Why does the refrigerator not cool in the upper compartment, but the freezer works?

The situation when you open the refrigerator, and it’s warm inside, while the frozen food at the bottom remains hard, causes understandable panic. This is a common breakdown scenario and indicates a problem with refrigerant circulation or problems with the defrost system. Many equipment owners immediately write off the unit for recycling, but often the reason lies in a specific part, the replacement of which will cost much less than buying a new device.

Modern two-chamber models, be it Indesit, Atlant or Beko, most often use a No Frost system or a weeping evaporator, where the cold is distributed unevenly when failures. If lower chamber continues to freeze, it means that the compressor is working and freon is present in the system, but the path to the upper compartment is blocked. Understanding the physical processes will help you avoid unnecessary expenses on calling a technician to diagnose basic things.

In this article we will analyze in detail the mechanical and electrical reasons for this temperature asymmetry. We will look at how it behaves, why the thermostat fails and how to check the defrost system without special equipment. It is important to act consistently so as not to aggravate the situation through improper operation. Clogged capillary tube, why the thermostat fails and how to check the defrost system without special equipment. It is important to act consistently so as not to aggravate the situation through improper operation.

Principle of operation and distribution of cold in two-chamber models

To understand the nature of the malfunction, you need to briefly recall the basic principle of operation of the refrigeration circuit. The refrigerant (freon), compressed by the compressor, passes through the condenser, where it gives off heat, and then enters the evaporator. In classic models evaporator it is located in the freezer compartment, and cold air is forced or naturally supplied to the upper compartment.

If the freezer is working normally, this indicates that the main cooling cycle has started. However, additional controls such as flaps, fans and sensors are critical for the overhead compartment. In models with the system No Frost the fan drives cold air through special channels. If this air flow is blocked by ice or the damper mechanism is jammed, the upper chamber stops receiving cold.

In refrigerators with a “crying” system (drip) the situation is different. Here the evaporator is hidden behind the rear wall of the upper chamber. If there is little freon in the system (leak), it may only be enough to freeze the first section of the circuit - the freezer, and the refrigerant simply does not reach the top in the required state of aggregation. It is also worth considering that thermostat may be installed incorrectly, turning off the compressor ahead of time.

⚠️ Attention: Do not try to open the sealed circuit yourself or check the freon pressure without a manometric manifold. This will lead to complete weathering of the gas and moisture entering the system, which will require expensive refilling.

Differences in design also dictate different methods for finding a breakdown. Owners of old Soviet units and new “smart” electronically controlled refrigerators LG or Samsung should take into account different approaches to diagnostics. In the first case, mechanics are often to blame, in the second - electronic sensors.

Mechanical reasons: freon leak and system blockages

One ​​of the most common reasons why the upper chamber stops cooling is a partial leak of refrigerant. When the amount of freon in the system drops below a critical level, it is not enough for a full cycle. The gas boils and cools only the initial section of the evaporator in the freezer, not reaching the upper circuit. Visually, this may manifest itself in the form of swelling of the rear wall or the appearance of rust in the places where the tubes are soldered.

The second mechanical problem is clogging of the capillary tube. During operation, microscopic particles of oxides or ice may form in the system (if there is moisture in the system). This blockage acts like a plug: the compressor hums, trying to push through freon, the freezer operates in increased mode, but circulation in the upper compartment stops. Often, you can hear gurgling sounds coming from the depths of the unit.

The third reason is the failure of the compressor itself. Although less common than leaks, sometimes valves inside the engine lose compression. The engine runs, hums, but does not create enough pressure to pump freon through the entire circuit. As a result, the pressure in the system drops and the cold ceases to be produced in full.

Diagnosing mechanical problems often requires the intervention of a specialist. However, you can conduct an initial inspection:

• 🔍 Inspect the back wall of the refrigerator for bulges, oil stains or corrosion.
• 👂 Listen to the operation of the compressor: is it running continuously or is it switching off frequently?
• ❄️ Check the uniformity of cooling of the evaporator (if there is access) - the cold should spread along the entire length.
• 🌡️ Pay attention to the temperature of the condenser grille at the back - it should heat evenly.

If you find oily spots near the tubes, this is almost guaranteed to indicate a leak. The freon evaporates, but the oil remains. In this case, simply filling with gas will not help - first you need to find and seal the fistula, and also replace the filter drier.

