The quiet hum of a running unit is normal for most modern models of refrigeration equipment. However, when the usual background sound is replaced by a loud hum, sharp knocks or obsessive gurgling, it becomes impossible to ignore it. Extraneous noise often serves as the first signal that a malfunction has occurred in the operation of the refrigeration system refrigeration system
A constant background noise not only irritates the nervous system, but can also indicate critical wear of components, which in the future will lead to expensive repairs or complete replacement of equipment. Understanding the nature of sounds helps to distinguish a harmless installation defect from a serious breakdown compressor or refrigerant leak.
In this article we will analyze in detail the physical and mechanical causes of noise, self-diagnosis methods and ways to troubleshoot problems. You will learn to determine by the nature of the sound which part has failed, and you will understand when to take up the tools and when you need to call a technician.
Natural sounds of refrigeration equipment
Before sounding the alarm, it is important to understand what sounds are normal for your device. Modern refrigerators, especially models with the No Frostsystem, produce a number of specific sounds during normal operation. These include periodic switching on and off of the motor-compressor, which may be accompanied by a characteristic click of the relay.
A quiet gurgling or murmur that occurs when refrigerant circulates through the tubes of the evaporator and condenser is also considered normal. This sound may intensify immediately after the compressor is turned off, when the pressure in the system equalizes. If you hear a slight crackling sound, it may be that the plastic of the inner housing or water collection tray is expanding due to temperature changes.
It is important to consider that the noise level directly depends on the type of compressor installed. Inverter models operate much quieter, maintaining a constant rotation speed, while classic linear units operate jerkily, creating a more noticeable acoustic background when starting up.
⚠️ Attention: If you have just installed the refrigerator and turned it on for the first time, let it run for several hours. Sometimes the lubricants in the compressor must warm up for the noise level to drop to the specified values.
The normal noise level can be determined by comparing it with the characteristics declared by the manufacturer, which are usually indicated in the technical documentation or on a sticker inside the chamber. The standard level is up to 40 dB, which is comparable to a quiet conversation.
Installation problems and vibration of the housing
One of the most common reasons for a sudden strong hum is improper installation of the unit. If the refrigerator is not level, its body can resonate with the vibrations of the operating compressor, amplifying the sound many times over. In such cases, even working equipment begins to hum so that it can be heard throughout the entire apartment.
The first thing that needs to be checked is the horizontalness of the installation. To do this, use a building level or simply shake the body. If the refrigerator is wobbly, the support legs need to be adjusted. Many models are equipped with screw supports, which allow you to accurately set the position of the unit relative to the floor.
The second important aspect is the distance to walls and furniture. The back wall of the refrigerator should not fit closely to the wall, since the condenser tubes and the compressor itself are located there, requiring free space for heat exchange and air circulation.
☑️ Installation diagnostics
Also check that internal elements, such as shelves, drawers or bottles on the door, are not touching the walls of the chamber. Vibration from the compressor is transmitted to all loose objects, causing them to rattle and create the effect of a “loose” refrigerator.
Diagnostics of compressor malfunctions
The compressor is the heart of the refrigerator, and it is the main source of noise. If you hear a loud, strained hum that turns into a metallic clang, or a knock that sounds like a jackhammer, the problem most likely lies in this unit. Motor-compressor it can make noise for several reasons: worn bearings, loose mounting bolts, or internal mechanical damage.
A frequent problem is the failure of the starting relay. In this case, the refrigerator may try to start, make a loud clicking sound, hum for a few seconds and turn off again. This cycle can be repeated endlessly until the motor winding burns out.
If the compressor is mounted on the frame using rubber shock absorbers, over time they may dry out or burst. As a result, the metal motor housing begins to vibrate against the metal frame, creating a strong ringing sound. The solution is to replace the shock absorbers or install additional rubber gaskets.
⚠️ Attention: Repairing or replacing the compressor requires special equipment for pumping out and filling freon. It is strictly not recommended to open the circuit yourself without skills and tools.
The table below shows the main types of compressor sounds and their probable causes:
| Type of sound | Probable cause | Degree of danger |
|---|---|---|
| Uniform hum | Normal operation | Normal |
| Loud knocking when starting | Piston group wear | High |
| Metal clanging | Loose fasteners | Medium |
| Clicks and buzzing without starting | Faulty start relay | High |
How to extend the life of the compressor?
