The situation when the compressor of a refrigeration unit hums without interruption, and the desired temperature inside the chamber is not reached, is familiar to many owners of household appliances. This is not just an annoying noise that interferes with sleep, but also a serious signal that cooling system it is working in emergency mode. If measures are not taken, the motor may burn out and the food may deteriorate, since the temperature in the chamber will be higher than the required norm.
In modern models, such as LG, Bosch or Indesit, the electronics can diagnose some of the problems themselves, displaying an error code on the display. However, in older models or in case of hidden breakdowns, the user is left alone with a humming unit. Understanding the physics of the process will help determine whether you need urgent help from a specialist or you can try to solve the problem yourself.
Often the reason lies in banal things: a door that is not tightly closed, the fast freezing mode is turned on, or simply hot weather outside the window. But there are also more complex technical malfunctions that require intervention refrigeration circuit. Let's look at all possible scenarios, from the simplest to the most critical, so that you can accurately determine the source of the problem.
Violation of chamber seals and operating errors
Before suspecting the breakdown of expensive components, it is necessary to exclude the human factor. The most common reason for this is a violation of the tightness of the internal volume. If warm air from the room constantly gets inside, the compressor is forced to work continuously, trying to compensate for the heat gain. the refrigerator does not turn off, lies in the violation of the tightness of the internal volume. If warm air from a room constantly flows inside, the compressor is forced to work continuously, trying to compensate for the heat gain.
Pay attention to the rubber seal on the door. Over time, it dries out, cracks, or simply becomes contaminated with fat, which is why it no longer fits tightly to the body. Even a small gap causes the sensors to record an increase in temperature and does not allow the motor to rest.
- 🔍 Check whether something is preventing the door from closing tightly: a pan handle, a bag of food or a crooked shelf can create a gap.
- 🧼 Wash the seal thoroughly with warm soapy water to remove sticky residue, which interferes with the fit.
- 🌡️ Make sure that you have not turned on the
Super Freeze(Super Freeze) mode, which forcibly keeps the compressor on for a long time.
If you notice that the door does not close tightly, try restoring the elasticity of the rubber. To do this, you can warm up the damaged area with a hairdryer or pour boiling water into the deformed areas, and then press the door tightly for several hours. In cases where the rubber has completely lost its shape, it will need to be replaced.
Malfunctions of the thermostat and temperature sensors
The thermostat (thermostat) is the “brain” that decides when to turn the compressor on and off. In mechanical models it is a simple button with a capillary tube, in electronic models it is a complex sensor. If this element fails, it may “stick” in the “on” position, and then the refrigerator will work without stopping, ignoring the achieved temperature.
In models with the system No Frost several sensors monitor the temperature: in the evaporator, in the refrigerator compartment and in the freezer. Failure of any of them can lead to incorrect operation of the entire cycle. The electronic control module receives incorrect data and continues to pump cold.
⚠️ Attention: Diagnosing the electronic thermostat requires a multimeter. If you are not skilled in working with electrical circuits, do not try to disassemble the control unit yourself - this may result in a short circuit.
To check the mechanical thermostat in older models, such as Atlant or Biryusa, you can temporarily short-circuit its contacts. If after this procedure the compressor starts working, then the problem is in the regulator. However, you can only operate a refrigerator without a thermostat for a short time, otherwise the food will defrost.
How to check the thermostat with a multimeter?
To check, you need to remove the thermostat, set the multimeter to dial mode and touch the probes to contacts. At room temperature the circuit should be closed (beeping). If you place the sensing element in the cold (for example, in the freezer for 10 minutes), the circuit should break. If there is no break, the thermostat is faulty and requires replacement.
Refrigerant leak and problems with the compressor
One of the most serious reasons for continuous operation is a freon (refrigerant) leak. In this case, the compressor works hard, trying to build up pressure, but due to a lack of substance in the system, the temperature does not drop to the required values. The cycle does not complete, and the motor hums for days.
Leakage symptoms are often accompanied by overheating of the compressor. It becomes hot to the touch, sometimes even scalding. Another sign may be swelling of the back wall inside the refrigerator compartment or the appearance of yellow oily spots where the tubes are damaged.
The compressor may also fail mechanically. Wear of the piston group or valves leads to a drop in performance. The motor hums, but does not create enough pressure to circulate freon. In this case, a characteristic metallic clang or knock is often heard when starting up.