Problems with the defrost system (No Frost)

In refrigerators with the system No Frost the main reason for the lack of cold in the upper compartment when the freezer is running is a violation of the defrost cycle. The essence of the problem is that the evaporator becomes overgrown with a “coat” of ice, which blocks the operation of the fan and blocks the air supply channels. The freezer can continue to freeze, since the evaporator is located there, but cold air simply cannot get up.

The key elements of this system are Defrost heating element, defrost thermostat (or sensor) and a timer (or electronic control module). If the heating element burns out, the ice does not melt. If the thermostat breaks down, it does not give the command to turn on the heating. As a result, in a couple of days a huge layer of ice grows, which tightly blocks the air channels.

Often owners notice that the refrigerator began to freeze worse after they did not open the door for a long time or, conversely, often kept it open. Humid air quickly turns into ice on a cold evaporator. If the defrost system is working properly, it will melt this ice. If not, the problem described above will begin.

Signs of a defrost system malfunction:

• 💧 The appearance of puddles of water under the vegetable boxes in the refrigerator.
• 🌬️ The fan in the freezer is humming or crackling, touching the frozen surface with its blades ice.

The easiest way to test this hypothesis is to completely defrost the refrigerator. It is necessary to turn off the device from the network, open all doors and leave it for at least 24 hours (preferably for a day). This time is necessary for the ice inside the channels, which you cannot see, to completely melt.

If after a day of defrosting and turning it back on, the refrigerator began to work normally and cold appeared in the upper compartment, but after 1-2 weeks the situation repeated itself, it means that the defrosting system is faulty and requires replacement of components. Most likely, the heating element or sensor has burned out.

⚠️ Attention: It is strictly forbidden to try to break off the ice with a knife or other sharp objects. Damage to the evaporator (especially a foamed one) will lead to an immediate leak of freon and complex, expensive repairs with re-soldering.

Failures of the damper and fan

In models with one compressor and system No Frost (for example, many models Indesit i Stinol) the supply of cold to the upper chamber is regulated by a special air damper. It opens at the command of the thermostat, allowing cold air from the freezer to flow upward. If the damper mechanism is stuck in the closed position or the drive motor is burned out, the upper chamber will remain warm.

Circulation is also critically important. It is located in the freezer and drives air through the channels. If the fan stops, cold air remains in the freezer, creating excess cooling there, but does not reach the refrigerator compartment. The reason for the stop may be either a burnt-out motor winding or simple icing of the blades. fan circulation. It is located in the freezer and drives air through the channels. If the fan stops, cold air remains in the freezer, creating excess cooling there, but does not reach the refrigerator compartment. The reason for the stop may be either a burnt-out motor winding or simple icing of the blades.

Diagnostics of these components requires partial disassembly of the freezer chamber. The back panel must be removed to gain access to the evaporator and fan. When you turn on the refrigerator, the fan should start working (if the door is open, it may stop - this is normal, check the door switch).

Possible symptoms:

• 🔇 Complete silence in the freezer when the compressor is running (the fan does not make noise).
• 🚪 The damper is not responds to turns of the temperature regulator.
• 🌡️ In the freezer, the temperature is below normal (-24°C and below), but it is warm at the top.

How to check the fan without disassembling?

In some models, you can carefully remove the plastic grill in the freezer and visually assess the condition of the blades. If they are covered with ice, the problem is in the defrost system. If the blades are clean, but do not spin when the door is closed, the fan motor has burned out.

Electrical faults: thermostat and sensors

In refrigerators with electromechanical control, thermostatis responsible for the temperature. This device senses the temperature in the evaporator or chamber and opens the compressor power circuit. If the thermostat is “stuck” in the open state or its sensitivity is impaired, the compressor may not turn on at all or work too little to cool the large chamber, although the small one (freezer) still keeps the cold due to inertia.

In modern models with electronic control (Bosch, LG, Samsung) instead The thermostat uses air sensors and evaporator sensors. If the upper chamber sensor gives incorrect readings (for example, it shows that it is -5°C, although in fact it is +10°C), the control module simply will not start the active cooling mode or will not open the damper.

