Sudden stoppage of the compressor is one of the most frightening situations for the owner of household appliances. The refrigerator hums, trying to start, but after a few seconds there is a click and there is silence. In most cases, the culprit of this behavior is precisely starting relay, which stops supplying voltage to the motor windings. This device plays the role of a starter, briefly connecting the starting winding to create torque.
Before calling a technician or buying a new compressor, it is worth conducting independent diagnostics. Often the problem is solved by replacing a small and inexpensive part that can be found in spare parts stores. Understanding how this system works will allow you to save a significant amount and avoid equipment downtime. Next, we will look at how the mechanism works and what tools are needed for testing.
It is worth noting that the symptoms of a malfunction may be similar to problems in the electrical wiring or the engine itself. However, statistics show that the relay fails more often than other components due to constant thermal and electrical loads. If you notice that refrigerator turns on for just a couple of seconds and then stalls, most likely the problem is in the starter.
⚠️ Attention: Carry out any work on diagnosing and repairing electrical appliances only with the power completely disconnected from the network. Do not touch live parts if the cord is plugged into the outlet, even if the equipment is turned off with a button.
Design and principle of operation of the starting relay
The starting relay is a compact unit mounted directly on the compressor housing. An electrical circuit is hidden inside the plastic case, which can be implemented in different ways. In older models of equipment, devices with a posistor were often used, and in more modern ones there are electromagnetic or thermal options. The main task of the element is to apply an impulse to the starting winding at the moment of start and turn it off when the rotor reaches the required speed.
The principle of operation is based on the physical properties of materials. In posistor models, when current is applied, the ceramic element heats up and sharply increases its resistance, actually breaking the starting winding circuit. In electromagnetic versions, current passes through a coil, creating a magnetic field that opens the contacts when the engine starts. If this process is disrupted, the compressor cannot reach operating mode and goes into protection.
It is important to distinguish between the types of relays, since the methods for testing them may differ slightly. Posistor often fails due to disruption of the crystal structure due to overheating. Electromagnetic coils may burn out or become mechanically stuck. Understanding exactly what type is installed in your unitwill help more accurately determine the cause of the breakdown.
Is it possible to use a relay from another refrigerator?
Using a relay from another model is only possible if the electrical characteristics, connection type and overall dimensions match. It is strictly not recommended to install the part “by eye”, as this can lead to burning of the compressor windings or a fire. Always check the markings.
External signs of starter malfunction
You can determine the breakdown not only using instruments, but also by paying attention to the characteristic signs in the behavior of the equipment. The first signal is the unnatural sound accompaniment of the work. Instead of a steady hum, you hear a series of clicks followed by attempts to start. The compressor may twitch and vibrate, but a full start-up does not occur.
Another important indicator is the housing temperature. If the relay is working properly, it may heat up slightly during operation, but should not be red-hot. If, after several attempts to turn on, you feel intense heat emanating from the side wall in the compressor area, this indicates a short circuit inside the circuit or jammed contacts. In such cases diagnosis should be carried out immediately.
It is also worth paying attention to the smell. Burnt plastic or scorched wiring is a sure sign that a breakdown or melting of the contacts has occurred inside the relay. A visual inspection can confirm guesses: a blackened case, traces of burning or melted plastic indicate that the part requires replacement without further checks.
- 🔊 A loud click is heard, after which the refrigerator goes silent.
- 🔥 The relay or compressor housing gets very hot in a short time.
- 🌫️ There is an unpleasant smell of burning or smoke in the area of the engine compartment.
- 💡 The light inside the refrigerator is on, but no cold is produced.
⚠️ Attention: If you smell a burning smell, immediately unplug the refrigerator. Continued operation may lead to a wiring fire or failure of an expensive compressor.
Necessary tools for diagnostics
To properly check the start relay, you will need a minimum set of tools that most home craftsmen can find. The main device will be a multimeter (tester), which allows you to measure resistance and check the integrity of the circuit. Without this device, accurate diagnosis is almost impossible, since it is difficult to visually determine the condition of the internal contacts.
In addition to the measuring device, you will need screwdrivers to remove the protective cover of the engine compartment and disconnect the terminals. Some models may require pliers or side cutters if the wires are secured with cable ties. It is also a good idea to have electrical tape and a marker on hand to mark the position of the wires before dismantling, although modern connectors usually have a unique shape.
It is important that the multimeter probes are in good working order, and that the device itself shows zero when the probes are shorted to each other. If you are using a dial analog tester, make sure it is calibrated. Digital multimeters are more convenient to use and give accurate readings, which is critical when checking posistorthe resistance of which changes dynamically.
