After purchasing and delivering a new one household appliances in the home, many users are faced with anxiety: why does the device make loud sounds? The question of how long the refrigerator hums when you first turn it on is one of the most common questions in maintenance services. Immediately after connecting to the power supply, the unit begins active work to cool the internal volume, and this process is accompanied by the characteristic noise of a running motor.
The intensity and duration of the sound depends on many factors: the type of compressor, the condition of the floor, correct installation and ambient temperature. During the first hours of operation refrigeration circuit it is filled with refrigerant, and the oil in the compressor is distributed throughout the system, which can cause gurgling and humming. Understanding the physical processes occurring inside the case will help distinguish normal operation from signs of malfunction.
In this article we will examine in detail the time frame for normal operation, permissible decibel levels and situations when professional intervention is required. It is important not to panic ahead of time, but also not to ignore obvious signals for help from your equipment. Correct diagnosis at an early stage will save nerves and budget.
Physics of the process: what happens inside at startup
The moment you first plug the plug into the socket, a complex thermodynamic cycle starts into the system. Compressor, which is the heart of the unit, begins to build up pressure, pushing refrigerant through pipes. It is at this moment that the maximum noise level is observed, since the system needs to overcome the inertia of rest and create primary pressure in the circuit.
Liquid freon, passing through the capillary tube and entering the evaporator, expands sharply and boils. This process is often accompanied by sounds reminiscent of gurgling water or the pouring of liquid. Such acoustic effects are absolutely normal for modern models using inverter or classic motors. The sound may increase or decrease depending on the phase of the gas compression and expansion cycle.
In addition, during the first start, thermal relays are often activated and valves, emitting characteristic clicks. Thermostat or the electronic control module constantly monitors the temperature and gives commands to turn the motor on and off. If the room is hot, the motor will run longer and louder, trying to achieve the set parameters.
⚠️ Attention: If the hum is accompanied by vibration that is transmitted to the walls or furniture, check the distance between the back wall of the refrigerator and the surface. The gap should be at least 5 cm for normal air circulation.
Temporary standards: how long should the motor run before turning off
One of the main questions that concerns owners: after what time should the refrigerator first turn off? The duration of the first cooling cycle directly depends on the temperature inside the chambers and in the room. Typically, the process of initial temperature rise takes from 2 to 12 hours, depending on the volume of the chambers and the power of the compressor. During this time, the motor can operate continuously or with short pauses. This is a normal situation, called “entering the regime.” The unit must cool not only the air, but also the walls of the chambers, shelves and products, if they are already loaded. compressor.
During this time, the motor can run continuously or with short pauses. This is a normal situation, called “entering the regime.” The unit must cool not only the air, but also the walls of the chambers, shelves and products, if they are already loaded. The first automatic shutdown of the compressor should occur after reaching the set temperature, which usually happens after 4-8 hours of continuous operation.
If the motor has been humming for more than 12-14 hours without a break, it is worth checking the tightness of the door and integrity of the seal. Also, the cause of endless operation may be incorrect setting of the thermostat to maximum cold immediately after switching on. Give the equipment time to stabilize the climate before demanding ideal efficiency from it.
It is important to consider that modern models with the function No Frost can work longer due to the need to freeze massive evaporators. In summer, when the ambient temperature is high, the operating time also increases. You should not artificially speed up the process by opening the doors every five minutes to check the cold.
Permissible noise level: decibels and subjective sensations
Sound pressure level is a parameter that is indicated in the technical data sheet of the product. For most household models, the range from 36 to 42 dB is considered the norm. However, in practice, subjective perception may differ. What seemed like a quiet hum in the store can be annoying at home in the silence of the night.
It is worth distinguishing between the types of sounds it makes refrigeration unit. A uniform low-frequency hum is the work of the motor. Periodic clicks - relay activation. Gurgling is the movement of freon. All these sounds together create an acoustic background. If the noise level has increased sharply or a metallic clanging sound has appeared, this is a cause for concern.
| Sound type | Description | Status |
|---|---|---|
| Monotonous hum | Uniform low sound | Normal |
| Gurgling | Sound of flowing liquid | Normal |
| Sharp click | Single sound at start/stop | Normal |
| Metal knocking | Vibration of tubes on the body | Requires editing |
| Whistling or hissing | Continuous high sound | Fault |
The volume also depends on the materials from which the case and internal shelves are made. Glass shelves can resonate, increasing vibration. Empty chambers often “sound” louder than filled ones, as the contents act as a sound absorber. If the noise bothers you, try loading the chambers evenly.
