Why the refrigerator sometimes freezes or not: finding the cause and solution

The situation when the refrigerator sometimes freezes, sometimes it doesn’tcan unsettle any owner of household appliances. Food begins to thaw, puddles appear on the floor, and equipment makes strange sounds or, conversely, remains suspiciously silent. This behavior of the unit indicates that the control or cooling system operates intermittently, without returning to normal mode.

Unstable operation compressor or the defrost system is not just an inconvenience, it is a direct risk of inventory damage. In some cases, the problem is solved by simple adjustment, in others, serious intervention by a specialist is required. The critical feature is cyclicity: if pauses in operation become longer than cooling periods, you cannot delay diagnostics.

In this article we will analyze in detail the main causes of malfunctions characteristic of different models of equipment from older ones Soviet "Saratov" to modern LG i Indesit. You will learn how to carry out initial diagnostics yourself and understand when calling a specialist is inevitable.

⚠️ Attention: If you notice that the refrigerator body or compressor is getting very hot, or you hear a burning smell, immediately unplug the appliance. Continued operation in this condition may result in a fire.

Malfunction of the thermostat or air sensor

The most common reason the refrigerator sometimes freezes and sometimes it doesn’tis the failure of the thermostat. This element is responsible for controlling the temperature inside the chamber. When the air cools to the set point, the thermostat opens the circuit and turns off the compressor. If it is faulty, the contacts may “stick” or open too early.

In older models, a mechanical thermostat with a capillary tube is used. Over time, the bellows loses its seal or the tube becomes dislodged, causing the sensor to “feel” the temperature incorrectly. In modern models with the system No Frost air sensors (thermistors) are responsible for this, which transmit data to the electronic module.

Symptoms of failure are usually the following: the refrigerator may not turn on for a long time, which is why the food is defrosted, or, conversely, it works without stopping, freezing everything to the point of stone. In the “this and that” mode, this manifests itself as chaotic turning on and off.

• 🔍 Check: Try to forcefully unplug the refrigerator for 15-20 minutes, then turn it on. If it works normally for one cycle and then starts to fail again, there is likely a failure in the control system.
• 🔧 Diagnostics: Mechanical thermostats often require a “test” with a multimeter in cold and warm states.
• ❄️ Symptom: A “fur coat” freezes in the chamber at the back wall, although the compressor is often stopped.

Replacing the thermostat is a simple procedure, but requires precision. It is important to choose the right analogue, since the temperature range of operation may differ for different models. An error in choice will lead to the fact that the problem “it either freezes or not” will persist.

How to check a thermostat with a multimeter?

To check, remove the thermostat, immerse its sensitive tube in water with ice (about 0°C) and ring the contacts. They must open up. When heated in the hands (up to +5...+10°C), the contacts should close. If the circuit does not change, the part is faulty.

Problems with the defrost system (No Frost)

If your the refrigerator freezes sometimes, sometimes it doesn't, and at the same time you hear that it is working, but does not give cold, the problem may lie in the automatic defrosting system. In units with No Frost the evaporator is hidden behind a plastic panel. Periodically it must be thawed using heating elements. If this process is disrupted, the evaporator becomes overgrown with ice, blocking air circulation.

As a result, the fan circulates air, but no cold enters the chamber. The compressor is working hard, trying to cool the sensor, but cannot. After some time, the ice may partially melt (for example, when the door is opened or left idle for a long time), and the cold will appear again, creating the illusion of unstable operation.

The main culprits in this chain:

• 🔥 Heating element defrost: it could burn out, which is why the ice does not melt.
• 💧 Drainage system: the hole for water drainage is clogged with debris or ice.
• ⏱️ Timer or module: does not give a command to turn on the defrost mode.

For diagnostics it is often required partial disassembly of the rear wall of the freezer. A visual inspection of the evaporator will immediately indicate the presence of an ice shell. If there is ice, but the heating element is intact, check the defrost sensor and fuse.

Leakage of refrigerant (freon)

One of the most serious reasons why the refrigerator sometimes freezes and sometimes it doesn'tis freon leakage. The refrigerant circulates in a closed circuit, and in good condition its quantity does not change for years. However, corrosion of tubes, mechanical damage or manufacturing defects in soldering can lead to microcracks.

If there is a small leak, the refrigerator continues to work, but its performance drops. It can freeze for a long time, then stop to rest, but does not reach the required temperature. Then the cycle repeats. Visually, this looks like unstable operation: it seems to be colder, then warm again.

Indirect signs of a leak:

• 🌡️ Temperature: the condenser (grid at the back) is only partially warm or completely cold.
• 🧊 Ice: only appears in the freezer at the entrance of the tubes, the rest is warm.
• 🔊 Sound: the compressor works almost without interruption, trying to compensate for the lack of freon.

