The situation when the refrigerator is humming and works without interruptions is familiar to many owners of household appliances. At first glance, it seems that there is nothing wrong with this: if the compressor is working, it means that the temperature inside is maintained and the food is safe. However, continuous operation of the motor is always a signal of system overload, which can lead to serious damage and expensive repairs.
A constant hum indicates that the unit cannot reach the set temperature or does not receive a stop signal from the control electronics. In normal mode compressor it should turn on and off at certain intervals, creating a so-called cooling cycle. If this does not happen, the resource of expensive components is consumed many times faster.
In this article we will analyze in detail the main causes of the malfunction, methods for diagnosing them and ways to eliminate them. You will learn when you can deal with the problem yourself, and in what cases you need to call a technician to replace the freon or compressor.
How to understand that the refrigerator is not working correctly
Modern models of household appliances, such as Liebherr or Bosch, are equipped with systems that can operate quieter or louder depending on the mode. However, there are clear signs that indicate a failure. If the refrigerator does not turn off more than 24 hours, this is already a cause for concern. Under normal conditions, the operating cycle ranges from 15 to 40 minutes, followed by a pause of the same duration.
Pay attention to the nature of the noise. A quiet hum may be normal, but if the sound becomes loud, intermittent, or accompanied by chassis vibration, the system is in emergency mode. Often, back wall an ice crust may form inside the chamber, or, conversely, the chamber becomes too warm.
Check the temperature inside the chambers. If food begins to deteriorate or, conversely, freeze (in the case of vegetables), this is a sure sign of a violation of thermoregulation. It’s also worth listening: if the hum comes not from the motor, but from the fan or pipes, the problem may lie in the heat removal system.
External factors: improper installation and microclimate
Before looking for a breakdown inside the unit, it is necessary to exclude the influence of the external environment. Often the reason that the refrigerator is humming and does not turn off lies in a banal failure to comply with operating rules. The unit is a complex mechanism that is sensitive to environmental conditions.
First, check the location of the device. If it is placed close to a wall or furniture, the heat from the condenser cannot be dissipated effectively. This causes the compressor to work harder, trying to compensate for the lack of cooling. It is also important to consider the distance to the heating devices.
- 🌡️ Room temperature: if the room is hotter than +30°C, the refrigerator will work almost non-stop, this is a physical feature of the refrigerant.
- 🚪 Closing density of doors: a skewed door or a worn seal allows warm air to pass through, causing the motor to hum constantly.
- 🧊 Loading chambers: too much warm food or, conversely, empty chambers disrupt heat exchange.
⚠️ Attention: If you have just brought the refrigerator from the store or rearranged it, do not plug it in for at least 2-4 hours. The oil in the compressor must drain into the crankcase, otherwise starting will lead to water hammer and breakdown.
Particular attention should be paid to the rubber seal. If it does not fit tightly, warm air saturated with moisture constantly enters the chamber. Sensors detect temperature increases and prevent the compressor from going into rest mode. You can check the tightness using a sheet of paper: clamp it with the door and try to pull it out. If the sheet is removed easily without resistance, the seal requires replacement or adjustment.
Malfunctions of the thermostat and temperature sensors
One of the most common reasons why the refrigerator does not turn offis the failure of the thermostat. This small device is responsible for controlling the temperature inside the chambers. It is he who gives the signal to the compressor: “stop, it’s cold enough” or “turn on, it’s warm.”
In mechanical models, the thermostat is a capillary tube with a bellows filled with freon. When the temperature changes, the gas expands or contracts, opening or closing contacts. If there is a gas leak from this tube or the contacts are stuck, the compressor will hum endlessly, because it “does not know” that the goal has been achieved.
In modern models with a system No Frost and electronic control, the role of a regulator is performed by temperature sensors (thermistors). They transmit data to control module. If the sensor “lies” and shows that the chamber is +10°C instead of the required +4°C, the module will keep the compressor on.
Diagnostics of the thermostat often requires disassembling and using a multimeter. However, there is a simple folk method: if when you turn the thermostat knob to the “minimum” or “off” position, the compressor does not stop and continues to hum, most likely the problem is in this unit.
How to replace the thermostat with your own hands?
To replace it, you need to disconnect the refrigerator from the network, remove the plastic lining inside the chamber (usually the top one), and disconnect the capillary tube from the evaporator and remove the terminals. The new regulator is installed in the reverse order. It is important to choose the right model, since the length of the capillary and the temperature range from different manufacturers (for example, Indesit or Atlant) may differ.
Refrigerant problems: freon leak
If you notice that the refrigerator is humming, the engine is hot, but there is no cold inside - these are classic signs of a refrigerant leak. Freon is the working fluid of the refrigeration cycle. If its amount in the system decreases due to microcracks in the evaporator or condenser tubes, the cooling efficiency decreases.
The compressor tries to compensate for the lack of refrigerant by working non-stop. However, even with round-the-clock operation, it cannot reach the required temperature, since the physics of the process is broken. The pressure in the system drops, the motor overheats, but the target indicators are not achieved.
