A continuous or intermittent hum emanating from a working refrigeration chamber can infuriate even the calmest person. This sound breaks the silence in the apartment, prevents you from sleeping at night, and often becomes the first signal that something wrong is going on with your household appliances. However, loud operation does not always compressor mean a critical breakdown that requires an immediate call to the technician.
In most cases, sources of extraneous sounds can be identified independently if you know the design of the unit. Bosch refrigerators, LG or Indesit may have their own design features, but the principles of operation of the motors are similar. Understanding the nature of sound will help you save your budget on repairs and avoid panic at the first unusual hum.
In this article we will analyze in detail the physics of the cooling process, divide normal operating noise into alarm signals and provide a step-by-step action plan to eliminate irritating factors. You will learn to distinguish the harmless bubbling of the refrigerant from bearing wear.
Physics of the process: when noise is the norm
Modern refrigeration units do not operate silently, and this is an axiom that consumers have to put up with. Work cycle A compressor involves compressing gaseous refrigerant, turning it into liquid and evaporating again, which is inevitably accompanied by sound effects. If you hear a uniform, monotonous hum, which either subsides or increases, this is the normal operating mode.
This is especially noticeable in models with one compressor two cameras. When the engine starts, it picks up speed, creating a characteristic low-frequency hum. After reaching the set temperature inside the chambers thermostat the circuit opens and the engine stops. At this moment, a clicking sound and a fading gurgle may be heard.
⚠️ Attention: If your refrigerator emits a quiet, uniform hum that does not change in tone and volume throughout the entire operating cycle, most likely the equipment is working. Attempts to “treat” a working device can lead to unnecessary costs.
It is important to consider the age of the equipment. Older models from 10-15 years ago are significantly louder than modern models due to the use of less efficient insulating materials and older-style motors. New inverter compressors are quieter, but they are not completely devoid of sound.
External factors: vibration and incorrect installation
Before you climb inside the housing or look malfunction in the electrical circuit, it is necessary to eliminate banal installation errors. Often the cause of rattling is not the motor itself, but the resonance of the housing or poor interaction with the floor surface. Vibration from a running engine is transmitted to the floor, causing a hum.
The first thing to check is the horizontal installation. If the refrigerator is skewed, the gravity vector is distributed unevenly, which increases vibration frames. Use a building level to check. Adjustment is carried out using the front supports, which can be unscrewed or tightened.
The second important point is the distance to the walls and furniture. The rear grille should not touch the wall, and the side walls should have a gap of at least 5 cm for air circulation. If the case vibrates against a cabinet or wall, the hum will increase many times over.
☑️ Diagnosis of external causes of noise
It is also worth inspecting the interior space. Rattling can occur from poorly secured shelves, bottles or containers that resonate with the frequency of the motor. Sometimes it is enough to simply correct plastic elements or replace the egg tray so that the extraneous sound disappears.
Problems with the compressor and start relay
If external causes are excluded, and the humming of the refrigerator motor is still loud and alarming, the problem may lies in the heart of the unit - the compressor. This is a complex mechanical assembly in which moving parts wear out over time. Wear of the piston group or bearings leads to the appearance of a metallic knock, clanging or strong buzzing.
Particular attention should be paid to the starting relay. This small element is responsible for starting the engine. If the relay contacts are burnt or the mechanism is stuck, the compressor may hum but not start, or make intermittent clicking noises. In such cases, the motor tries to start, but the current passing through the windings causes a strong hum.
The table below shows the main symptoms of compressor group malfunctions:
| Symptom | Probable cause | Sound character | Need for repair |
|---|---|---|---|
| Strong vibration of the case | Unbalanced motor | Low frequency hum | High |
| Clicks before starting | Relay malfunction | Sharp knocking, buzzing | Medium |
| Metal clanging | Bearing wear | Loud grinding | Critical |
| Humming without cooling | Piston jamming | Smooth hum | Critical |
Repair making a compressor with your own hands is possible only in theory, but in practice it requires special equipment for evacuation of the system and refueling with freonReplacing this unit is an expensive procedure, which is often compared to buying a new refrigerator.
Is it possible to lubricate the compressor?
It is impossible to lubricate the compressor without opening the system. Attempts to drill a hole or add oil through the tubes will lead to depressurization of the circuit and moisture ingress, which will permanently damage the unit.
No Frost system fan
In models with a system No Frost or Full No Frost for cold circulation Fans provide air. There may be one or two of them: in the freezer and refrigerator compartments. If the refrigerator motor is humming, but the sound is more like a howl or crackling, the problem often lies there.
Over time, an ice crust builds up on the fan blades, or moisture and dust get into the motor bearing. This causes rotational imbalance. As a result, the fan begins to vibrate, touching the ice or the walls of the air duct with its blades, creating an unpleasant noise.
