The situation when the refrigerator stops cooling, and the compressor is either silent or makes only short clicks and buzzes for a couple of seconds, is familiar to many owners of household appliances. Often the reason for this behavior is the failure of the starting relay, which is responsible for starting the engine. Replacing this component is one of the most accessible procedures for self-repair, which does not require calling a technician and expensive equipment if you have basic skills in handling tools.
However, before you grab a screwdriver, you need to clearly understand what kind of part you are dealing with, since starting relay is not just a switch, but a complex electromechanical assembly. Incorrect connection or ignoring safety precautions can lead to final breakdown of the compressor or even fire of the wiring. In this article we will analyze in detail the process of diagnosing, selecting and installing a new element so that you can confidently restore the functionality of your unit.
It is worth noting that modern models of refrigerators, be it Indesit, Atlant or Bosch, can be equipped with different types starters, and there is no universal solution “for everyone”. You will need to carefully study the markings of the old part and strictly follow the connection diagram, since mixed up contacts are the most common mistake of beginners. Let's figure out how to avoid these mistakes and perform the replacement correctly.
Diagnostics of a faulty starting relay
The first step should always be an accurate diagnosis so as not to change working parts. If you hear a distinctive click, followed by a hum from the compressor, and then another click and silence, this is a sure sign that the engine is unable to start. At this moment trigger mechanism tries to apply voltage to the winding, but the current increases sharply, and the thermal protection opens the circuit to prevent the motor from burning out.
Visual inspection often helps identify the problem without complex instruments. After removing the casing from the compressor, pay attention to the appearance of the relay: the presence of melted plastic, blackened contacts or a burning smell clearly indicates the need for replacement. It is also worth checking the integrity of the wires going to the terminals, since vibration during operation of the refrigerator sometimes leads to their fracture or oxidation.
For a more accurate check, you can use a multimeter in resistance measurement mode. In a working device, the resistance between the contacts should be close to zero (or several ohms), and if the device shows infinity or an “open”, it means that the internal coil has burned out. You should not rely only on the sound of operation, as sometimes the relay can “stick” mechanically without opening the circuit in time.
⚠️ Attention: Before starting any work on diagnosing and replacing the relay, be sure to disconnect the refrigerator from the power supply! Working with live electrical wiring is deadly. In addition, the compressor must cool completely to avoid burns when touching metal parts.
If after replacing the relay the situation has not changed and the compressor still hums and turns off, the problem may lie deeper. Perhaps the piston mechanism of the compressor itself has jammed or a breakdown of the motor windings has occurred. In such cases, simply replacing the starter will not help, and more serious repairs or replacement of the entire unit will be required.
Types of starting relays and their features
Understanding the differences between types of relays is critical for the correct selection of spare parts. In household refrigerators, two main types of devices are most often found: posistor and induction (electromagnetic). Posistor relay works on the basis of a thermistor, which, when heated by current, sharply increases its resistance, opening the starting circuit. These are more modern and reliable devices, often used in models of recent decades.
Induction relays, in turn, work on the principle of an electromagnet: the current passing through the coil draws in the core, which closes the contacts of the starting winding. As the engine picks up speed, the current drops and the spring returns to the core, breaking the circuit. Such models are often marked with an orientation (arrow up), since their operation depends on gravity.
When purchasing a new part, pay attention not only to the appearance, but also to the technical characteristics indicated on the case. Engine power, refrigerant type and connection diagram - all these parameters must match. Using an unsuitable analogue may result in the contacts burning out faster, or the engine will not be able to reach operating mode.
Is it possible to install a relay from another manufacturer?
Yes, it is often possible if the mounting dimensions, number of contacts and electrical parameters match. However, it is better to look for original spare parts or proven universal analogues, specially designed to replace several models at once.
There are also universal kits that are suitable for a wide range of compressors. They are often supplied with a set of adapters and instructions for adapting to different types of connectors. This is a convenient option if you cannot find an original spare part for an old refrigerator, for example, models ZIL or early Saratov.
Preparation of tools and workplace
The success of the repair largely depends on proper preparation. You don't need a complex professional tool, but you should have the necessary tools at hand. Collect everything in one place in advance so as not to be distracted by searching during the work process, when the compressor is already disassembled.
To replace the relay you will need:
- 🔧 Screwdrivers (Phillips and flat) for removing the back cover and clamps.
- 🔨 Pliers or pliers for removing terminals and clamps.
- 🧹 A brush with hard bristles to clean contacts from dust and carbon deposits.
- 🔋 Multimeter for checking circuit continuity and resistance.
- 🧤 Dielectric gloves for additional safety.
Organize your workspace to provide good access to the back wall of the refrigerator. Move the unit away from the wall, providing a gap of at least 50-70 cm. This will not only facilitate access to the compressor, but also provide the necessary ventilation if the refrigerator accidentally turns on during testing.
☑️ Preparation for repair
Pay special attention to lighting. The compressor area is often dark and shadows can hide important details such as cracked wires or pin markings. Use an additional light source, such as a headlamp or lamp, to clearly see all the elements of the circuit.
