The situation when the refrigerator clicksbut does not start or makes strange sounds during operation is familiar to many owners of household appliances. This sound can be barely noticeable or loud, frightening, reminiscent of electric shocks or mechanical knocking. Most often, the problem lies in the electrical part of the unit, namely in the engine starting system.
Ignoring such symptoms can lead to serious consequences, including failure of compressor the most expensive component of the refrigerator. It is important to correctly classify the sound: is it a single click before starting, a series of quick clicks, or a rhythmic knocking while the engine is running. The repair method depends on the accuracy of the determination.
In this article we will analyze in detail the design of the starting mechanism, the causes of malfunctions and how to fix them with your own hands or with the help of a specialist. You will learn how to distinguish normal thermostat operation from an alarm signal and when it is required immediate replacement of the starting relay to avoid burnout of the motor windings.
The design of the starting relay and the principle of its operation
The main source of the characteristic click in most models of refrigerators is starting relay. This is an electromechanical switch that supplies voltage to the compressor starting winding only at the moment of starting. As soon as the motor rotor reaches the required speed, the relay opens the circuit and the motor continues to operate on the main winding. It is the moment the circuit opens that is accompanied by a sound effect.
In older models, relays with a posistor or an electromagnetic principle of operation are often found. Inside the housing there is a coil and a movable core. When current is applied, the core retracts, closing the contacts. If the engine does not start, the current in the circuit increases, which leads to the protection being activated again and a new click. Modern inverter models are designed differently, but classic single-phase compressors work exactly according to this scheme.
⚠️ Attention: Residual voltage may remain inside the starting relay even after the refrigerator is disconnected from the network. Before opening the case, be sure to wait until the capacitors have discharged or use an insulated tool.
Understanding how it works start-up protection devicehelps you find the problem faster. If the clicks are repeated at a certain frequency (for example, every 10-15 seconds), this means that the system is trying to start the engine, but is encountering an obstacle. The protection is triggered, opening the circuit, then cools down and tries again.
Relay operating diagram
Inside the relay body there is a bimetallic plate or electromagnetic coil. When voltage is applied, the contacts close, starting the engine. If the current exceeds the norm (the motor is jammed), the plate heats up and opens the circuit, producing a click.
Main causes of clicking when starting the refrigerator
If you hear a click, followed by a hum, and then silence and a second click after a while, the problem is systemic. The most likely reason is a malfunction of start relayitself. The contacts inside could be burned, oxidized, or stuck, causing them to be unable to keep the circuit closed long enough to start the motor.
The second common cause is turn-to-turn short circuit in the compressor windings. In this case, the engine tries to start, hums, but cannot turn the shaft due to a violation of the electromagnetic field. The thermal relay detects an overcurrent and turns off the power in an emergency, which is accompanied by a sound. This is a more serious breakdown, often requiring replacement of the entire unit.
- 🔌 Open circuit or short circuit in the power circuit of the relay itself - often occurs after power surges in the network.
- 🧊 Compressor jamming is a mechanical failure in which the piston group cannot move, causing hum and clicking of the protection.
- 📉 Voltage drop in the network - if there is less than 190-200 Volts in the socket, the motor does not have enough power to start, and the relay constantly clicks, trying to help.
It is also worth considering the condition of the wiring. Oxidized contacts where the relay is connected to the compressor can create high contact resistance. This leads to local heating and false activation of thermal protection. Visual inspection of the terminals often helps to identify traces of carbon deposits or plastic melting.
Diagnostics: how to determine the source of the sound
To accurately determine the malfunction, it is necessary to localize the source of the sound. Listen carefully to where the click comes from: from the lower rear part of the housing where the motor is located, or from the upper part where thermostatis located. If the sound comes from above, perhaps the temperature sensor is simply triggered, which is normal.
If the clicks come from below, you should carry out a visual diagnosis. Unplug the refrigerator, move it away from the wall, and remove the back metal panel. You will have access to the compressor and the black plastic barrel attached to it - this is the start relay. Gently shake it: if a ringing or knocking sound is heard inside, as if from broken glass, it means starting relay it is faulty and requires replacement.
⚠️ Attention: Do not try to repair sealed starting relays by disassembling the housing. They are not intended for maintenance and can only be completely replaced with a similar model.
Also check the condition of the contacts. If black carbon deposits are visible on them or they are melted, the device will not work correctly. In some cases, the relay may be serviceable, but not suitable for a specific type of compressor in terms of operating current. Therefore, when replacing, it is important to pay attention to the markings.
