The situation when the refrigerator Bosch stops starting always takes you by surprise, threatening the safety of food. The owner is faced with silence where there should be the usual hum of the compressor, or, conversely, hears strange clicks without subsequent start. Before calling a technician, it is worth carrying out an initial diagnosis, since often the problem lies in banal things that can be easily fixed on your own.
Modern models, whether classic KGV39 or advanced Series 6 with a system NoFrosthave complex electronic components. However, the basic principles of operation remain unchanged: to start, you need a stable current, a working trigger mechanism and the absence of blockages from the control system. In this article, we will analyze in detail why equipment refuses to work and how to bring it back to life.
Initial check of power supply and external factors
The most obvious, but often ignored reason is the lack of voltage in the outlet. If the refrigerator Bosch does not turn on, the first thing you need to check is whether electricity is supplied to the power cord. Sometimes the problem lies not in the equipment itself, but in a burnt-out light bulb in the socket or a broken circuit breaker in the panel, especially if powerful devices are connected to this line.
Pay attention to the condition of the power cord. Visually inspect it along its entire length for kinks, melts or traces of rodents, which is important for equipment standing on the floor or in the garage. If the cord is damaged, further operation is strictly prohibited to avoid short circuit or fire.
⚠️ Attention: If you smell a burning smell or see sparking in the plug area, immediately unplug the device and do not try to turn it on again until you replace it cord.
It is also worth checking the outlet itself by connecting another device to it, for example, a hair dryer or charger. If other appliances are working, but the refrigerator is silent, then the problem is localized inside the unit body. In rare cases, the internal wiring or terminal block where the power cable fits may fail.
☑️ Power diagnostics
Malfunctions of the starting relay and compressor
If everything is in order with electricity, but the engine does not start, there is a high probability of problems with the starting relay or itself compressor. The relay is responsible for sending an impulse that starts the motor. Models Bosch often use relays such as RT, R-1, R-2 or more modern posistor elements. When they fail, the compressor either hums, but does not start, or makes a quiet click and goes silent.
A characteristic sign of a faulty starting device is a cycle: an attempt to start, a buzz, a shutdown click, and the process repeats after a few minutes. If you touch the compressor at this point, it may be hot, which indicates an overload of the windings. In such a situation, it is necessary to replace the relay, selecting an analogue according to the markings indicated on the part body.
A more serious problem is turn-to-turn short circuit of the compressor windings. This condition is often accompanied by a specific smell of burnt insulation and knocking out plugs when trying to turn on. You can check the integrity of the windings with a multimeter by ringing the motor terminals. If the resistance tends to zero or infinity, the compressor requires replacement.
Sometimes the compressor OK, but mechanically jammed. This happens after long periods of downtime or due to resource exhaustion. Attempts to “unwedge” it by hitting the body with a hammer, as advised in some old manuals, for modern sealed units Bosch are ineffective and dangerous.
Problems with the thermostat and temperature sensors
The refrigerator electronics will not give a command to start the compressor if it does not receive a signal about need for cooling. This is responsible for this in mechanical models thermostat, and in electronically controlled systems - temperature sensors (NTC). If the thermostat is “stuck” in the “off” position or its contacts have oxidized, the compressor power circuit remains open.
In refrigerators Bosch with a display and system MultiAirflow an electronic module that reads readings from several sensors Failure of one of them (for example, the evaporator sensor or the air in the chamber) may block startup. In this case, the malfunction indicator often lights up on the display or the temperature symbol flashes.
To check the mechanical thermostat, you can close its contacts directly. If after this manipulation the refrigerator starts working, it means that the regulator is faulty and requires replacement. However, such experiments cannot be carried out with electronic sensors - this can lead to the control board burning out.
It is also worth considering that some models are equipped with a restart protection function. If you just turned off the refrigerator or there were power surges, the appliance may not start right away. It is necessary to wait 10-15 minutes for the pressure in the system to equalize and the electronics to reset the protection timer.
Failures in the operation of the control module
Modern refrigerators Bosch are controlled by complex electronic boards. Voltage surges in the network, lightning strikes or simply natural wear and tear of components can lead to malfunction control module. In this case, the compressor may be working properly, but the “brain” of the refrigerator does not send a start signal to it.
Signs of a board malfunction may be random blinking of indicators, lack of response to control panel buttons, or, conversely, constant operation of the fans when the compressor is turned off. Sometimes it helps to simply resetting errors by completely de-energizing the device for 15-20 minutes.
