The situation when the compressor of a refrigeration unit works without interruption often causes panic among owners of household appliances. The humming of the engine, which does not subside for hours, can signal serious internal malfunctions or be the result of trivial operating errors. If you notice that your refrigerator has stopped “resting”, it is important not to ignore this symptom, since continuous operation leads to rapid wear of expensive components.
In this article we will analyze in detail the main reasons why equipment goes out of normal mode, and we will explain how to distinguish a software failure from physical damage. Understanding the operating principles of thermostat and the defrosting system will help you make the right decision about the need to call a technician.
Sometimes the problem lies not in the unit itself, but in the conditions of its placement. Check whether the equipment is standing too close to a wall or a heat source. The critical factor is the room temperature: if it is below +10°C or above +32°C, the standard operating cycle of the compressor is disrupted.
Consequences of continuous operation of the compressor
Continuous operation of the internal circuit motor is an extreme mode, for which household appliances are not designed under normal conditions. First of all, it suffers: the oil in it overheats, loses its lubricating properties, which leads to jamming of the piston group. Replacing this unit is often comparable in cost to buying a new refrigerator. compressor: the oil in it overheats, loses its lubricating properties, which leads to jamming of the piston group. Replacing this unit is often comparable in cost to buying a new refrigerator.
In addition, the cooling system suffers. The evaporator is covered with a “coat” of ice, which does not have time to thaw, which blocks air circulation. Products in the chamber can either be frozen, turning into ice blocks, or, conversely, spoil due to lack of cold if the system is completely clogged with ice.
Do not forget about energy consumption. A device operating 24 hours a day without stopping consumes 2-3 times more energy than a working device. This is immediately reflected in your electricity bills at the end of the month.
⚠️ Attention: If you smell a burning smell or see that the rear grille of the refrigerator (condenser) is red hot, immediately unplug the appliance. Further operation may lead to a fire.
Prolonged load also negatively affects the door sealing rubber bands. Constant temperature changes and vibration lead to their drying out and loss of elasticity, which aggravates the problem of heat loss.
External factors and operating errors
Before looking for complex technical faults, it is worth eliminating external causes. Often, users themselves create conditions under which the refrigerator cannot reach the desired temperature and, therefore, does not receive a signal to turn off.
One of the most common reasons is a violation of the seal of the chamber. If the door does not close tightly, warm air constantly enters. The temperature sensor detects the heating and commands the compressor to work continuously.
- 🔍 Check if anything is preventing the door from sealing tightly: hanging food, dishes or foreign objects.
- 🧊 Make sure you have not put hot or warm food in the chamber. This creates a colossal load on the system.
- 🌡️ Assess the temperature in the room. If the kitchen is hot (for example, in the summer or when the oven is running nearby), the refrigerator will work longer.
- 🚪 Check if the door is warped. This is a common problem after transportation or long-term use.
It is also worth paying attention to the location of the refrigerator. If it stands close to a wall or in a niche without gaps for ventilation, heat is not removed from the condenser. This leads to the fact that the refrigerant does not cool effectively, and the cooling cycle is delayed.
Malfunctions of the thermostat and sensors
The “brain” of the refrigerator is the thermostat (thermostat) or an electronic temperature sensor. It is these elements that make the decision to turn the motor on and off. If the thermostat is “stuck” in the “on” position or its capillary tube has lost sensitivity, the compressor will hum endlessly.
In modern models with the system No Frost an electronic control module, which receives data from several sensors, is responsible for the temperature regime. The failure of even one sensor (for example, an evaporator sensor) can lead to the fact that the “brains” of the technician will consider that the cold is not enough and will not turn off the compressor.
Diagnostics of a mechanical thermostat is often possible at home. To do this, you need to get to its installation location (usually inside the camera or under the lamp shade) and carefully remove the terminals, shorting them together. If after this the compressor starts, then the problem is in the regulator.
How to check an electronic sensor with a multimeter?
To check the electronic sensor (thermistor), you need a multimeter in resistance measurement mode. The sensor is removed from the mounting location and its resistance is measured at room temperature. Then you need to cool it (for example, by putting it in the freezer for a couple of minutes) and measure it again. The resistance must change. If the values do not change or the sensor shows an open/short circuit, it must be replaced. Typical resistance at 25°C is about 10 kOhm, but the exact data depends on the model.
Problems with the defrost system (No Frost)
In refrigerators with an automatic defrost system ("No Frost"), continuous operation of the compressor is often associated with freezing of the evaporator. The ice coat on the heat exchanger blocks the airflow and the cold does not enter the chamber. The temperature sensor in the chamber “does not see” the cold and keeps the motor on.
The reasons for the formation of ice can be:
- ❄️ Malfunction Heating element defrost: the heating element burns out and does not melt the ice during a pause.
