A sudden stop in the operation of the refrigerator or characteristic clicks after which the motor does not start often indicate a failure of the start relay. This small but critical element is responsible for supplying voltage to the compressor windings at the moment of start. If you are faced with such a problem, replacing the relay yourself can be a quick and economical solution, allowing you to avoid an expensive call to a technician.
Before you start disassembling, you need to make sure that the problem lies in the relay, and not in the compressor itself or the wiring. Often, equipment owners mistakenly diagnose a breakdown without checking basic things, such as the presence of voltage in the outlet or the integrity of the power cord. Starting relay is an electromechanical switch that is activated by current, closing the starting winding of the engine, and opens it when the motor reaches the required speed.
In this article we will analyze in detail the algorithm of actions: from dismantling the old part to installing a new one. You will learn how to choose the right analogue if the original is no longer in production, and what safety measures must be observed when working with live electrical appliances. Correct installation guarantees long and stable operation of your refrigeration unit.
Fault diagnosis and signs of breakdown
The first sign of a malfunction start-up relay is a characteristic sound. You may hear a soft click, followed by the hum of the motor running for a few seconds, and then a second click and silence. This means that the motor is trying to start, but the relay cannot hold the starting winding circuit or the thermal protection is triggered. If you leave the equipment in this condition, the compressor may overheat and fail.
Sometimes the refrigerator may not make any sounds at all, except for periodic clicks of the thermostat. In this case, a visual inspection of the relay may reveal melted housing or blackened contacts. It is also important to check whether the compressor itself is jammed, since an attempt to start a blocked motor through a new relay will lead to its instant combustion. Diagnostics must be comprehensive.
⚠️ Attention: If after replacing the relay the refrigerator does not start again and makes a humming noise, immediately unplug it. Repeated startup attempts may lead to an interturn short circuit in the compressor windings, which will require replacement of the entire unit.
For an accurate check, you can use a multimeter in continuity mode. The resistance between the contacts must correspond to the technical characteristics of the specific model. If the device shows infinity (break) or zero (short circuit) where they should not be, the part requires replacement. Do not ignore the burning smell coming from the back of the refrigerator - this is a sure sign of an electrical fault.
Preparing tools and choosing a new relay
For a successful replacement, you will need a minimum set of tools that any DIYer can find in his home. The main attention should be paid to the safety and accuracy of the selection of components. Start relay - this is not a universal part, and installing an unsuitable analogue can lead to unstable operation of the refrigerator.
You will need the following tools and materials:
- 🔧 Screwdriver (Phillips or flathead, depending on the fastening of the casing).
- ✂️ Pliers or side cutters for cutting wires (if the terminals do not match).
- 🔌 Electrical tape or heat shrink for insulating connections.
- 🧤 Dielectric gloves for protection against residual current.
When choosing a new part, pay attention to the markings of the old relay. Most often they are divided into induction (for single-phase motors) and posistor (for refrigerators with the No Frost system). Induction relays have a movable core and operate on the principle of an electromagnet, while posistor ones use a thermoelement that changes resistance when heated.
If It is not possible to find an exact copy by number; you can select an analogue based on compressor power and type of refrigerant. However, it is best to search by the model of the refrigerator or compressor itself. The table below shows common types of relays and their compatibility with brands:
| Relay type | Application | Compatible brands | Features |
|---|---|---|---|
| RT (RTK, RTK-X) | Single-chamber, old models | Atlant, Minsk, Biryusa | Induction, vertical installation |
| LS (LSA, LIL) | Double-chamber, No Frost | Indesit, Ariston, Stinol | Posistor, requires precise selection |
| PTC | Modern models | Bosch, Siemens, LG | Compact, often comes complete with a capacitor |
Can a universal relay be used?
Universal relays (for example, 4-in-1) are suitable for many models, but their operation may be less stable compared to original parts. They often have different options for connecting contacts, which requires careful study of the diagram.
Removing the old start relay
The dismantling process begins with completely disconnecting the refrigerator from the electrical network. This mandatory requirement safety, since you will work in close proximity to live parts. After disconnecting, move the unit away from the wall to provide access to the rear panel.
