Situation when refrigerator compartment stops cooling food, and the compressor hums continuously, is a classic sign of a serious system malfunction. Unlike scheduled defrosting, when the unit is simply resting, here we observe “idle” operation. The motor is trying to catch up with the cold, but due to loss of refrigerant or blockage of heat exchange, the desired temperature is not reached, and the automation does not give the command to stop.
Ignoring the problem in the first hours can lead to spoilage of a large volume of products, but what happens to the product itself is more critical. compressor. Prolonged operation without rest cycles causes overheating of the motor windings, oil degradation and, ultimately, costly replacement of the unit. It is important to quickly understand whether the breakdown can be fixed on your own or whether you need to call a specialist.
In this article we will analyze in detail the main reasons why The refrigerator has stopped freezingbut continues to work without shutting down. We will look at mechanical damage, electrical faults and software failures so that you can correctly diagnose the problem.
Seal failure and refrigerant leak
The most common reason why the refrigerator works, but does not freeze, is a banal leak freon (refrigerant). In good condition, gas circulates in a closed circuit, changing its state of aggregation. If a microcrack has formed in the tubes, the gas gradually escapes. The pressure in the system becomes insufficient for effective cooling, therefore thermostat does not detect a decrease in temperature and keeps the motor on constantly.
Leakage can occur in different places: in the foamed part of the body, in the evaporator or at the joints of the pipes. This is often the result of metal corrosion or mechanical damage due to careless defrosting. If you notice that compressor it is hot, and the back wall inside the chamber is warm or at room temperature, this is a sure sign of a lack of freon.
It is difficult to visually determine a leak, since the gas is colorless and odorless. However, there are indirect signs indicating depressurization of the circuit.
⚠️ Attention: If you find an oily spot under the refrigerator or on the pipes at the back, this is almost guaranteed to indicate a leak along with oil from the compressor.
Diagnostics of a leak requires special equipment - a leak detector or a pressure gauge manifold. Finding and sealing the hole yourself, and then refilling the system with the correct amount of refrigerant is almost impossible without skills and a vacuum pump.
Malfunction of the thermostat or temperature sensor
The second most common reason for the continuous operation of the unit is failure thermostat (in mechanical models) or temperature sensor (in electronic control systems). It is this element that informs the control unit that the desired temperature has been reached and the motor can be turned off. If the contacts of the thermostat are “stuck” in the “on” position or the sensor transmits incorrect data, the refrigerator will work endlessly.
In older models with mechanical control, you can check the thermostat by temporarily removing it from the circuit. To do this, the wires suitable for the thermostat terminals are connected directly. If after this the compressor starts (if it was turned off) or continues to work, and cold appears inside, then the problem is in the regulator. However, in modern models with an electronic module, such a check will not give an accurate result without a tester. Symptoms of sensor failure are often accompanied by erroneous readings on the display or their complete absence. The system may “think” that it is +20°C in the chamber, although in reality it is already -5°C, and will drive the motor until it is completely worn out. No Frost and with an electronic module, such a check will not give an accurate result without a tester.
Symptoms of sensor failure are often accompanied by erroneous readings on the display or their complete absence. The system may “think” that the chamber is +20°C, although in reality it is already -5°C, and will drive the motor until it wears out completely.
⚠️ Attention: Do not try to adjust the mechanical thermostat with a screwdriver if you are not sure of your actions. Losing the calibration will result in incorrect temperature conditions.
Replacing a thermostat is one of the simplest repair procedures, but requires selecting an analogue with exactly the same parameters. Using the wrong thermostat can lead to too infrequent switching on or, conversely, to operation without stopping.
Clogged capillary tube or filter drier
The refrigerant circulation system includes narrow capillary tube and filter-drier, which retains moisture and foreign impurities. Over time, especially if there was moisture in the system or poor repairs were made, the filter may become clogged. This creates a plug that prevents the normal flow of freon.
When a blockage occurs, the compressor begins to pump refrigerant in one direction, creating excess pressure in front of the plug and a vacuum after it. As a result, the evaporator does not receive enough gas to cool. At the same time, the motor works with increased load, gets very hot and makes louder, more strained sounds than usual.
Often the blockage is accompanied by swelling of the filter drier or a change in its temperature. If the filter is colder or hotter than the tubes entering and leaving it, this is a reason to suspect a problem in this particular unit.
- 🧊 Symptom 1: The evaporator is covered with frost only at the beginning of the circuit, and then it is warm.
- 🔥 Symptom 2: The compressor is very hot to the touch, sometimes the thermal protection relay is triggered.
- 🔊 Symptom 3: Uneven operating noise, gurgling or its complete absence in the tubes.
To eliminate this malfunction, professional purging of the system with nitrogen is required, replacement filter-drier and evacuation of the circuit before refilling with freon.
Problems with the defrost system (for No Frost models)
In refrigerators with a system No Frost or Full No Frost the reason for the lack of cold when the compressor is running is often a malfunction of the defrost system evaporator. If the defrost heating element, timer or defrost sensor fails, a “coat” of ice grows on the evaporator, hidden behind the rear plastic panel.
