A sudden or regular loud knock in the refrigerator compartment can unsettle any owner. Usually we get used to the monotonous hum of the engine, but sharp, abrupt sounds clicks are often perceived as a signal of a serious breakdown. This does not always mean that the unit is out of order, but such symptoms also cannot be ignored.
Extraneous sounds can be caused by both natural physical processes and malfunctions of electrical components. It is important to learn to distinguish the nature of the noise in order to understand whether you need to immediately call a technician or whether the problem can be solved yourself. In this article, we will analyze in detail the mechanics of the device and pinpoint exactly the source of the problem.
Natural causes of knocking
Before you panic and look for the service center number, it is worth considering the physics of the operation of household equipment. Often loud sounds that frighten users are completely normal for certain operating modes. For example, expansion and contraction of materials under the influence of temperatures is a normal process.
The internal walls of the chamber and the evaporator are made of plastic and metal, which have different coefficients of thermal expansion. When the compressor is turned on, the temperature drops sharply, and when it is turned off, it rises. This cycle causes the panels to deform, which is accompanied by a characteristic cracking or clicking sound. If the sound is heard irregularly and is more like a crackling sound, then your Indesit or Bosch everything is fine.
⚠️ Attention: If the clicks are accompanied by a burning smell or visible sparking, immediately unplug the device from the power supply and check the outlet.
Another reason may be the movement of refrigerant through the pipes. When freon passes through narrow areas of the system or capillary tube, gurgling sounds may occur, turning into light knocks. This is especially noticeable in models with a No Frostsystem, where the circulation of gases is more active. It is also worth checking the stability of the unit itself on the floor.
Improper installation leads to vibrations that are transmitted to the case and amplify any mechanical sound. Make sure that the legs of the refrigerator are firmly against the floor and that the refrigerator itself is not touching a wall or furniture. Even a small gap of 5-10 centimeters can radically change the acoustics of the room.
Malfunctions of the starting relay and electrics
If natural causes are excluded, and the clicks are rhythmic, “metallic” in nature, the problem most likely lies in the electrical part. The most common culprit in such cases is the starting relay. This small unit is responsible for starting the compressor motor. When voltage is applied, the bimetallic plate inside the relay heats up and closes the contacts, producing a loud click.
If the relay is working properly, after the click the motor starts. However, if the contacts are oxidized or the mechanism is worn, you may hear a series of rapid clicks without a subsequent hum from the compressor. This means that the device is trying to start, but cannot, and the protection opens the circuit again. In modern models, such as LG or Samsung, this process can be controlled electronically, but the mechanical sound remains the same.
How to check the relay yourself?
To diagnose the relay, you need to carefully remove it from the compressor contacts (after turning off the refrigerator!). Shake the relay near your ear: if it rattles inside like a rattle, it means the mechanism is damaged and requires replacement. Also inspect the contacts for carbon deposits.
Another electrical cause may be a thermostat malfunction. When this sensor is triggered, it also makes a characteristic click, opening or closing the power circuit. If the thermostat is stuck or not working correctly, the on-off cycles may become too frequent, creating the feeling that the mechanism is constantly working.
The table below shows the main symptoms and probable causes of an electrical nature:
| Symptom | Probable cause | Required actions |
|---|---|---|
| Single click and engine starts | Normal relay operation | No diagnostics required |
| Series of clicks, motor does not start | Malfunction of the starting relay | Replacing the relay |
| Clicking every 10-15 minutes | Thermostat operation | Checking the temperature setting |
| Clicks and humming without cooling | Problem with the compressor | Call a technician |
Problems with the compressor and water hammer
The compressor is the heart of the refrigerator, and any anomalies in its operation are reflected in the noise level. If you hear a loud bang at the moment of startup, this may indicate a so-called hydraulic shock. This happens when liquid freon or oil enters the compression chamber, where only gas should be.
This situation is dangerous for the integrity of the valves and piston group. This often happens after improper transportation, when the refrigerator has been lying on its side and oil has flowed into the circuit. If you turn on such a unit immediately, a shock is inevitable. Also, water hammer can be a consequence of a malfunction of the compressor itself, when the tightness of the internal valves is broken.
Wear of the bearings or bushings of the engine shaft also leads to knocking. Unlike electrical clicks, this sound is more dull and is often accompanied by vibration of the housing. Over time, the gaps increase and the parts begin to hit each other. In models with an inverter compressor, for example Electrolux or Haier, diagnosis is more difficult, since there are fewer moving mechanical parts, but failure of the inverter board can also produce characteristic sounds.
