The situation when a household refrigerator turns on and immediately turns off, making a loud noise A clicking sound is a classic sign of a faulty electrical circuit or mechanical part of the unit. This sound is usually produced by starting relay, which is trying to start the motor-compressor, but due to overload or open circuit, it breaks the contact to prevent the windings from burning out. For the owner of the equipment, this means that the cooling cycle does not start, the temperature in the chambers rises, and the products may spoil.
Often users notice that the compressor housing remains cold, although the unit has just “tried” to start working. In other cases, the engine may hum for a few seconds, heat up, and shut down. It is important to understand that ignoring this symptom can lead to more serious damage, including the need to replace the compressor itself. In this article we will analyze in detail the main reasons for this behavior of the equipment and methods for eliminating them.
The principle of operation of the start relay and compressor
To understand the nature of the click, it is necessary to consider the basic structure of the refrigeration unit. The heart of the system is compressorwhich operates from single-phase electric current. However, it is impossible to start a powerful electric motor directly from a regular 220V outlet - it requires a short-term impulse to the starting winding. This function is performed by the starting relay.
When turned on, the refrigerator makes a characteristic click - this relay supplies voltage to the starting winding. If the engine starts successfully, centrifugal force or a change in the magnetic field opens the starting winding circuit, and the motor continues to operate on the main one. If the start does not occur, the relay is activated again after a certain interval, making a second click. It is this cycle of “start attempts” that users hear.
Modern inverter models may behave differently, but classic refrigerators with linear compressors demonstrate the mechanics described above very clearly. The click in this case is a protective mechanism that saves the motor windings from overheating and short circuit.
What is dangerous about frequent switching on and off?
Frequent starting attempts (so-called "cycling") lead to rapid heating of the windings stator. If the relay does not turn off the power in time, the insulation of the wires may melt, which will lead to an interturn short circuit and complete failure of the compressor.
Malfunctions of the start-up relay
The most likely reason why the refrigerator clicks and turns off is the failure of the start relay itself. This small plastic block that fits over the compressor rod is subject to wear and tear. Inside it there is a coil and a movable core, which can stick or oxidize over time.
If the contacts inside the relay are burnt, the current will not flow to the starting winding with sufficient strength. The compressor tries to start, hums, but the relay detects the lack of rotation and opens the circuit. It is difficult to visually determine a breakdown; it often requires opening the relay housing. Inside you can find melted plastic or blackened contacts.
It is important to know that relays come in different types: electromagnetic and posistor. Posistor relays (with a special ceramic tablet) are considered more reliable, but they also fail during voltage surges. Replacing this element is the simplest and cheapest type of repair, which often solves the problem.
- 🔌 Oxidation of contacts: Moisture can accumulate inside the relay, causing corrosion of the conductive paths, which prevents normal starting.
- 🔥 Overheating of the posistor: The ceramic element loses its properties after many cycles of heating and cooling, ceasing to pass the current of the required strength.
- 🧱 Mechanical jamming: The movable core in electromagnetic relays can get stuck in the lower position, constantly opening the circuit.
Problems with compressor windings
If replacing the relay did not help, and the refrigerator still turns on for a couple of seconds and turns off with a click, the problem may lie deeper - in the engine itself. The compressor windings (starting and operating) may have hidden defects. The most common reason is turn-to-turn short circuit.
When a short circuit occurs, the winding resistance drops and the current in the circuit increases sharply. A start relay or thermal protection relay (which is often built into the same unit) detects this jump and breaks the circuit in an emergency. This happens very quickly, so the compressor does not have time to spin up. The hum in this case may be lower and buzzing.
You can check the condition of the windings using a multimeter. It is necessary to ring the contacts between each other and on the housing. Normally, the resistance between the contacts should be in a certain range (usually from 10 to 30 Ohms for the working winding and slightly higher for the starting winding, depending on the model). If the device shows zero or infinity, there is a break or short circuit.
Seizing of the mechanical part of the compressor
Sometimes the electrical part is working properly, the relay sends a pulse correctly, but the compressor does not start due to mechanical jamming. The piston group inside the sealed casing could wear out, lose lubrication, or experience water hammer (liquid freon entering the cylinder). In this case, the motor does not have enough strength to turn the shaft.
The symptoms are similar: a start click is heard, the compressor hums, trying to move the pistons, but after 2-5 seconds the protection turns off the power. A characteristic symptom is the strong heating of the compressor housing in a short time. Vibration may also be observed that is different from normal operation.
In some cases, technicians try to “unwedge” the compressor by applying increased voltage to it with a short pulse, but this is a temporary measure. If jamming occurs, the resource of the node is exhausted. Continued operation will lead to the final burnout of the windings.
Low voltage in the network and wiring
Do not discount external factors. If the voltage in your apartment or house is unstable and falls below 190-200 Volts, the compressor may not start. At low voltage, the current in the windings increases, but the torque decreases. The engine hums, but does not start, and the thermal relay turns it off.
The problem could also be a poor connection in the outlet or an extension cord that you are using. If you connect the refrigerator through an extension cord with a thin wire, during the starting current there is a voltage drop across it, and not enough energy reaches the compressor to start.
Check whether the refrigerator is connected directly to the outlet. The use of surge protectors and tees is often the hidden cause of problems with starting powerful equipment. It is also worth measuring the voltage at the time of the startup attempt, if possible.
Can a stabilizer be used?
Yes, installing a high-quality voltage stabilizer is an excellent solution for old houses or areas with a poor electrical network. It will ensure a smooth start and protect the equipment from surges.
Diagnostics and fault table
To systematize knowledge about the causes of failure, we suggest that you familiarize yourself with the summary table. It will help compare symptoms and probable nodes that require attention. Remember that an accurate diagnosis can only be made by a specialist with the appropriate equipment.
| Symptom | Probable cause | Sound character | Compressor condition |
|---|---|---|---|
| Click after 1-2 sec | Faulty start relay | One clear click | Cold or slightly warm |
| Humming and clicking after 5-10 sec | Stuck compressor | Low hum, then click | Gets very hot |
| Click and silence | Breakage of winding or wiring | Quiet click or its absence | Cold |
| Periodic clicks | Low voltage in the network | Intermittent humming | Heats up slowly |
When carrying out diagnostics, be sure to turn off the power to the device before removing the covers and touching the electrical parts. Safety is priority number one