Many owners of household appliances are faced with a situation where when a newly purchased or defrosted unit begins to make unusual sounds. A panic immediately arises and the question of whether this is the norm or whether it’s time to call a specialist. It is important to understand that modern compressors and refrigerant circulation systems work differently than the bulky models of the last century, however, certain sound artifacts are natural for them.
The duration of the noise load directly depends on the state of the product inside the chambers and the ambient temperature. If you've just loaded warm food or defrosted the unit, the motor will work harder and longer, creating a constant background hum. In normal operation, working equipment should enter a cyclic rhythm, alternating periods of activity with complete silence.
In this article we will analyze in detail the time intervals during which the sound of a running motor is heard, and also consider the physical reasons for the occurrence of various sounds. You will learn to distinguish normal operation from the harbingers of a breakdown, which will save your budget on calling specialists and extend the life of the equipment.
First start-up and adaptation period of the equipment
After delivery of a new refrigerator or moving it to another room, time is required for stabilization technical fluids and oils in the compressor. It is usually recommended to wait 2 to 4 hours before plugging in to allow the oil to drain into the crankcase, but the primary cooling process itself takes much longer. During this period, compressor can work without stopping for up to 24 hours, until the set temperature is reached inside the chambers.
The intense hum in the first day is explained by the fact that the system is trying to cool not only the air, but also the walls of the chambers, and the loaded products. If there are warm objects inside when you turn it on, the engine's continuous operation time may increase. This is a normal situation for inverter and classic motors, which operate at maximum power at the start.
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It is worth noting that during the initial start-up, a higher decibel level is allowed than during normal operation. The metal case has not yet entered the temperature regime of expansion and contraction, so clicks and crackles of plastic may be heard. If after 24 hours of continuous operation the motor does not turn off and the noise level does not decrease, you should check the tightness of the door seals.
Normal operating time of the compressor per day
In normal mode, a working refrigerator does not work constantly. Its cycle consists of periods of activity and rest, the ratio of which depends on the thermal insulation and thermostat settings. It is considered normal if operating time it ranges from 30% to 50% of the total time of the day. This means that the unit can hum for a total of 7 to 12 hours a day, divided into many short cycles.
The duration of one switching cycle usually varies from 10 to 30 minutes, followed by a pause of the same or greater duration. If you notice that the motor turns on every 2 minutes and runs for 5 minutes, this is a sign of timing, which indicates a problem with thermoregulation or a freon leak. At the same time, rare switching on for a long time may indicate a violation of the door seal.
| Compressor type | Nature of operation | Average cycle time | Noise level |
|---|---|---|---|
| Usual (linear) | Turns on at full power, then turns off | 20-40 minutes | Average, with peaks at start |
| Inverter | Works constantly, changing speed | Continuous (background) | Low, even hum |
| Linear inverter | Smooth start and stop without sudden jumps | Varies | Minimum |
The duration of work is also affected by seasonality. In the summer, when the ambient temperature in the kitchen is high, heat transfer is difficult, and the motor is forced to work longer and more often. In winter, cycles become less frequent and pauses become longer. Therefore, the question of how long the device hums does not have a universal answer without reference to environmental conditions.
Physical causes of sounds
Understanding the nature of sound helps to calmly respond to the operation of equipment. The main source of noise is vibration compressor and the movement of refrigerant through the system pipes. When gaseous freon is compressed and turns into a liquid state, characteristic gurgling and shimmering sounds arise, which can be heard even after the motor is stopped.
Another common reason is thermal expansion and contraction of materials. The plastic of the internal shelves, the metal body and the evaporator change their geometric dimensions as the temperature changes. This process is accompanied by clicks, crackling sounds and short series of sounds reminiscent of gunshots or blows. This is especially often observed in models with a system No Frost, where temperature changes are sharper.
⚠️ Attention: If clicks are accompanied by a burning smell or visible sparking inside the chamber, immediately unplug the device. This may indicate a faulty electrical wiring or start relay.
Vibrations can be transmitted to the floor or walls if the refrigerator is not installed level. In this case, the hum is amplified due to resonance with the surfaces of the room. Correct installation on adjustable supports using a building level can significantly reduce the overall level of acoustic discomfort. Also, the source of rattling can be loose objects on the door or inside the chambers.
