If your refrigerator has stopped cooling, but at the same time makes a characteristic click, followed by a hum, and then silence, most likely the problem lies in the start relay. This small component is responsible for starting the compressor motor, and its failure is one of the most common causes of breakdowns in household appliances. Visually, the malfunction often looks like burnt plastic or carbon deposits on the contacts, but for accurate diagnosis and replacement it is necessary to dismantle the unit.
Many owners Indesit, Atlant or Beko are afraid to start repairs for fear of damaging an expensive compressor or compromising the tightness of the system. However, replacing a relay is a procedure that is accessible even to beginners, subject to strict adherence to safety precautions and sequence of actions. The main thing you will need is a minimum set of tools and an understanding of the mechanism, which we will discuss in detail below.
It is important to understand that before starting any work, the refrigerator must be completely disconnected from the power supply. Electric current poses a mortal danger, and residual voltage in the capacitors can lead to unpleasant consequences. Do not neglect this rule, even if it seems to you that you will just “look” at the part.
⚠️ Attention: Before removing the relay, be sure to wait until the compressor has completely cooled down. Working with a hot unit can lead to burns, as well as damage plastic fastening elements that have become brittle from heat.
Diagnosing a faulty starting relay
Before disassembling the equipment, you need to make sure that the problem is really in the starting device. Symptoms may be similar to a malfunction of the compressor or thermostat itself, so initial visual and acoustic diagnosis is critical. If you hear the motor trying to start, humming for a few seconds and clicking sharply as it turns off, this is a classic sign that starting relay cannot close the winding circuit.
Often the cause is a burnt-out nichrome spiral inside the relay or sticking contacts. In some models, for example, in old Soviet refrigerators or modern ones, the relay may have thermal protection, which also fails. If, after removing the casing, you see melted plastic, blackening or feel a burning smell, replacement is inevitable. Liebherr, the relay may have thermal protection, which also fails. If, after removing the casing, you see melted plastic, blackening, or smell a burning smell, replacement is inevitable.
- 🔊 A characteristic click when trying to start, followed by silence.
- 🔥 The presence of visible soot, melting or cracks on the body of the part.
- 🧊 The compressor is hot, but no cold is produced in the chambers.
- ⚡ Knocking out plugs or circuit breakers in the electrical panel when the refrigerator is turned on.
It is worth noting that in inverter models the starting system is implemented differently, and there may not be a classic relay in the usual sense. Therefore, if you have a modern refrigerator with a system No Frost and an inverter motor, it is better to check the manufacturer’s technical documentation.
Necessary tools and workplace preparation
To successfully complete the task of dismantling the relay, you do not need complex industrial equipment. The entire process can be completed with a basic DIY kit. The key point is to organize convenient access to the rear wall of the unit, since the compressor is usually located in the lower niche.
You will definitely need Pliers or pliers to remove the fixing brackets, as well as screwdrivers (Phillips and flathead) to dismantle the protective box. It would be a good idea to prepare a multimeter for subsequent checking of the circuit, although it is not needed for the removal process itself. Also, stock up on a flashlight, since lighting in the area of the compressor is often insufficient.
☑️ Preparation for repair
Pay special attention to the cleanliness of the work area. Dust and dirt trapped inside the compressor's electrical contacts may cause a short circuit in the future. It is recommended to first vacuum the back of the refrigerator, removing dust accumulated over the years of operation from the condenser grille.
Procedure for removing the protective casing and access to the compressor
The first stage of work is to free access to the motor-compressor. In most models, it is covered with a metal or plastic casing, which is secured with latches or screws. Removing this element requires care so as not to damage the cooling system tubes that fit the unit.
If the casing is secured with screws, use an appropriate screwdriver, putting the fasteners in a separate container so as not to lose them. Models Samsung or LG often use plastic latches that need to be pressed out with a flat-head screwdriver. Proceed with caution: old plastic can be dry and brittle.
After removing the lid, you will see the “heart” of the refrigerator. You will see a black cylindrical or pear-shaped cylinder - this is the compressor itself. At its end or side there will be a plastic box to which the electrical wires fit. It is this unit that we have to dismantle.
⚠️ Attention: It is strictly forbidden to bend the copper tubes coming from the compressor. Even a microscopic crack in the metal will lead to a leak of freon, after which repairs will become economically unfeasible.