Often the problem lies in oxidation of the contacts or broken wiring going from the sensors to the control board. This may occur due to vibration or moisture during defrosting. In such cases, error codes may light up on the display, but not always - some models do not have a self-diagnosis function with display.

To check the thermostat in mechanical models, you can close its contacts directly. If after this procedure the compressor starts working and it gets cold, the thermostat must be replaced. However, with electronic sensors, such experiments are dangerous and can damage the control board.

Diagnostic table: symptoms and probable causes

For convenience, we systematize the main symptoms of a malfunction. Compare the behavior of your refrigerator with the data in the table to narrow down your search.

Analyzing the table, you can see that more than 50% of cases when the freezer is working but the upper chamber is not are associated with impaired air circulation (ice, fan, damper) or micro-leaks of freon. Electrical breakdowns occupy a smaller share, but are also common.

When you need to call a technician

There is a fine line between do-it-yourself repairs and the need for professional intervention. If you successfully defrosted the refrigerator and it started working, but a week later the problem returned, this is a signal that one of the system components (heating element, sensor, thermostat) has failed. You can replace these parts yourself if you have the skills to work with a multimeter and a screwdriver.

However, if the diagnostics indicate freon leak or system clogged, you cannot do without a technician. For repairs you will need:

1. Specialized equipment (vacuum pump, pressure gauges, scales).

2. Set of tools for soldering copper tubes (torch, solder).

3. Access to refrigerants that are under pressure.

An attempt to independently refill with “cans with a straw” from a car service in 99% of cases leads to damage to the compressor. Refrigeration equipment uses other types of oils and freons, and the requirements for system cleanliness are an order of magnitude higher than in car air conditioners.

⚠️ Attention: If you smell burning or see sparking in the area of ​​the compressor or control board, immediately unplug the cord from the outlet. Operating such a device is a fire hazard.

You should also think about calling a specialist if your refrigerator is more than 10-12 years old. In such cases, the cost of spare parts and work to eliminate the leak can be up to 70% of the cost of a new unit. Sometimes it is more economically feasible to purchase new equipment with a guarantee and a modern energy efficiency class than to revive a “veteran.”

Prevention and operating rules

To prevent the situation when the refrigerator stops cooling in the upper compartment from happening again, it is important to follow the operating rules. Do not place hot food in the chamber - this creates excess moisture, which quickly turns into ice and loads the defrost system. Monitor the integrity of the door seals: if they do not fit tightly, the constant flow of warm, moist air is guaranteed to lead to icing of the channels.

Carry out preventive defrosting regularly, at least once a year, even if you have a system No Frost. This will help remove microscopic ice deposits in hard-to-reach places. Also keep the drain hole (if your model has one) clean so that condensation can drain freely.

Following these simple recommendations will extend the life of the compressor and control system, keeping your food fresh and your nerves in order. Remember that prevention is always cheaper than repairs.

Frequently asked questions (FAQ)

Is it possible to use a refrigerator if the upper chamber does not cool?

For a short time - yes, if the freezer is working. However, food in the upper compartment will quickly spoil. In addition, if the cause is a freon leak, the compressor will run non-stop, trying to gain temperature, which can cause it to overheat and burn out. It is better to eliminate the malfunction.

How long does it take to defrost the refrigerator to check?

The minimum time is 12 hours, but to completely melt the ice in the hidden channels of the system No Frost it is recommended to leave the refrigerator turned off with the doors open for 24 hours. The use of a hairdryer or hot water is prohibited, since a sharp temperature change can damage the plastic and tubes.

Why did the refrigerator work after defrosting, but a month later it stopped again?

This is a classic sign of a malfunction of the defrosting system. Defrosting temporarily removes the ice blockage, but since the heater, sensor or timer is not working, the ice builds up again, blocking air circulation. The faulty element needs to be replaced.

Does the amount of food in the refrigerator affect cooling?

Yes, it does. A refrigerator that is too tightly packed prevents air circulation. There must be a gap between the products for the free passage of cold flows. It is also not recommended to cover the ventilation holes inside the chamber with products.

Is it dangerous to change the thermostat yourself?

Replacing a mechanical-type thermostat is relatively safe if you turn off the power. The main thing is to choose the right model with similar characteristics. However, if you are not confident in your abilities, it is better to entrust this to a professional so as not to break the tightness or electrical circuit.