If the compressor makes sounds similar to metal hitting metal, further operation may lead to complete motor jamming. In this case, repairs are often not economically feasible, and replacement of the entire unit is required.
The influence of the defrosting system on the sound background
In refrigerators with an automatic defrosting system (No Frost), cyclic clicks can be associated with the operation of the defrost timer or heater. A timer is a mechanical or electronic device that switches between “cooling” and “defrosting” modes. At the moment of switching, a distinct, rather loud click is heard inside.
This sound is usually heard once every 8-12 hours. If you notice that the clicks begin to occur more frequently, the timer may be faulty and “jumping.” This leads to the fact that the refrigerator does not have time to gain cold or, conversely, defrosts too often. In models such as Stinol or Atlant, mechanical timers are common and are consumables.
☑️ Diagnostics of the defrosting system
It is also worth mentioning the sounds made by the defrosting process itself. Drops of water flowing onto a hot heating element (heating element) can hiss and sometimes make short crackling sounds. This is normal as long as the drainage system is not clogged. If ice accumulates on the evaporator and periodically breaks off in large pieces, the fall of ice to the bottom of the chamber or on engine parts will sound like a strong blow.
Diagnostics and methods for eliminating noise
To accurately determine the source of the problem, it is necessary to carry out an initial diagnosis. Start with visual inspection and listening. Place your hand on the back wall of the refrigerator near the compressor - you will be able to feel the vibration when it clicks. This will help isolate the source: is it electrical or mechanical.
If you suspect a problem with the relay, you can replace it yourself if you have electrical skills and a suitable screwdriver. The new relay must exactly match the markings of the old one. For compressors from different manufacturers (Danfoss, Secop, Embraco), different types of starting devices are used, and there are no universal solutions here.
⚠️ Attention: Before any manipulations inside the case, be sure to unplug the refrigerator. Working with live electrical components is deadly!
If the problem is vibration of the tubes, they can be carefully corrected. The copper tubes should not touch each other or the walls of the housing. For insulation, you can use special vibration-proofing materials or ordinary foam rubber. However, proceed with caution: copper is a soft metal, and if strongly compressed, the tube may burst, which will lead to freon leakage.
When you need to call a specialist
There are a number of symptoms in which self-repair is not only useless, but also dangerous. If after replacing the relay the refrigerator continues to click and does not start, the problem is deeper. Perhaps the compressor winding burned out or a breakdown occurred on the housing.
A technician is also needed if recharging with refrigerant is required. A freon leak is not just a loss of cooling capacity, it is a violation of the tightness of the circuit. Finding the location of the leak requires special equipment (leak detector), and refilling requires evacuation of the system and accurate weighing of the refrigerant.
Do not try to disassemble the compressor itself. This is a sealed unit that cannot be repaired at home. Any intervention will lead to the final failure of the unit. If the diagnosis indicates a malfunction of the motor-compressor, get ready to replace it.
Is it worth repairing an old refrigerator?
Repair is advisable if the cost of spare parts and work of a technician does not exceed 50-60% of the cost of a new similar device. For older models (>10 years), replacing the compressor is often unprofitable.
Prevention of noisy operation
In order for your refrigerator to operate quietly and for a long time, it is important to follow the operating rules. Regularly clean the condenser (grid at the back) of dust and animal hair. A clogged condenser causes the compressor to work with overload, which increases wear on parts and noise levels.
Make sure the door is closed tightly. If the seal is worn and allowing heat to pass through, the compressor will turn on more often, increasing the number of start cycles and, accordingly, the number of relay clicks. Change the seal if cracks appear or loss of elasticity.
Do not place hot foods in the chamber. A sharp temperature change forces the system to operate in extreme mode, which also affects the sound of processes. Following these simple rules will extend the life of your Beko, Liebherr or any other brand.
Is it normal if the refrigerator clicks immediately after turning it off?
Yes, this is absolutely normal. When the compressor is turned off, the pressure in the system changes sharply, and refrigerant may flow back or valves may operate, causing noise. Also, cooling metal makes compression sounds.
Can a new refrigerator click?
Yes, new models, especially with the No Frost system, can make sounds when setting the temperature settings for the first time. Sound from expansion of new materials is also possible. If after 1-2 days the noise does not stop and intensifies, contact service.
Why does the refrigerator click but does not freeze?
This is a classic sign of a faulty start relay or compressor. The relay clicks, trying to start the motor, but the motor does not start due to a breakdown. Diagnostics of the electrical circuit is required.
Does the floor level affect clicks?
Indirectly - yes. If the refrigerator is not level, the vibration from the compressor is transmitted unevenly to the body, causing rattling and resonance, which can be perceived as clicks or knocking.