The situation when the refrigerator hums without interruption, and the food inside begins to deteriorate or, conversely, freeze into ice, causes panic in anyone home cook. Continuous operation of the compressor is an alarm indicating that the cooling system cannot reach the set temperature, or the control electronics have ceased to receive correct data about the state inside the chambers. Unlike short-term failures, a constant hum indicates a serious mechanical or electrical malfunction that requires immediate attention.
Ignoring this problem can lead to the motor burning out, since it is working for wear, without proper pauses for cooling. Modern models, whether Indesit, Atlant or premium ones, are equipped with protection, but you cannot rely on it forever. In this article, we will analyze in detail the main reasons why the compressor does not turn off and draw up an action plan for diagnosis. Liebherr, are equipped with protection, but you cannot rely on it forever. In this article we will analyze in detail the main reasons why the compressor does not turn off and draw up an action plan for diagnosis.
The first thing to do is not to panic and carry out an initial visual inspection. Often the reason lies in trivial things that are easy to fix on your own. However, if simple methods do not help, you will have to delve into the technical part of the device.
⚠️ Attention: If you smell burning, see sparking or hear sharp clicks, immediately unplug the refrigerator from the power supply. Further operation may lead to a fire.
Primary diagnostics: excluding external factors
Before grabbing the tools, it is necessary to exclude factors not related to the breakdown of the unit itself. Improper operation often imitates a serious malfunction. Make sure the refrigerator is on a level surface and does not rock. If it is skewed, the door may not fit tightly, allowing warm air to pass through, causing the sensors to constantly require cooling.
Check the operating mode. You may have accidentally activated the function Super Freeze (Super Freeze) or Max Cool. In this mode, the compressor works non-stop to quickly freeze large quantities of food. Usually this mode turns off automatically after 24-48 hours, but sometimes manual shutdown is required.
It is also worth checking the rubber seals on the doors. If they are worn out, dirty or have lost elasticity, the seal of the chamber is compromised. Warm air from the room constantly flows inside, and thermostat does not give the command to stop the engine. Wipe the rubber bands with a damp cloth and check the tightness around the entire perimeter.
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 mechanical or electronic device is responsible for controlling the temperature inside the chamber. If its contacts are stuck in the "on" position or it transmits incorrect readings to the control module, the compressor will run indefinitely.
In models with electronic control (for example, Samsung or LG with a display) for temperature control respond sensors (thermistors). There may be several of them: in the refrigerator, in the freezer, on the evaporator. If one of them “lies” and shows that it’s warm inside, although it’s actually cold, the system will drive the cold until it’s victorious.
To check a mechanical thermostat, it is often necessary to remove it and “test” it with a multimeter when the temperature changes. Electronic sensors are checked by measuring their resistance. If the resistance does not change during heating or cooling, the part must be replaced.
☑️ Checking the thermoregulation system
It is worth noting that in two-compressor models the problem may affect only one chamber. If the freezer is working normally, but the refrigerator compartment does not turn off, then look for a malfunction in the circuit responsible specifically for the refrigerator compartment.
Problems with the defrost system and freezing of the evaporator
If you hear the compressor humming, but there is no cold inside, or very little of it, there is a high probability of freezing of the evaporator. In refrigerators with a system No Frost a defrost system, consisting of a heating element, a timer (or electronics) and a defrost sensor, is responsible for removing ice. If one of these elements breaks, ice builds up on the evaporator in a thick layer.
The ice “coat” works as a heat insulator, preventing freon from cooling the air in the chamber. The temperature sensor “sees” that there is not enough cold and does not give a command to stop the compressor. As a result, the engine works at its limit, but it’s warm inside. A characteristic sign may also be that the back wall of the chamber is unevenly covered with frost or ice.
For diagnostics in No Frost models, it is often necessary to disassemble the back panel in the freezer in order to visually assess the condition of the evaporator. If it is completely hidden under the ice, and the heating element does not heat up when turned on, the problem is in the defrosting system.
How to defrost a refrigerator correctly?
If you find frosting, do not try to pick off the ice with a knife - you can damage the evaporator tubes. The safest way is to unplug the refrigerator, open the doors and leave it for 10–12 hours (preferably a day) to completely defrost. Place rags on the floor, as there will be a lot of water.
In drip systems (crying back) the problem may be due to a loose door fit, due to which moisture from the air constantly gets inside and freezes, blocking heat exchange. Also here the thermostatitself may be faulty, which does not sense that an ice piece of the required size has already formed on the back wall.
Refrigerant leak and capillary tube blockage
The most unpleasant and technically complex reason — freon (refrigerant) leak or capillary tube clogged. In both cases, the circulation of refrigerant through the system is disrupted. The compressor tries to pump gas, but due to an insufficient amount of substance or an obstruction in the tube, the pressure does not reach the values at which the thermal relay or shutdown timer is activated.
