the cylinder in a liquid state. This causes a dull, powerful impact and a subsequent hum. If the cause is not eliminated (often a freon leak or a malfunction of the thermostat), the compressor may burn out.
| Sound type | Probable cause | Necessary actions |
|---|---|---|
| Monotonous hum turning into a roar | Compressor wear or lack of lubrication | Diagnostics by a technician, motor replacement possible |
| Humming with periodic clicks | Faulty start relay | Replacement of relay (available for independent repair) |
| Whistling or hissing | Leakage of refrigerant (freon) | Searching for leaks and refilling the system |
| Metal rattling | Touching the pipes about the housing or compressor | Bending tubes, installing dampers |
⚠️ Attention: Independent disassembly of the compressor or soldering of tubes without a license and equipment is prohibited and dangerous to life. If you hear sounds indicating problems with the sealed circuit, call a specialist.
Problems with the defrosting system and fans
In refrigerators with the system No Frost fans are responsible for air circulation. If the refrigerator hums but does not freeze, or hums intermittently, the problem may be with them. The fan blades can become coated with ice, become deformed, or simply wear out, starting to make noise at high speeds.
The defrosting system can also be a source of sound. When the heating element is heated, the ice melts and water drips into the pan. If the drain hole is clogged, the water may boil or gurgle, creating strange sounds. Sometimes an ice crust on the evaporator interferes with the fan, causing it to hum until the system goes into defrost mode.
Check whether ice has frozen on the fan blades. To do this, you often have to remove the back panel in the freezer. If the fan is noisy “dry”, its bearings require replacement or lubrication, although most often the entire assembly is replaced.
☑️ Fan and defrosting diagnostics
The influence of refrigerant and pipelines
Movement moving refrigerant through the pipes is a physical process that is not always silent. Normally, you may hear a quiet gurgling or gurgling sound, especially immediately after the compressor is turned off. This is normal: freon flows from a high pressure zone to a low pressure zone.
However, if the sound becomes loud, whistling or resembles rolling stones, this is an alarming symptom. This often indicates that the pressure in the system has changed, perhaps due to a leak or clogged capillary tube. In such cases, the compressor begins to work with increased load, trying to compensate for the lack of pressure, which causes a strong hum.
Another reason is the resonance of the tubes themselves. If they are located too close to each other or to the walls of the housing, vibration from the passage of gas causes them to rattle. The technician can eliminate this by carefully straightening the tubes or installing special damper gaskets.
When you need to call a technician
There is a fine line between something that you can fix with your own hands and a situation that requires professional intervention. If you have checked the installation, removed unnecessary items, made sure the condenser is clean, but the refrigerator continues to hum constantly and loudly, most likely there is a technical problem.
An urgent call to a technician is necessary if:
- 🆘 The hum is accompanied by the smell of burning or scorched wiring.
- 🆘 The compressor is hot to the touch, but no cold is created in the chambers.
- 🆘 A distinct knock of metal on metal inside the unit is heard.
- 🆘 The device often turns off and on (clocking).
Remember that timely repairs are often cheaper than Replacing a burnt out compressor or the entire refrigerator. Professional diagnostics will allow you to accurately determine the source of the noise and eliminate it, returning you silence in the kitchen.
Why did the old refrigerator begin to hum more than before?
Over the years, the compressor shock absorbers wear out, the grease in the motor and fan bearings dries out, and the fastenings of the internal panels may also become loose. All this leads to increased vibration and noise. Regular maintenance and replacement of worn rubber bands can extend the quiet life of your unit.
Can a refrigerator hum due to power surges?
Yes, unstable voltage in the network causes the compressor to work abnormally, which can cause humming and overheating. To protect equipment, it is recommended to use a voltage stabilizer or surge protector with surge protection.
Is it normal for the refrigerator to hum immediately after defrosting?
In the first hours after defrosting and turning on, the refrigerator may work more intensely, restoring the temperature regime. At this time, the compressor operates at full power, which may be accompanied by increased hum. If after 5-8 hours the sound does not subside, look for another reason.
How to reduce the noise of a refrigerator yourself?
In addition to leveling, you can place special anti-vibration mats or pieces of thick rubber under the legs. It also helps to clean the condenser (grid at the back) from dust, which makes the motor easier to operate and reduces the noise level.
Does the amount of food in the refrigerator affect the noise level?
A full refrigerator operates more stable and quieter, since the products act as cold accumulators, smoothing out temperature changes. An empty refrigerator is forced to turn on more often, which can create the impression of a more frequent and intrusive hum.