The situation when a household unit turns on, hums, the light inside is on, but the food begins to deteriorate causes panic in any home cook. Often, owners are faced with the fact that two-chamber refrigerator works, but does not freeze, and the reason lies not in the lack of electricity, but in a violation of the cooling cycle. The first step is to evaluate the nature of the motor’s operation: does it hum constantly without stopping or, on the contrary, does it turn on rarely and for a short time.
It is important to immediately understand what exactly has stopped functioning: the freezer compartment, the refrigerator compartment, or both at once. In modern models with system No Frost and drip defrosting, diagnostic algorithms may differ. If you notice that the “snow” coating has disappeared on the back wall of the main chamber, and the ice is melting in the freezer, this is a clear signal of a malfunction.
You should not immediately call a technician if you do not have technical skills, but you can carry out the initial diagnosis yourself. This will help you more accurately describe the problem to a specialist or, perhaps, fix a minor problem yourself. In this article we will look at the main reasons why compressor it hums, but there is no cold, and how to act in each specific case.
Improper operation and external factors
Before sinning to break internal components, it is necessary to eliminate banal operating errors. Often two-chamber refrigerator does not freeze due to violation of placement or loading rules. If the unit is placed too close to the wall, the air circulation necessary to remove heat from the condenser is disrupted. The distance to the back wall should be at least 5-7 centimeters.
Another common reason is overloading the chambers with products. If you have just loaded a large amount of warm food into the freezer or filled the refrigerator compartment to capacity, thermostat it may not cope. The air simply does not circulate between the shelves, and the sensors show the wrong temperature, which is why the compressor does not turn on or runs idle.
Also check the tightness of the door. If sealing rubber band is worn out, dirty or deformed, warm air constantly enters the chamber. In this case, the unit will work almost non-stop, trying to compensate for heat loss, but there will be no stable cold.
- 🧊 Check that the door is not pressed by a foreign object or the edge of the carpet.
- 🧊 Make sure that the products do not block the openings for air circulation inside chambers.
- 🧊 Assess the condition of the seal: it should be clean, soft and fit tightly to the body around the entire perimeter.
Problems with the thermostat and temperature sensors
If the refrigerator is workingbut does not reach the desired temperature, the thermostat is often the culprit. This component is responsible for turning the compressor on and off depending on the temperature inside the chambers. Older models use a mechanical thermostat, modern ones use an electronic sensor.
If the mechanical thermostat fails, the circuit opens and the signal to start the motor is not received, although there is voltage in the network. In electronic models, a failure of the temperature sensor causes the control module to “think” that the cold has already been reached and does not start the cooling cycle. Diagnostics requires checking the contacts or replacing the element with a known good one.
⚠️ Attention: Before replacing the thermostat, be sure to disconnect the refrigerator from the power supply! Working with live electrical circuits is life-threatening.
In models with the No Frost system, the defrost sensor often fails. If it is “stuck” in the “defrost” position, the compressor will not turn on until the system goes into cooling mode, which may take a long time or may not happen at all without the intervention of a technician.
How to check the thermostat with a multimeter?
To check a mechanical thermostat, remove it, immerse the sensitive tube in cold water with ice. Test the contacts with a multimeter: if the circuit does not close during cooling, the part is faulty and requires replacement.
Faults of the compressor and start relay
The most serious and expensive problem is a malfunction compressor. If you hear the motor humming, clicking and turning off after a few seconds, but there is no cold, most likely the problem is in the start relay or the motor windings. The relay is responsible for starting the engine, and if it burns out, the compressor cannot start working.
Sometimes the compressor works, but does not create the necessary pressure in the system. This may be a consequence of interturn short circuit of the windings or mechanical wear of the piston group. In this case, freon circulates, but does not cool the evaporator to the required values. This can only be determined by indirect signs: weak heating of the condenser (grid at the back) and the absence of cold.
Replacing a compressor is a complex technical process that requires evacuation of the system and charging of refrigerant. It is impossible to perform this operation independently without special equipment. If the diagnostics indicated the motor, you will have to contact a service center.