Why do old refrigerators hum louder?
Models of the last decade used compressors with a crank mechanism and less effective sound insulation of the housing. Modern inverter motors operate almost silently, and the walls often have a multi-layer structure that dampens sound.
The influence of installation and transportation on the hum level
Improper installation is the most common cause of excess noise in the first days of operation. If the refrigerator is not level, vibration from the operating compressor is transmitted to the floor and amplified by the furniture body. Be sure to use a building level to adjust the support legs.
Transportation also plays a role. If the unit was transported lying down, oil could get into the refrigerant circuit. When starting, the compressor will try to pump this mixture, which will cause a strong hum and the risk of water hammer. This is why manufacturers insist on standing equipment in a vertical position.
- 🔧 Check that all transport bolts and fasteners have been removed before turning on.
- 📏 Make sure that the refrigerator does not touch the wall, cabinets or other objects.
- ⚖️ Adjust the legs so that the doors closed themselves at a slight angle.
- 🧹 Clean the floor under the installation site from small debris that can cause rattling.
⚠️ Attention: If you transported the refrigerator at temperatures below +5°C, let it warm up to room temperature for 4-6 hours before turning it on. Condensation on electronic parts can cause a short circuit.
Vibration can also be transmitted through the floor, especially if it is a wooden floor or laminate on a soft substrate. In such cases, it is recommended to use anti-vibration pads under the feet. This simple action often reduces the overall noise level in the room by 20-30%.
Differences in the operation of different types of compressors
The nature and duration of the hum directly depend on the type of engine installed. In modern refrigerators you can find three main types of motors, and each of them behaves differently when first started.
Conventional linear compressors work on the principle “turned on - cooled - turned off”. When starting, they gain full speed, creating maximum noise, then stop abruptly. This cycle can be repeated many times a day. The hum here is more pronounced and sharp.
Inverter models, on the contrary, after the start smoothly gain power and then operate at low speeds, maintaining the temperature. They practically do not make sharp sounds of starting and stopping. Their hum is a quiet, even hum that lasts for hours, but is almost imperceptible to the ear.
☑️ Check after the first start
There are also linear inverter systems that combine advantages of both types. They have fewer rubbing parts, which makes them quieter. However, when first turned on, even they can work more intensely than usual, until the control system calibrates the operating parameters for a specific thermal load.
Alarming symptoms: when it’s time to call a technician
Despite the acceptability of various sound effects, there are signs that cannot be ignored. If your refrigerator makes a noise that shakes the glasses in the cabinet, or the sound changes from a hum to a grinding sound, this indicates a mechanical problem. Most often, the compressor shaft bearing fails or the tube comes off.
Another alarming symptom is the engine running without stopping for more than 24 hours. This indicates that the system cannot reach temperature. The reasons may lie in a freon leak, a clogged capillary system, or a loss of circuit tightness. In this case, refrigerator not only makes noise, but also stops freezing.
Pay attention to the smell. If you smell burning or burning plastic along with the hum, immediately unplug the device. This may indicate overheating of the motor windings or faulty wiring. Further operation in this mode will lead to complete combustion of the motor.
Why does the refrigerator hum after defrosting?
After defrosting, excess moisture may remain in the system, which creates noise when freezing. It is also possible that you turned on the device too early, and condensation remained in the tubes. This usually goes away after a few hours of operation.
Can an empty refrigerator hum louder?
Yes, empty chambers work as resonators. Food and liquid containers absorb sound waves and stabilize the temperature, causing the compressor to turn on less often. Loading the refrigerator at 60-70% is optimal for quiet operation.
Does the network voltage affect noise?
Low voltage in the network causes the compressor to work with overload, trying to start. This causes humming, heating and buzzing in the relay. If your light often fluctuates, it is recommended to use a voltage stabilizer.
In conclusion, the first start of the refrigerator is a stress test for all systems. A slight hum that lasts several hours is a sign of life, not death, of the unit. The main thing is to ensure the correct operating conditions and monitor the behavior of the equipment on the first day. If doubts remain, it is better to consult with a specialist than to bring the equipment to major repairs.