⚠️ Attention: Diagnostics and repair of the electronic control board require special knowledge and equipment. Do not try to solder capacitors or change microcircuits without experience, this may make the situation worse.
If the problem persists after a reboot, a module replacement or flashing will most likely be required. In some cases, the capacitors on the board may swell, which can be seen during visual inspection, but it is better to entrust the diagnosis to a service center specialist.
Faults in the NoFrost and defrosting system
In refrigerators with the system NoFrost the start of the compressor may be blocked due to a malfunction of the defrost system. If the evaporator heating element, defrost thermostat or timer (in mechanical models) fails, a coat of ice builds up on the evaporator. The fan stops moving air, and the temperature sensor detects overheating or, conversely, does not see cold, prohibiting the operation of the compressor.
Symptoms of this problem are often extraneous sounds (ice grinding on the fan blades), lack of cold when the engine is running, or a complete stop of the unit with an alarm light on. In some models Bosch if the drainage channel is clogged, water may flow onto the control board, causing a short circuit.
For diagnostics, you need to defrost the refrigerator for 24 hours. If after complete defrosting and drying the equipment started working, then the problem was in the defrosting system or drainage. It is necessary to check the heating element, defrost sensor and wiring integrity.
Why is drainage important?
Clogged drainage hole leads to the fact that water from melted ice does not go into the tray, but accumulates inside the housing. This can cause corrosion of metal parts and short circuit of electrical contacts, which often causes equipment failure.
Diagnostic table of main faults
For the convenience of systematizing problems, we present the main symptoms and probable causes in tabular form. This will help you quickly navigate the nature of the breakdown.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| Buzzes, but does not start, clicks | The starting relay is faulty or the compressor is jammed | Replacing the relay, checking the compressor |
| Complete silence, the light is on | The thermostat or control module is faulty | Thermostat test, board diagnostics |
| Indicators are flashing, no cold | Electronics or sensors failure NoFrost | Error reset, sensor check |
| Burning smell, knocks out automatic machines | Short circuit in the wiring or compressor | Urgent call for a technician, replacement of the wiring |
When you need to call a specialist
Despite the desire to save money, there are situations when independent repairs are not only useless, but also dangerous. If you have detected a freon leak (oily stains around the pipes, chemical smell), no amount of electrical manipulation will start the refrigerator. The system requires sealing, evacuation and charging with refrigerant.
Professional intervention is also necessary if a compressor or electronic module is suspected of malfunctioning. Replacing these components requires special tools and skills. An attempt to replace the compressor yourself without soldering and correct selection of oil will lead to rapid failure of the new part.
⚠️ Attention: Opening the refrigeration circuit (resoldering tubes) without a license and equipment is prohibited by the legislation of many countries due to environmental regulations regulating the release of freon.
In addition, if the refrigerator is on warranty, any independent intervention will void the manufacturer's warranty. In this case, the only correct solution would be to contact an authorized service center Bosch.
What is an inverter compressor?
Modern Bosch models often use inverter motors. They work smoothly, without sudden starts. If such a compressor does not start, the reason most often lies in the inverter board, and not in the motor itself. Diagnostics of such systems is more complicated and requires special testers.
Why does a Bosch refrigerator hum but does not freeze?
If you hear a hum, but there is no cold, the compressor may be idling due to a freon leak or a clogged capillary tube. Also, the cause may be a faulty fan in the NoFrost system, which does not circulate cold air.
Can the refrigerator be used if it has been turned off for a long time?
Yes, but before turning it on after a long period of inactivity (more than a month), the refrigerator must stand in an upright position for at least 4-6 hours. This is necessary so that the oil flows into the compressor, otherwise water hammer and motor breakdown are possible.
What to do if the red temperature indicator lights up?
The red indicator signals an increase in the temperature in the chamber. If the refrigerator does not start, check to see if the door is open tightly or if it is loaded with warm food. If after several hours of operation the indicator does not go off, there may be a sensor malfunction or a refrigerant leak.
How to reset errors on a Bosch refrigerator?
On many models, errors are reset by long pressing the defrost button or a combination of buttons (depending on the model). A universal method is to completely disconnect from the network for 15-20 minutes. However, if the fault is physical, resetting will only temporarily clear the indication.
Why does the refrigerator not turn on after defrosting?
Water from melted ice could get on the electrical contacts, causing a short circuit or oxidation. The defrost sensor could also be faulty. It is necessary to thoroughly dry all accessible components with a hairdryer (cold air) and allow the equipment to dry in a warm room for a day.