It is impossible to eliminate the leak on your own. It is necessary to search for the location of the damage, solder and refill the system with new refrigerant in compliance with the dosage. The use of household “refuelers” often leads to the final failure of the compressor.

Failure of the compressor or start relay

The “heart” of the refrigerator - the compressor - can also fail. If the refrigerator sometimes freezes, sometimes it doesn’t, perhaps the problem is in the starting relay or motor windings. The relay is responsible for starting the engine; if it is worn out, the compressor may hum, click, but not start, or start jerkily.

Another problem is inter-turn short circuit of the windings. In this case, the compressor may work for some time, overheat and turn off due to the thermal protector. After cooling, it turns on again, creating a “running-stopping” cycle. This is a classic picture of unstable frost.

What you can do yourself:

1. Listen to the sounds. Loud knocking, humming with vibration or frequent clicking are signs of a problem.
2. Check the temperature of the compressor housing. If it is hot to the point where you cannot touch it with your hand, but there is no cold, this is a bad sign.
3. Try to carefully (with the device turned off) remove the starting relay and shake it. If you hear a ringing sound (as if from broken ceramics), the relay needs to be changed.

The influence of the fast freezing and loading mode

Sometimes the reason why the refrigerator freezes or notlies not in a breakdown, but in improper operation. Many users forget to turn off the Super Freeze (Super Freeze) mode. In this mode, the compressor operates non-stop, ignoring the thermostat readings, which can lead to overheating and subsequent emergency shutdown.

It is also important to take into account the thermal load. If you have loaded a large amount of warm food into the chamber, the refrigerator will work in enhanced mode. After reaching temperature, it may "rest" longer than usual to stabilize the system, which is perceived as interruptions in operation.

Check the following settings:

• ❄️ Freeze mode: make sure the "Freeze" button or switch is off.
• 🚪 Closing tightness: Is the door warped by a heavy shelf or bottle?
• 🌬️ Ventilation: Is the refrigerator standing close to the wall, blocking air access to the condenser.

⚠️ Attention: Specifications and location of controls may vary depending on the model. Always check the official manufacturer's instructions for your specific device.

Diagnostic table of main symptoms

For ease of troubleshooting, we have compiled a summary table. It will help compare symptoms and probable causes.

By analyzing the data from the table, it is possible to determine the repair vector with a high degree of probability. Remember that a combination of several symptoms (for example, water flows AND does not freeze) most often indicates a complex problem with the defrosting system.

When you need to call a technician

Independent repair is possible at the stage of diagnosing and replacing simple elements like thermostats or relays. However, if the refrigerator sometimes freezes and sometimes it doesn't due to problems with the sealed circuit or electronics, it is better not to risk it. Opening a sealed circuit requires special equipment: a vacuum pump, a pressure gauge station and scales.

Also, you should not go inside if you do not have experience working with live electricity. Modern inverter compressors and complex electronic control modules are sensitive to static and connection errors.

Call service immediately if:

• 🛑 Smell: there is a persistent smell of galled wiring or burnt rubber.
• 🔥 Heating: the compressor is hot, and the tubes near it are cold.
• 💥 Bloating: swelling is visible on the walls of the refrigerator (a consequence of corrosion).

A professional technician can accurately determine the pressure in the system, check the current consumption of the compressor and find hidden leaks using a leak detector. This will save you money on the purchase of unnecessary spare parts.

Why does the refrigerator turn on for 1 minute and turn off?

Most likely, the thermal protection of the compressor is triggered. Reasons: a faulty starting relay, an interturn short circuit in the motor windings, or a critical lack of freon, which is why the motor cannot start and overheats.

Is it possible to use a refrigerator if it freezes every once in a while?

Short-term - yes, but storing perishable food in it is risky. Unstable temperature conditions promote the growth of bacteria. In addition, working in irregular mode quickly wears out the compressor.

How long should the refrigerator rest between starts?

In normal mode, the operating cycle looks like this: 20-40 minutes of operation and 15-30 minutes of rest. If the breaks last for hours or, conversely, the compressor hums without stopping, this is a sign of a malfunction.

Does the network voltage affect unstable operation?

Yes, strong voltage surges can lead to malfunctions of the electronic control module, which causes chaotic switching on. Also, low voltage does not allow the compressor to develop the required power.

What to do if, after defrosting, the refrigerator started working, but after a week it stopped again?

This is a classic sign of a clogged defrost system (in No Frost models) or a beginning freon leak. Water from the melted ice temporarily restored circulation or pressure, but the root of the problem (a faulty heating element, timer or hole in the circuit) has not gone away.