A sudden stop of the compressor or refusal of the refrigerator to turn on is a situation that can take any owner of household appliances by surprise. Often the cause of a breakdown is not the motor itself, but a failed one starting relay, which is responsible for starting the motor and protecting its windings. If you notice that the unit hums but does not start, or, conversely, clicks and goes silent, there is a high probability that the problem lies in this small but critical component.
Replacing the part yourself is a real opportunity to save a significant amount on calling a technician, since the procedure does not require specialized expensive equipment. However, before starting work, it is necessary to clearly understand the structure of the unit and follow electrical safety rules, because the work will involve electric current and refrigerant. In this article, we will look in detail at how to diagnose a malfunction, choose the right spare part and make a replacement without the risk of damaging the equipment.
The principle of operation and functions of the starting relay
The starting relay is an electromechanical switch that supplies current to the starting winding of the compressor only at the moment of startup. As soon as the engine rotor reaches the required speed, the relay opens the starting winding circuit, and the refrigerator goes into normal operation. Modern models most often use induction-dynamic devices where the contacts are closed under the influence of the magnetic field of the coil.
The second important function of the element is thermal protection. There is often a built-in device inside the housing that opens the circuit when the compressor overheats, preventing the windings from burning out. If the temperature inside the motor housing exceeds permissible limits, the bimetallic plate bends and de-energizes the unit. This saves the equipment from expensive overhauls. thermal relay, which opens the circuit when the compressor overheats, preventing the windings from burning out. If the temperature inside the motor housing exceeds permissible limits, the bimetallic plate bends and de-energizes the unit. This saves equipment from expensive overhauls.
⚠️ Attention: Some models of refrigerators, especially old Soviet or specific industrial designs, may have a relay with a mercury capsule. If such a part is damaged, mercury may leak, which is hazardous to health. Be extremely careful when opening old components.
Understanding the physics of the process helps to quickly find the cause of the breakdown. If the contacts inside the relay burn out or stick, the engine does not receive the impulse to start. In other cases, when the mechanism “sticks” in the closed state, the starting winding may burn out due to overload. That is why timely diagnosis and replacement of a faulty element is the key to the long life of your refrigerator.
Fault symptoms and initial diagnostics
You can determine that the problem lies in the starting relay by the characteristic signs that appear when the refrigerator is operating. The most obvious symptom is a distinctive clicking sound, followed by a humming sound from the compressor that lasts a few seconds, followed by silence. This cycle can be repeated at intervals of several minutes until the thermostat completely turns off the power supply.
It is also worth paying attention to the state of the relay itself. If, after removing the casing, you see blackened plastic, melted contacts, or smell a burning smell, then the part definitely requires replacement. Sometimes a breakdown is accompanied by a complete lack of reaction from the refrigerator when plugged in, although the light inside is on.
For accurate diagnosis, you can use a multimeter. By ringing the contacts, you can determine the integrity of the coil and the mobility of the contacts. In good condition, the coil resistance should be in a certain range, and the contacts should open and close freely when rocked.
- 🔊 The refrigerator makes a loud click, hums for 3-5 seconds and goes silent.
- 🔥 The compressor heats up to a very high temperature, but does not start.
- 💡 The light in the chamber is on, but the cold is not produced for a long time.
- 👃 You can smell burning wiring or plastic in the motor area.
It is important not to confuse the symptoms of a relay failure with a malfunction of the compressor or thermostat itself. If the motor hums, but the shaft does not turn, this may indicate a wedge in the piston group, and replacing the relay will not help here. Therefore, a visual inspection and a simple continuity test are mandatory steps before purchasing spare parts.
Choosing a compatible starting relay
The spare parts market offers many relay options, but there are practically no universal solutions. Each compressor model requires a relay with certain current characteristics. There is always a marking on the body of the part that contains information about the type, operating current and manufacturer. The most common brands are Danfoss, Secop and Atlant.
When choosing a new part, pay attention not only to the appearance, but also to the parameters indicated in the technical data sheet or on the label of the old relay. The critical parameter is the current rating. If you install a relay with a lower current, it will constantly turn off the compressor, preventing it from starting. If it is large, the starting winding of the engine may burn out.
| Parameter | Description | Where to find the value |
|---|---|---|
| Rated current | Current strength at which the relay triggered | Marking on the case (for example, 1.2 A) |
| Type of contacts | Pin connection diagram | Visual comparison with the old relay |
| Orientation | Installation position (vertical/horizontal) | Instructions for the compressor or marking |
| Presence of thermal protection | Is there a thermal relay built in | Casing design (separate or combined block) |
Sometimes it is impossible to find an original part, and then you have to select an analogue. In this case, it is necessary to strictly observe the coincidence of the current characteristics and the contact layout. It is possible to use universal relays, which come complete with a set of adapters for different types of compressors, but their reliability is often lower than that of the original components.
Is it possible to use a relay from another refrigerator?
You can use a relay from another model only if the current characteristics and connection diagram are completely the same. Even if the connectors fit perfectly, a mismatch in the operating current will either cause permanent shutdowns or burn out the compressor winding. It is better to choose an exact analogue from the manufacturer's catalog.
