The situation when Something is knocking in the No Frost refrigeratorcan unsettle any owner of household appliances. If the unit previously worked silently, but now makes rhythmic knocks or periodic rumbles, this cannot be ignored. Such sounds often indicate that the air circulation system or compressor operation is broken and requires immediate attention.
No Frost system refrigerators are more complex than conventional models, since air is forced to circulate in them. Fan, evaporator and defrost system — all these components can become a source of extraneous noise if they break down. In contrast to the quiet hum characteristic of normal operation, knocking indicates the mechanical impact of parts against each other or against the walls of the case.
Before calling a technician, it is worth conducting an initial diagnosis yourself. In many cases, the reason lies in improper installation or simple icing, which can be eliminated without expensive repairs. However, if vibration is transmitted to the housing and increases over time, this may be a sign of a serious compressor malfunction.
Natural sounds or a sign of breakdown?
The first thing the owner needs to do is learn to distinguish between operating noises and malfunction signals. Modern refrigerators, such as Samsung or LG, make specific sounds when the No Frost system is operating. Periodic crackling of plastic or hissing of refrigerant is normal, as materials expand and contract with temperature changes.
However, if you hear a distinct knocking sound, similar to the impact of a metal object, or a hum that increases and decreases, this is an alarming signal. Metal clanging often indicates that Some part has become loose and when the compressor operates it hits adjacent elements. It is important to listen exactly when the sound appears: immediately after turning on, during operation, or when the engine is stopped.
Often users confuse the normal operation of the refrigerant supply valve with a breakdown. This valve may make clicking or short knocking noises. But if knock becomes a constant companion to the operation of the unit, it is necessary to look deeper for the source of the problem. Ignoring such symptoms can lead to complete failure of the refrigerator compartment.
⚠️ Attention: If the knock is accompanied by a sharp increase in temperature in the refrigerator compartment or the appearance of ice on the back wall, use of the device should be stopped until the reasons are determined.
Problems with compressor and start relay
The compressor is the heart of the refrigerator, and it is it that most often becomes the source of noise during malfunctions. If there is something knocking in the No Frost refrigerator at a certain frequency, coinciding with the motor switching cycles, the problem may lie in the compressor itself or its mounting. Over time, the shock absorbers on which the motor is suspended dry out or break, allowing it to hit the metal casing.
Another common reason is a malfunction of the start relay. This small element is responsible for starting the engine. If the relay is worn out, it may not operate the first time, causing a characteristic clicking sound followed by a buzzing sound and a knock. In such cases, the engine tries to start, but cannot, which leads to a protective shutdown and a second attempt after a while.
Diagnostics of the compressor requires caution. You will need to move the refrigerator away from the wall and remove the back panel (if there is one) to gain access to the motor. When you turn on the appliance, place your hand on the compressor body: if you feel a strong, chaotic vibration accompanied by a knocking, the internal parts have probably worn out or the alignment has been disturbed.
It is important to note that replacing a compressor is a complex process that requires evacuation of the system and charging with freon. It is impossible to perform this procedure independently without special equipment. If the problem lies precisely in the “heart” of the refrigerator, you cannot do without calling a specialist.
Fan malfunctions in the No Frost system
The No Frost system cannot do without a fan that drives cold air through the chambers. If the fan is knocking in the refrigerator, this is usually accompanied by a characteristic buzzing sound, turning into crackling or banging. Most often, the reason lies in icing of the blades or wear of the motor shaft bearing.
When the defrosting system does not work correctly, ice builds up on the evaporator and fan blades. When the blades rotate, they touch the ice crust, producing a loud cracking or knocking noise. This is especially typical for models Indesit and Beko, where the gap between the blades and the channel wall can be minimal. In this case, it is necessary to defrost the refrigerator completely, leaving it turned off for a day.
If after defrosting the noise returns after a few days, then the problem is in the defrosting system (heating element, timer or sensor). If the fan makes noise even on a unit that is clear of ice, the grease in the bearing may have dried out or the shaft itself may be broken. In this case, the unit requires replacement.
Replacing a fan usually does not take much time and does not require calling a technician with freon, since the circuit is not opened. It is enough to purchase a similar fan model and connect it according to the diagram. The main thing is to make sure that the new element rotates freely and has no play.
Violation of installation and operation rules
Sometimes the answer to the question why there is something knocking in the No Frost refrigeratorlies on the surface. A simple violation of installation rules can turn the quiet operation of equipment into a concert of percussion instruments. If the refrigerator is not level, vibration from the compressor is transmitted to the floor and intensifies, causing rattling and knocking of the legs on the coating.
Check the horizontal installation. To do this, you can use a building level or simply shake the refrigerator. It should stand stable on all four legs. Height adjustment is usually done by unscrewing or tightening the front supports. Also make sure that the case does not touch walls, furniture or curtains, since during operation vibration is transmitted to them, causing resonance.
