The situation when the refrigerator stops turning off and works non-stop is familiar to many owners of household appliances. This is not just an annoying hum that prevents you from sleeping at night, but also a direct signal that the cooling system is functioning critically. In normal operation, the compressor should turn on and off cyclically, maintaining the set temperature inside the chambers.
If the motor hums continuously, this may indicate a wide range of problems: from a simple operating error to a serious refrigerant leak. Modern inverter models they may work longer than usual, but even they have their limits. Ignoring the problem often leads to complete failure of an expensive unit and damage to products.
In this article we will analyze in detail the mechanics of the process, explain why compressor does not receive a stop signal, and help diagnose the breakdown before calling a technician. Understanding the reasons will allow you to avoid unnecessary panic and, perhaps, save on repairs if it’s a simple setup.
The mechanism of operation and why the cycle goes wrong
To understand the essence of the malfunction, you need to briefly refresh your memory on the principle of operation of the refrigeration circuit. The compressor compresses the gas, turning it into a high-pressure liquid, which then passes through the condenser and evaporator, taking heat from the chambers. This entire process is monitored freon, turning it into a high-pressure liquid, which then passes through the condenser and evaporator, taking heat from the chambers. This whole process is monitored thermostat or an electronic control module.
When the temperature inside reaches the set value, the sensor must break the electrical circuit and stop the motor. If this does not happen, it means that either the sensor “does not see” that the cold has already been reached, or the cold leaves faster than it is produced. Refrigerant leak is one of the most common reasons that forces the system to wear out in an attempt to compensate for the lack of working fluid.
It is also worth considering that in the hot season or when When the chambers are fully loaded with warm products, the compressor operating time can naturally increase. However, if the unit works for days without a break, this is already beyond the norm. The critical threshold is considered to be continuous operation for more than 20-24 hours without stopping.
⚠️ Attention: If you smell a burning smell or see that the wires on the back wall are very black, immediately turn off the power to the device. Long-term operation at maximum power can lead to a fire in the wiring.
It is important to distinguish between models with a drip defrosting system and a system No Frost. In the latter, the operating cycle may be longer due to periodic switching on of the defrost heaters, but they must also rest periodically. Understanding the type of equipment you have will help you more accurately determine whether the motor’s behavior is abnormal.
Checking the tightness of the chambers and the integrity of the seal
The simplest and most common reason for continuous operation is a violation of the tightness of the internal volume. If warm air from the room constantly gets inside, temperature sensor records an increase in degrees and does not give a command to turn off. Most often, the culprit is the rubber door seal.
Over time, the rubber loses elasticity, cracks, or simply becomes contaminated with grease and crumbs, no longer fitting tightly to the body. The door could also be warped due to improper installation or loose hinges. As a result, a microscopic gap is formed through which constant heat exchange occurs.
To check the tightness, you can use a simple paper sheet. Clamp the sheet between the door and the body around the entire perimeter. If in some place the paper falls out or is pulled out without resistance, it means that the clamp is broken there. Wear of the seal requires its replacement or restoration.
☑️ Diagnosis of the seal
Sometimes The problem lies not in the rubber itself, but in the fact that something is preventing the door from closing completely. This could be an incorrectly installed shelf, bulging packaging, or an adhered layer of ice in the rebate area. In models No Frost ice can block closure if the defrost system is faulty.
Faults of the thermostat and temperature sensors
The thermostat (thermostat) is the “brain” that decides when to turn the compressor on and off. If this element fails, it can permanently close the contacts, sending a false signal that the chamber is too warm. As a result, motor-compressor buzzes without interruption, trying to cool already frozen foods.
In modern models, instead of a mechanical thermostat, electronic sensors (thermistors) are used. They are more accurate, but are also prone to breakage. If the sensor is stuck or shows incorrect values, the electronic control module will keep the compressor on. Diagnosis of such elements often requires special equipment.
Symptoms of a thermostat malfunction often include not only continuous operation, but also the absence of a characteristic click when supposed to turn off. You can try to check mechanical regulators by temporarily closing the contacts, bypassing the device, but this is a job for those who understand electricity.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, it must be removed and placed in the cold (for example, in the freezer) for 15-20 minutes. After this, test the contacts with a multimeter: if the circuit does not close, the device is faulty. However, even a working thermostat may not turn off the compressor if the capillary tube has lost its seal and the filler gas has left it.
Replacing the thermostat is a relatively inexpensive and quick procedure. However, if you have a complex electronic control panel, the problem may be deeper: a malfunction of the control unit itself can lead to incorrect reading of readings from working sensors. data-i="96">One of the most serious reasons why the refrigerator does not turn off is a refrigerant leak. Freon circulates in a closed circuit, and if a microcrack appears in the system (often in the foamed part of the housing or in solder areas), the gas gradually evaporates. control unit may lead to incorrect readings from working sensors.
