The situation when a household refrigerator stops turning off is familiar to many owners of household appliances. Compressor, which in normal mode should periodically quiet down, begins to hum continuously, creating constant background noise and causing concern for the safety of food. This is not just an irritating factor, but also a signal that the cooling system is wearing out, trying to achieve the set temperature parameters, which can ultimately lead to failure of expensive components.
The first thing to do when such a problem is detected is not to panic, but to carry out an initial diagnosis. Often the reason lies in trivial things: a door that is not tightly closed, food that is too hot, or a malfunction in the thermostat settings. However, if you have checked all the obvious points, and the unit continues to work non-stop, then the problem is of a technical nature and requires deeper intervention.
In this article we will analyze in detail the main reasons why refrigerator may not turn off, consider methods for troubleshooting yourself and determine in which cases calling a technician is the only correct solution. Understanding the principles of operation of the system will help you save time and money on repairs.
Why is it dangerous: the risks of continuous operation of the compressor
Continuous operation of the motor-compressor is an extreme mode for any household appliance. Resource equipment designed for cyclic work, in such conditions is exhausted many times faster. The main consequence is overheating of the motor and compressor windings, which can lead to its complete combustion and the need to replace the entire assembly.
⚠️ Attention: Operating the refrigerator 24/7 without interruptions can lead to ignition of the wiring or failure of the start relay. If you smell a strong burning smell or see sparking, immediately unplug the device!
In addition, constant operation leads to overspending. electricity. Electricity bills can double or more as your refrigerator consumes maximum kilowatt-hours. The quality of cooling also suffers: due to system overload, the temperature in the chambers may become unstable, which will lead to spoilage of food.
External factors and operating errors
Before looking for complex technical faults, it is worth eliminating the influence of external factors. Very often, users themselves create conditions under which refrigerator compartment cannot reach the desired temperature. For example, if the unit is installed too close to the wall, the radiator on the rear panel does not have time to release heat to the environment. Air circulation is broken, and the compressor is forced to work longer to cool the condenser.
Another common one mistake - placing too hot food in the chamber. If you put a pot of freshly cooked soup, the cooling system will suffer a powerful thermal shock. The sensors will detect a sharp increase in temperature and will not allow the compressor to turn off until the heat is completely removed outside.
Also check the tightness of the door. Sealing rubber over time it dries out, cracks or becomes dirty, which is why warm air from the kitchen gets inside the chamber. The compressor tries to compensate for this heat gain by running non-stop. To check, you can clamp a sheet of paper with the door: if it can be easily removed, it means that the seal is broken.
Malfunctions of the thermostat and temperature sensors
One of the most common reasons why refrigerator turns off, the thermostat has failed. This device is responsible for monitoring the temperature inside the chambers and sends a signal to turn off the compressor when a specified threshold is reached. If the thermostat is broken, it simply “does not see” that it is already cold in the chamber and continues to keep the circuit closed.
In modern models with the system No Frost electronic sensors (thermistors) are responsible for this process. They can fail due to power surges or natural wear and tear. Unlike mechanical thermostats, it is better to diagnose them using a multimeter, measuring the resistance at different temperatures.
How to check the thermostat yourself?
Unplug the refrigerator, remove the thermostat. Close the contacts coming from the thermostat directly. If, after being connected to the network, the compressor starts working, but when the circuit is opened, it stops, it means that the thermostat is faulty.
Symptoms of a faulty thermostat often manifest themselves in the fact that the products in the refrigerator compartment begin to freeze, turning into ice, or, conversely, deteriorate if the contact is “stuck” in the “on” position, but the cooling capacity has dropped. Replacing the thermostat is a simple procedure and is often performed independently if there is access to the unit.
Refrigerant (freon) leakage and system blockage
If visually everything is in order with the refrigerator, but it hums continuously and does not cool well, there is a high probability Freon leaks. The refrigerant circulates in a closed circuit, and if a microcrack has formed in the tubes (often due to corrosion or mechanical damage), the gas escapes. The compressor tries to compensate for the lack of refrigerant, working at its limit, but the temperature does not drop to the desired level.
