Situation, when lower chamber the refrigerator is working properly and the food in the freezer freezes, but the upper compartment is at room temperature or even warm, is one of the most common complaints from users. This is a classic symptom that indicates a violation of the circulation of cold air within the system. In modern models, especially those equipped with a system No Frost, air is generated in the evaporator and forced by a fan into both chambers through special air ducts.
If the upper part does not cool, this almost always means that the cold flow simply does not reach the upper shelves. There may be several reasons: from simple ice blockage to failure of electronic control components. It is important not to panic and carry out an initial diagnosis to understand the scale of the problem. In 80% of cases, the problem lies in a violation of air circulation due to freezing of the evaporator or a malfunction of the damper, and not in a complete breakdown of the compressor.
Further actions depend on how long ago the problem appeared and whether it is accompanied by extraneous sounds. If you notice an ice crust on the back wall or a lack of fan hum, the algorithm of actions will differ from the scenario when the equipment simply stopped cooling after a power surge. Let's look at the main factors influencing the distribution of cold.
⚠️ Attention: If you smell burning or see sparking in the area of the compressor or rear panel, immediately unplug the device from the power supply. Further operation may lead to a fire in the wiring.
The main reasons for poor air circulation
The most common reason why the refrigerator has stopped cooling in the upper compartment lies in the air mass distribution system. In two-chamber models, the evaporator is usually located in the freezer compartment (top or bottom, depending on the design). The fan drives cold air up the duct into the refrigerator compartment. If this process is disrupted, the upper chamber remains warm.
Often the culprit is flow control damper (damper). This is a mechanical or electrical valve that opens and closes based on a signal from the thermostat. If the damper is stuck in the closed position or its actuator is broken, air cannot physically enter the upper section. In electronically controlled models, the damper motor itself often fails.
Another critical element is evaporator fan. If its blades are iced up or the motor winding is burned out, the circulation stops completely. In some cases, the fan works, but due to heavy ice build-up in the air duct, the air flow is blocked. The ice acts like a plug, preventing the cold from going further into the freezer.
Problems with the defrosting system and freezing
The system No Frost implies periodic defrosting of the evaporator using a heating element. If this cycle is disrupted, a “coat” of ice grows on the evaporator, which blocks the openings for air intake and supply. As a result, the fan hums idle, and the cold does not enter the chambers. This is a classic situation when the freezer is working at the limit, but it’s warm at the top.
Three main elements are responsible for the defrosting process: the evaporator heating element, the timer (or electronic module) and the thermal fuse. If the heating element burns out, the ice does not melt. If the thermal fuse fails, it breaks the power supply circuit of the heating element, and defrosting does not begin. In older models, a mechanical timer could be stuck, which simply did not switch the refrigerator to defrost mode.
You can diagnose freezing visually by removing the back panel in the freezer. However, before this, the equipment must be defrosted naturally. If after 24 hours of defrosting the refrigerator worked normally, but after a week the problem returned, it means that one of the elements of the defrosting system is faulty and requires replacement.
How to check the heating element with a multimeter?
To check the heating element, you need to call its resistance with a multimeter. The normal resistance value for a heating element with a power of 200-400 W is approximately 200-400 Ohms. If the device shows a break (one or infinity), the heating element has burned out and requires replacement.
Malfunctions of the thermostat and temperature sensors
The operation of the compressor and fans is controlled based on sensor readings. If temperature sensor in the refrigeration chamber it transmits incorrect data (for example, it shows that it is already -10°C, although in fact it is +15°C), the controller “thinks” that there is no need to cool, and does not open the damper or does not turn on the compressor at full power.
In mechanical refrigerators, this is responsible thermostat (thermostat). Its sensing tube is attached to the evaporator or inserted into the channel. If the tube has become dislodged or the thermostat itself has failed, the compressor power circuit may open too early. As a result, the operating cycle is short, the freezer has time to freeze, but the cold does not reach the top.
In modern models with an electronic control module, sensors (thermistors) have a certain resistance that changes with temperature. A failure in one of the sensors often results in an error on the display (error code), but not always. Sometimes the equipment simply works in emergency mode, ignoring the needs of the upper chamber.
⚠️ Attention: Do not try to heat the sensors with a hairdryer or check their operation by holding them in your hands if you do not have skills in working with electronics. Incorrect diagnosis can lead to a false conclusion about the serviceability of the part.
