The situation when your Bosch refrigerator suddenly stops freezing always takes you by surprise. It may be warm inside the chambers, food begins to spoil, and an alarm indicator lights up on the display or in the corner of the freezer. In this case, there is no need to panic, since modern units of the German brand have a reliable design, and often the problem is solved without calling a technician.
The first thing that needs to be done is to carry out an initial visual diagnosis and understand the scale of the problem. Is only one chamber freezing or is it warm throughout? Can you hear the sound of a running engine or is there deathly silence? The answers to these questions will help you narrow down the range of possible malfunctions and determine whether you can cope with the breakdown yourself or whether components will need to be replaced.
In this article we will analyze in detail the main reasons for the failure of the cooling system, algorithms for checking electronic components and mechanical parts. It is important to understandthat ignoring the first signs of a malfunction can lead to more expensive repairs, so you need to act promptly and consistently.
Primary diagnosis and simple causes
Before disassembling the back panel or delving into the depths of the compressor compartment, it is worth eliminating trivial but common causes. Sometimes The Bosch refrigerator does not freeze due to the fact that the door was not closed tightly or the operating mode was violated. Check to see if a foreign object is stuck in the seal, and make sure that the appliance is level.
Particular attention should be paid to the NoFrost system, if it is present in your model. If the evaporator is covered with a thick “coat” of ice, the fan may simply not cope with air circulation. In this case, the unit requires complete defrosting during the day with the doors open.
⚠️ Attention: Do not try to chip the ice with a knife or sharp objects. Damage to the evaporator tubes will lead to an immediate release of refrigerant and will require complex factory repairs with soldering.
Also check the temperature settings. Accidental pressing of buttons by children or with wet hands could reset the settings to “minimum” or enable the “Vacation” mode. The normal operation indicator should be lit on the display or regulator inside the chamber.
Malfunctions of the NoFrost defrosting system
If the refrigerator is working, the compressor is humming, but the cold does not enter the chambers, most likely the problem lies in the defrosting system. In models Bosch with NoFrost technology, ice freezes on a hidden evaporator, and if the mechanism for removing this ice breaks, the air channels are blocked.
The main elements of this system are a heating element (heater), a defrost sensor and a timer or electronic control module. If the heating element burns out, the ice does not melt and turns into a monolithic block. The sensor, in turn, may “stick” and not give a command to turn on the heating, even if there is ice.
- 🔥 Defrost heating element: most often it burns out due to scale or aging of the nichrome thread, requires testing with a multimeter.
- 🌡️ Defrost sensor: thermostatic element, which should open the circuit when a certain temperature is reached; often fails.
- ⏱️ Timer or board: controls operating cycles; if the electronics fail, the refrigerator “forgets” when to turn on defrosting.
To check these elements, you will need a multimeter. You need to get to the evaporator by removing the back panel in the freezer. Resistance The heating element should be within normal limits (usually 200-400 Ohms), and the sensor should “ring” at room temperature and open the circuit when cooling.
☑️ Diagnostics of the NoFrost system
Problems with the compressor and start relay
The compressor is the heart of the refrigerator. If Bosch refrigerator it is silent or makes short clicks, but does not start, the problem may be in the start relay or the motor itself. The relay is responsible for supplying voltage to the motor windings at the time of start.
A situation often occurs when the relay “sticks” or burns out. This is an inexpensive part that you can replace yourself. However, if there is a loud click when you turn it on, the motor tries to start, hums for a few seconds and turns off - this is a bad sign. This is how a compressor behaves with an interturn short circuit or a jammed mechanism.
| Symptom | Probable cause | Action |
|---|---|---|
| Silence, no reaction | Relay malfunction or wiring | Replacing the start relay |
| Humming and clicking | Compressor jammed | Call a technician, replace the motor |
| Hot motor housing | Overload or breakdown | Diagnostics of windings |
If you find that the compressor housing is hot to the point where it is impossible to touch it, immediately disconnect the device from the network. Operation in this mode is a fire hazard and will finally kill the engine.
Is it possible to knock on the compressor?
