The situation when No Frost refrigerator stops turning off often takes you by surprise and causes panic. Instead of the usual cycle of work and rest, the compressor hums continuously, and the inside of the chamber may be too cold or, conversely, not cool enough. This not only leads to excessive consumption of electricity, but also creates the risk of early failure of an expensive unit.
The reasons for this behavior can be either simple errors in operation or complex technical breakdowns of the control or cooling system. Modern models electronically controlled ones have many sensors, and even one of them fails capable of disrupting the entire operating algorithm of the device. Understanding the principles of operation of the system No Frost will help you localize the problem faster.
In this article we will look in detail at why the compressor does not go into rest mode, how to carry out initial diagnostics yourself and in which cases you can’t do without calling a technician. Continuous operation of the compressor for more than 24 hours often indicates a critical refrigerant leak or thermostat failure. Important act consistently so as not to aggravate the situation.
Features of the No Frost system and compressor cycling
To understand the essence of the problem, you need to know what is normal functioning refrigerator. Unlike older models with a drip defrosting system, the technology No Frost implies forced air circulation. The fan drives air masses through the evaporator, where they are cooled, and then distributes them among the chambers. This process requires constant operation of the motor at certain intervals.
In ideal operating mode, the compressor turns on, cools the chamber to the set temperature, after which thermostat or the electronic module gives a command to stop the engine. The duration of the work and rest cycle depends on many factors: food load, room temperature, frequency of door opening. Typically, the refrigerator runs for about 10-20 minutes, followed by a break.
⚠️ Attention: If your refrigerator works without a break for more than a day, this is not the norm, even in hot weather. Long-term load leads to overheating of the compressor windings and eventual combustion.
The system No Frost also includes regular evaporator defrost cycles. At this time, the compressor may also not work while the heating elements thaw the ice. If this cycle is disrupted or the sensors transmit incorrect data about the evaporator temperature, the refrigerator may “freeze” in cooling mode, trying to compensate for the imaginary lack of cold.
External factors and operating errors
Before looking for complex breakdowns inside the unit, it is worth eliminating trivial causes that are often overlooked. Sometimes refrigerator it does not turn off simply because its operating conditions have changed or the installation rules have been violated. Checking these points will take a few minutes, but can save diagnostic time.
One of the most common reasons is a loose door fit. If sealing rubber is worn out, dirty or deformed, warm air from the room constantly enters the chamber. Sensors detect an increase in temperature and command the compressor to work continuously to compensate for the heat influx.
It is also worth paying attention to the location of the equipment. If refrigerator stands too close to a wall, radiators or in direct sunlight, heat transfer is disrupted. The radiator grille on the rear wall does not have time to cool down, the cooling efficiency drops, and the motor is forced to work in increased mode.
- 🔍 Check whether food is preventing you from tightly closing the refrigerator door.
- 🌡️ Make sure that the room temperature does not exceed +30°C, which is critical for the climate class of the equipment.
- 🚪 Inspect the seal for cracks, tears or sticky deposits that impede sealing.
- 📏 Maintain a minimum distance of 10 cm from the back wall of the refrigerator to the wall or furniture.
Faults of the thermostat and temperature sensors
If external factors are excluded, the problem is more likely everything lies in the control components. In mechanically controlled refrigerators, thermostatis responsible for turning the compressor on and off. This device measures the temperature in the chamber and opens the electrical circuit when the desired level of cold is reached. If the contacts of the thermostat are “stuck” or its sensing tube fails, the circuit will not break.
In models with electronic control (No Frost often equipped with just such systems), the role of the thermostat is performed by thermostat (temperature sensor), which transmits data to the main control module. If the sensor “lies” and shows that the chamber is warm, the module will keep the compressor on. The evaporator sensor, which controls the defrosting process, often fails.
Diagnostics of the thermostat in mechanical refrigerators is possible at home. It is necessary to disconnect the contacts coming from the thermostat and close them directly. If after this the compressor starts working (in normal switching mode), then the problem is in the regulator. However, replacement will require opening the case and technical skills.
How to check a temperature sensor with a multimeter?
To check the temperature sensor (thermistor), you need to remove it and connect it to the multimeter in resistance measurement mode. When the temperature changes (for example, if you hold the sensor in your hand or put it in the refrigerator), the resistance should change smoothly. If the readings stay the same or are equal to zero/infinity, the sensor is faulty and requires replacement.
Problems with the evaporator defrosting system
The key difference between the system No Frost is the absence of ice in the visible part of the chamber. All moisture settles on a hidden evaporator, which is periodically heated by heating elements for defrosting. If the water drainage system or heating elements are faulty, the evaporator becomes covered with ice. The fan stops moving air efficiently, and the sensors “see” insufficient cooling, forcing the compressor to work without stopping.
A frequent cause is burnout defrosting element or a malfunction of the defrost timer/relay. In this case, the ice freezes in a layer, blocking the air circulation channels. The refrigerator is humming, trying to cool the chamber, but due to the ice jam it is impossible. Visually, the chamber may be normal, but behind the back panel there is a lump of ice.
