The situation when a Bosch refrigerator stops freezing always takes you by surprise, threatening food damage and requiring immediate intervention. The owner immediately notices that the chamber has become warmer, the ice in the freezer has begun to melt, and the food has lost its freshness or has begun to defrost. This is a critical moment when it is important not to panic, but to correctly assess the scale of the problem in order to understand whether the problem can be fixed on your own or whether you need to call a technician.
Often the cause is a simple lack of defrosting, contamination of the radiator, or a failure in settings that are easy to fix. However, in some cases, equipment failure indicates serious breakdowns compressor, refrigerant leakage or failure of electronics. In this article, we will analyze in detail the main reasons why your unit has stopped gaining cold, and we will suggest an algorithm of action.
The first thing you need to do is listen to the operation of the motor. If it hums normally, but there is no cold, the problem may be in the circulation of freon. If the motor is silent or, conversely, hums too loudly and immediately turns off, these are signs of electrical or mechanical failure. Understanding these nuances will help you save time and money during diagnostics.
Checking settings and operating mode
Before looking for hidden breakdowns, make sure that the equipment has not switched to a special mode. Often, users accidentally touch the control panel, activating the function SuperCool or the “Vacation” mode, which changes the algorithm of the compressor. In some models with electronic control, the controller may have failed, which reset the settings to factory settings or, conversely, blocked the cooling.
Pay attention to the room temperature. If the refrigerator is placed near a radiator or in direct sunlight, it may overheat. In such conditions thermostat does not give a command to turn on the compressor, because it “thinks” that it is already cold enough inside, or the protection system blocks the start to avoid overheating of the engine.
It is also worth checking whether the refrigerator is loaded too tightly. If food blocks the vents, cool air cannot circulate through the compartment. In models with the system NoFrost this is especially critical, since a violation of airflow leads to local overheating of the evaporator and cooling stops.
⚠️ Attention: If you notice that the Bosch refrigerator does not freeze after defrosting, wait 4-6 hours before turning it on. Starting the compressor with residual moisture in the system can lead to water hammer and serious damage.
Problems with the NoFrost defrosting system
Modern Bosch models are often equipped with a system NoFrostthat prevents the formation of ice. However, this system is a common cause of cooling failure. If Defrost heating elementburns out, the timer breaks or the defrost sensor fails, a “coat” of ice grows on the evaporator. This ice blocks the operation of the fan, and the cold stops flowing into the chamber.
Visually this can manifest itself as follows: the motor is running, the fan is humming, but no air flows. After some time, the compressor may overheat and turn off via the thermal relay. In such cases, it is necessary to completely defrost the refrigerator within 24 hours (at least 24 hours) with the doors open.
☑️ Diagnostics of the NoFrost system
If after defrosting the refrigerator started working, but a week later the problem recurred, it means that one of the elements of the defrost system is faulty and requires replacement. Most often in Bosch it is the sensors or the heating element itself that fail.
Refrigerant leak and problems with freon
One of the most unpleasant reasons for the lack of cold is a freon leak. The refrigerant circulates in a closed circuit, and if a micro-hole is formed somewhere (due to corrosion or mechanical damage), the gas escapes. Without enough freon, the compressor runs wasted, moving air but not creating cold.
Signs of a leak often appear gradually. First, the refrigerator begins to freeze worse, the compressor works non-stop, trying to compensate for the lack of cold. Then, swellings or, conversely, areas without frost may appear on the back wall. Ultimately, the equipment simply stops freezing at all.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| The compressor is hot, but does not freeze | Freon leak or blockage | Call a technician to find a leak |
| The refrigerator is silent | Faulty electronics or start relay | Checking voltage and relays |
| Ice only at the entrance of the tubes | Partial leakage or blockage of the capillary | System diagnostics |
| Frost along the entire rear wall | Normal operation or leakage | Observation or check of the seal |
It is impossible to eliminate the leak on your own, since special equipment is required for evacuation of the system and filling with freon. Attempts to simply “add” freon without eliminating the leak will only give a short-term effect. Professional soldering and sealing of the circuit is required.