If freon leaks, the compressor can operate almost silently or with a characteristic gurgling sound. The engine is hot, but there is no cold. If the capillary tube is clogged, the compressor, on the contrary, can work very loudly, trying to push freon, and the condenser (grid at the back) will only be partially hot or not heat up at all.
| Symptom | Freon leak | Clogged capillary tubes | Compressor malfunction |
|---|---|---|---|
| Operation sound | Quiet, with gurgling | Loud, strained | Loud knocking or silence |
| Condenser heating | Cold or lukewarm | Hot only at the outlet | Very hot |
| Inside temperature | Does not cool | Cools poorly | Does not cool |
| Actions | Search for leaks, refill | Purge the system, replace filter | Replacing the motor |
Diagnostics of these faults requires special equipment: a pressure gauge station for checking pressure and a leak detector. It is almost impossible to independently determine the location of the leak or break through the blockage without a vacuum pump and freon.
⚠️ Attention: Freon is a gas under pressure. Attempting to open the system or replace a compressor on your own without the skills and equipment is dangerous and may result in injury. In addition, the release of freon into the atmosphere is harmful to the environment.
Faults in the control module and start relay
In modern refrigerators, the “brain” is the electronic control module. It is he who receives signals from sensors and commands the compressor. If the triac on the control board that controls the motor burns out, or a failure occurs in the firmware, the relay can constantly supply voltage to the motor windings, preventing it from stopping.
It is also worth paying attention to the starting relay of the compressor itself (if it is remote and not built into the inverter motor). Sticking contacts in the relay can cause the circuit to not open. This is a common problem in older models. In inverter refrigerators (Bosch, Electrolux), the inverter unit is responsible for startup and operation, which can also fail.
Diagnostics of the module begins with a visual inspection of the board for blackening, swelling of capacitors or a burning smell. However, internal component faults can only be identified by a specialist with an oscilloscope. At home, you can only check the integrity of the fuses and the reliability of the contacts.
When you need to call a technician
Despite the desire to save money, there are situations when independent repairs are impractical or dangerous. If you checked the thermostat, seals and operating modes, but the problem was not solved, most likely the problem is in the “internals” of the refrigeration circuit.
A call to a specialist is required in the following cases:
- 🔧 Replacement of the compressor or soldering of pipes is required (nitrogen, freon, burner are needed).
- ❄️ A freon leak is suspected (a leak detector and a filling station are needed).
- 💻 The electronic control module is faulty (professional diagnostics are needed).
- 🔌 Problem with the inverter motor (requires specific knowledge and spare parts).
A professional technician will arrive with the necessary equipment, accurately diagnose the unit and give a guarantee for the work. An attempt to replace the compressor yourself “on the knee” often leads to repeated failure after a short period of time due to poor-quality evacuation of the system or incorrect dosage of oil and freon.
How much does the repair cost?
The cost of the repair consists of the price of the spare part (compressor, filter-drier, freon) and the work of the technician. Replacing a compressor is one of the most expensive procedures, often accounting for up to 50% of the cost of a new refrigerator.
Prevention and proper use
In order for the compressor of your refrigerator to last a long time and turn off on time, it is important to follow the operating rules. Do not place hot pots inside - this puts enormous strain on the system. Make sure that food does not block the ventilation holes inside the chambers.
Regularly defrost the refrigerator (if it is not No Frost), wash the drainage hole so that the water does not stagnate. Check the cleanliness of the condenser at the back: a layer of dust and pet hair impairs heat transfer, causing the motor to work longer and harder.
By following these simple rules, you will extend the life of your refrigerator and avoid expensive repairs. Remember that a timely response to a change in the sound of operation or the switching mode is the key to a long service life of the equipment.
Frequently asked questions (FAQ)
Why does a new refrigerator work without interruption?
A new refrigerator, after first turning on or after defrosting, can work for up to 24 hours without stopping, gaining temperature. This is fine. Also check if the fast freezing mode is turned on.
Is it possible to operate the refrigerator if it does not turn off?
For a short time - you can while you are waiting for the technician. But long-term operation without stopping will lead to overheating of the compressor windings and its combustion. Products can also deteriorate due to temperature violations.
Does the compressor hum if freon runs out?
If freon leaks, the compressor may hum quieter than usual or intermittently (turn on and off frequently), but not gain cold. However, in some cases, it may operate continuously in an attempt to compensate for the lack of refrigerant.
How to check if the thermostat is working?
In mechanical models, you can carefully short the wires running from the thermostat to the compressor. If the engine starts, the thermostat is faulty. But this method requires caution and basic knowledge of electrical engineering.