Another problem is clogged capillary tube. An ice or oil plug may form in the cooling system, which prevents the normal circulation of freon. The pressure in the system drops, and the compressor runs idle, trying to pump gas through the blockage.
⚠️ Attention: You cannot look for a leak or clean the system yourself without special equipment (vacuum pump, pressure gauge station)! You can permanently damage the circuit or release remaining gas.
To diagnose leaks, technicians use leak detectors or simply check the system for oil stains in the soldering areas (freon often comes out along with the oil). If a leak or blockage is confirmed, professional repairs are required: finding the location of the damage, soldering, evacuating the system and filling with new gas.
Problems with the compressor and start relay
Compressor is the “heart” of the refrigerator. Over time, its power may decrease due to the deterioration of the piston group or valves. In this state, it is simply not able to create the necessary pressure for effective cooling, so it works constantly. This can be determined by the characteristic sound: the engine is humming, but the gas circulation in the tubes is weak or absent.
Also often fails start relay. This small element is responsible for starting the engine. If the relay contacts are burnt or stuck, the compressor may not start the first time or work intermittently, which is perceived as continuous operation with attempts to start.
| Symptom | Possible cause | Solution method |
|---|---|---|
| Humming, but not cooling | Freon leak / Clogging | Gas filling / Blowing the system |
| Humming and turns off after 1-2 min | Malfunction of the start relay | Replacement of the relay |
| Humming constantly, there is cold | Thermostat is faulty | Replacement of the thermostat |
| Extreme noise and vibration | Compressor wear | Replacement of the compressor |
Failures in the electronic control module
In modern models of refrigerators (for example, Liebherr, Bosch, Samsung) the entire process is controlled by an electronic module. This is the “brain” of the device, which reads sensor readings and controls the compressor, fans and defrost heating elements. If a failure occurs in the control board (the triac has burned out, the contacts have oxidized, the track is damaged), it may send an incorrect signal to turn on the compressor.
Often such breakdowns occur after power surges. Outwardly, this may look like chaotic behavior of the refrigerator: it either does not turn off, then does not turn on, or blinks the indicators on the control panel. Diagnostics of the module requires special knowledge in electronics.
Repair of the control module may involve resoldering burnt elements or completely replacing the board. In some cases, flashing the microcircuit is required, which is only possible in a specialized service.
Self-diagnosis algorithm
If you encounter a problem with the continuous operation of the refrigerator, act consistently. Eliminate simple causes first, then move on to more complex ones. This will help save time and, possibly, avoid calling a technician.
☑️ Initial check checklist
Pay attention to the nature of the noise. If the compressor runs smoothly but does not turn off, look for the cause in a leak or thermostat. If you hear clicks or an intermittent hum, the problem is in the start relay or the compressor itself. It is important to correctly interpret the signals that the equipment gives.
Do not forget that in the hot season or when the refrigerator is heavily loaded with food, the compressor operating time may naturally increase. However, even in such conditions, it must periodically turn off.
Frequently asked questions (FAQ)
How long should the refrigerator work and how long should it rest?
In normal mode, the operating cycle looks something like this: the compressor runs for 15–20 minutes, then rests for 20–30 minutes. The work rate is about 40-50%. If the refrigerator works for 40 minutes and rests for 5, this is already a cause for concern.
Can the refrigerator not turn off in winter?
Yes, if the refrigerator is installed in an unheated room where the temperature drops below +10°C...+15°C. Under such conditions, the oil in the compressor thickens, and the thermostat may not turn off, since the temperature difference between inside and outside is minimal. Many manufacturers do not recommend operating refrigerators at low temperatures.
What to do if the refrigerator does not turn off after defrosting?
After defrosting, the refrigerator takes time (from 2 to 6 hours) to gain temperature and return to normal operation. During this time, the compressor can operate without interruption. If more than 6-8 hours have passed and the shutdown has not occurred, the system may have been damaged during defrosting or the electrical contacts have been flooded with water.
Is it dangerous to leave the refrigerator running continuously overnight?
Short-term operation (one night) usually does not lead to fatal consequences, but leaving the equipment in this condition for a long time is impossible. This is fraught with overheating and fire. If you are leaving for several days, it is better to turn off the faulty device.