Preparation for repair and necessary tools
Before proceeding with dismantling, it is necessary to ensure safe working conditions. The first and most important step is to completely disconnect the refrigerator from the electrical network. It is not enough to simply turn off the button; you need to unplug the plug from the socket to eliminate the risk of electric shock.
Next you need to provide access to the compressor. In most refrigerator models, such as Indesit, Beko or LG, the compressor is located in the lower rear part of the case. You will need to move the unit away from the wall to allow easy access from all sides. If the compressor is closed with a decorative casing, it must be removed by unscrewing the mounting screws or releasing the latches.
☑️ Preparing to replace the relay
For work you will need a minimum set of tools: Phillips and flathead screwdrivers, pliers, a multimeter to test the circuit, and possibly some electrical tape or heat shrink to insulate the connections. It is also recommended to prepare gloves to avoid getting your hands dirty with oil or getting hurt on the metal edges of the casing.
Pay attention to the condition of the wiring. If the insulation of the wires going to the relay is cracked or melted, it must be repaired before installing a new part. Working with damaged wiring is unacceptable, as this can lead to a short circuit.
Step-by-step instructions for replacing a relay
The replacement process begins with dismantling the old device. The relay is usually mounted on three pins extending from the side of the compressor and secured with a metal bracket or plastic clip. Carefully remove the retaining element and pull the relay down, being careful not to damage the suitable wires.
After removing the part, carefully inspect the seat on the compressor. There should be no oxides, soot or moisture. If the contacts on the compressor pins are oxidized, they can be carefully cleaned with fine sandpaper or a needle file, but this must be done extremely carefully so as not to break the ceramic insulators.
Installing a new relay is done in the reverse order of removal. Align the holes in the relay housing with the compressor pins and push it tightly until it stops. Make sure the piece sits level and securely in place. Then connect the wires to the appropriate terminals, observing the polarity and the diagram, which it is advisable to photograph before disassembling.
⚠️ Attention: The starting relay has a strictly defined installation position, indicated by the “UP” or “Down” arrow. If you install it upside down, the mechanism will not work correctly and the compressor will not start.
After connecting all the wires and fixing the bracket, you can proceed to testing. Plug in the refrigerator and listen. If you hear a confident click, followed by the smooth hum of the running motor, and after a while cold starts to appear, the replacement was successful.
Frequent errors during self-repair
One of the most common mistakes is ignoring the reason for the failure of the old relay. If the relay burns out due to a power surge or wiring problem, the new part can also fail quickly. Always check the mains voltage and the condition of the socket before connecting a repaired device.
Another mistake is the incorrect selection of an analogue. Trying to “fit” an unsuitable relay by bending contacts or using twists instead of soldering often results in poor contact. Poor contact causes sparking, heating and repeated breakdown, sometimes with damage to the compressor.
Some technicians try to clean the burnt contacts of the old relay and it. This is a temporary measure that rarely has a long-term effect. The relay mechanism wears out, and after cleaning it can work from several hours to a couple of days, after which the breakdown will occur again.
- 🚫 Installing the relay in the wrong orientation (upside down).
- 🚫 Using a part with the wrong operating current.
- 🚫 Poor fixation wires leading to sparking.
- 🚫 Ignoring checking the voltage in the apartment's electrical network.
It is also worth mentioning the rush. Attempting to make repairs without waiting for the compressor to cool completely or without turning off the power may result in personal injury. Patience and attentiveness are the best tools in a home handyman's arsenal.
Prevention and extension of service life
In order for the new starting relay to last as long as possible, it is important to ensure good operating conditions for the entire refrigeration unit. The compressor should not overheat, so you need to keep the condenser (grids at the back) clean and ensure normal air circulation around the back wall of the refrigerator.
Check the door seals regularly. If the door does not close tightly, the compressor is forced to work almost non-stop, which leads to overheating and increased load on the starting equipment. Timely defrosting also reduces the load on the system.
The stability of the network voltage is another factor in longevity. If power surges frequently occur in your home, it is recommended to use a stabilizer or surge protector for the refrigerator. This will protect not only the relay, but also the electronic control board, if it is present in your model.
How often do you need to change the starting relay?
The starting relay does not have a specific replacement period and serves until it fails. On average, the service life of a high-quality relay is 5-10 years, but under unfavorable conditions (voltage surges, overheating) it can burn out in 2-3 years. Scheduled replacement is not required; change only when symptoms of a malfunction appear.
Is it possible to repair an old relay?
Theoretically, if the relay is inductive, you can try to clean the contacts or replace the burnt out coil. However, in practice this is a labor-intensive process that requires fine tuning. Considering the low cost of new parts, repairing an old relay is not economically feasible and less reliable.
Why does the new relay click, but the compressor does not start?
This may indicate several problems: incorrect selection of the relay (wrong current), a malfunction of the compressor itself (an interturn short circuit or wedge), or a problem with the wiring. It is also worth checking whether the relay is tightly attached to the pins of the compressor.
Is independent replacement dangerous for the warranty?
If the refrigerator is under warranty, any independent intervention, including replacing the relay, will lead to loss of warranty. In this case, it is strongly recommended that you contact only the manufacturer’s authorized service centers.
Where can you find the relay markings?
The marking is usually applied to the side or top edge of the plastic relay case. Information can also be found on a sticker attached to the case. If the marking is erased, look for the compressor model and select a relay from compatibility catalogs.