A sudden knocking sound in the refrigerator can turn a quiet evening into a painful wait for a breakdown. This sound is often ignored, believing that the equipment is simply “working”, but ignoring the symptoms can lead to serious consequences. Extraordinary noise This is always a signal that there has been a failure in the refrigerant circulation system or the mechanics of the unit.
Before calling a technician or looking for a service number center, it is important to conduct a primary diagnosis. The nature of the sound, the frequency of its occurrence and accompanying vibrations can tell an experienced diagnostician a lot. In this article, we will look at the main reasons why the refrigerator is knockingand determine what steps need to be taken to eliminate the problem.
It is immediately worth noting that some sounds are normal for certain types of equipment. However, if the knocking appears sharply and differs from the usual hum, you should be wary. A sharp metallic knock when starting the engine in 90% of cases indicates mechanical damage to the compressor suspension or wear of the bushings.
Natural sounds and operating features of equipment
Not every sound indicates a breakdown. Modern models of refrigerators, especially those equipped with the No Frostsystem, make specific sounds during operation. This is due to the cyclical operation of the compressor and fans. Periodic cracking of plastic or gurgling in tubes is often simply thermal expansion of materials or movement of freon.
It is important to distinguish between operating noise and pathological knocking. If the refrigerator emits a steady hum, which either subsides or intensifies, this is normal mode. The problem is considered to be rhythmic tapping, rattling or metal hitting metal. Understanding the physics of the processes helps the owner not to panic ahead of time.
However, if you notice that the nature of the sound has changed, you should listen more carefully. Sometimes “normal” sounds mask an emerging problem. For example, a slight hum can turn into vibration if you do not check the stability of the case.
Installation problems and external factors
The most common, but common cause of knocking is incorrect installation. If the refrigerator is not level, vibration from the operating compressor is transmitted to the floor and walls, amplified by resonance. This creates the effect of constant knocking or rattling.
Check whether the unit is level. Use a building level or just rock the body. The legs should rest firmly on the floor. If the floor is uneven, the height of the support screws must be adjusted. Also check the distance to walls and furniture: vibration can be transmitted when touched.
- 🔨 Support legs: Check that the adjusting bolts are not loose and tighten them if necessary.
- 🧱 Contact with the wall: Make sure that the back wall of the refrigerator does not touch the wall or heating pipes.
- 📦 Internal contents: Sometimes it is not parts that knock, but bottles or cans that vibrate on the shelves.
⚠️ Attention: If the refrigerator is installed on a slippery floor (tile, laminate), vibration may cause it gradual shift. Use special anti-vibration pads under the feet.
After making sure that external factors are excluded, you can move on to more complex internal causes. Often the problem lies in something that we do not immediately see without disassembling the case.
Faults of the compressor and start relay
The heart of the refrigerator is the compressor. It is this that creates the pressure for the circulation of the refrigerant. If the refrigerator knocks loudly just when the motor starts or stops, the problem most likely lies in the compressor suspension system or in the start relay. The compressor is mounted on springs or rubber shock absorbers inside the housing. Over time, the metal gets tired and the rubber dries out. As a result, when starting, the engine begins to hit the walls of the casing, producing a characteristic metallic clang. This is one of the most common reasons why start relay.
The compressor is mounted on springs or rubber shock absorbers inside the housing. Over time, the metal gets tired and the rubber dries out. As a result, when starting, the engine begins to hit the walls of the casing, producing a characteristic metallic clang. This is one of the most common reasons why the refrigerator knocks during operation..
Is it possible to change the springs yourself?
Replacing compressor springs is a complex procedure that requires complete disassembly of the unit and working with copper tubes. Without skills and tools, there is a high risk of damaging the cooling system, so it is better to entrust this work to professionals.
Another reason for knocking is a malfunction of the start relay. If the contacts inside the relay are stuck or burned, it may make a clicking or cracking noise when you try to start the engine. In this case, the engine may hum, but not start, accompanied by rhythmic knocks.
- 🔊 Metallic clanging: Indicates that the compressor is touching the casing or frame.
- ⚡ Relay clicks: Indicates problems with the electrical part of the start.
- 📉 Case vibration: Excessive shaking indicates wear on the motor shock absorbers.
Diagnostics of the compressor requires caution. If you hear that the motor is running intermittently and with strong shocks, it is better to disconnect the device from the network until the technician arrives in order to avoid complete failure of the unit.
Fan noise in the No Frost system
In refrigerators with the system No Frost the fan is responsible for the circulation of cold air. Over time, ice may build up on the blades, or the fan motor bearing may wear out. This causes a characteristic knocking or hum, which is often confused with the noise of a compressor.
