A sudden failure of refrigeration equipment often takes you by surprise, and one of the most common causes of such a breakdown is the failure of the start-up relay. This compact but critical component is responsible for starting the compressor motor and protecting its windings from overloads. If you notice that your Indesit or Atlant hums, but does not start, or the compressor only works for a few seconds and clicks, then most likely the problem lies in this component.
Replacing the relay yourself is a real opportunity to save on calling a technician and bring the equipment back to life in one evening. However, the procedure requires attention to detail and strict adherence to electrical safety rules, since you will be working with mains voltage. In this article, we will analyze in detail the design of the unit, diagnostic methods and an algorithm of actions that will allow you connect the relay correctly without the risk of damaging an expensive compressor.
Before you begin disassembling, you need to understand that different models of refrigerators can be equipped with different types of starters. There are induction devices with a posistor and thermal releases, each of which has its own installation features. An incorrectly selected or installed part can lead to repeated breakdown or even fire of the wiring, so approach the issue of replacement with maximum responsibility.
Diagnostics of the fault and signs of breakdown
The first step before purchasing a new part and starting work should be an accurate diagnosis. Often the symptoms of a relay malfunction are disguised as other problems, for example, a freon leak or a compressor wedge. If the unit turns on, makes a characteristic click and turns off after 3-5 seconds, this is a classic sign that the starting mechanism cannot break the starting winding circuit or is not able to start the rotor.
For the initial check, it is not necessary to immediately disassemble the unit. Listen carefully to the operation of the motor. If you hear a hum, but do not start, try to gently touch the compressor housing (without burning yourself) - it may be hot, which indicates attempts to start. It is also worth checking the integrity of the contacts on the relay itself: oxidation or carbon deposits can prevent the flow of current.
There is a simple way to check the functionality of the device, which allows you to eliminate mechanical damage. To do this, the relay is removed from the compressor and gently shaken next to the ear. If a ringing or knocking sound is heard inside, it means that the contact group or posistor is damaged, and the part requires mandatory replacement.
- 🔊 A characteristic click when turned on and the subsequent attenuation of the sound after a few seconds.
- 🔥 Strong heating of the compressor housing when the engine is not running.
- ⚡ Absence of the characteristic hum of a running motor when the refrigerator is plugged in.
- 💥 Broken plugs or tripped circuit breaker when trying to start the equipment.
⚠️ Attention: If after replacing the relay the situation repeats, the compressor itself may be faulty (interturn short circuit) or there are problems with the wiring. Continuing operation in this mode is dangerous!
Selecting a suitable starting relay
The key to successful repairs is the selection of an identical or compatible part. Start relays are not universal and installing the wrong component may burn out the motor windings. First of all, you need to focus on the markings on the body of the old device, as well as on the model of your refrigerator, be it LG, Beko or Stinol.
When choosing, pay attention to the type of compressor and its power. Devices are divided into single-phase and two-phase, and also differ in the method of fastening and the location of contacts. For example, compressors Danfoss often require specific relays with side mounting, while domestic models can use vertical installation.
If you cannot find an original spare part, you can use universal analogues, but only if the electrical characteristics match. It is important to check the current parameters: the cut-off current must correspond to the requirements of the motor, otherwise the protection will trigger falsely or, conversely, will not work in case of overload.
| Parameter | Description | Importance |
|---|---|---|
| Connection type | Vertical or horizontal arrangement on the shaft | High |
| Number of contacts | Usually 3 or 4 pins for connecting wires | Critical |
| Strength current | Value in Amperes (for example, 1/4 HP, 1/3 HP) | High |
| Manufacturer | Original or certified analogue (Danfoss, Embraco) | Average |
Preparation of tools and safety measures
Working with electrical appliances requires compliance with strict safety rules, neglect of which can lead to injury electric shock. Before starting any manipulations, be sure to disconnect the refrigerator from the electrical network by removing the plug from the outlet. Even if the equipment seems to be turned off, there may be a residual charge in the capacitors.
To carry out high-quality repairs, you will need a minimum set of tools that any DIYer can find in his home. Pay special attention to the condition of the wire insulation: if the braid is dry and cracked, it must be restored before connecting a new relay to avoid a short circuit.
It is also worth preparing the work area. Remove the rear panel of the refrigerator to gain access to the compressor. Dust and animal hair often accumulate there, which can cause overheating, so cleaning the space around the motor will not be superfluous.
- 🔧 A set of screwdrivers (phillips and flat) for removing the casing and clamps.
- 🧤 Dielectric gloves to protect your hands when working with wiring.
- 🔦 Flashlight for high-quality illumination of the working area in the compressor niche.
- 🧹 Brush or vacuum cleaner to clean the contacts and surface of the motor from dust.
⚠️ Attention: It is strictly forbidden to carry out repair work if the floor in the room is wet or you are standing on a metal surface without dielectric shoes.
☑️ Readiness to replace the relay
Removing the old starting relay
The process of removing the faulty part begins with a visual inspection of how it is attached to the compressor. In most modern models, the relay is simply slipped onto the three pins of the compressor and secured with a bracket or plastic clip. Your task is to carefully remove the fixing element, without using excessive force, so as not to damage the copper tubes.