Connection diagram and installation process
The replacement process begins by removing the old relay. It is usually mounted on three pins coming out of the compressor and secured with a metal bracket. Carefully remove the bar by bending its edges and pull the relay down. Do not use excessive force to avoid damaging the compressor tubes.
Now the most important thing is the correct connection. There are markings on the relay body and on the compressor connector: R (Run) - working winding, S (Start) - starting winding, and common wire. By mixing them up, you risk burning out the new part or not starting the engine. In some models, for example Indesit or Stinol, the connectors may differ in shape, which reduces the risk of error, but it is still necessary to check the circuit.
| Relay contact | Designation | Function | Wire color (often) |
|---|---|---|---|
| Top pin | Common (C) | Common power input | Red / White |
| Left pin | Run (R) | Working winding | Black / Green |
| Right pin | Start (S) | Start winding | Blue / Yellow |
| Side terminals | Thermal | Thermal protection | Depends on the model |
Install the new relay onto the compressor pins until it stops. Make sure it fits snugly and doesn't wobble. Then replace the retaining bar and tighten the screws. Connect the wires to the terminals according to the photo or diagram you took earlier. If you are using a universal relay, carefully read the instructions, as the pin layout may differ from the original.
⚠️ Attention: Make sure the relay is installed in the correct orientation. Many models have an arrow UP or the words "THIS SIDE UP" indicating that the device should be placed vertically. Incorrect position may impair the operation of the mechanical parts inside the relay.
After assembly, do not rush to close the back cover. Plug in the refrigerator and listen. The compressor should start with a characteristic hum, the relay may click quietly after a few seconds (this is normal, the starting winding is turned off). If the motor runs smoothly and begins to cool, the replacement can be considered successful.
Common mistakes when replacing relays
Even experienced craftsmen sometimes make mistakes, let alone beginners. One of the most common problems is incomplete connection of the relay to the compressor contacts. If the device is not put on completely, the contact will be poor, which will lead to sparking, heating and rapid failure of the new part. Always check the tightness of the fit.
Another common mistake is ignoring the state of the thermal protection. Often it is built into the relay housing or mounted separately on top. If you install a new relay, but leave the old, tired thermal protection, it may trip prematurely, preventing the compressor from working at full capacity. It is better to change the entire assembly.
Some users try to clean the burnt contacts of the old relay with sandpaper and put it back. This is a temporary measure that can help in an emergency, but such a relay will not last long. Violation of the geometry of the contacts and changes in resistance lead to unstable operation and eventual breakdown of the compressor.
It is also worth mentioning the error associated with the choice of power. Installing a relay designed for lower engine power will lead to its immediate burnout. If you are not sure of the parameters, it is better to take a relay with a slightly larger current reserve than with a smaller one, although the ideal option is always an exact match with the marking.
Checking performance after installation
After a successful launch, it is important to carry out a full test cycle. Let the refrigerator run for at least 30-40 minutes without loading food. At this time, periodically (but not too often, so as not to disturb the temperature regime) check the temperature of the condenser (grids at the back or on the sides). It should heat up evenly.
Pay attention to the operating cycle: the compressor should work for a certain time, then turn off and turn on again according to the thermostat signal. If the refrigerator runs continuously, the problem may not only be with the relay, but also with a freon leak or a malfunction of the thermostat. In this case, replacing the relay only temporarily solved the starting problem, but did not restore the cold.
Listen to the sounds. A running compressor emits a smooth, monotonous hum. If you hear knocking, rattling, or whistling noises, this may indicate mechanical problems within the motor or improperly installed tubing that may be touching the housing. Vibration should not be transmitted too strongly to the body of the refrigerator.
What to do if, after replacing the relay, the refrigerator does not turn on?
Check the presence of voltage in the outlet and the integrity of the power cord. Make sure all wires are connected tightly. If the compressor hums but does not start, the motor itself may be jammed or the thermal protection is faulty. Try to carefully (with your hand, not a tool!) check the temperature of the relay case - if it heats up in seconds, it means that current is flowing, but there is no start.
Is it possible to temporarily start a refrigerator without a relay?
Theoretically, you can start the compressor by applying voltage directly to the working and starting windings, but this is extremely dangerous and requires an accurate calculation of the time to turn on the starting winding (literally for 1-2 seconds). It is strictly not recommended to do this without special skills and equipment, since there is a high risk of burning the motor windings forever.
How often do you need to change the starting relay?
The service life of a high-quality relay is 10-15 years or more. However, frequent power surges in the network can reduce this period to 3-5 years. If you live in an area with unstable power supply, it makes sense to install a voltage stabilizer to protect all your household appliances.
In conclusion, properly replacing the start relay can give your refrigerator a second life. The main thing is to act carefully, follow safety precautions and use high-quality components. If after all the manipulations the cold does not appear, perhaps it’s time to turn to professional technicians for a deeper diagnosis of the system.