Freon leak and refrigerant circulation problems
One of the biggest reasons why a refrigerator won't turn off is a refrigerant leak. Freon circulates in a closed loop, and if a microcrack appears in the system (often in the foamed part of the housing or in soldering areas), the gas gradually evaporates. The pressure in the system drops, and the compressor works non-stop, trying to reach the required temperature, but cannot do this physically.
An indirect sign of a leak The condenser (grid at the back) may be only partially hot or, conversely, cold, or there may be no cold when the engine is running. Sometimes you can hear a characteristic hissing sound or see oily spots where the tube is damaged.
Another problem in this series is a clogged capillary tube. Oil breakdown products or moisture can clog the thin channel, preventing the normal circulation of freon. The compressor creates pressure, but the refrigerant does not pass through the system, so no cooling occurs and the cycle is not interrupted.
| Symptom | Possible cause | The nature of the motor operation |
|---|---|---|
| The refrigerator hums, but does not cold | Freon leak | Works constantly, hot |
| Motor is hot, clicks and turns off | Faulty starting relay | Short cycles switching on |
| Frost only at the rear wall | Clogged capillary tube | Long operation without shutdown |
| Temperature is normal, but does not turn off | Faulty thermostat | Continuous cycle |
Repair of the circulation system requires calling a specialist. The technician must find the leak, solder it, evacuate the system and fill in a new volume of freon. It is impossible to independently eliminate such a malfunction without a vacuum pump and a pressure gauge station.
Influence of the external environment and improper operation
Before sinning to break, it is worth analyzing the conditions in which the equipment operates. If the refrigerator is standing next to the radiator, in direct sunlight or in a niche with poor ventilation, heat exchange is disrupted. Condenser does not have time to cool down, efficiency drops, and the compressor is forced to work longer.
Also a common mistake is placing hot foods inside cameras Trying to cool a pot of soup or roast meat puts extreme stress on the system. In such cases, the equipment can work for hours until the temperature stabilizes.
Do not forget about the “Super Freeze” mode. If you accidentally activate this feature (usually the snowflake light or Fast Freeze button comes on), the compressor will run continuously, overriding the standard thermostat settings. Disable this mode and operation should return to normal.
It is important to ensure proper clearances around the chassis for ventilation. Air should circulate freely around the back wall and sides. If the refrigerator is built into a kitchen unit, make sure that ventilation holes are provided according to the manufacturer's instructions.
Wear of the compressor and start relay
The compressor itself is a complex mechanical unit that wears out over time. Reducing compression (performance) leads to the fact that the engine seems to be working, but does not create enough pressure for effective cooling. As a result, it hums constantly, trying to compensate for the loss of power.
Often, along with the compressor, the starting relay fails. This small element is responsible for starting the engine. If the relay is "stuck" in the "on" position, current continues to flow to the windings even after reaching the desired temperature. This may be accompanied by strong heating of the motor housing.
⚠️ Attention: If the compressor operates continuously and gets very hot (to the point where it is painful to touch), there is a risk of the piston group jamming. In this case, further operation will lead to combustion of the windings.
It is difficult to diagnose compressor wear without professional tools. Typically, technicians measure current consumption and pressure in the system. If the “death” of the motor is confirmed, it needs to be replaced. This is an expensive repair, which is often comparable to buying a new refrigerator if the model is old.
Frequently asked questions and answers (FAQ)
How long should a refrigerator operate normally?
Under normal conditions, the refrigerator operates approximately 30-40% of the time of the total cycle (for example, 10 minutes on, 20 minutes off). In winter, operating hours may be reduced, and in summer they may increase. However, periods of rest must be present.
Is it possible to use a refrigerator if it does not turn off?
Short-term - yes, but this is emergency mode. Long-term operation without stopping will lead to overheating of the winding insulation, melting of the plastic and eventual combustion of the motor. Products can also spoil due to incorrect temperature conditions.
Why does a new refrigerator last longer than an old one?
Modern models often have inverter compressors that do not turn off completely, but reduce speed. This is fine. Also, new refrigerators can take longer to reach the first temperature after the first turn on (up to 24 hours).
What to do if the refrigerator is humming after defrosting?
After complete defrosting, the refrigerator takes time (from 2 to 8 hours) to reach operating mode. During this period, the compressor can operate without interruption. If after a day the situation has not changed, look for a malfunction.
Does the amount of food affect the operating time?
Yes, a full refrigerator holds the cold better, but it will take longer to initially cool a large volume of warm food. An empty refrigerator reacts faster to opening the door, starting the compressor more often, but not for long.