After removing the fasteners, you need to disconnect the wires. Before doing this, it is strongly recommended to photograph the connection diagram or sketch it, since the color marking of the wires from different manufacturers (Electrolux, Haier, Liebherr) may differ. Remember which wire was connected where, so that during assembly you do not confuse phase and zero.
When removing the old relay from the compressor contacts, proceed carefully. Rock it from side to side, gradually pulling it down. If the part is stuck or rusted, do not use force - it is better to carefully treat the joint with a rust remover or slightly warm it up (with caution).
After dismantling, inspect the contact group on the compressor itself. If you notice traces of carbon deposits, oxidation or melting, clean the contacts with fine sandpaper or a file. Clean contacts will ensure a reliable connection and prevent sparking in the future.
What to do if the contacts on the compressor are oxidized?
If the compressor pins are blackened or covered with a green coating, they must be cleaned to a metallic shine. Use fine sandpaper or a special contact cleaner spray. After cleaning, wipe the surface with a dry cloth. If the oxidation is deep and the pins are corroded, soldering or replacing the supply wires may be required, but this is a more complex repair.
Step-by-step diagram for connecting a new relay
Installing a new starting relay is a process reverse to dismantling, but it requires increased concentration. First of all, make sure that the new device is oriented correctly: there is usually a marking UP or arrow on the case indicating the top position. Incorrect orientation will result in the mechanism not working.
Push the relay onto the contact pins of the compressor until it stops. It should fit tightly and not wobble. If the fit is different, you may need an adapter, which is often included with universal models. Make sure that the contacts fit into the relay sockets without distortion.
Now the most important thing is connecting the wires according to the previously made diagram or photograph. Connect the phase and neutral wires to the corresponding relay terminals. Color differentiation is usually used, but you cannot rely on color alone - check the markings on the case or the diagram in the instructions.
Connection diagram (standard):L (Line) -> Phase (usually brown/black)
N (Neutral) -> Zero (usually blue/white)
G (Ground) -> Grounding (yellow-green)
After connecting the wires, secure the relay with a fixing bracket or strip. Check the reliability of all connections: the wires should not sag or touch hot parts of the compressor or sharp edges of the housing. It is critical that no wires touch the copper pipes of the refrigeration system.
Testing and first launch of the system
After installation is completed, it is necessary to carry out a preliminary check before installing the protective casing in place. Plug in the refrigerator and carefully monitor the behavior of the compressor. In the first seconds, a confident startup sound should be heard, without a long hum or sparking in the relay area.
If the startup was successful, let the equipment run for 10-15 minutes in the open state. At this time, you can check the current consumption using a multimeter (if you have the skill) or simply monitor the heating of the relay. It may be slightly warm, but should not be scalding hot.
Make sure that the refrigerator and freezer compartments have started to get cold. If after 20-30 minutes of operation (the evaporator) begins to cool and the relay does not make any extraneous clicks, the repair can be considered successful. Now all that remains is to put the protective cover of the compressor back in place.
- ✅ The compressor started on the first try without a long buzz.
- ✅ There is no sparking or burning smell in the connection area.
- ✅ The relay does not heat up above 60-70 degrees during the process operation.
- ✅ The refrigerator began to gain temperature in normal mode.
⚠️ Attention: If, after turning on, the machine knocks out or a cracking sound is heard, immediately disconnect the device from the network. This indicates a short circuit or incorrect connection of the wires.
Frequent errors and troubleshooting
Even with a careful approach, beginners can make mistakes that will negate all efforts. One of the most common problems is ignoring the orientation of the device. Many people forget to turn the relay to the desired position, which is why the posistor does not cool or the contacts do not close correctly.
Another common mistake is poor contact in the terminals. If the wire is not inserted completely or is oxidized, heat will begin to be generated at the connection point, which will lead to melting of the plastic and repeated failure. Always check the tightness of the wires and tighten the terminals if necessary.
Also, do not forget about compatibility. Installing a relay with a lower cutoff current will lead to constant false shutdowns, and with a larger one, it will lead to overheating of the windings. If you are not sure about the parameters, it is better to consult with a specialist or find an exact analogue in the catalog.
Is it possible to use a relay from another refrigerator?
You can use a relay from another model only if their electrical characteristics (current, type of compressor) and geometric dimensions completely coincide. Visual similarity does not guarantee performance. It is better to choose an analogue by catalog number.
Why did the new relay burn out immediately after installation?
This can happen due to a malfunction of the compressor itself (short circuit of the windings), a power surge in the network or incorrect connection of the wires (the phase and zero are reversed if the relay is sensitive to polarity, although for most this is not critical, but it is important grounding).
How long should the relay operate before turning off?
The starting relay only works when the engine starts (1-3 seconds). After the rotor starts, it should click and turn off the starting winding. If it does not turn off, the compressor will quickly burn out.
Do you need to lubricate the relay contacts?
No, you cannot lubricate the contacts inside the relay or on the compressor. This will lead to the formation of carbon deposits and disruption of electrical conductivity. Everything should be dry and clean.
Is it dangerous to change the relay yourself?
The procedure is not complicated, but is associated with the risk of electric shock 220V. If you are not confident in your abilities or do not have basic electrical skills, it is better to entrust the repair to a professional.