☑️ Diagnosis of freon leaks
If the cause is a leak, a simple reboot or replacement of parts will not help. It is necessary to call a technician with special equipment to find the location of the damage, solder and refill the system with new refrigerant. It is almost impossible to eliminate a leak in a sealed circuit on your own.
Clogged capillary tube and heat removal system
Inside the refrigeration circuit there is a very narrow capillary tube that regulates the flow of freon. Over time, a blockage may form in it due to oil oxidation products or moisture. Freon cannot circulate normally, the pressure in the system drops, and the compressor works non-stop, trying to push through the plug.
Another common problem is contamination of the condenser (the black grille at the back). If dust, animal hair or fluff has accumulated between the rods, heat exchange is disrupted. Freon does not cool down properly, and the cooling efficiency drops, forcing the equipment to work in increased mode.
| Symptom | Probable cause | Characteristic symptom |
|---|---|---|
| Dirty condenser | Dust and wool | The grill is hot, but unevenly |
| Clogged capillary | Oxidation products | The evaporator is cold only at the entrance |
| Fan malfunction | Motor breakdown | Lack of airflow in the chamber No Frost |
| Compressor wear | Mechanical wear | Low outlet pressure, quiet hum |
To eliminate a clogged capillary tube, professional high-pressure nitrogen purging and replacement of the filter-drier are required. You can and should clean the condenser yourself using a vacuum cleaner or a soft brush, having first disconnected the device from the mains.
Problems with the defrost system (for No Frost)
In refrigerators with a system No Frost continuous operation of the compressor is often associated with a malfunction of the evaporator defrost system. If the defrost heating element, timer or defrost sensor fails, a “coat” of ice builds up on the evaporator. This ice blocks the channels for cold air circulation.
As a result, the chamber becomes warm, the temperature sensor requires cooling, and the compressor turns on again and again. But cold air simply cannot penetrate into the chamber due to the ice plug. This is a classic vicious circle that leads to motor failure.
You can check for ice by disassembling the back panel in the freezer. If you see a massive layer of frost or ice blocking the fan, then the defrost system is not working. In this case, the refrigerator can freeze only around the evaporator, but not in the total volume.
⚠️ Attention: Do not try to pick out the ice with a knife or sharp objects! You can puncture the thin evaporator tubes, causing an immediate freon leak and costly repairs. Use only a hair dryer for gentle defrosting.
The influence of external temperature and installation location
Sometimes the reason lies not in the breakdown, but in the operating conditions. If the refrigerator is placed close to a wall or in a niche where air circulation is impaired, it will overheat. The compressor cannot efficiently transfer heat, and its performance drops, which leads to an increase in operating time.
The ambient temperature (room temperature) is also critically important. Most refrigerators are designed to operate between +16°C and +32°C. If you place the refrigerator on an unheated loggia in winter or in the kitchen, where in summer the temperature rises above +35°C, it may stop turning off or, conversely, not turn on.
Particular attention should be paid to models with one compressor. In summer, when the room is hot, the load on them increases many times over. During such periods, an increase in engine operating time to 70-80% of the total cycle may be a normal option if cold remains inside.
Frequently asked questions and answers (FAQ)
How long should a refrigerator operate normally?
In normal mode, the operating time ratio is about 30-40%. This means that out of one hour the compressor works for 20-25 minutes and rests for 35-40 minutes. If it works for 40 minutes or more without a break, this is a cause for concern.
Is it possible to use a refrigerator if it does not turn off?
Short-term - yes, but you cannot operate the equipment like this for a long time. The compressor is not designed for constant operation and will quickly overheat, which will lead to its combustion. In addition, food can spoil due to temperature violations.
Why does the refrigerator hum but not freeze?
This is a sure sign of a freon leak or a severely clogged system. The compressor pumps, but there is little or no refrigerant in the system. Urgent repairs with leak detection and refilling are required.
Does the amount of food affect the operating time?
Yes, a full refrigerator keeps the cold better, and the compressor turns on less often. An empty refrigerator heats up faster when the door is opened, causing the motor to run more often. However, this should not cause continuous operation.
What to do if the refrigerator does not turn off after defrosting?
You may have damaged the defrosting system or there is moisture left in the system. Let the refrigerator stand turned off for 5-6 hours. If after turning on the problem repeats, most likely the defrost sensor or thermostat has failed.