Remove the compressor protective cover, which is usually secured with latches or screws. Below this you will see a black cylindrical or box-shaped piece attached to the side of the compressor. This is where the wires from the thermostat and power cord fit. Carefully take a photo of the connection diagram before disconnecting anything - this will help to avoid errors during assembly.
Remove the old relay by pulling it down or snapping the latches. It may be tight, so be careful not to force it too hard to avoid damaging the compressor leads. If the relay is stuck, you can slightly rock it from side to side. Inspect the seat: there should be no traces of burning or oxidation.
☑️ Safe dismantling
Connection diagram and installation of a new relay
Installation of the new element is carried out in the reverse order of dismantling. The main rule: the contacts on the relay and on the compressor must match completely. If you purchased a universal relay, carefully study the attached diagram, which indicates which contact is responsible for what (start, operation, ground). They are usually marked with the letters S (Start), R (Run) and C (Common).
In some cases, the terminals on the new relay may not match the wires of your refrigerator. Then you have to cut off the old terminals and strip the wires, connecting them to new contacts by twisting, followed by soldering or using couplings. Insulation such places must be ideal to prevent short circuits.
⚠️ Attention: Make sure the relay is installed in the correct position. The case often has an arrow or inscription
UPpointing to the top. Induction relays only work in a vertical position, otherwise the core will not be able to move correctly.
After physically connecting, slide the relay onto the compressor rod until it stops. Check that the fixation is secure: the part should not dangle. Then reinstall the compressor protective casing, but do not screw it tightly yet in order to be able to observe the first start.
Checking operation and first start
After installing all elements, you can plug the refrigerator into the network. In the first seconds, you can hear a characteristic click - this is the relay activated, starting the motor. If the compressor starts smoothly, without humming or vibration, and after some time cold begins to appear in the chamber, it means the replacement was successful.
Pay attention to the operating time of the motor. It should turn off when the set temperature is reached, and not run continuously. If the refrigerator runs nonstop, the relay may be incorrectly selected or there may be a problem with the thermostat. Also check the temperature of the relay housing: it may become slightly warm, but should not be hot.
During the first hours of operation, it is recommended to periodically check the back wall of the refrigerator for overheating. If all parameters are normal, you can finally secure the casing and move the refrigerator to the wall. Stable operation system is the main indicator of the quality of the repair.
Typical installation mistakes
One of the most common mistakes is ignoring the orientation of the relay during installation. As mentioned earlier, many models are position sensitive. An attempt to push a part “as it fits” often leads to the fact that the mechanism simply does not work, and the motor hums in vain.
Another common mistake is poor contact in the connections. If you changed the terminals, make sure the wire is firmly seated in the clamp. Poor contact causes sparking, heating and eventual melting of the plastic. This can cause a fire, so you cannot skimp on high-quality connectors or solder.
Also, beginners often confuse the starting relay with a capacitor or thermal release, although in modern models they can be combined into one unit. Before purchasing, always check the appearance and number of contacts. Incorrect installation An unsuitable part can damage the compressor.
What to do if the new relay clicks, but the refrigerator does not freeze?
If you hear clicks, but the compressor does not start or stalls immediately; perhaps the problem is not in the relay, but in the compressor itself (an interturn short circuit or a wedge). It is also worth checking the capacitor, if there is one in the circuit, and the condition of the motor windings.
Is it possible to repair an old relay?
Theoretically, you can clean the contacts or replace a burnt out coil, but in practice this is a temporary measure. The cost of a new relay is low, and the reliability of a factory-made product is much higher than that of a home-made one.
Why does the relay heat up during operation?
A little heating is acceptable, but if the relay gets hot, this indicates an overload, incorrect selection of power, or problems with the compressor, which consumes too much current.
How often do you need to change the starting relay?
The service life of the relay depends on the quality of electricity in the network and the frequency of switching on the refrigerator. On average, a part lasts 5-10 years, but power surges can shorten this period to 1-2 years.