Regularly clean the condenser (grid at the back) of dust. Dust acts as a heat insulator, causing the compressor to work longer and harder, resulting in overheating and noise. Also, do not place the refrigerator close to heating appliances.
Fan noise in the No Frost system
Refrigerators with the system No Frost are equipped with fans that circulate cold air inside the chambers. Over time, these fans can become a source of unpleasant noise. Most often, the problem lies in the freezing of ice on the blades or hub of the fan motor.
When ice freezes on the axis, the fan begins to hum, squeak or make a cracking sound, touching the blades with the ice crust. This happens especially often in the freezer, where the temperature is lower. The sound may appear or disappear depending on the defrosting cycle.
Another reason is the grease drying out in the fan bearings or foreign objects (crumbs, pieces of packaging) getting there. In such cases, the fan begins to vibrate and hum at high pitches. To fix it, you need to remove the back panel in the chamber, dismantle the fan, clean it of ice and dirt, and lubricate it or replace it if there is severe wear.
Sometimes fan noise occurs due to the fact that its impeller is unbalanced or cracked. In this case, only complete replacement of the unit with a new original or compatible analogue will help.
Extraneous sounds in the refrigerant circuit
If you hear constant or periodic gurgling, hissing or whistling, this indicates processes occurring inside the copper tubes. The movement of freon and oil through the pipeline system is a natural process, but a change in the nature of the sound can signal problems.
Loud bubbling and “overflowing” of the liquid often indicates that air or moisture has entered the system, or the amount of refrigerant has changed (leakage or, conversely, refilling). Freon leak is a serious malfunction that not only creates noise, but also causes the refrigerator to stop freezing.
A whistling sound can occur in places where the pipeline is narrowed, for example, in a capillary tube or filter drier, if an ice plug or blockage has formed there. This creates excess pressure, which the compressor tries to overcome by operating under overload.
⚠️ Attention: If you smell a chemical or oil smell along with hissing, the circuit may have depressurized. In this case, you must immediately disconnect the device from the network, ventilate the room and call a technician.
To accurately diagnose the condition of the circuit, a pressure gauge station is required, with which the technician measures the pressure in the system and compares it with standard indicators for a given type of refrigerant.
Mechanical malfunctions and rattling
The source of noise can also be external, seemingly insignificant factors. The rattling noise is often caused by condensation dripping onto the hot tubes at the back of the refrigerator and evaporating with a hissing sound. This is absolutely normal, but if the water tray is installed crookedly, drops may fall from a great height, creating an annoying sound.
Check the rear metal grill (condenser). If it is loose or has a manufacturing defect (poor welding), it will resonate with the vibration of the compressor. It is enough to lightly press it with your hand while the refrigerator is running to understand whether this is the problem. You can secure the grill using clamps or wire.
Also inspect the tray above the compressor. If it is plastic and not firmly secured, vibration will cause it to knock against the motor housing. In some cases, placing a piece of foam rubber or rubber between the tray and the compressor helps.
Don't forget to check the contents of the refrigerator itself. Glass bottles touching each other or the walls may ring due to the vibration of the shelves. Make sure that all shelves fit tightly in the grooves and do not loosen.
FAQ: Frequently asked questions
Why is the new refrigerator making a loud noise?
A new refrigerator may make more noise due to the fact that the lubricant in the compressor has not yet been distributed evenly, and the door seals are still hard. Also check that all shipping bolts and wedges, if provided by the design, have been removed. Let the equipment run idle for 1-2 days.
Is it dangerous if the refrigerator crackles and stops freezing?
Yes, it is dangerous. A cracking sound could mean a broken piston rod or a jammed compressor. Operating such a device can lead to overheating of the wiring and fire. Immediately unplug the unit.
Can a refrigerator make noise due to power surges?
Yes, unstable mains voltage causes the compressor to work abnormally, which can cause humming or buzzing from the transformer (if there is one). For protection, it is recommended to use a voltage stabilizer.
How to reduce the noise of an old refrigerator with your own hands?
Try replacing the rubber feet with thicker anti-vibration pads, moving the refrigerator away from the wall, checking the fastening of the rear grille and lubricating the fans. If the compressor is noisy, you can make a soundproofing box, but only if there is good ventilation.