Faults of the compressor and start relay
The compressor is the “heart” of the Bosch refrigerator. If it is faulty, there will be no cooling. Often the problem lies not in the motor itself, but in start relaythat supplies current to it. If the relay is burned out, the compressor hums and clicks, but cannot start. After some time, the thermal protection is triggered and a shutdown click is heard.
If the compressor works, but does not create pressure (does not pump), this indicates an interturn short circuit of the winding or mechanical wear of the piston group. In such cases, a characteristic metallic knock or hum is heard. Replacing a compressor is a complex procedure that requires a skilled technician.
How to check the start relay?
Remove the relay from the compressor contacts (after first disconnecting the refrigerator from the network). Shake it: if you hear a ringing or knocking sound inside, the core is broken and the relay must be replaced. You can also test the contacts with a multimeter.
It is important to note that frequent power surges in the network could lead to failure of the compressor control electronics, especially in models with inverter motors. In this case, the engine may not start at all, although visually it appears to be working.
Failure of the thermostat or temperature sensors
The thermostat (or temperature sensor in electronic models) tells the control unit when to turn on the cooling and when to turn it off. If this element “lies” and shows that it is already -20°C in the chamber, the compressor simply will not receive the command to start. The refrigerator will remain turned off until the food spoils.
In mechanical Bosch models, the thermostat is a capillary tube that may lose its seal. In electronic models, this is responsible for sensors that can oxidize or break. Diagnostics is carried out using a multimeter: when the temperature changes, the resistance of the sensor should change.
- ❄️ The sensor shows an open circuit - the element needs to be replaced.
- ❄️ The resistance does not change when heating/cooling - the sensor is faulty.
- ❄️ The thermostat contacts are stuck - cleaning or replacement is necessary.
Replacing the thermostat is one of the simplest and most inexpensive repair procedures. Often, after installing a new sensor, the refrigerator begins to work like new, effectively maintaining the set temperature.
Clogged capillary tube
In the freon circulation system there is a narrow section - a capillary tube. Over time, blockages may form in it due to oil oxidation products or moisture entering the circuit. This creates a plug that prevents freon from circulating. The pressure at the outlet of the compressor increases, and at the inlet it drops, and cooling stops.
Symptoms of a blockage are similar to a leak: the compressor runs for a long time and heats up, but there is little cold. Often, at the site of the blockage (usually before entering the evaporator), you can notice swelling of the filter-drier or the absence of frost in a certain section of the tube.
⚠️ Attention: Cleaning the capillary tube requires purging with nitrogen under high pressure and replacing the filter-drier. At home, this operation is almost impossible to perform efficiently.
If the problem is a blockage, the technician will have to open the system, blow it out, change the filter and refill the refrigerator. Ignoring this problem will lead to overload and eventual combustion of the compressor.
When an urgent call is necessary masters
There are situations when independent repairs are not only useless, but also dangerous. If you hear a burning smell, see sparking, or feel electric current flowing through the housing, immediately unplug the appliance. Also, do not hesitate if the Bosch refrigerator has not frozen for more than a day, and food begins to deteriorate.
Professional diagnostics allows you to accurately determine the unit that has failed. The technician uses pressure gauges to check pressure, leak detectors to look for leaks, and testers to check electronics. This ensures that you will not change serviceable parts at random.
Regular maintenance and timely defrosting prolong the life of the equipment. However, if a breakdown has already occurred, a correct and quick repair will give your Bosch refrigerator a second life and keep your food fresh.
Why does a Bosch refrigerator hum, but does not freeze?
If the motor hums, but there is no cold, most likely the problem is a freon leak, a clogged capillary system or a compressor malfunction (it hums, but does not shakes). It is also possible that the start relay may become stuck.
How long should defrosting last?
The NoFrost system and evaporator require a minimum of 24 hours to completely defrost. A shorter defrosting may not melt the ice plug in hard-to-reach places.
Is it possible to use a refrigerator if it does not freeze?
For a short time - yes, if the food does not spoil. But long-term operation in this mode (especially with a faulty compressor or leak) can lead to the final failure of the equipment and a fire hazard.
Why is it warm in the Bosch refrigerator, but cold in the freezer?
This is a classic sign of a malfunction of the NoFrost system (the air supply channel is frozen), a fan failure or a freon leak when there is a supply There is only enough cold for the freezer.