Refrigerant leakage and problems with the compressor
A more serious reason why the refrigerator does not freeze well above is a partial leak of freon. When there is little gas in the system, there is not enough gas for a full cooling cycle. Since the evaporator is located closer to the freezer, it cools first, and the refrigerant reaches the upper compartment either warm or not at all.
Signs of a leak are often:
- 🧊 Hot or barely warm condenser the grille at the back (normally it should be hot).
- 🔇 The compressor works almost non-stop, trying to gain temperature.
- ❄️ There is cooling only near the evaporator in the freezer, the rest of the chamber is warm.
If the compressor hums, it clicks and immediately turns off, there may be a problem with the start protection relay or the motor itself. But in the case of a working freezer and a cold top, a refrigerant leak is a more likely scenario than a compressor failure.
Symptom diagnosis table
To simplify troubleshooting, use the following table. Compare the symptoms of your equipment with the described signs to narrow down your search.
| Symptom | Probable cause | Difficulty of repair | Necessary actions |
|---|---|---|---|
| The fan does not noisy, no ice | Fan motor burnt out | Medium | Replacing the fan |
| A hum is heard, but there is no cold | The air duct is clogged with ice | Low | Complete defrosting (24-48 hours) |
| The compressor runs without stopping | Freon leak or capillary blockage | High | Call a technician, refuel |
| Short operating cycles | Faulty thermostat/sensor | Average | Replacement of sensor or thermostat |
| The damper does not open | Failure of the damper drive | Medium | Replacing the damper motor |
Algorithm for self-checking and defrosting
Before calling the wizard, try running complete defrosting. This is a universal tool that helps in cases where the problem is caused by a failure in the defrost system or temporary icing of the channels. The procedure is simple, but it requires time and discipline.
Unplug the refrigerator. Remove all food. Leave doors open for at least 24 hours (preferably 48 hours). Do not use a hairdryer or boiling water to speed up the process - a sudden temperature change can damage the plastic and evaporator tubes. The water should drain naturally.
☑️ Checklist for proper defrosting
After turning on the equipment, let it work for 2-3 hours without loading food. If the upper chamber began to get colder, then the problem was in the ice. If the situation repeats after a day, diagnostics of electronics or mechanics is required.
⚠️ Attention: Manufacturers can change the design of components and the location of sensors in different modifications of the same model. Before disassembling, be sure to check the technical documentation or diagrams for your specific series of refrigerator.
When you need to call a specialist
There are situations when do-it-yourself repair is not only ineffective, but also dangerous. If the problem persists after defrosting, parts will most likely need to be replaced or the refrigerant circuit needs to be rebuilt. These works require special tools and skills.
You need to contact the service center if:
- 🛠 You find mechanical damage to the tubes or traces of oil (a sign of a freon leak).
- ⚡ There is a suspicion of a malfunction of the electronic control module (board).
- 🔧 Replacement of the compressor or sealing of the system is required (a vacuum pump and scales are needed).
- 📉 The equipment is under warranty (opening the seals will void your warranty).
An attempt to replace freon yourself or solder pipes without experience often leads to final failure of equipment. The cost of such errors can exceed the price of a new refrigerator.
Why did the refrigerator stop cooling again after a week after defrosting?
This is a sure sign of a malfunction of the automatic defrosting system. Most likely, the evaporator heating element or thermal fuse has burned out. Ice again accumulates on the evaporator and blocks the air supply channels. Replacement of burnt elements is required.
Is it possible to temporarily use the refrigerator if the top does not freeze?
It can be used, but with restrictions. Perishable food in the upper compartment will spoil. In addition, the compressor will work hard trying to reach the set temperature, which can lead to overheating and failure. It is better to minimize the load.
Does the position of the refrigerator affect the cooling of the top?
Yes, if the refrigerator is positioned with a strong slope, the door of the upper chamber may not close tightly due to the geometry of the case, or the oil from the compressor may not circulate properly. The gap at the rear wall is also important for ventilation of the condenser.
What to do if the damper is frozen with ice?
The damper must not be torn off by force - you will break the plastic or the drive. The only way is to completely defrost the refrigerator within 24-48 hours. After this, check whether the damper moves freely. If the problem recurs, change the defrost system.