A sudden loud noise from a refrigerator can disturb the peace in any home. Compressorwhich is the heart of the refrigeration unit is in good condition operates almost silently or emits a barely audible low hum. However, if the unit begins to rattle, knock or make sharp sounds, this cannot be ignored.
Often users are afraid that the equipment has completely failed and requires expensive replacement. In fact, the reasons can vary from banal instability of the case to serious mechanical damage to internal components. Timely diagnostics allows you to prevent breakdowns and extend the service life of the equipment.
In this article we will analyze in detail why extraneous sounds occur, how to distinguish normal operation from a malfunction, and in what cases you can deal with the problem yourself. Understanding the nature of sound is the first step to successful repair.
Natural causes of noise and features of engine operation
Loud operation does not always indicate a breakdown. Modern refrigerants engine designs have their own acoustic characteristics. For example, when starting the engine or immediately after stopping it, a short-term hum or gurgling may occur, which is caused by the movement of freon through the system.
It is also worth considering that refrigerators with a system No Frost or inverter compressors may sound differently than older models. Inverter motors run continuously to regulate power and may produce a low-frequency hum, which is not a sign of trouble. It is important to listen to the nature of the sound: if it is monotonous and does not change sharply, most likely the equipment is functioning normally.
In some cases, the volume depends on the position of the equipment. If the refrigerator is too close to the wall, sound waves bounce off the surface, creating an amplification effect. It is enough to simply move the unit away to reduce the level of discomfort.
⚠️ Attention: If, after purchasing a new refrigerator, you hear a loud knock when you turn it on for the first time, wait 10-15 minutes. This often happens due to the fact that the oil in the compressor has not yet been distributed throughout the system after transportation.
Noise level in modern models it should not exceed 40 dB, however at the time of startup this figure may increase briefly.
Mechanical problems: wear of fasteners and shock absorbers
The most common reason that the compressor rattles is the weakening of fasteners. The vibration that occurs during operation of the piston group over time loosens the bolts and nuts. Shock absorbersthat dampen vibrations may also lose their properties or become deformed.
If you hear rattling or metallic clanging, check the external fasteners. Often the problem lies in the compressor casing, which does not fit tightly. It is enough to tighten the fasteners or install rubber gaskets to eliminate the noise. In more complex cases, it is necessary to replace the rubber bushings on which the motor itself is suspended.
Long-term operation without maintenance leads to the fact that vibration loads transferred to the body and floor. This not only creates noise, but can also lead to depressurization of the tubes. Regular checking of fastening tension is a simple procedure accessible to every user
☑️ Diagnostics of fastenings
Water hammer and refrigerant problems
One of the most dangerous symptoms is a loud bang or knocking sound that sounds like a hammer blow. This phenomenon is called hydraulic hammer. It occurs when liquid freon or oil enters the compressor cylinder at a time when the valve should be closed. The piston, trying to compress an incompressible liquid, experiences a colossal overload.
The reasons for liquid entering the cylinder can be different: a malfunction of the thermostat, which does not allow the compressor to turn off in time, or an excess of refrigerant in the system. This can also be caused by a clogged capillary tube, which interferes with the circulation of substances. If the cause is not eliminated, valve group it will quickly fail.
Repeated water hammers lead to destruction of the internal parts of the motor. In this case, simply changing the oil or topping up with freon will not help - serious repairs or replacement of the entire compressor will be required. It is important to prevent equipment from operating in extreme conditions.
| Sound type | Probable cause | Risk of breakdown | Actions |
|---|---|---|---|
| Monotonous hum | Normal operation or bearing wear | Low | Observation |
| Metal knocking | Looseness | Medium | Tightening bolts |
| Loud bang | Water hammer | High | Call a technician |
| Whistling or hissing | Freon leak | Critical | Looking for a leak |
Faulty electrical part and start relay
If the compressor hums, but does not start, or emits an intermittent crackling sound, the problem may lie in the electrical system. Often the culprit is starting relay. This element is responsible for supplying current to the motor windings at the time of start. When the contacts wear out, the relay begins to click or hum, trying to start the motor.
Another reason is an interturn short circuit in the windings of the motor itself. In this case electric motor the buzz is much louder than usual, gets very hot and can spontaneously turn off via a thermal protection relay. Operating equipment with a faulty winding is a fire hazard.