- ⏱️ Defrost timer failure: the mechanism that switches the “cooling” and “defrost” modes is stuck in one position.
- 💧 Drain hole clogged: melt water does not drain, freezes below and gradually freezes onto the evaporator.
If you noticed that a dense layer of ice or snow had formed in the freezer compartment on the back wall, and it was warm in the main chamber; most likely, the problem was in the defrost system. In this case, it is necessary to defrost the refrigerator during the day (with the doors open) and then replace the faulty elements.
☑️ Symptoms of problems with defrosting
Refrigerant leak and problems with the circuit
Paradoxically, if freon (refrigerant) leaks, the refrigerator can also work without stopping. Since there is little gas in the system, the pressure does not reach the required values, and the compressor tries to “catch up” the temperature, working to wear out. However, there will be no cold in the chambers, or it will be very weak.
Signs of a leak:
- 📉 The compressor works constantly, but the condenser grille at the back remains cold or barely warm.
- 💨 Traces of oil are visible in places where the tubes are soldered or on the evaporator (freon circulates along with the oil).
- 🌡️ The temperature in the chambers does not drop below +10...+15°C even after many hours of work.
It is impossible to eliminate the leak on your own. You need to call a technician with equipment to find the location of the damage, seal the circuit and charge it with new refrigerant. Long-term operation of the compressor in vacuum mode (if there is a leak) often leads to its combustion, since the motor is cooled precisely by the passing freon.
Comparative table of symptoms
To make it easier to navigate the possible causes, we have compiled a table comparing symptoms with probable malfunctions.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| The compressor is humming, the chambers are warm, the back is cold | Freon leak or capillary blockage | High (needs a technician) |
| The refrigerator does not turn off, but freezes normally | Thermostat is faulty | Medium (part replacement) |
| Ice on the back wall of the freezer, it’s warm in the refrigerator compartment | Failure of the defrost system (No Frost) | Medium (replacement of the heating element/timer) |
| Noisy operation, motor overheating | Compressor wear or poor ventilation | High (compressor replacement) |
| The door does not fit, condensation outside | Deformation of the seal or door misalignment | Low (adjusting/replacing the rubber band) |
When you need to call a technician
There are a number of situations where attempts at self-repair can only do harm. If after complete defrosting (at least 24 hours) and checking the tightness of the door, the situation has not changed, most likely the problem is within the technical circuit.
Be sure to contact a specialist if:
- 🛠️ You hear relay clicks, but the compressor does not start or hums and immediately stalls.
- 🔌 Traces of soot or melted wiring are visible on the compressor housing.
- 🩸 Oily stains were found on the tubes or inside the chamber.
Remember that modern inverter compressors require special equipment for diagnostics. It is difficult to check them using conventional methods, and incorrect actions can damage the expensive control board.
⚠️ Attention: Do not try to open a sealed circuit yourself or solder pipes without skills and equipment. This is dangerous to health and can completely destroy the refrigerator.
Prevention and proper operation
To extend the life of the refrigerator and avoid situations with continuous operation, follow simple rules. Regularly, at least once every six months, defrost the equipment (if not No Frostand wash the drainage hole.
Keep the condenser grid at the back of the refrigerator clean. Dust and pet hair that stick to it act as a heat insulator, interfering with heat transfer. Vacuuming the grill is a great habit that reduces the load on the motor.
Do not load the refrigerator to capacity with food. Air circulation must be free. Also, do not place the equipment close to the wall - leave a gap of at least 10 cm for ventilation.
How often do you need to change the seal?
The sealing rubber lasts an average of 5-7 years. If it becomes hard, cracked or no longer holds the magnet (check with a piece of paper: hold it with the door and try to pull it out - it should pull out with force), the rubber band needs to be changed. Otherwise, the compressor will wear out.
Is it possible to leave the refrigerator on if it does not turn off on its own?
It is absolutely not possible. Long-term operation without stopping will lead to overheating and combustion of the compressor or melting of the wiring. If such a malfunction is detected, the device must be disconnected from the network and diagnostics carried out.
Why is the refrigerator humming, but not freezing?
Most likely, there is a refrigerant leak or the capillary tube is clogged. The compressor idles, trying to create pressure that is not there. Professional repair is required.
Does the amount of food affect the operating time of the refrigerator?
Yes. Loading with warm products or completely clogging the chamber (impairing air circulation) causes the compressor to work longer. However, in good condition, it should still turn off periodically.
What to do if after defrosting the refrigerator does not turn off again?
If defrosting within 24 hours did not help, then the reason is not the ice, but a malfunction of the components: the thermostat, sensors, defrost heating element or freon leak. You need to call a specialist.