The situation when the refrigerator continues to hum, the light inside is on, but the food begins to spoil, and the ice melts in the freezer, causes panic. This is a classic scenario indicating that cooling system has failed, although the electrical circuit and motor-compressor are formally functioning. Owners often mistakenly believe that a running engine guarantees cold, but in reality the compressor can spin oil or drive gas through an empty circuit without creating the necessary temperature difference.
The first thing to do when a problem is detected is to carry out initial diagnostics without disassembling the unit. Pay attention to the nature of the noise: if it becomes quieter than usual or, conversely, the motor runs intermittently and immediately turns off, this is an alarming signal. It is also important to check whether the condenser is clogged with dust and whether there are any foreign objects that are interfering with air circulation around the rear grille.
You should not immediately call a technician, since in 30% of cases the cause lies in simple things that can be fixed on your own in a few minutes. However, ignoring the problem can lead to a complete replacement of expensive components, so you need to act quickly and consistently, eliminating simple options before moving on to complex ones.
Important: if you hear a sharp click and the refrigerator has stopped cooling, but continues to consume electricity, immediately disconnect it from the network. Long-term operation in this mode can lead to a wiring fire or complete failure of the compressor.
Problems with the thermostat and sensors
One of the most common reasons why refrigerator stops freezing is the output The thermostat is faulty. This small device is responsible for turning the compressor on and off depending on the temperature inside the chambers. If its contacts are stuck or the calibration is lost, the motor may simply not receive a command to start, or, conversely, work without stopping, but ineffectively.
In modern models with a system No Frost instead of a mechanical regulator, electronic sensors (thermistors) are used. They are more accurate, but are sensitive to voltage changes and moisture. If the sensor is lying and shows that it is -20°C in the chamber, the compressor will not turn on and the food will begin to defrost.
- 🔍 Check the position of the thermostat knob: perhaps it is accidentally moved to minimum or to the "Off" mode.
- ❄️ Listen to the clicks: a working thermostat should make a characteristic sound when switching modes.
- 🔌 In electronic models, a sensor error is often indicated by blinking indicators or a code on the display.
⚠️ Attention: When replacing the thermostat, it is important not to damage the capillary tube. Its deformation will lead to freon leakage and will require calling a specialist with refilling equipment.
How to check the thermostat with a multimeter?
To check, remove the thermostat and ring its contacts in cold and warm states. If the device shows “infinity” or “zero” in both cases, the regulator is faulty and requires replacement.
Leakage of refrigerant (freon)
The most unpleasant and technically difficult reason for the lack of cold is depressurization the circuit. Freon is a working fluid that circulates through tubes, picking up heat. If a microcrack appears in the system (due to corrosion or mechanical damage), the gas evaporates and cooling stops, although the compressor continues to run idle.
It is almost impossible to determine the leak visually, since freon is colorless and odorless. An indirect sign may be the appearance of oily stains under the refrigerator or on the back wall near the compressor. Also, only a partial “snow cap” may form on the evaporator instead of uniform icing.
If a leak is confirmed, simple refilling is not enough. It is necessary to find the location of the damage, seal it and only then pump in new gas. It is impossible to carry out this operation independently without a vacuum pump and a pressure gauge station.
It is worth noting that in older models it was often used Freon R12, which has now been replaced with more environmentally friendly analogues. When making repairs, it is important to use the correct type of refrigerant indicated on the unit nameplate.
Malfunction compressor
The compressor is the “heart” of the refrigerator. If it works, but does not create the pressure necessary to circulate freon, no cold is generated. This may occur due to burnout of the valves inside the piston group or inter-turn short circuit of the windings.
In some cases, the motor hums, but cannot start. This is often accompanied by a characteristic hum and a subsequent clicking sound from the protection relay. If the compressor is hot to the touch, but the refrigerator is warm inside, there is likely a loss of performance.
Diagnostics of the compressor requires professional skills. The master measures the resistance of the windings and the strength of the starting current. If the winding shows a short circuit or break, the unit must be replaced. Attempts to “revive” a burnt-out motor with additional capacitors give only a temporary effect.
Modern inverter compressors work quieter and more economical, but their diagnosis is more difficult. They do not emit the usual on/off sounds, operating in constant mode at different shaft rotation speeds.
Clogged capillary tube
The capillary tube is the thinnest channel connecting the condenser and the evaporator. It is here that a sharp drop in refrigerant pressure occurs, which causes its evaporation and heat absorption. Over time, oil oxidation products, moisture or debris can accumulate inside the system, causing clogging.