Diagnostics of electrical components requires skills in working with a multimeter. It is necessary to test the windings for resistance and check the integrity of the relay contacts. If you are not confident in your abilities, it is better not to take risks, since working with high voltage requires compliance with safety precautions.
⚠️ Attention: Before any check of electrical components, be sure to disconnect the refrigerator from the power supply! Residual voltage in capacitors can be dangerous.
How to check the starting relay?
To check the relay, it must be removed from the compressor. Shake it: if a ringing sound is heard inside (like from broken glass), it means the posistor or contacts are damaged. You can also test the contacts with a multimeter - they should close in a certain position. The faulty relay is replaced with a similar one according to the marking.
Wear of bearings and internal components of the compressor
When the engine's service life comes to an end, the bearings crankshaft begins to wear out. This leads to the appearance of a characteristic howl or increasing hum, which intensifies over time. Metal shavings formed during friction are carried by oil throughout the system, contaminating it.
In piston compressors, knocking may occur due to wear out in the cylinder-piston group. The gaps increase, the piston begins to hang out and hit the cylinder walls. This sound cannot be eliminated by adjustment; replacement of the unit is required. Sealed housing The compressor does not allow bearings to be repaired at home.
Often wear is accompanied by a drop in performance: the refrigerator freezes worse, runs longer and consumes more electricity. If you hear the motor “fighting” or making a grinding noise, this is a sure sign of mechanical failure of internal parts.
External factors and incorrect installation
Sometimes the source of noise is not inside the motor at all, but outside. Check whether the tubes of the refrigeration unit are touching each other or the walls of the housing. When vibrating, they can resonate, creating an unpleasant ringing sound. Gently separate the tubes with your hands (with the refrigerator turned off and cooled down) to eliminate contact.
Incorrect installation of the refrigerator is another common reason. If the floor is uneven and the legs are not adjusted, the body will warp. This places additional stress on the compressor and causes vibration. Use a building level to check the horizontal position.
Also pay attention to the objects standing on the refrigerator. Microwave ovens, jars, or decorative items may vibrate along with the appliance. Remove all excess from the top cover and check if the noise has disappeared.
When you need to call a specialist
There are situations when independent repair is impossible or dangerous. If you determine that the problem lies inside the sealed circuit, you can hear a burning smell, or the compressor constantly turns off via a thermal relay, you need a professional. Specialist has the necessary equipment to evacuate the system and charge the refrigerant.
Also the help of a specialist necessary if the compressor needs to be replaced. This is a complex process that includes unsoldering the tubes, installing a new motor, checking for leaks and accurately charging with freon. Errors at any stage will lead to rapid failure of the new part.
Do not try to open the sealed compressor casing at home. Even with the tools, it is almost impossible to put it back together while maintaining tightness and correct gaps. Saving on calling a technician in this case may lead to the purchase of a new refrigerator.
⚠️ Attention: Technical characteristics and requirements for refrigerants may change. Always check the technical documentation of a specific refrigerator model before ordering spare parts.
Is it possible to repair the compressor yourself?
Theoretically, replacing the start relay or tightening the fasteners is available to everyone. However, repair of internal mechanics (piston group, valves) requires factory conditions, special oil and a vacuum pump. In everyday life, such repairs are unprofitable and unreliable.
Why does the refrigerator hum loudly only at night?
At night, the overall noise level in the apartment decreases, and the operation of the refrigerator becomes more noticeable. In addition, at night the voltage in the electrical network may stabilize or, conversely, jump, which affects the operation of the motor. Also, at night, the fast freezing mode turns on more often if you opened the door during the day.
Is it dangerous to continue using a rattling refrigerator?
If the sound is caused by loose fastenings, it is not dangerous, but noisy. If you hear the piston knocking or water hammer, further operation may lead to jamming of the motor and the need for an expensive replacement. It is better to carry out diagnostics.
How long does a compressor last in a refrigerator?
The average service life of a modern compressor is 10-15 years. Inverter models can operate for up to 20 years or more due to the absence of constant on-off cycles. However, the resource depends on the operating conditions and the quality of the voltage in the network.
Can a new refrigerator make noise?
Yes, new refrigerators can make more noise in the first days of operation, while parts are being ground in and oil is distributed. Also, some models initially have a higher noise level indicated in the passport (up to 40-42 dB).