If the fan hits the ice with its blades, you will hear a cracking noise, similar to the sound of a propeller hitting a branch. This often happens if the door seal is leaking, allowing moist air to enter the chamber. Ice freezes on the evaporator and interferes with the rotation of the impeller.
☑️ Fan diagnostics
A worn fan bearing emits a monotonous hum that turns into a knock at high speeds. In this case, the entire fan assembly must be replaced. Ignoring this problem will result in the motor burning out and the system stopping cooling food.
⚠️ Attention: When working with a fan in the freezer, be careful with the plastic blades. They become brittle at low temperatures and break easily.
Fixing the problem often requires completely defrosting the refrigerator for 10-12 hours. If the sound disappears after defrosting, then ice was the cause. If the knocking noise remains, there is a mechanical problem.
Icing and problems with defrosting
The formation of excess ice is the enemy of quiet operation of the refrigerator. Ice can block the operation of not only the fan, but also the damper that regulates the air supply. The damper in the system Multi Air Flow is controlled by an electric drive, and if it is frozen, the motor will try to open it, making cracking and knocking noises.
Ice can also accumulate on the evaporator tubes. When refrigerant passes through ice-clogged areas, water hammer or simply a change in the nature of the flow noise may occur. Regular defrosting is the best way to prevent such problems.
If you notice that the refrigerator has started knocking after it has not been defrosted for a long time, let it stand turned off with the doors open for a day. This will help melt the ice in hidden cavities that cannot be reached with a rag.
It is also important to check the drainage hole. If it is clogged, the condensation does not go away, freezes and turns into an ice plug, which, when expanded, can make sounds and disrupt the operation of the defrost system.
Comparative table of sounds and causes
To make it easier for you to determine the cause of the noise, we have compiled a table comparing the nature of the sound with the probable malfunction. This will help formulate the problem when talking with a technician.
| Sound type | Probable cause | Difficulty of repair | Necessary actions |
|---|---|---|---|
| Metallic clanging when starting | Wear of compressor springs | High | Replacing shock absorbers |
| Crackling and noise in the freezer | The fan touches the ice | Average | Defrosting or replacing the fan |
| Gurgling and hissing | Freon movement (normal) | Not required | Observation |
| Rhythmic clicks | Relay or thermostat malfunction | Medium | Relay relay |
| Humming turning into knocking | Wear of motor bearings | High | Replacement of the compressor |
As can be seen from the table, some sounds do not require intervention, while others signal critical malfunctions. Diagnostics by sound allows you to save time on finding a breakdown.
If you are not confident in your abilities, it is better not to take risks. Repairing refrigeration equipment requires specific knowledge and tools. Improper disassembly can lead to freon leakage.
Prevention and care of the refrigerator
So that the refrigerator serves for a long time and quietly, behind it need to be looked after properly. Regular defrosting, even if the manufacturer claims the system No Frost, prolongs the life of the equipment. Once every 6-12 months, it is recommended to completely turn off the device and wash it.
Monitor the condition of the rubber seals on the doors. If they leak warm air, the compressor will run non-stop, overheat and wear out faster. Wipe the seals with a soft cloth and check their fit.
- 🧹 Cleaning the condenser: Periodically vacuum the rear radiator grille to prevent the engine from overheating.
- ❄️ Temperature control: Do not put hot foods in the refrigerator, this causes excessive steam formation and ice.
- 🔧 Checking the fasteners: Once a year, check the tightness of the bolts and the condition of the legs.
⚠️ Attention: Specifications and maintenance requirements may vary depending on the model. Always check the user manual for your specific device.
Following simple operating rules will avoid most problems with knocking and noise. Remember that prevention is always cheaper than repairs.
FAQ: Frequently asked questions
Why does a new refrigerator make strange sounds?
New equipment can make “noisy” during the break-in period. The compressor parts are ground in and the oil is distributed. If the knock is not metallic and is not accompanied by vibration of the case, this is normal. Let the refrigerator operate for 2-3 days.
Is it possible to operate the refrigerator if it is knocking?
For a short time, it is possible if it is not accompanied by a lack of cold. However, working for a long time with a faulty compressor or fan will lead to costly repairs. It is better to identify the cause immediately.
How to understand that the compressor has burned out?
If the refrigerator hums, clicks, but does not start, and after a while a loud click of the relay is heard and the buzzing stops, the compressor is probably jammed or the winding is burned out. A call to a technician is required.
Will an anti-vibration pad help?
Yes, if the knocking is caused by the resonance of the case or the transmission of vibration to the floor. Special rubber mats or footrests effectively dampen low-frequency vibrations.
Is it dangerous if the refrigerator only knocks at night?
At night, extraneous sounds are more audible due to the silence in the apartment. If the knocking is rhythmic and associated with the cycles of turning on the motor, this indicates a real mechanical problem, and not the time of day.