The situation when the refrigerator does not turn off i makes an unusually loud hum can cause panic in any owner of household appliances. The constant operation of the motor-compressor not only leads to an increase in energy bills, but also creates the risk of complete breakdown of the unit at the most inopportune moment. The hum can be different: from a low growl to a piercing whistle, and each sound indicates a specific problem within the system.
In this article we will analyze in detail the mechanics of the refrigeration circuit so that you can understand why compressor stopped resting. It is important to distinguish between normal operation in hot weather and a real malfunction that requires the intervention of a technician or self-repair. Ignoring the first symptoms often leads to expensive restoration or complete replacement of equipment.
You should not immediately look for the number of a service center, since in some cases the reason lies in banal operating errors. However, if you notice that temperature in the chamber has fallen below normal, and an ice crust has formed on the walls, this is a signal of a serious failure. Let's look at all possible scenarios, ranging from simple settings to complex technical breakdowns.
Violation of temperature conditions and tightness
The most common reason why the refrigerator does not turn offlies in a violation of heat transfer. If heat from the outside constantly enters the chamber, the automation forces the compressor to work without interruption, trying to compensate for the loss of cold. Often the culprit is the rubber seal on the door, which has dried out over time, cracked or simply become dirty.
Check the tightness of the door: if it does not slam shut the first time or a gap is visible between the body and the rubber, cold air leaves and warm air enters. It may also be due to the habit of users leaving the door open during cooking or defrosting. In such cases, sensors detect an increase in temperature and give a command for continuous operation.
- 🔍 Check that the sealing rubber is clean and free of crumbs or sticky deposits.
- 🚪 Make sure that the door is not warped and the hinges have not weakened over time.
- 🌡️ Assess the temperature in the room: if the kitchen is hotter than +30°C, the refrigerator can work in increased mode.
⚠️ Attention: If you notice that the seal is deformed or has deep cracks, a simple wash will not help. The part needs to be replaced, otherwise the compressor will burn out from overload within a few weeks.
Another factor is the loading of the chambers. If you put a large amount of warm food in the refrigerator, the system will work hard until it cools the entire volume. Also, do not tightly pack the shelves so that air does not circulate - this interferes with the uniform distribution of cold.
Malfunctions of the thermostat and sensors
Responsible for turning off the compressor in normal mode thermostat (thermostat). This is a mechanical or electronic device that reads the temperature inside the chamber and opens the electrical circuit when a predetermined threshold is reached. If the thermostat is out of order and “stuck” in the “on” position, the refrigerator will hum endlessly, even if ice has already formed inside.
In modern models with a system No Frost or electronic control, the role of a thermostat is performed by air sensors. They may transmit incorrect data to the control board due to oxidation of the contacts or a software failure. As a result, the “brain” of the refrigerator “thinks” that it is warm in the chamber and does not give a command to stop the engine.
Diagnostics of the thermostat often requires testing the contacts with a multimeter. In mechanical models, you can try to temporarily bypass the contacts (close them directly), but this should only be done if you have electrical skills. If the situation has not changed after replacing the sensor, the problem may be deeper.
- 🛠️ Mechanical thermostats are characterized by a clicking sound when turned off; if it is not there, the device is faulty.
- 💻 Electronic sensors require checking the resistance, which changes depending on the temperature.
- ❄️ Incorrect sensor readings can lead to deep freezing of food.
How to check the thermostat yourself?
To check mechanical thermostat, it must be removed from the chamber (after disconnecting the refrigerator from the network). Place the sensing tube in a container of water at room temperature. If the contacts do not open after some time, the device is faulty. However, for accurate diagnostics it is better to use professional equipment.
It is important to note that in some models the sensors are located in hard-to-reach places, hidden behind plastic panels. Careless disassembly can lead to damage to plastic fasteners or wiring.
Refrigerant leakage and problems with the compressor
One of the most serious reasons why the refrigerator hums and does not turn offis a freon leak. The refrigerant circulates through the system, picking up heat from the chambers. If its quantity decreases due to microcracks in the evaporator or condenser tubes, the cooling efficiency decreases. The compressor tries to compensate for the lack of freon, working non-stop, but the desired temperature is never achieved.
When there is a leak, you can often hear a change in the nature of the sound: the humming becomes more strained, sometimes accompanied by gurgling or hissing. In such conditions, the motor-compressor operates under increased load, which quickly leads to overheating and thermal breakdown. If the leak is not eliminated in time and the system is not refilled, you will have to replace an expensive unit.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| Humming, but no cold | Complete leak freon | Searching for a leak, evacuation, refueling |
| Buzzing, weak cold | Partial leakage | Pressure diagnostics, soldering, refueling |
| Buzzing and clicks | Start relay or compressor wedge | Replacing the relay or repairing the compressor |
Another problem associated with the compressor is loss of power or mechanical wear. The piston group can exhaust its life, and the engine ceases to create the necessary pressure in the system. In this case, freon circulates, but does not have time to cool the evaporator to the required values, so the cycle is not interrupted.
⚠️ Attention: Self-filling the refrigerator with freon is prohibited without special equipment and a license. An incorrect amount of refrigerant or the presence of air in the system will lead to instant failure of the compressor.
Clogged capillary tube and filter-drier
There are bottlenecks in the refrigeration circuit that are critical for the circulation of the refrigerant. Capillary tube and the filter-drier are responsible for throttling and cleaning freon from moisture and impurities. Over time, ice plugs or blockages may form in the system due to oil breakdown products and oxidation. This prevents the normal flow of gas.
