A sudden stop of the refrigerator often takes you by surprise, causing you to panic due to the risk of food spoilage. However, in many cases, the problem lies not in complex electronics or a burnt-out motor, but in the failure of the starting relay, which can be replaced independently. This small device is responsible for starting the compressor engine, and when it breaks down, the unit either hums but does not start, or makes clicks and immediately goes silent.
The process of connecting a new element requires care and compliance with safety precautions, since the work is carried out with high voltage electric current. Correct connection of the compressor relay guarantees not only the restoration of cold, but also the long-term operation of the entire system. In this article, we will analyze all the nuances of diagnostics, dismantling the old part and installing a new one, so that you can cope with the repair without calling a technician.
Before taking active steps, you need to make sure that the reason is in this unit, and not in the lack of voltage in the network or a broken power cord. Start relay is an electromechanical switch that supplies an impulse to the starting winding of the engine only at the moment of start, after which it turns off. If this mechanism jams or burns out, the starting cycle is interrupted and the compressor cannot enter operating mode.
Diagnosis of a faulty starting device
The first sign that refrigerator relay has failed is the characteristic behavior of the unit when connected to the network. You may hear a quiet hum that lasts a few seconds, followed by a loud clicking sound and the engine stopping. After some time, the thermal release cools down, and the cycle is repeated again and again, which indicates an attempt to start, which was unsuccessful.
For accurate diagnosis, it is necessary to visually inspect the part after removing it from the refrigerator. If traces of burning, melted plastic are visible on the case, or the smell of burnt wiring is felt, replacement is inevitable. It is also worth shaking the device near your ear: if you hear a knock inside, it means that the mechanical part is destroyed or the contacts are burnt out and dangling inside the case.
⚠️ Attention: Before any diagnostics, be sure to disconnect the refrigerator from the power supply! Working with live components is deadly and can lead to electric shock.
Sometimes the problem may lie in the compressor itself, which is jammed, and the relay has nothing to do with it, although it is the one that suffers first. To eliminate this possibility, experienced craftsmen check the resistance of the motor windings, but for the initial replacement of the relay it is enough to make sure that it is physically intact and matches the markings. If after replacing the relay the engine hums, but does not start, and after 10-15 seconds a click is heard, the compressor itself or the starting capacitor may be faulty.
Preparation for replacement and necessary tools
For successful repair work, professional equipment is not required; a standard home handyman’s kit is sufficient. You will need a flathead and Phillips screwdriver to remove the protective covers, and side cutters or a wire stripper if you need to extend the terminals. It will not be superfluous to use pliers and a multimeter to check the continuity of the circuit, although in many cases replacement is made based on a visual malfunction.
It is critically important to choose the right one starting relay for a refrigeratoras there are no universal solutions. Each compressor model requires a specific type of device that corresponds to the engine power and winding connection diagram. The marking is usually applied to the side of the case or stamped on the metal cover, and these are the numbers you need to look for when purchasing a new part.
Before starting work, prepare your work area: move the refrigerator away from the wall, providing access to the rear lower part where the compressor is located. If the floor is cold or dirty, lay down cardboard or a rag to avoid damaging the floor covering and to avoid getting dirty with oil that may drip from the system if handled carelessly.
You should also prepare a container with soapy water in case you have to disconnect the tubes, although this is rarely required when replacing a relay. The main thing is to ensure good lighting of the working area, since the lower part of the refrigerator is often dark, and it can be difficult to see small markings on the wires.
☑️ Preparation for repair
Removing the old relay and cleaning the contacts
The process of removing a faulty part begins with removing the compressor protective cover, which is usually secured with latches or bolts. Carefully remove the casing, being careful not to damage it, as it protects the mechanism from dust and moisture. Under the cover you will see the compressor itself, to the side or top of which there is a plastic box attached - this is our desired device.
To remove starting relay, you need to disconnect the terminal block with wires that comes to it from above. In some models, it is secured with an additional clamp or screw, which must first be loosened. After disconnecting the wires, carefully pull the relay down or to the side (depending on the design) to remove it from the compressor contacts.
Carefully inspect the contact group on the compressor itself: oxidation or carbon deposits often accumulate there, which will interfere with normal current. Clean the contacts with fine sandpaper or a file to a metallic shine, but be careful not to bend the pins. Oxidized contacts can cause repeated failure even of a new relay, so special attention should be paid to this stage.
If the wires going to relays are melted or too short, they need to be extended or cleaned. Use heat shrink to insulate the connections to prevent short circuits. Never leave the twists open, as the vibration of a running compressor can break contact and cause sparking.
Connection diagram and marking of contacts
The most critical stage is connecting a new device, and here you cannot act at random, since an error can lead to burnout of the motor windings. On the body of each relay there is a connection diagram, where the letters indicate the contacts: M (Main) - working winding, S (Start) - starting winding, L (Line) - power line, C (Common) - common wire R (Run) - working contact. In different models of refrigerators, such as Indesit, Atlant or Beko, the markings may vary slightly, so always check the instructions on the box.
Usually the wires are color-coded, but you cannot rely on color alone, since they could have been confused during previous repairs. The red or brown wire most often goes to phase, the blue one to zero, but this is not an axiom. It is best to navigate by the location of the pins on the compressor: they are arranged in a triangle, and the relay is put on them in only one correct position.