There is a “folk” method of resuscitating a jammed compressor with light blows of a hammer. However, in modern Bosch inverter models this is strictly prohibited and will lead to destruction of parts.
Refrigerant leak and capillary blockage
If the motor runs continuously without turning off, hums, but there is no cold or it is very weak, most likely, the circulation of freon in the system is impaired. In Bosch refrigerators this may be a leak or blockage of the capillary tube.
Leakage often occurs in the foamed part of the case or in the places where the circuit is soldered. Finding the location of a leak visually is almost impossible without special equipment (leak detector). A characteristic sign is swelling of the inner wall of the freezer or the appearance of oily spots under the unit.
Clogging of the capillary tube occurs due to moisture or oil breakdown products entering the system. In this case, the filter drier turns black, and the tube after the compressor may be hot, while the evaporator remains only partially cold or does not get cold at all.
⚠️ Attention: Self-charging with freon is impossible without a vacuum pump and scales. An attempt to simply “add gas” will lead to mixing of refrigerants and final breakdown of the compressor.
Repair in this case involves finding a leak, overcooking the circuit (or installing a sealed evaporator), replacing the filter and evacuating the system. This is a complex technical procedure that requires qualifications.
Failure of the electronic control module
Modern models Bosch are stuffed with electronics. If all the mechanical parts are in good working order, but the unit behaves inappropriately (turns off spontaneously, does not maintain temperature, the display is glitchy), the control board is to blame.
Elements on the board could have burned out due to a voltage surge in the network or simply from old age. Often the contacts oxidize or the relay solder “falls off”. In some cases, flashing helps, but more often replacement of the module or individual radio elements is required.
- 💡 Indication: flashing lights or error codes (for example, E01, E09) directly indicate an electronic failure.
- 🔌 Voltage surges: the main reason for the failure of control units, requires installation stabilizer.
- 🧊 Condensation: moisture getting on the board during the shadow of ice causes a short circuit of the tracks.
Diagnosing the module often requires connecting special test equipment. At home, you can only visually inspect the board for burning, swelling of capacitors or signs of corrosion.
Malfunction of the thermostat or air sensor
In older models, a mechanical thermostat is responsible for the temperature, in new ones - air sensors (thermistors). If the refrigerator does not freezeperhaps the sensor is “lying” to the control module, reporting that it is already too cold inside.
The mechanical thermostat is checked by checking the contacts. When the temperature changes, the rod must close or open the circuit. If the contacts are stuck open, the compressor simply will not receive a command to start.
Air sensors are thermal resistances. Their resistance changes depending on temperature. The test is carried out with a multimeter in resistance measurement mode (Ohm) at different ambient temperatures. A discrepancy with the table of values means the need for replacement.
⚠️ Attention: When replacing sensors, it is important to use original spare parts or complete analogues. Installing an unsuitable resistor will lead to incorrect operation of the entire cooling cycle.
Replacing these elements usually does not take much time and does not require complex tools. The main thing is to correctly install the new sensor in the seat so that it correctly reads the air temperature in the chamber.
Frequently asked questions (FAQ)
Why a refrigerator Bosch hums, but does not freeze?
This may indicate a freon leak, a clogged capillary system, or a malfunction of the compressor that is running idle. It is also possible that the evaporator is frozen, blocking the air flow.
How long should defrosting take?
To fully and efficiently defrost the NoFrost system, it is recommended to leave the refrigerator turned off with the doors open for at least 24 hours. A shorter procedure may not melt the ice in the hidden channels.
Is it possible to use a refrigerator if it does not freeze well?
It is not recommended to operate the equipment in this mode. The compressor will work hard, trying to gain temperature, which will lead to its rapid combustion. Products can also spoil.
What does a flashing temperature indicator mean?
Flashing indicates that the temperature in the chamber has risen above the permissible limit. This may be a consequence of a recent loading of warm products, a door that is not tightly closed, or a technical malfunction.
Do you need to call a technician to replace the heating element?
If you have the skills to work with a multimeter and a screwdriver, you can replace the heating element yourself. However, if disassembly of a complex pipe system or soldering is required, it is better to contact a professional.