Owners of high-quality German equipment are often faced with a situation when Bosch refrigerator no longer maintains the set temperature. This can manifest itself either in the complete absence of cold or in insufficient cooling of food in the main chamber or freezer. Ignoring initial signs of malfunction often leads to damage to a large supply of food and requires more expensive repairs later.
Modern models, be it NoFrost or a classic drip system, are a complex unit where the failure of one element disrupts the operation of the entire chain. Most often, the problem lies not in a breakdown of the electronics, but in a banal refrigerant leak or a stuck thermostat. Understanding the principles of operation of the compressor and the heat removal system will help you quickly diagnose the problem.
In this article we will analyze in detail the main reasons why Bosch refrigerator does not freeze welland determine what steps you can take on your own and when you need to call a technician. It is important not to panic, but to consistently check each link of the system, starting from the simplest settings.
Errors in operation and temperature settings
Before suspecting a serious breakdown, it is necessary to exclude the human factor. Often, users accidentally change the settings or overload the camera, which interferes with normal air circulation. In models with a system NoFrost this is especially critical, since air flows must freely wash all products.
Check the position of the temperature regulator. If it is set to the minimum value, the compressor may not be able to cope with the load during the hot season. It is also worth paying attention to the density of the load: if the products lie close to the back wall or block the ventilation holes, the cold will not be distributed evenly.
⚠️ Attention: Leaving the door open for a long time or a loose seal will lead to freezing of the evaporator and stopping the cooling cycle. Check the cleanliness of the sealing gum.
Another common reason is the placement of hot or warm products inside the chamber. Thermostat records a sharp jump in temperature and causes the compressor to wear out, but the unit cannot quickly cool a large volume of heat. This creates the illusion of a breakdown, although the equipment simply works in extreme mode.
Problems with tightness and refrigerant leakage
One of the most common technical reasons why Bosch refrigerator stopped freezing is a freon leak. The refrigerant circulates in a closed circuit, and if a microcrack forms in the tubes or condenser, the gas gradually evaporates. Without a sufficient amount of freon, heat exchange is impossible, and the temperature inside the chambers begins to rise.
Leakage can occur due to metal corrosion, mechanical damage during transportation, or manufacturing defects in welds. It is difficult to visually notice a leak, since freon is colorless and odorless. However, an indirect sign may be swelling of the chamber wall or the appearance of oily spots near the compressor.
If you suspect a leak, under no circumstances try to refill the refrigerator yourself without looking for the location of the damage. Refilling freon without eliminating the leak will only have a short-term effect, after which the gas will come out again. Professional diagnostics are required using a leak detector.
Symptoms of a lack of refrigerant often appear unevenly: the freezer may still freeze, but it is already warm in the main chamber. Or the compressor works almost non-stop, trying to gain temperature, but does not turn off.
Faults of the compressor and start relay
The compressor is the heart of the refrigeration unit, ensuring the circulation of the refrigerant. If compressor is faulty, the cold will not be produced at all. Bosch refrigerators can use both conventional piston and quieter inverter motors, each of which has its own diagnostic features.
A frequent problem is the failure of the start relay. This small element is responsible for starting the engine. If the relay is burned out, you can hear a characteristic click, after which the compressor hums for a few seconds and goes silent. After some time, the cycle repeats. This is a clear sign that the motor cannot start.
- 🔥 The compressor gets very hot and does not start - the winding is probably burned out or the piston is jammed.
- 🔇 Complete absence of sounds from the motor when the lights are on - a problem in the electronics or wiring.
- ⚡ Frequent switching on and turning off with clicks - a malfunction of the start-up relay.
In the case of inverter models, diagnostics are more complicated, since motor starting is controlled by a special module. An error in the operation of the inverter can simulate a breakdown of the compressor itself. To accurately determine the malfunction, you need to measure the resistance of the windings and check the input voltage.
Is it possible to replace the compressor yourself?
Replacing a compressor is a complex procedure that requires evacuation of the system, soldering of tubes and precise filling with freon. Without special equipment and skills, it is impossible to perform this work efficiently. An attempt to replace it yourself will result in damage to the new compressor and loss of warranty.
Failures in the operation of the defrost system (for NoFrost models)
In refrigerators with the system NoFrost the automatic defrost system plays a critical role. It consists of a heating element (heater), a defrost sensor and a timer or electronic control module. If any of these elements fails, a coat of ice begins to grow on the evaporator.
Ice blocks the channels through which cold air should enter the chambers. As a result, the fan hums, but there is no airflow. The products stop cooling, although the evaporator itself may be covered with a thick layer of ice. This is a classic situation when the refrigerator hums, but does not freeze.
To check, you need to dismantle the back panel in the freezer and visually assess the condition of the evaporator. If it is completely or partially covered with ice, the problem lies in the defrost circuit. Most often, the heating element itself burns out or the sensor sticks, not giving a command to turn on the heating.