Another common reason is closely spaced bottles or cans inside the chambers. When the compressor operates, they can roll and hit each other or the walls of the refrigerator, creating the illusion of equipment failure. Check the contents of the shelves and doors.
☑️ Checking the installation of the refrigerator
In addition, during transportation the refrigerator could have received a blow that displaced the internal tubes. If the copper tubes of the condenser or capillary are in contact with each other or with the housing wall, they will vibrate and knock when the compressor operates. By carefully bending the tubes by hand (with the device turned off!), you can eliminate this contact.
Diagnosis table for noise sources
To simplify troubleshooting, use the following table. It will help classify the sound and suggest the cause.
| Sound type | Probable cause | Localization | Difficulty of repair |
|---|---|---|---|
| Rhythmic metal knocking | Faulty compressor or relay | Bottom, rear wall | High |
| Crackling turning into humming | Fan icing | Freezer compartment | Average |
| Casing rattling | Incorrect installation | Legs, contact with wall | Low |
| Periodic clicks | Thermostat or valve operation | Inside the chamber or behind | Normal |
By analyzing the data in the table, you can understand whether it is worth taking on the repair yourself or preparing for a visit from a specialist. For example, rattling can be easily eliminated on your own, but the knocking of the compressor requires professional intervention.
Foreign objects and internal vibration
There may be elements inside the refrigeration chamber that are not part of the structure, but create noise. These could be forgotten lids, egg trays or decorative items. When the shelves vibrate, they begin to move and knock. It is also worth checking the fastenings of the shelves: if they are not inserted completely, the glass may rattle.
Pay special attention to the No Frost system. On some models, the meltwater tray located above the compressor may not be securely secured. When the motor is running, it vibrates and knocks against metal parts. Secure it or place a piece of foam rubber for insulation.
⚠️ Attention: Do not use superglue or tape in heated areas to secure trays or panels. The plastic can become deformed and the glue can melt, creating a toxic odor.
If you find that the plastic panel itself inside the freezer is making a knocking sound, it may simply not be latched all the way. Remove it, check for ice and install it back, making sure that the fasteners fit snugly.
When you need to call a technician
There are a number of situations when self-repair not only will not help, but will also aggravate the situation. If after defrosting and checking the installation knock in the refrigerator it does not stop, and the temperature no longer remains at the desired level, the problem is serious. This could be a freon leak, a clogged capillary system, or a compressor wedge.
Opening the freon circuit without a license and equipment is prohibited and dangerous. In addition, incorrect diagnosis can lead to the purchase of unnecessary parts. If you are not confident in your abilities, it is better to entrust the repair to professionals.
Is it worth repairing an old refrigerator?
Repairing makes sense if the refrigerator is less than 7-10 years old and there is no visible corrosion. If the equipment is very old and the cost of replacing the compressor is high, sometimes it is more advisable to buy a new unit with a guarantee and energy efficiency class A++.
The technician will be able to accurately determine the source of the noise using a stethoscope and special tools. He will check the pressure in the system, the amperage of the compressor and the integrity of the electrical circuits. This guarantees that the repair will be carried out efficiently and the refrigerator will last for a long time.
Prevention of noisy operation
To prevent the question “why there is something knocking in the No Frost refrigerator" from arising in the future, it is important to follow the rules of prevention. Regularly, at least once a year, completely defrost the refrigerator, even if it is a No Frost system. This will help avoid the build-up of hidden ice on the evaporator, which will eventually reach the fan.
Keep the condenser (grid at the back) clean. Dust and pet hair accumulate on the pipes and compressor and impair heat transfer. The motor begins to work harder and longer, which leads to overheating and accelerated wear of parts, increasing the likelihood of knocking.
Also, do not overload the refrigerator with food. Packing that is too dense interferes with air circulation, forcing equipment to work at its limit. Following these simple rules will help maintain silence in your kitchen.
Is it possible to operate a refrigerator if it is knocking?
Short-term operation is possible if the knocking is not accompanied by heating of the body or lack of cold. However, prolonged noise indicates worn parts, which can lead to costly repairs. It is better to eliminate the cause immediately.
Why does knocking appear only at night?
At night, the overall noise level in the apartment decreases, and the sounds of operating equipment become more audible. In addition, the network voltage may be more stable at night, which affects the operation of the compressor. If the knocking really gets worse, check to see if the refrigerator is standing on a resonating surface.
How long can a knocking compressor last?
It is impossible to predict the exact period. It could be a week, or it could be several years. However, the operation of a faulty compressor leads to increased energy consumption and the risk of complete breakdown of the cooling system at the most inopportune moment.