☑️ Primary noise diagnosis
Comparison of relay types and their compatibility
There are many modifications of starting devices on the spare parts market. They are divided into induction (electromagnetic) and posistor. Induction relays work due to the magnetic field of the coil, and posistor relays - due to changes in the resistance of a special element when heated. Compatibility Here plays a key role: installing the wrong type can lead to the compressor burning out in a few minutes.
It is important to pay attention to the permissible current If you install a relay with less tripping current than required, it will continually trip. If it is large, the overload protection will not work. Below is a table for approximate selection.
| Relay type | Operation principle | Characteristic sound | Compatibility |
|---|---|---|---|
| Induction (RTK) | Electromagnet | Loud metallic click | Old models Atlant, Biryusa |
| Posistor (RTP) | Heating crystal | Quiet, soft click | Modern models, No Frost |
| Combined | Posistor + bimetal | Medium volume | Universal spare parts |
| Electronic | Microcircuit | Silent or quiet click | Inverter systems |
Upon purchase For a new spare part, be sure to compare the markings on the old device. Even if the (shape) is the same, the electrical parameters may differ. Use multimeter to check the resistance of the compressor windings before installing a new relay to ensure that the motor is working properly.
Extraneous sounds: ventilation and defrosting
Clicks do not always indicate a breakdown. In refrigerators with No Frost system, periodic sounds may be associated with the operation of the fan or the defrost cycle. When the plastic parts of the case, as well as the evaporator tubes, heat and cool, the material expands and contracts, producing characteristic crackling and clicking sounds.
If the sound is heard in the upper part of the chamber or behind the back wall, most likely it is thermal expansion. This happens especially often immediately after the compressor is turned on or, conversely, after it stops, when the temperature of the elements changes sharply. Such sounds do not pose a threat and are considered normal for this design.
However, if a grinding or humming noise is added to the clicks, it is worth checking the fan. Ice on the blades or worn bearings can cause rhythmic beating. In this case, it is necessary to defrost the refrigerator for 10-12 hours or replace the fan.
Algorithm for replacing the starting relay with your own hands
If diagnostics have confirmed that the relay is faulty, replacing it is a procedure accessible even to a novice. The main thing is to follow safety precautions and sequence of actions. You will need a new spare part, a flathead screwdriver and possibly some pliers.
First make sure that the refrigerator is unplugged. Remove the back cover and locate the compressor. A plastic relay casing is placed on its protruding shaft. Carefully remove the retaining bracket or bar that holds the housing in place. Pull the relay down, disconnecting it from the compressor contacts.
⚠️ Attention: When removing the relay, be careful not to damage the thin copper tubes of the compressor. They easily break under mechanical stress, which will lead to freon leakage.
Install the new relay in the same position as the old one (usually the "UP" arrow should point up). Place it over the contacts and secure with the retaining bar. Reassemble everything in reverse order and turn on the refrigerator. If after 10-15 seconds you hear a confident start of the motor and the cracking noise disappears, the repair was completed successfully.
Prevention and care of the compressor area
To extend the life of the start relay and compressor, it is necessary to ensure good ventilation at the back of the refrigerator. Dust, animal hair and fluff, settling on the condenser grille and the motor itself, create a “fur coat” that interferes with heat dissipation. Overheating is the main enemy of electrics, it accelerates the degradation of insulation and oxidation of contacts.
It is recommended to carry out at least once a year preventative cleaning. To do this, just vacuum the rear grille and the area around the motor. Also check that the refrigerator is securely fastened: if it is not level, vibrations during operation can loosen the contacts and fastenings of the relay, causing rattling.
Make sure that the voltage in the network is stable. Frequent surges or chronically low voltage cause the starting relay to work in extreme mode, constantly turning the protection on and off. Using a surge protector or stabilizer will help avoid premature failure of expensive components.
Why does the refrigerator click but does not freeze?
If you hear clicks, but it is warm inside the refrigerator, this means that the compressor does not start. Most often, the cause is a burnt-out start relay or a jammed motor. The relay tries to start the engine, clicks, but due to a breakdown, the start does not occur, and no cold is produced.
Is it dangerous to continue operating when there are clicks?
Operating a refrigerator with a constantly clicking relay is dangerous. The motor is energized, hums and heats up, but does not rotate. This can lead to burnout of the compressor windings in a short time, after which repairs will become economically unfeasible.
Is it possible to replace the relay with a universal one?
Yes, there are universal starting relays with a set of adapters for different types of compressors. The main thing is to make sure that the current range of the universal relay covers the parameters of your motor. Typically, there is a compatibility table on the packaging of a universal relay.
How much does it cost to replace a start relay?
The cost of the spare part itself is usually low and varies depending on the model of the refrigerator. However, if you are not confident in your abilities, calling a specialist will cost more than the part itself. Self-replacement takes 10-15 minutes.