The situation when the refrigerator hums continuously, but the temperature inside is at room temperature, and food begins to spoil, is familiar to many owners of household appliances. This is a classic scenario indicating a serious cooling system failure. In normal mode compressor operating cycle implies periods of on and off, which allows you to maintain a given temperature without overloading the nodes. When this cycle is disrupted and the motor works “to wear out,” this is a signal that the cold is not produced or is not stored inside the chamber.
There can be many reasons for this behavior of the equipment: from a banal door that is not tightly closed to a complex refrigerant leak. It is important to understand that long-term operation of the refrigeration unit in non-stop mode without reaching the target temperature leads to critical overheating compressor. In the best case, the thermal protection relay will work, and the equipment will go into deep sleep, in the worst case, an inter-turn short circuit of the motor windings will occur, which will require an expensive replacement of the motor.
Before calling a technician, it is necessary to carry out an initial diagnosis to exclude external factors. Often the problem lies not in the “stuffing” of the refrigerator itself, but in its operating conditions or incorrect settings. If you notice that the unit has not turned off for several hoursand the temperature on the indicator does not drop, immediately check the tightness of the seals and the position of the temperature regulator.
Malfunctions of the thermoregulation system and sensors
One of the most common reasons uninterrupted operation is the failure of thermostat or the electronic temperature sensor. It is this element that is responsible for sending a signal to the compressor to turn off when the required cold is reached in the chamber. If the thermostat contacts are stuck in the “on” position or the electronic module receives distorted data from the sensor, the motor will work constantly, trying to cool an already cold space, or simply ignoring the real temperature.
In models with the system No Frost the air sensor located in the evaporator or duct. Its malfunction can cause the refrigerator to “think” that it is warm inside and not stop the cooling cycle. Replacing a thermostat is a relatively simple procedure, but it requires precise adjustment or selection of an analogue with identical parameters.
⚠️ Attention: If you plan to change the thermostat yourself, make sure that the new device has exactly the same markings and capillary tube length. Installing an unsuitable element will lead to incorrect operation of the refrigerator or its complete refusal to turn on.
Diagnostics of the thermostat is often carried out by testing the contacts with a tester. When the temperature drops (if the thermostat is mechanical), the contacts should open with a characteristic click. The absence of a click or ringing of the chain under any conditions indicates a breakdown.
Freon leak and problems with refrigerant circulation
If the compressor is working, humming, but there is no cold, and it does not turn off, there is a high probability refrigerant leaks. Freon is the working fluid of the refrigeration cycle. When its amount in the system drops below a critical level, the compressor simply cannot create the necessary pressure for gas condensation and subsequent evaporation with heat absorption. The motor tries to compensate for the lack of refrigerant by continuous operation, but physically cannot cool the chamber.
Often a leak occurs in places where pipes are soldered or due to corrosion of the evaporator, especially if you previously tried to defrost the refrigerator with a knife or sharp object, damaging the wall. In such cases, oily spots may be visible on the tubes, since freon circulates along with compressor oil.
The second option for problems with circulation is clogged capillary tube. An ice or mud plug could have formed in the system, blocking the freon passage. The symptoms are similar: the compressor works, the pressure builds up, but there is no circulation. This can be determined by touch: the condenser (grid at the back) may be only partially hot or cold, and the return pipe going to the compressor will be at room temperature, although normally it should be cool.
| Symptom | Probable reason | Characteristic sign |
|---|---|---|
| The compressor is hot, there is no cold | Freon leakage | Oil stains on the tubes, a quiet hum |
| Loud knocking, absence cooling | Clogged system | Intermittent operation, clicking |
| The motor turns off after 1-2 minutes | Faulty start relay | Clicking and stopping the engine |
| The refrigerator freezes, but does not turn off | The thermostat is faulty | Icing on the back wall |
Wear of the compressor and start relay
The most expensive and difficult part to repair is this motor-compressor. Over time, its mechanical part wears out and the piston group loses compression. In this condition, the engine may hum and vibrate, but not create enough pressure for the system to operate. It will work constantly, trying to “catch up” with the cold, which will not exist.