☑️ Diagnostics of the NoFrost system
It is important to regularly monitor the cleanliness of the drainage hole, which drains water after the ice melts. If it is clogged with dirt or mold, water will accumulate at the bottom and freeze, forming an ice plug, which will also disrupt the operation of the system.
Diagnostics of temperature sensors and thermostat
Temperature sensors and mechanical or electronic thermostats are responsible for maintaining the set temperature. If thermostat is faulty, it may not send a signal to turn on the compressor, even when the chamber becomes warm. As a result, the food is defrosted, and the equipment is idle.
Modern Bosch models use several sensors: in the main chamber, in the freezer, on the evaporator. Failure of any of them can lead to incorrect operation of the control algorithms. The electronics receive incorrect data and either do not turn on the cooling or freeze until it stops, turning the chamber into a glacier.
Diagnostics of the sensors is carried out using a multimeter, measuring their resistance at different temperatures. The values must correspond to the specifications of the specific model. A scatter of readings indicates the need to replace the element.
| Element | Fault symptom | Check method |
|---|---|---|
| Thermostat | The compressor does not turn on | Closing contacts manually |
| Air sensor | Incorrect temperature on the display | Resistance measurement |
| Defrost sensor | Ice build-up on the evaporator | Continuity in warm/cold state |
| Defrost heating element | The ice does not melt, there is no cold | Resistance measurement (should be normal) |
Sometimes the problem lies not in the sensor itself, but in oxidation of the contacts or a break in the wiring going to it. Vibration during compressor operation can over time disrupt the connection in the connectors.
Clogged capillary tube and filter drier
The capillary tube is a very thin channel through which the refrigerant enters the evaporator. Due to its small diameter, it is sensitive to contamination. A blockage may form in the system caused by oil oxidation products, moisture or solder residues after poor-quality past repairs.
If formed clogging, the circulation of freon stops or becomes very difficult. The compressor tries to push gas, working with overload, but the cooling capacity drops to zero. A characteristic sign is a hot condenser (grid at the back) and a cold or room temperature evaporator.
Often, along with a clogged capillary, the filter-drier fails, which traps moisture and debris. If the filter is clogged, it creates additional resistance to flow. In such cases, it is necessary to purge the system with nitrogen and replace the filter.
⚠️ Attention: Purging the system requires the use of professional equipment (nitrogen cylinder, reducer, burner). Independent attempts to clean the tube using improvised means can lead to rupture of the circuit or damage to the compressor.
The influence of the environment and installation conditions
Brand equipment Bosch is sensitive to operating conditions. If the refrigerator is installed close to the wall or in a niche without gaps for ventilation, heat exchange is disrupted. The condenser does not have time to cool, the pressure in the system increases, and the operating efficiency decreases.
It is also important to take into account the climate class of the device. If a refrigerator designed for a temperate climate (SN, N) is installed in an unheated room at a temperature below +10°C or in a kitchen where it is hotter than +32°C (class ST, T), the thermostat may not work correctly. In cold weather, the oil in the compressor thickens, and in hot weather, the system cannot cope with heat transfer.
Direct sunlight falling on the housing, especially on dark models, also heats up the unit, forcing the compressor to work in increased mode. This is not a breakdown, but leads to increased wear and deterioration in the quality of freezing.
When you need to call a technician
There are a number of situations when self-repair is not only ineffective, but also dangerous. If you have checked the settings, defrosted the unit, made sure that the seal is intact, but the problem has not disappeared, then most likely, specialist intervention is required.
This is especially true for work related to a sealed circuit. Replacing a compressor, searching for leaks, evacuation and refilling with freon require a license, special tools and experience. An error at any stage can completely disable the equipment.
The technician will also be able to accurately diagnose the electronic control module, which in modern Bosch models is a complex computer. It is almost impossible to fix software failures or burnout of tracks on the board yourself.
Why does a Bosch refrigerator work normally, but the freezer does not freeze?
Most often this indicates a freon leak or a clogged capillary system. In such cases, there is only enough refrigerant for the main circuit or it does not reach the evaporator of the freezer. There may also be a malfunction of the damper that regulates the flow of cold air between the chambers.
How long should the refrigerator cool down after defrosting?
After complete defrosting (at least 24 hours without power), the refrigerator requires 2 to 4 hours of operation to reach operating temperature. It is recommended to load products in full only after the temperature has stabilized.
Can a power surge damage the compressor?
Yes, modern inverter compressors are sensitive to voltage changes in the network. The surge may damage the control module or motor windings. For protection, it is recommended to use a voltage stabilizer or surge protector.
What to do if there is a burning smell inside?
Immediately unplug the refrigerator. A burning smell may indicate overheating of the wiring, melted insulation, or a compressor malfunction. Operating such a device is a fire hazard. An inspection of the electrical part by a technician is required.
Is it true that Bosch refrigerators defrost themselves?
Models with the NoFrost system defrost the evaporator automatically during the defrost cycle; there is no need to collect water. Models with a drip system (crying wall) also drain water into the drainage, but the freezer (if it is not NoFrost) must be defrosted manually 1-2 times a year.