If partially clogged, the refrigerator may freeze, but weakly, or do so with long interruptions. When completely clogged, circulation stops completely. A characteristic sign is that the condenser (grid at the back) remains cold or warm only at the outlet of the compressor, and the rest of the part does not heat up.
To remove the blockage, technicians use the method of purging with nitrogen under high pressure. If this does not help, the capillary tube has to be changed. This is a labor-intensive process that requires opening the foamed layer of insulation.
Failures in the defrosting system (No Frost)
In refrigerators with the system No Frost frost should not form, since moisture is removed outside the chambers. However, if the automatic defrost system fails, the evaporator becomes covered in ice, which blocks the ventilation ducts. Cold air stops flowing into the chamber, although the freezer can still maintain the temperature for some time.
The main culprits in this situation are the defrost heating element, the timer (or electronic control module) and the defrost sensor. If the heating element burns out, the ice does not melt and grows until it blocks the path of air flow.
- 🔥 The defrosting heating element must heat up to a certain temperature according to a timer signal.
- ⏱️ The timer or control board regulates the freezing and defrosting cycles.
- 🌡️ The defrost sensor monitors the temperature of the evaporator so that the heating element does not overheat.
You can diagnose the problem by defrosting the refrigerator manually for 24 hours. If after turning it on it starts to freeze normally, but after a week or two the problem returns, the problem is definitely in the defrosting system.
⚠️ Attention: Do not try to chip ice from the evaporator with a knife or sharp objects. Damage to aluminum plates or evaporator tubes will lead to an immediate leak of freon.
Comparative table of faults
For a quick reference to possible causes, use the table below. It will help narrow down the search for a problem before calling a technician.
| Symptom | Probable cause | Difficulty of repair | Necessary equipment |
|---|---|---|---|
| The compressor does not turn on, the lights no | No power, relay burned out, socket faulty | Low | Multimeter |
| Humming, but not cold, capacitor is cold | Freon leak or blockage | High | Vacuum pump, freon |
| It freezes slightly, the fur coat freezes | No Frost system malfunction (heating element, sensor) | Average | Tester, new heating element |
| Works without stopping, it’s warm inside | Loss of tightness, compressor wear | High | Pressure gauges, spare compressor |
| On and off immediately | Faulty start relay or compressor | Medium | New relay |
When professional repairs are needed
Despite the desire to save money, there are situations where the intervention of an unqualified user will only aggravate the breakdown. If the problem lies in a sealed circuit (leakage, blockage, compressor replacement), you cannot do without special tools.
It is also worth contacting a professional if you are not confident in your abilities when working with electricity. High voltage in the compressor and start relay circuits is life-threatening. In addition, incorrect installation of new parts can lead to a fire.
Modern refrigerators are full of electronics. If the control board is faulty, repairing it requires circuit knowledge and the availability of original components. It is often cheaper and more reliable to replace the entire module, which can only be done by a certified specialist.
⚠️ Attention: If your refrigerator is more than 10 years old, repairs and replacement of the compressor may not be economically feasible. The cost of work and spare parts can be up to 70% of the price of a new device.
☑️ Diagnostics before calling a technician
Frequently asked questions (FAQ)
Why the refrigerator hums, but does not freeze after defrosting?
If after complete defrosting (24 hours) the refrigerator turned on, worked for a couple of hours and stopped freezing again, this is almost guaranteed to indicate freon leakage or clogging of the capillary system. Water that entered the system during defrosting could freeze in a narrow place, creating an ice plug, or the leakage of the circuit was confirmed.
Is it possible to operate a refrigerator if it is bad is it freezing?
For a short time - yes, but you can’t work like that for a long time. If the cause is a leak, the compressor runs without load and may burn out. If the problem is with the No Frost system, ice may damage the fan or sensors. It is better to eliminate the malfunction.
How much does it cost to refill a refrigerator with freon?
The cost depends on the type of refrigerant and the amount of work. Typically the price includes a technician’s visit, diagnostics, evacuation of the system and refilling. On average, this constitutes a significant portion of the repair cost, so it is important to first find and eliminate the cause of the leak.
Why does the upper chamber freeze, but the lower one does not (or vice versa)?
In two-compressor models, this indicates a breakdown of one of the compressors or circuits. In single-compressor systems (where one motor pumps gas to both circuits), this may be a sign of a blockage in one of the circuits or a malfunction of the solenoid valve that switches the flows.