For diagnostics, it is often necessary to remove the back panel in the freezer. If you hear that the sound intensifies when the door is opened (in some models the fan turns off when opened), then it falls on this node. Sometimes simple defrosting for 24 hours helps, which will melt the ice on the blades.
However, if after defrosting the sound returns after a few days, it means that the fan bearing has exhausted its service life. In this case, replacement fan with a new one is required. This is a relatively inexpensive and quick repair that you can do yourself if you have basic skills.
The influence of the refrigerant and capillary system
Sometimes users mistake the sounds made by the refrigerant itself for the hum of the motor. When freon moves through the evaporator and condenser tubes, gurgling, hissing or liquid overflow may occur. This is an absolutely normal physical process, especially noticeable immediately after the compressor stops.
However, if an air lock has formed in the system or a leak has occurred, the nature of the sounds may change. The motor begins to work with increased load, trying to compensate for the lack of pressure, which leads to a louder and longer hum. Capillary tube may be clogged with oil breakdown products or moisture.
If you hear that the refrigerator is humming almost without interruption, without turning off, and At the same time, it does not freeze well, this is a sure sign of a violation of the refrigerant circulation. In such a situation, the compressor overheats, which can lead to its combustion.
⚠️ Attention: Trying to refill the refrigerator with freon on your own without looking for a leak is a futile exercise. The gas will escape through the same hole in a few days or weeks, and the compressor will continue to operate in emergency mode.
To accurately diagnose the condition of the cooling system, a pressure gauge station is required. The technician connects it to the process fitting and measures the pressure. This is the only way to distinguish the noise from an “air” compressor from the noise of a clogged capillary.
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Do-it-yourself methods for reducing noise levels
If the refrigerator is technically working, but the noise level still causes discomfort, you can resort to a number of organizational measures. First, check if there are any foreign objects on the refrigerator. Cans, bottles or decorative items can resonate and increase vibration.
Second, use anti-vibration pads under the feet. Hardware stores sell special rubber mats or pads that dampen vibration transmitted to the floor. This is especially true for owners of old models or appliances installed on linoleum or tiles.
Thirdly, do not load the refrigerator to capacity with food. Overloaded shelves and drawers begin to rattle from the vibration of the compressor. Distribute the products evenly, leaving space for air circulation.
It is also worth paying attention to the condition of the back wall. If you see that the condenser tubes (the black grille at the back) are touching the wall or each other, carefully (with the appliance turned off!) move them apart or place a piece of foam rubber or rubber between them.
Is it possible to soundproof a refrigerator?
Gluing the body of the refrigerator with soundproofing materials (for example, for cars) is absolutely not recommended. This will disrupt heat exchange, lead to overheating of the compressor and increased energy consumption.
When you need to call a technician
There are a number of symptoms, ignoring which can lead to expensive repairs or complete replacement of equipment. If the humming is accompanied by a lack of cold, the appearance of ice in the wrong places or a burning smell, you should not hesitate.
Calling a specialist is required in the following cases:
- 🔥 The compressor hums, gets very hot and turns off after 1-2 minutes of operation (the thermal relay is activated).
- 💧 A puddle of oil or water has formed under the refrigerator, accompanied by a change in the sound of operation.
- ⚡ You can hear the crackling of an electric arc or the smell of melted wiring.
- 🧊 The refrigerator has stopped freezing, although the motor continues to run continuously and loudly.
Professional diagnostics will allow you to accurately determine whether the compressor needs to be replaced, the control board repaired, or simple cleaning of the system. Remember that complex components, such as inverter unit or a sealed circuit, require qualifications and special tools.
Why does the new refrigerator hum louder than the old one?
Modern compressors often operate at higher speeds to achieve class A+ energy efficiency. In addition, new models use less metal in the body structure to save resources, which can reduce sound insulation. Also, the new motor requires a “break-in” period, after which the noise level may decrease.
Is it possible to use the refrigerator if it hums a lot?
If the hum is caused by vibration or installation, you can use it, but this affects comfort. If the compressor is worn out or the fan is faulty, prolonged operation can lead to overheating and a fire hazard. It is better to carry out diagnostics.
Does the temperature in the room affect the noise of the refrigerator?
Yes, in a hot room the compressor is forced to work longer and more intensely in order to maintain the set temperature inside the chambers. This leads to an increase in the operating time of the motor and, accordingly, the overall noise level in the apartment.
What to do if the refrigerator hums after defrosting?
If a new sound appears after defrosting, check whether the equipment is completely dry before turning it on. Water may have gotten into electrical contacts or onto the fan blades. Leave the refrigerator turned off for a few more hours. If the sound remains, a breakdown is possible.
Is it normal for the refrigerator to hum when it is first turned on?
When starting for the first time after purchase or long-term transportation, the compressor can work in increased mode for up to 10-12 hours until it reaches the temperature. At this time, the buzzing may be more intense. It was also important to let the equipment sit for 2-4 hours after delivery before turning it on.