Also often the problem lies in start-up relay. This small element is responsible for starting the motor windings and protecting against overloads. If the relay is “stuck” or its contacts are burnt, it may not give a command to turn off or, conversely, not allow the engine to start, making only clicks. In some cases, the relay may pass current continuously, causing the compressor to work without interruption.
Checking the compressor requires skills and tools. It is necessary to measure the resistance of the windings and check whether the motor “breaks through” the housing. If the winding resistance is normal, but there is no compression, the unit needs to be replaced.
Is it possible to restore the compressor?
Replacing the internal parts of the compressor at home is impossible and not economically feasible. If a mechanical failure of the motor is diagnosed, a complete replacement of the unit is required, followed by evacuation of the system and refilling with freon.
Problems with tightness and thermal insulation
Sometimes the refrigerator does not turn off not because of the failure of the units, but because the cold simply “escaps” from the chambers. The main reason is wear of the sealing rubber on the doors. If the rubber has dried out, cracked or deformed, warm air from the room constantly enters the chamber. Sensors detect an increase in temperature and command the compressor to work continuously.
You can check the tightness with a simple test with a sheet of paper. Clamp the sheet with the door around the perimeter. If it comes out too easily or, conversely, the door does not close with the sheet, the seal requires replacement or adjustment.
It is also worth checking the door hinges. If they are weakened, the door warps and the seal is broken. In two-chamber models with a system No Frost the problem may be a clogged drainage hole or water drainage channel, which leads to the formation of an ice plug and disruption of air circulation, although formally this has more effect on the distribution of cold than on the continuity of engine operation.
The influence of external factors and improper operation
You should not discount the conditions in which the refrigerator is located. If the unit is installed too close to a wall, heating appliances or is in direct sunlight, heat exchange is disrupted. The condenser does not have time to cool down, the cooling efficiency drops, and the refrigerator is forced to work longer and more intensely.
Loading the refrigerator with warm food is another reason for continuous operation. If you put a pot of hot soup inside, the compressor will work until it cools the entire volume of air and food to the set temperature. This may take several hours.
In addition, in the summer, when the ambient temperature in the room is high, it is more difficult for the refrigerator to release heat. In hot rooms, equipment can work almost without stopping, and this may be normal if it still copes with cooling.
⚠️ Attention: Do not install the refrigerator close to the wall. The gap between the rear condenser grille and the wall must be at least 10 cm to ensure normal air circulation.
Self-diagnosis algorithm
Before you panic or look for service center contacts, try performing a step-by-step check. This will help narrow down the troubleshooting or even solve the problem without cost.
☑️ Primary diagnostics of the refrigerator
Start with a visual inspection and listening. If the compressor runs smoothly but does not turn off, check the thermostat and tightness. If you hear clicks or the hum is interrupted, look at the start relay. If the engine is hot, but there is no cold, there is likely a leak or loss of compression.
It is also important to check if the Super Freeze function is turned on. In this mode, the refrigerator operates continuously, ignoring the thermostat readings. Disable this function and wait a few hours.
Frequently asked questions (FAQ)
How long can the refrigerator operate without interruption? normal?
In normal mode, the operating coefficient is approximately 30-40%. This means that out of an hour it works for 20-25 minutes. In intensive freezing mode or high room temperature, it can work 50-60% of the time. Working without stopping for more than 2-3 hours while maintaining a high temperature inside is a sign of a malfunction.
Why does the refrigerator not turn off after defrosting?
After complete defrosting, the refrigerator takes time (from 2 to 6 hours) to return to operating mode and freeze food. During this period, continuous operation of the compressor is acceptable. If after 8-10 hours there is still no cold, there is a problem.
Is it possible to operate the refrigerator if it does not turn off?
For a short time, it is possible to save food. But long-term operation in this mode will lead to overheating and combustion of the compressor, after which repairs will become much more expensive. It is better to turn off the device and call a technician.
Why does a new refrigerator constantly work?
When turned on for the first time or after a long transportation, a new refrigerator can gain temperature for up to 24 hours. Also check whether the fast freezing mode is turned on and whether the temperature is set correctly.