☑️ Repair tools
Step-by-step instructions: how to remove and check relay
The diagnostic process begins with the complete de-energization of the refrigerator. Unplug the cord and move the appliance away from the wall to gain access to the back panel. Remove the cardboard or metal cover covering the compressor. You will see a view of the motor and a black plastic block attached to it on the side or top - this is the start relay.
Carefully disconnect the connector with the wires coming from the refrigerator body. Then remove the relay itself from the compressor contacts. Usually it is simply put on three pins and secured with a bracket or clamp. Be careful not to pull sharply to avoid damaging the associated wires. After dismantling, inspect the body for cracks and melting.
Now let's move on to measurements. Turn the multimeter into continuity mode or resistance measurement mode (Ohm). For posistor relays, the resistance between the contacts should be low (about 20-60 ohms) when cold. If the device shows one or infinity, the circuit is broken and the part is faulty. For electromagnetic relays, the integrity of the coil is checked.
There is a simple way to check the functionality of a posistor, which requires caution. You can apply 220V voltage to the relay contacts through a fuse outside the refrigerator. A working posistor should begin to heat up and its resistance should begin to increase, which will lead to a decrease in current. If the current does not drop and there is sparking or smoke, the element is broken. However, this method is dangerous for beginners, so it is better to limit yourself to ringing.
| Relay type | Normal resistance (Cold) | Fault symptom | Action |
|---|---|---|---|
| Posistor (RTK) | 10 - 60 Ohm | Infinity or 0 Ohm | Replacement |
| Electromagnetic | Depends on the coil | Open coil circuit | Replacement |
| Thermal | Low (close to 0) | No contact when heating | Replacement |
| Combined | Checking both circuits | Failure of any element | Replacement of unit |
Typical mistakes in self-repair
One of the most common mistakes is ignoring compressor condition. If the start relay is burned out, this is often the effect, not the cause. Heavy stroke of the piston group or turn-to-turn short circuit in the motor windings creates an increased load that the relay cannot withstand. Installing a new element on a faulty compressor will lead to instant combustion of the new part.
Also, amateur craftsmen often confuse the contacts during reassembly. Although connectors are often fool proof, older models or when using generic relays can be foolproof. Incorrect connection of phase and zero, or starting and operating windings, can lead to the engine humming but not rotating, which will quickly disable it.
Another mistake is using a relay with inappropriate parameters. Even if the connector matches, the current characteristics may differ. If you install a relay with a lower rated current, it will constantly turn off the compressor. If it is large, the overload protection may not work, which is dangerous for electrical wiring the apartment.
Replacement of the part and final assembly
If the check confirms the malfunction, you must purchase an analogue. It is best to look for a relay by the markings indicated on the body of the old part. Manufacturers like Indesit, Atlant, Beko often use standardized components, but it is better to double-check compatibility. Installation is carried out in the reverse order: first, the relay is put on the pins of the compressor, then it is fixed with a bracket and the block with wires is connected.
Make sure that the relay sits tightly and does not dangle. The vibration of a running compressor can loosen a loose element, leading to loss of contact and sparking. After assembly, do not rush to close the back cover. Plug in the refrigerator and listen. The start-up should be smooth, without unnecessary clicks or buzzing.
During the first hour of operation, periodically check the temperature of the new relay. It may get hot, but should not burn your hands. If everything went well, you can install the engine compartment cover in place. Regular preventive maintenance and timely replacement of worn-out elements will extend the life of your equipment for many years.
⚠️ Attention: Technical characteristics and markings of parts may vary depending on the year of manufacture and model of the refrigerator. Before purchasing, always check the article numbers with the manufacturer’s documentation or a store consultant.
Is it possible to repair a burnt-out relay yourself?
In most cases, repairing the starting relay is impossible and impractical. Inside there is a sealed capsule or ceramic element that cannot be restored. Attempts to disassemble the housing will lead to a violation of tightness and safety. It’s easier and cheaper to buy a new original or high-quality analogue.
Why does a new relay burn out immediately after installation?
This is a sure sign that the problem lies deeper. Most likely, the compressor itself is faulty (interturn short circuit, piston wedge) or there are problems with the wiring of the refrigerator. Also, the reason may be incorrect assembly or the use of a part with unsuitable current characteristics.
How often do you need to change the starting relay?
The service life of the relay depends on the operating conditions and the quality of the electrical network. On average, a part lasts 5-10 years. Frequent power surges, overheating of the engine compartment due to poor ventilation or a dirty condenser can significantly reduce this period.