When clogged, the compressor works with increased load, trying to “push” freon through the obstacle. A characteristic sign of such a malfunction is a very hot condenser (grid at the back) in the upper part and a cold or room temperature one in the lower part. Swelling of the walls of the refrigerator may also be observed if the tubes are built into the housing.
Removing the blockage requires professional cleaning of the system with high-pressure nitrogen, replacing the filter-drier and vacuuming. Sometimes the capillary tube itself needs to be replaced. This is a complex technical procedure that cannot be performed at home without a set of tools.
- 🧊 Ice plugs often form due to moisture entering the system during previous repairs.
- 🛢️ Oil oxidation products clog the filter, especially in old refrigerators.
- 📉 The pressure at the compressor outlet increases, and at the evaporator inlet it drops.
If you ignore the symptoms of a blockage, the compressor can work until the winding burns out or one of the pipes will not burst due to high pressure. Therefore, if you hear that the refrigerator is buzzing more than usual, but there is no cold, this is a reason for urgent diagnosis.
Problems with the starting relay and electrics
Sometimes the reason for the continuous hum lies not in the mechanics, but in the electrical part. Start relay responsible for starting the engine compressor. If it is faulty, the contacts may stick and current will continue to flow to the windings even when the thermostat asks to stop. In such cases, the refrigerator may hum, but not start, or work continuously.
It is also worth checking the wiring and contacts. Oxidized compounds create additional resistance, which leads to a voltage drop across the motor. The motor begins to hum, overheat and does not develop full power, which is why it cannot reach the required temperature to turn off.
Sequence of checking the relay:1. Disconnect the refrigerator from the network.
2. Remove the back cover and find the relay on the compressor.
3. Carefully remove the relay (usually it is held on by latches).
4. Shake the relay: if you hear the sound of the insides, it is broken and requires replacement.
5. Check the contacts for carbon deposits.
In models with inverter compressors the situation is more complicated: there the electronic control unit is responsible for starting and operation. If the refrigerator's brain malfunctions, it may incorrectly control the engine speed, preventing it from stopping. Diagnostics of such systems requires connection to the service port.
⚠️ Attention: Before any check of electrical components, be sure to disconnect the refrigerator from the power supply. Working under 220V voltage is dangerous to life!
☑️ Primary electrical diagnostics
The influence of external factors and operating conditions
Do not forget that the refrigerator is not an isolated system, it depends on the conditions in which it stands. If the unit is installed next to a radiator, stove, or in direct sunlight, it will experience a constant heat load. In such conditions operating mode shifts towards continuous operation.
The gap between the back wall of the refrigerator and the wall of the room is also important. For the condenser to operate efficiently, free air circulation is necessary. If the refrigerator is moved close to the wall or closed with a decorative box without ventilation, the heat is not removed and the compressor does not turn off.
The seasonal factor also plays a role. In summer, when the temperature in the apartment reaches +28...+30°C, the refrigerator takes more time to cool the chambers. During this period, work cycles may lengthen and pauses may shorten. This is a normal phenomenon if the temperature inside the chambers is maintained within specified limits.
- ☀️ Direct sunlight heats the case, causing the sensors to react to heat.
- 🍳 The stove next to the refrigerator is a source of constant heat that disrupts the thermal balance.
- 🌬️ Absence a gap of 10-15 cm at the back blocks the exit of hot air.
Analyze whether you have recently changed the installation location of the equipment or whether new powerful equipment has appeared nearby that heats the air. Sometimes the solution to the problem lies not in repair, but in rearranging the furniture.
Is it possible to build an ordinary refrigerator into a closet?
Ordinary refrigerators are not designed to be built into blind niches without special ventilation. If you have built a free-standing model into a closet, the lack of air circulation is guaranteed to lead to continuous operation of the compressor and its rapid breakdown.
Frequently asked questions (FAQ)
How long should the refrigerator work and how long should it rest?
Under normal conditions, the operating cycle is usually about 10-20 minutes of work and 20-40 minutes of rest. The ratio of work time to rest time (working time ratio) is normally about 0.3–0.5 (that is, the refrigerator works 30-50% of the time). If it works more than it rests, this is a cause for concern.
Why does the new refrigerator hum loudly and does not turn off?
When turned on for the first time, a new unit can work for up to 24 hours without interruption. This is necessary for the initial cooling of the entire volume of the chambers and freezer to the specified temperatures. If the mode has not returned to normal within 24 hours, it is worth checking the settings and location.
Is it dangerous if the refrigerator works without interruption?
Yes, it is dangerous. The compressor is not designed for 24/7 operation without stopping. This leads to overheating of the oil, loss of its lubricating properties, jamming of the piston group and, ultimately, to expensive repairs or replacement of the compressor.
Could the “Super Freeze” mode be the reason?
Yes, if you accidentally activated the “Super Freeze” or “Quick Cool” function, the refrigerator will work continuously, ignoring the thermostat readings until you manually turn off this mode or the timer has passed (usually 24-48 hours).
What to do if the refrigerator is humming, but not freezing?
This is a classic sign of a freon leak or a seriously clogged capillary system. You must immediately disconnect the device from the network, defrost it (if there is ice) and call a technician. Further operation in this mode will finish off the compressor.