☑️ Compressor diagnostics
Refrigerant leak and capillary system clogged
If the refrigerator turns on, it works for a long time, but does not freeze, and the tubes inside the chambers remain warm, there is a high probability of freon leakage. The refrigerant can evaporate through microcracks in the evaporator, which are formed due to corrosion or mechanical damage during careless defrosting with a knife.
Another common reason is clogged capillary tube. Oil circulates in the system, which over time can thicken or mix with decay products, blocking the narrow channel. As a result, freon does not enter the evaporator and cooling does not occur. In this case, the compressor can work continuously, trying to pump the refrigerant.
The symptoms of leakage and blockage are similar, but there are nuances. If there is a leak, the condenser (rear grill) will be cold or lukewarm. When clogged, part of the grill may be hot and part cold. Only a master with a manometric manifold can make an accurate diagnosis.
| Symptom | Freon leakage | Capillary clogged | Compressor malfunction |
|---|---|---|---|
| Operation motor | Long, non-stop | Long, with overheating | Short cycles or humming without starting |
| Condenser temperature | Cold or warm | Partly hot | Barely warm |
| Evaporator condition | Warm, without frost | Partially covered with frost | Warm |
| Sound of operation | Smooth hum | Gurgling, hissing | Clicks, buzzing |
Failures in the defrost system (for No Frost)
In refrigerators with a system No Frost, the lack of cold is often caused by a malfunction of the defrost system. If the heating element, defrost timer or defrost sensor fails, the evaporator becomes coated with ice. This ice blocks the channels through which cold air should enter the chambers.
As a result, the fan hums, the compressor can work, but the cold air simply does not reach the food. This can be seen visually if you remove the back panel in the freezer: the evaporator will be covered with a thick layer of ice or snow.
To fix the problem it is required defrosting within 10-12 hours (complete thawing of the ice) and subsequent replacement of the faulty element (most often the heating element or sensor). Operating a refrigerator with inoperative defrosting will lead to rapid failure of the compressor due to overload.
When you need to call a specialist
There are a number of situations when independent repairs are not only useless, but also dangerous. If you have checked the thermostat, made sure that the seal is intact and is placed correctly, but the refrigerator does not freezeprofessional intervention is most likely required. Especially when it comes to a sealed circuit.
A technician is needed to find and eliminate leaks, replace the compressor, refill with freon and repair electronic control modules. These works require special tools, knowledge and compliance with safety regulations. An attempt to solder tubes or change the motor yourself can finally finish off the unit.
Also, the help of a specialist is needed if the refrigerator is under warranty. Any interference with sealed components (compressor, capillary tube) automatically voids the manufacturer's warranty.
⚠️ Attention: Modern refrigerants (R600a) are explosive when in contact with air in a certain concentration. Refilling and repair of the circulation system should only be carried out by a certified specialist.
Frequently asked questions (FAQ)
Why does the refrigerator hum, but does not freeze after defrosting?
If you have just defrosted the unit, but it does not start to freeze, the thermostat or timer may not have worked. The cause may also be a freon leak, which appeared precisely after the defrost-freeze cycle due to the expansion of the metal. Let the refrigerator operate for 2-3 hours without loading food.
Can the refrigerator not freeze due to a power surge?
Yes, a power surge could damage the compressor start relay or electronic control module. In this case, the engine may not start or may operate intermittently. Diagnostics of the electrical circuit is required.
How long does it take the refrigerator to gain temperature after switching on?
Usually, an empty refrigerator takes from 2 to 4 hours to reach operating temperature. If after 5-6 hours of compressor operation the temperature does not drop, then there is a malfunction.
What to do if there is cold in the freezer, but it is warm in the refrigerator compartment?
This indicates problems with air circulation (the channels are clogged with ice in No Frost) or a malfunction of the damper that regulates the supply of cold. It is also possible that the capillary system is partially clogged or there is a lack of freon.