A leak can be caused by corrosion of metal-plastic evaporators (often found in models Stinol or old Beko) or mechanical damage to the tubes during inaccurate defrosting. Sometimes freon leaves through a factory soldering defect.
| Symptom | Probable cause | Action |
|---|---|---|
| Humming, no cold, the condenser is warm | Leakage freon | Call a technician, search for leaks, refill |
| Humming, weak freezing, ice freezing | Partial leak or blockage | Diagnostics of pressure in the system |
| It hums, turns off, but rarely | Wear of the compressor | Replacing the motor-compressor |
It is important to understand: it is impossible to fix the leak and fill the refrigerator with freon on your own. This requires special equipment: a vacuum pump, a pressure gauge station and scales. In addition, you need to know exactly the type of refrigerant (R134a, R600a) and its quantity.
Clogged capillary tube and compressor malfunction
Another technical reason why the refrigerator does not turn off and makes a loud hum is a clogged capillary tubes. This is a narrow copper tube connecting the condenser and evaporator. Over time, plugs from paraffins contained in the oil or oxidation products may form inside it.
If clogged, the refrigerant circulation is disrupted. The compressor runs "idle", creating excess pressure on one side and vacuum on the other. This is often accompanied by a characteristic sound: the engine hums, then a click is heard and it stalls, after which the cycle repeats. However, in the early stages, it may simply work continuously, but ineffectively.
The compressor itself can also be a source of problems. If its motor life is exhausted, it loses power. The piston group wears out, the valves no longer hold pressure. In this state, the unit is not able to create the required temperature difference and works without rest, trying to complete the task.
☑️ Compressor diagnostics
If the compressor fails, it must be replaced. Repairing older models is often not economically feasible, since the cost of a new motor and replacement work can be up to 70% of the price of a new refrigerator.
Failures in the electronic control module
In refrigerators with a system No Frost and display, the electronic module is responsible for all processes. This is the "brain" of the device. If voltage surges occur in its circuit or moisture enters, it may begin to issue erroneous commands. For example, send a constant signal to turn on the compressor, ignoring sensor readings.
Often the module “glitches” after a thunderstorm or power surges. Visually, swollen capacitors or traces of burning may be visible on the board. In some cases, flashing or simply resetting errors helps, but more often the control unit needs to be replaced or repaired by a service provider.
It is also worth checking the start-protection relay. This device starts the motor and protects it from overloads. If the relay is stuck in the "on" position, the compressor will hum continuously. If it cannot start the motor, you will hear short beeps and clicks.
⚠️ Attention: The refrigerator electronics are sensitive to voltage quality. If your network has frequent surges, be sure to use a voltage stabilizer to protect the control module.
Specifics of operation of No Frost refrigerators
Owners of units with the system No Frost (for example, Samsung, LG) may encounter peculiarities of fan operation. If the refrigerator is humming, but there is cold, perhaps the problem is not in the compressor, but in the blowing system. The fan can work constantly if the melt water drainage channel is clogged or the defrost sensor is faulty.
In such models, ice builds up on the evaporator, hidden behind the back wall. If the defrosting system (heating element, timer, sensor) does not work, ice blocks the airflow. The compressor continues to hum, trying to cool the chamber, but the cold air simply does not reach the food due to the ice plug.
You can diagnose this by defrosting the refrigerator completely (for 24 hours with the doors open). If after turning it on it worked normally, but after a week the problem returned, it means that the defrosting system is faulty. It is necessary to check the evaporator heating element and the defrost sensor.
Why does a two-compressor refrigerator hum constantly?
In two-compressor models (separate motor for freezer and refrigerator) the problem may be localized in one of the chambers. If the refrigerator motor is humming, but the freezer is working normally, look for a leak or a malfunctioning thermostat in the upper compartment. Often in such models one compressor fails while the second one is working properly.
Does the amount of products affect the operation of the motor?
Yes, it does. An empty refrigerator loses cold faster when the door is opened, causing the motor to turn on more often. However, packing food too tightly interferes with air circulation. The optimal load is about 50-60% of the volume so that cold air can circulate freely around the products.
Frequently asked questions (FAQ)
How long should the refrigerator be silent after turning off?
Normally, the pause between compressor cycles is from 15 to 40 minutes, depending on the model, chamber load and room temperature. If the pause lasts only 2-3 minutes, this is a sign of a malfunction of the thermostat or a freon leak.
Is it dangerous if the refrigerator hums all night?
Short-term operation all night is possible in hot weather or after loading a large amount of warm food. But if the situation repeats regularly, this leads to overheating of the compressor windings and its rapid failure. It is necessary to look for the reason.
Is it possible to operate the refrigerator if it does not turn off?
It is possible to operate it, but not for long. Constant work without rest reduces the life of the compressor significantly. In addition, this leads to excessive consumption of electricity up to 30-40% above normal. It is better to eliminate the malfunction.
Why is the new refrigerator humming loudly?
New models may be louder due to the design of the compressor or refrigerant circulation system. Also make sure that the refrigerator is level and not touching the walls. If the hum does not subside after 2-3 days of operation, contact the service center under warranty.
What to do if the refrigerator does not turn off after defrosting?
If after complete defrosting (24 hours) the refrigerator continues to work without interruption, most likely the problem is not ice, but a freon leak or a malfunction of the thermostat. Diagnostics by a specialist using pressure gauges is required.