Below is a table of contact correspondence for the most common types of relays so that you can navigate when connecting:
| Designation on the relay | Function contact | Wire color (typical) | Where to connect |
|---|---|---|---|
| L (Line) | Power line (Phase) | Red / Brown | From thermostat / network |
| C (Common) | Common wire | Black / White | Motor common terminal |
| S (Start) | Start winding | Yellow / Green | Upper motor pin |
| M/R (Run) | Working winding | Blue / White | Motor side pin |
If you are installing a universal relay, inside the box there is often instructions with several diagrams for different types of compressors. Choose the option that matches the arrangement of contacts on your engine. Universal relays often require connecting a capacitor if it was not in the old circuit, or vice versa - they require removing the standard capacitor if it is built into a new part.
What to do if the wires are mixed up?
If you are not sure about the correct connection colors, use a multimeter in dial mode. Find the common terminal on the compressor (the resistance between it and the other two will be the same and average). Power is usually connected to the common terminal. The starting winding has a higher resistance than the working winding. However, the most reliable way is to find an exact copy of the old relay or use the service manual for your refrigerator model.
Installing a new relay and assembling the system
After the wires are connected to the terminals of the new device, you need to securely fasten them. If connectors are used, make sure they are tight and will not come loose due to vibration. In some cases, it is necessary to crimp the contacts with special pliers to ensure a high-quality electrical connection. Weak contact will lead to heating and repeated failure of the part.
Now carefully place the relay on the contact group of the compressor. It should snap into place with a characteristic click or firm force. Do not use excessive force: if the relay does not fit, you have chosen the wrong position or the model is not suitable. Check the orientation: usually the arrow UP or the inscription should face up, since many relays only work in a certain spatial position.
Replace the terminal block with the power wires and secure it with a clamp or screw. Make sure that no wires touch the compressor housing or tubes, as they may become hot or chafe. All live parts must be insulated and protected by a plastic relay casing.
The final stage of installation is to return the protective metal or plastic casing to the compressor. Bolt or snap it in place to seal the compartment. This will protect the mechanism from dust, animal hair and accidental impacts, which can damage fragile elements of the system.
First launch and performance check
After assembly, you can begin testing, but this must be done carefully. Plug in the refrigerator and listen: you should hear the smooth hum of a running motor. If you hear a click, followed by a hum, and then another click and silence, it has not started. In this case, immediately turn off the unit and double-check the connection diagram.
If the compressor starts running smoothly, without any extraneous sounds or vibrations, wait 10-15 minutes. During this time, the condenser tubes (located at the back) should begin to heat up, and the freezer compartment will become cold. This is a sure sign that the refrigerant is circulating through the system and relay replacement was successful.
⚠️ Attention: If after replacing the relay the compressor works but does not cool, there may be a freon leak in the system or a clogged capillary tube. In this case, replacing the relay only temporarily solved the starting problem, but you need to call a technician to fill the refrigerant.
During the first hours of operation, monitor the temperature of the relay housing: it should not get hot. Only slight heating is acceptable, which is the norm for electromechanical devices. If the plastic begins to melt or a burning smell appears, turn off the refrigerator immediately - there is a bad contact or a short circuit somewhere.
Common mistakes and precautions
One of the most common mistakes is installing a relay of inappropriate power. Visually they may be similar, but different models are designed for different current strengths. Installing a weak part on a powerful compressor will lead to its rapid burnout, and a too powerful one may not open the starting winding circuit in time, which will burn out the engine.
They also often forget about the capacitor, if it is provided for in the design. In some circuits starting capacitor it is in conjunction with a relay, and its absence or malfunction will not allow the engine to develop the required speed. Always check the condition of the capacitor: if it is swollen or leaking, it must be replaced along with the relay.
Do not ignore the condition of the wiring: if the insulation of the wires is cracked from time and temperature, it must be restored. Using ordinary electrical tape in a refrigerator is not always effective; it is better to use heat-shrinkable tubes that are not afraid of moisture and temperature changes.
Remember that the compressor is the heart of the refrigerator, and any manipulations with its electrical part require care. Wrong connection can lead to inter-turn short circuit of the windings, after which repairs will become economical inappropriate. If you doubt your abilities at least at one of the stages, it is better to stop and turn to professionals.
Is it possible to repair an old relay?
In theory, the starting relay can be disassembled and cleaned the contacts or replace a burnt-out coil, but in practice this rarely works long-term result. The mechanism wears out evenly, and cleaning the contacts will only prolong the agony for a short time. Considering the low cost of new parts, repairing an old relay does not make sense.
Questions and answers about connecting the relay
Is it possible to use a universal relay instead of the original one?
Yes, universal relays are suitable for most compressor models if their power range covers the power of your engine. The main thing is to choose the right connection diagram inside the universal case, since the pinout may differ from the original.
Why did the new relay burn out immediately after installation?
There may be several reasons: a jammed compressor that creates an overload, a faulty starting capacitor, a short circuit in the wiring, or incorrectly selected relay power. It is also possible that power surges are occurring in the network.
Is it necessary to defrost the refrigerator before replacing the relay?
Full defrosting is not required, since access to the compressor is at the rear bottom. However, if the refrigerator was working before the breakdown and there is a lot of ice inside, it is better to let it stand turned off for a couple of hours to avoid excess moisture during diagnostics.
How to determine which relay to buy?
Remove the old relay and look for markings on it (for example, PTC, R600a, R134a and power numbers). It is best to take the old part with you to the store or take a clear photo of the markings for the seller.
Is it dangerous to change the relay yourself?
The process of replacing the mechanical part is safe if the refrigerator is unplugged. The only danger is when the device is plugged in during work. If you follow electrical safety rules, the risk is minimal.