To eliminate this problem, you need to completely defrost the refrigerator for at least 24 hours (preferably more). If, after switching on, the equipment started working in normal cyclic mode, then the problem was ice freezing. If after a few days the situation repeats, it is necessary to change the elements of the defrost system.
☑️ Diagnostics of the No Frost system
Freon leak and compressor malfunction
One of the most serious reasons why refrigerator does not turn off is a refrigerant (freon) leak. The gas circulates in a closed loop, and if a microcrack has formed somewhere (often in the foamed part of the housing or in solder areas), the pressure in the system drops. The compressor is working hard, trying to gain the required pressure, but physically cannot reach the target temperature.
Signs of a leak are often: hot side walls (instead of barely warm), lack of cold in one of the chambers, strange sounds (gurgling, hissing) when the motor is running. In some cases, partial frosting can be seen on the evaporator only at the beginning of the circuit, while the rest of the tubes remain warm.
Another possible reason is loss of productivity yourself compressor. Over time, the mechanism wears out, the valves weaken, and the motor cannot create enough pressure to effectively circulate freon. It works continuously, but does not produce cold. In this case, the compressor needs to be replaced, which is an expensive repair.
| Symptom | Possible cause | Difficulty of repair | Necessity masters |
|---|---|---|---|
| Compressor is hot, no cold | Freon leak | High | Mandatory |
| Ice behind the rear wall | Defrost fault | Average | Desirable |
| The refrigerator does not turn off, but freezes | Thermoregulator/Sensor | Low | Possibly with your own hands |
| Humming and vibration, poor cooling | Compressor wear | High | Required |
Algorithm of actions when a malfunction is detected
If you notice that your refrigerator does not turn off, do not immediately panic or call a technician. Start with simple steps that will help you narrow down your problem. A competent diagnosis will allow you to understand the scale of the disaster and the approximate cost of future repairs.
First of all, disconnect the equipment from the network and let it stand to defrost for at least 10-12 hours. This will eliminate the possibility of the electronics “freezing” or the formation of an ice plug. After switching on, observe the operating cycles. If the problem persists, check the tightness of the doors and the cleanliness of the condenser at the back.
⚠️ Attention: Do not attempt to open the sealed circuit of the cooling system yourself or change the compressor without a license and special equipment. This is life-threatening and requires professional tools.
If simple methods do not help, analyze the behavior of the unit: is there cold? Do the sides get hot? Is there ice in the freezer? This data will be extremely useful to the specialist during a telephone consultation. Write down the model of the refrigerator and the approximate year of manufacture, since different manufacturers (LG, Samsung, Bosch, Indesit) may have their own "diseases".
Prevention and extension of service life
In order for refrigerator to serve for a long time and not cause problems with continuous operation, it is important to follow the operating rules. Regular defrosting (even for No Frost systems at least once a year) helps keep the system clean. It is also important to keep the rear grill where the condenser is located clean - dust and animal hair impair heat transfer.
Do not load hot foods into the chamber. This creates a sharp jump in temperature and humidity, forcing the compressor to work in extreme mode, and the No Frost system to intensively fight condensation. This is a direct path to the formation of ice plugs and damage to the sensors.
Timely replacement of seals and monitoring the temperature in the room also play an important role. If you live in a region with a hot climate, make sure that your refrigerator corresponds to the required climate class (SN, N, ST, T) specified in the technical data sheet.
Frequently asked questions (FAQ)
Can a refrigerator not turn off due to the heat in the room?
Yes, if the room temperature exceeds the permissible temperature for a given climate class (usually above +32°C), the refrigerator will work almost without interruption, trying to cool down. However, it should still turn off at least briefly. If there are no breaks at all, this is a sign of overheating or malfunction.
How long should the compressor operate normally?
Under normal conditions, the compressor operating ratio is about 30-40%. This means that out of one hour he works for about 20-25 minutes, and rests the rest of the time. With heavy load or high temperature in the room, the operating time can increase to 50-60%.
Is it dangerous if the refrigerator hums but does not freeze?
Yes, this is dangerous for the unit itself. Idle operation without heat removal leads to rapid overheating of the motor windings and can cause a fire or complete combustion of the compressor. It is better to immediately turn off such equipment before the technician arrives.
Why, after defrosting, did the refrigerator start working again without stopping?
If after complete defrosting (more than 24 hours) the problem returned after 1-2 days, then the reason is not an ice plug, but a component malfunction: a freon leak, a broken temperature sensor, or a loss of compressor performance. Professional diagnostics are required.
Is it possible to operate the refrigerator if it does not turn off?
For a short time (several hours) - it is possible to save food. Long-term operation in this mode is unacceptable, since the compressor’s life is exhausted in a matter of days, and the electricity bill can be an unpleasant surprise. In addition, there is a risk of the wiring catching fire.