A sudden extraneous sound in the operation of household appliances always causes alarm, especially when it comes to such an important unit as Bosch refrigerator. A characteristic click, repeated with a certain frequency or occurring at the moment of startup, can signal either a harmless failure in the control system or a serious breakdown of the motor-compressor. Owners of German equipment are often faced with a situation where the device makes a sound, tries to start, but then goes silent again, leaving food without cooling.
Understanding the nature of this sound is the first step to solving the problem. Bosch Refrigerators equipped with a complex protection and automation system that responds to any deviations in operation electrical network or mechanical components. The clicking sound is essentially the physical action of an electrical relay or trigger trying to apply voltage to the motor. If this is followed by silence or a hum that ends abruptly, it means that the system has detected an obstacle or malfunction.
In this article we will analyze in detail the main reasons why Bosch refrigerator clicksand consider the algorithm of actions for diagnostics. It is important not to ignore these signals, as timely identification of the problem can save the compressor from costly replacement. We will consider both external factors, such as power surges, and internal failures of components.
⚠️ Attention: Before starting any diagnostics or disassembling the refrigerator, be sure to disconnect it from the electrical network. Working with electrical appliances under voltage is dangerous to life and health.
The principle of operation of the starting relay and compressor
To understand the source of the sound, you need to understand the device compressor group. The heart of any refrigerator, including models Bosch Classixx or Bosch Serie 4, is the compressor, which is a sealed electric motor. To start this engine, a short-term current pulse is required, which is supplied through a special device - a starting relay. It is this element that most often produces a characteristic click.
When the refrigerator is turned on to the network or when trying to start after stopping the thermostat, the relay closes the contacts. If the startup is successful, the relay opens the starting winding, which is also accompanied by a sound. However, if the engine fails to start due to a seizure or low voltage, the relay will re-activate after a certain period of time, creating a cyclic knocking noise. This is a protective mechanism that prevents the windings from burning out.
Start relay performs a critical function: it connects the motor starting winding only while the rotor is accelerating. Modern models Bosch often use PTC-type relays (posistors), which operate silently, but classic electromagnetic relays make a distinct click when switching. Understanding this process helps distinguish normal operation from an emergency situation.
Technical details of relay operation
In electromagnetic relays, current passes through a coil, creating a magnetic field that draws in the core and closes the contacts. In posistor (PTC) starters, current passes through a ceramic element, which heats up and changes its resistance, opening the circuit. PTC resistors are considered more reliable, but they can also fail, losing their properties.
Main causes of clicks and startup failures
If Bosch refrigerator clicks and does not turn on, or the clicks become too frequent, this indicates specific malfunctions. There are several basic scenarios, each of which requires a different approach to repair. Diagnostics begins with an analysis of the frequency of sounds and the behavior of indicators on the control panel.
The most common reason is the failure of itself start relay. The contacts inside it could be burnt or stuck, which does not allow the necessary impulse to be transmitted to the engine. In this case, the relay clicks in an attempt to start the engine, but the circuit does not close properly. Replacing this component often solves the problem if the compressor itself is working.
Another serious cause is a malfunction thermostat or electronic control module. If the temperature sensor transmits incorrect data about the state inside the chamber, the controller can give a command to start the compressor at the wrong time or, conversely, block its operation, causing chaotic relay clicks. In models with the system No Frost the defrost sensor may also malfunction.
- 🔌 Surges voltage: Sudden changes in the power supply can lead to the protective relay constantly tripping, turning off the compressor.
- 🧊 Icing: Ice on the evaporator or in the condensate drainage channel can create mechanical resistance or disrupt the operation of the sensors.
- 🔩 Compressor stuck: Mechanical failure inside the motor when the piston group cannot turn, causing a hum and subsequent click of the protection.
⚠️ Attention: If you hear a loud metallic clanging or knocking sound immediately after the click, stop trying to turn on immediately. This may indicate destruction of the internal parts of the compressor, and further operation will lead to complete failure of the unit.
Diagnostics of the starting relay and electrical circuit
Checking start relay is the first step that you can do yourself if you have basic skills and tools. The relay is usually located in a niche on the back wall of the refrigerator, next to the compressor. To access it, you will need to remove the protective cover and carefully disconnect the wires.
Visual inspection allows you to identify obvious signs of a malfunction: blackened contacts, melted plastic or a burning smell. If the relay looks intact on the outside, you can check it with a multimeter. In the “bell” position, a serviceable electromagnetic relay should show the circuit is closed in a certain position, and a posistor should show resistance, which changes when heated. However, the most accurate result is obtained by replacing it with a known-good analogue.
When diagnosing, you should also check the integrity of the supply wires. Oxidation of the contacts in the connector between the relay and the compressor can create high contact resistance, which is why the engine does not receive enough power to start. Cleaning the contacts and treating them with a special lubricant often eliminates the problem of unstable starting.
☑️ Checking the start relay
It is worth noting that Bosch refrigerator relay can be integrated into the common control board in some modern inverter models. In such cases, diagnosis requires special knowledge and equipment. If you are not confident in your abilities, it is better to contact specialists, since incorrect replacement can damage an expensive electronic module.
Problems with the compressor and motor
The most expensive and unpleasant cause of clicking is a malfunction of the motor itself compressor. If the relay is working properly and supplies voltage, but the engine only hums and clicks without starting, there may be a break in the starting winding or an interturn short circuit. In such a situation, the current in the winding increases sharply, which triggers the thermal protection relay, which makes a click, breaking the circuit.