Ice blocks the circulation of cold air. The fan is humming, the compressor is running, but the air simply cannot pass through the frozen radiator into the refrigerator chambers. As a result, the products in the main chamber become warmer, and the motor works without interruption, trying to compensate for the lack of cold.
You can diagnose this problem by listening to the operation of the fan. If you do not hear the characteristic blowing noise, although the compressor is humming, most likely the evaporator is clogged with ice. Another sign may be water leaking from under the refrigerator, or swelling of the back wall inside the chamber.
How to defrost a No Frost refrigerator correctly?
To completely defrost the No Frost system, it is not enough to turn off the refrigerator for 2 hours. Ice in hidden channels can take up to 24 hours to melt. It is recommended to leave the unit turned off with the doors open for a day. Do not use a hairdryer or hot water to speed up the process - this can damage the plastic parts and lead to cracks in the evaporator.
If, after complete defrosting (within 24 hours), the refrigerator begins to freeze and switches off cyclically, then the problem lies in one of the elements of the defrost circuit: Heating element, temperature sensor or timer.
Reduced compressor performance
Sometimes compressor is the cause of the problem. During long-term operation, wear may occur on the piston group or engine valves. The compressor continues to hum and give the appearance of working, but its real performance (compression) drops below a critical level. It is not able to create the necessary pressure for freon circulation.
You can check the compression by connecting a pressure gauge to the service fitting. If the discharge pressure is too low and there is no vacuum at the suction, then the motor is “dying”. Another sign may be that the motor is running too quietly compared to normal or, conversely, a loud knocking sound.
In some cases, the compressor may be mechanically sound, but have problems with the start relay. If the relay is “stuck” or does not supply current correctly, the engine may operate in the wrong mode without developing full power.
| Parameter | Good compressor | Worn compressor |
|---|---|---|
| Temperature body | Warm / Hot (cyclically) | Very hot, does not cool down |
| Operation sound | Uniform humming | Quiet hum, knocking, metallic clanging |
| Discharge pressure | High (corresponds to the type of freon) | Low, does not rise |
| Consumption current | Within normal limits passports | Reduced or increased |
Replacing a compressor is a complex and expensive repair that requires soldering pipes, refilling and often replacing the filter-drier. The economic feasibility of such repairs should be assessed based on the age of the refrigerator.
Diagnostics and procedure for failure
If you are faced with the problem described, do not panic. Consistent actions will help localize the fault and make the right decision. The first thing to do is to assess the scale of the disaster: how long ago the refrigerator stopped freezing and whether there are any extraneous sounds.
☑️ Primary diagnostics of the refrigerator
Next you should carry out a visual inspection. Open the door: if it is light inside, but there is no cold, and the back wall (in crying models) is dry and warm - this is a bad sign. In No Frost models, remove the back plastic panel in the freezer: the presence of a thick layer of ice on the radiator will indicate a problem with defrosting.
⚠️ Attention: Before any manipulations inside the refrigerator, be sure to disconnect it from the power supply. Working with live electrical components is life-threatening.
If you do not have the skills to work with a multimeter and a soldering iron, further diagnostics should be carried out by a specialist. Independent disassembly of units containing freon is prohibited and can be dangerous.
Prevention and care of the cooling system
To avoid situations when refrigerator stops freezing, it is important to follow the operating rules. Regular defrosting (even for No Frost systems, once a year is recommended) helps prevent ice from accumulating in hard-to-reach places. You should also avoid mechanical damage to the interior of the chamber.
It is important to keep the condenser (grid at the back) clean. If it is clogged with dust and animal hair, heat exchange is disrupted, the compressor overheats and operates under overload, which reduces its service life. Cleaning the condenser with a vacuum cleaner or brush is a simple procedure that should be done every six months.
Do not put hot foods in the refrigerator. This places unnecessary stress on the system and leads to condensation, which can cause corrosion or defrost problems. Maintaining the temperature conditions for loading food will extend the life of your unit.
Frequently asked questions (FAQ)
Is it possible to use a refrigerator if it does not freeze, but does it work?
You cannot use it to store food - it will spoil. However, short-term switching on for diagnostic purposes is acceptable. Long-term operation in this mode (a day or more) will lead to the compressor burning out due to overheating.
Why did the refrigerator turn on after defrosting, but after an hour it stopped freezing again?
Most likely, there is a freon leak or a blockage in the system. Defrosting temporarily eliminated the ice plug (if there was one in the capillary), but the main reason (lack of gas) did not go away. A search for leaks and refilling is required.
How much does it cost to repair if the refrigerator does not turn off?
The cost depends on the breakdown. Replacing the thermostat is one of the cheapest procedures. Freon refilling and leak detection are more expensive. Replacing a compressor is the most expensive option, which is often comparable to buying used equipment.
How to understand that the compressor has burned out, and not just a relay?
If you hear a click when you turn it on, the motor hums for 5-10 seconds, then a second click is heard and the hum stops (and so on in a circle) - most likely the problem is in the starter relay or compressor jamming. If the motor is silent, the winding may have burned out or there is no power.