Why can you hear the murmur of water?
Gurgling and gurgling is the sound of the refrigerant (freon) moving through the capillary tube and evaporator. After the compressor stops, the pressure in the system equalizes, and the remaining liquid refrigerant flows, creating characteristic sounds. This is absolutely normal and indicates the integrity of the circuit.
Differences in noise in different types of refrigerators
Different cooling technologies require different acoustic patterns. Classic models with a weeping evaporator are quieter in standby mode, but make more noticeable noise when starting the engine. Systems No Frost require constant air circulation, which is provided by an additional fan. It is the sound of rotating blades that often becomes a source of concern for owners.
In models with two compressors (separately for the freezer and refrigerator compartments), noise can occur independently in different compartments. This creates the illusion of almost continuous operation, since while one motor is resting, the other can work. Inverter systems, on the contrary, do not have sharp starts, so their sound is more monotonous and quiet, but is present almost constantly.
It is important to consider the volume of the chambers: the larger the refrigerator, the more powerful the compressor required and the larger the area of the heat exchanger through which the refrigerant moves. Accordingly, large-sized ones American or European models may be noisier than their compact counterparts simply due to their design and power.
⚠️ Attention: Technical specifications for noise levels may vary depending on the specific modification and year of manufacture. Always check the specifications of your model with actual sensations, as testing standards among manufacturers may differ.
When noise becomes a sign of malfunction
There are a number of sound signals that cannot be ignored. If the humming changes to a metallic clanging, grinding or high-pitched whistling sound, this indicates a mechanical failure. Most often, the compressor bearing fails or the tubes are deformed, which begin to touch each other during vibration.
A loud knocking sound when starting or stopping the engine often indicates a faulty start relay or wear on the internal compressor suspension. In such cases, the unit may try to start, make a clicking sound and stall. Operating equipment in this mode is unacceptable, as this can lead to burnout of the motor windings.
A constant, incessant hum for several days with no output on the rest cycle indicates that the system cannot reach temperature. The reasons may lie in a freon leak, a clogged capillary tube, or loss of tightness of the door seal. In this case, diagnosis a specialist is necessary to prevent a complete loss of cooling capacity.
Methods for reducing noise levels on your own
Before contacting the service, try to eliminate external factors. Make sure the refrigerator is level. The legs should be adjusted so that the body leans back a little, ensuring the doors close themselves, but at the same time rests firmly on all four points. The use of anti-vibration pads under the supports also gives an excellent effect.
Check that the pipes from behind do not touch each other or the cabinet wall. If necessary, carefully (without using force, so as not to pinch!) move the tubes apart or move the equipment away from the wall. The gap at the back should be at least 5-10 cm for free air circulation, which also reduces the load on the motor.
If shelves or bottles inside are noisy, use special silicone gaskets or simply organize more tightly space. Sometimes the source of rattling is a decorative panel on the door or an egg tray - check that they are securely fastened. Regular washing and lubrication of door hinges also helps to avoid squeaks.
⚠️ Attention: It is strictly forbidden to open the compressor casing or cut seals on your own. Any tampering with the sealed circuit or the electrical part of the motor will void the warranty and may be life-threatening.
Frequently asked questions (FAQ)
How long should the refrigerator be silent between cycles?
In normal mode, the pause between turning on the compressor should last at least 10-15 minutes. This time is necessary to equalize the pressure in the system and rest the engine. If pauses are shorter than 5 minutes, this indicates an overload or malfunction of the thermostat.
Why does an old refrigerator make more noise than a new one?
Over time, the compressor shock absorbers wear out, the oil dries out, and play appears in the bearings. In addition, the old seal holds the cold worse, forcing the engine to work more often. New models (inverter) were initially designed with low noise levels in mind.
Is it normal for the refrigerator to hum when the door is open?
Yes, this is normal. When the door is open, warm air enters the chamber, sensors record the temperature increase, and the fan (in No Frost systems) or compressor can work more actively. Also, the sound may change due to changes in the acoustics of the room.
Can the noise level depend on the fullness of the chambers?
A fully loaded refrigerator operates more stable and quieter, since food accumulates cold and reduces the frequency of switching on. An empty unit heats up faster from the slightest opening of the door, causing the motor to turn on more often.