Mechanical wear also plays a role. Over time, the rubbing parts inside the compressor wear out, and the oil loses its properties or thickens. When trying to start, the piston group may jam. Sometimes “wedging” the compressor by applying increased voltage helps, but this procedure should only be carried out by professionals, since the risk of completely killing the motor is very high.
Inverter compressors, which are installed in premium models Bosch, operate on a different principle and do not have a classic start relay. Clicks in them can be produced by solenoids or elements of the inverter board. Diagnostics of such systems requires connecting to the service connector and reading error codes, which cannot be done without special software.
| Symptom | Probable cause | Required actions |
|---|---|---|
| Single click, then silence | Faulty relay or winding | Replacing the start relay |
| Frequent clicks every 10-20 seconds | Thermal protection tripped | Checking the compressor and voltage |
| Clicking and buzzing | Compressor jammed | Call a technician, possible motor replacement |
| Clicks without attempts to start | Electronics failure or thermostat | Diagnostics of the control module |
The influence of voltage drops and network stability
The quality of electricity in our networks often leaves much to be desired, and Bosch refrigeratorsas sensitive equipment, they are the first to respond to anomalies. If the mains voltage drops below the permissible limit (usually 190-200 Volts), the compressor cannot develop the necessary power to start. The starting relay is triggered, the engine tries to turn over, but due to lack of current it stops, and the relay opens the circuit again with a characteristic click.
Constant operation in low voltage conditions is extremely harmful to the motor windings. They heat up and the insulation is destroyed, leading to a short circuit. Therefore, if you notice that the refrigerator clicks it is during peak network load hours (in the evening, when neighbors turn on powerful appliances), this is an alarming signal.
To protect expensive equipment, it is recommended to use a voltage stabilizer or voltage control relay. These devices cut off power when parameters go beyond safe limits and resume operation only after the situation has returned to normal. This simple solution can extend the life of the compressor for several years.
⚠️ Attention: Using conventional surge protectors (extension cords with a button) does not protect the refrigerator from power surges. For correct operation, it is necessary to install a specialized stabilizer with a power reserve.
The role of the thermostat and temperature sensors
The thermostat (or temperature sensor in electronic models) is the “brain” that decides when to turn on the cooling. If this element is faulty, it may send erratic signals to turn on and off. As a result, compressor relay begins to click frequently, trying to execute the command, although the temperature in the chamber has not yet risen to the desired level.
In mechanical thermostats, the problem may be a weakening of the bellows tube or a leak in the capillary. In electronic systems Bosch thermistors themselves often fail. Their resistance changes nonlinearly, which confuses the controller. Replacing the sensor is a simple procedure, but it requires selecting an element with similar characteristics.
It is also worth checking the settings. If you accidentally set the "Super Freeze" mode or the minimum temperature, the refrigerator will work almost non-stop, and the clicking sounds will only mean regular on/off cycles in an attempt to achieve an unattainable ideal. Resetting settings to factory settings often helps eliminate a software glitch.
When professional repairs are needed
Despite the desire to save money and get it done do-it-yourself repair, there are situations where the intervention of an unqualified user can only cause harm. If diagnostics have shown that the problem lies in a sealed circuit, freon leakage or mechanical destruction of the compressor, you cannot do without special equipment and skills.
Masters use vacuum pumps to remove moisture and air from the system, manometric manifolds to control pressure and scales for accurate filling refrigerant. An independent attempt to replace the compressor or solder the tube without evacuation will lead to the fact that the system will quickly become clogged with moisture and acid formed during oil combustion, and the new motor will burn out in a few months.
In addition, modern refrigerators Bosch often require reflashing the control module after replacing components. Without service software and an adapter, new spare parts may not work correctly. Therefore, if you have exhausted simple methods (checking the socket, relay, thermostat), it is better to call a specialist.
Is it worth replacing the compressor?
Replacing a compressor is an expensive procedure, the cost of which can be up to 70% of the price of a new refrigerator. If your unit is more than 10 years old, it is often more economically feasible to purchase a new model that will be more energy efficient and quieter.
Prevention and care of the refrigerator
To avoid situations when the refrigerator clicks and stops freezing, it is important to follow the operating rules. Regular defrosting (for drip systems), cleaning the condenser from dust and ensuring a gap between the back wall and the furniture for ventilation will help the compressor operate in a gentle mode.
Make sure that the door seals are tightly sealed. If the rubber has dried out and allows heat to pass through, the compressor will be forced to work almost non-stop, trying to compensate for the heat gain. This leads to overheating and accelerated wear of the starting equipment. The seals can be checked using a sheet of paper: it should be tightly clamped by the door around the entire perimeter.
Timely maintenance and attention to the first signs of malfunction are the key to the long service of your equipment. Do not ignore changes in operating sound, condensation on external walls, or increased frequency of power cycles. These little things help prevent a major breakdown.
Why does the refrigerator click but does not freeze?
This is a classic symptom of a faulty start relay or compressor. The relay tries to start the motor (clicking), but the motor does not start due to a breakdown, so cooling does not occur. Diagnostics of the compressor group is required.
Is it possible to operate the refrigerator if it clicks?
For a short time - it is possible, but not recommended. Frequent clicks mean that the compressor is operating in emergency mode, overheating and may burn out completely. It is better to turn off the device until the reasons are determined.
How much does it cost to replace the starting relay with Bosch?
The cost of the relay itself is low (usually from 500 to 2000 rubles, depending on the model), but the price of the technician’s work may be higher than the cost of the part. Replacing it yourself saves the budget if you have the skills.
Is it dangerous if the refrigerator hums and clicks?
Yes, this indicates that the motor is trying to start, but cannot. This creates a high load on the network and the engine itself. Leaving the device in this state for a long time is dangerous due to fire due to overheating of the wiring.