Technology for removing the relay from the compressor
The process of removing the relay itself varies depending on its design, but the general principle remains the same. The device is placed directly on the contact rod of the compressor and is fixed either with a special bracket or spring clips. Your task is to release the latches without applying excessive force to the rod itself.
In classic versions, such as the relay series RT or RKT, a U-shaped metal strip is used. It covers the relay body and is secured with a screw or simply clamped onto a spring. To remove it, you need to carefully press the edges of the strip with pliers and pull it down. In more modern models, plastic latches can be used that snap off with light pressure.
After removing the clasp, the relay must be carefully pulled towards you. It should come off the three contact pins of the compressor. It is important here not to rock the part from side to side too much, so as not to loosen the soldering joints of the tubes inside the compressor housing. If the relay has become “stuck” due to time and temperature, you can slightly rock it, holding the body and not the wires.
What to do if the relay cannot be removed?
If the relay does not budge, do not use brute force. Try gently heating the plastic case with a hairdryer at low temperature for 10-15 seconds - the plastic will become more elastic. You can also use penetrating lubricant (WD-40) on the joint, but be careful not to get it on the electrical contacts or in the compressor connector.
When the part is removed, carefully inspect the seat on the compressor. There should be no oxides or moisture there. If the contacts are oxidized, they can be carefully cleaned with fine sandpaper, but this must be done extremely delicately.
Relay types and compatibility table
There are many types of starting relays, and they are not always interchangeable. The main difference lies in the principle of operation (electromagnetic, posistor) and the location of the contacts. Installing an unsuitable part can lead to burnout of the compressor windings.
The most common are posistor relays, which operate silently and have no moving mechanical parts inside. Electromagnetic options, on the contrary, make a clicking sound every time they start. When purchasing a new part, be sure to check the markings.
| Relay type | Operating principle | Characteristic sound | Compatibility |
|---|---|---|---|
| Posistor (PTC) | Heating of the resistance element | Absent | Most modern models |
| Electromagnetic | Retracting the core | Loud click | Old models, industrial |
| With thermal protection | Bimetallic plate | Clicking when overheated | Combined units |
| Universal | Combined | Depends on type | Requires selection adapter |
When choosing an analogue, pay attention to the number of contacts and their geometry. Even if the electrical parameters match, a physically unsuitable connector will not allow the part to be installed. The marking is usually applied to the side or top edge of the case, for example 17-119 or 345U.
Installation of the new part and testing performance
The process of installing a new relay is a mirror image of dismantling. First, make sure that the new part fully matches the removed one in appearance and connector. Carefully push the relay housing onto the contact pins of the compressor until it stops. You should feel a tight fit.
Then return the retaining bracket or latch back into place. Make sure it holds the device securely and does not wobble. If a screw fastening is used, tighten it, but not too much, so as not to strip the threads in the plastic base. After this, you can connect the wires to the relay contacts if they were disconnected.
At this stage, it is important to correctly position the wires so that they do not touch the hot parts of the compressor or moving elements, if any. Secure the wires with standard clamps or clamps. Now you can return the protective cover of the engine compartment to its place and secure it.
The final stage is to turn on the refrigerator. In the first seconds, listen to the operation of the unit. The compressor should start smoothly, without a humming sound and a subsequent shutdown click. After 10-15 minutes of operation, check whether the condenser grille at the back or the side walls (depending on the model) begins to heat up, which indicates the start of refrigerant circulation.
⚠️ Attention: If, after replacing the relay, the refrigerator makes unusual sounds or knocks out the circuit breaker, immediately unplug it. This may indicate a malfunction of the compressor itself, which could have suffered due to working with an old relay.
Frequently asked questions (FAQ)
Is it possible to repair a burnt out relay or just replace it?
In the vast majority of cases, repairing a relay is impossible and inappropriate. Inside there is a nichrome spiral or posistor, which, when burned out, changes its physical properties. Attempting to solder contacts or replace internals often results in unstable operation and risk of fire. The cost of a new part is low, so replacing it with a new one is the only correct solution.
Why does a new relay burn out after a short time?
If replacing the relay does not solve the problem and the new part fails, the reason lies deeper. Most often, this is a malfunction of the compressor itself (turn-to-turn short circuit of the windings), problems with the thermostat (does not turn off the compressor, causing overheating) or power surges in the network. In such cases, professional motor diagnostics are required.
What is the difference between the relay for a single-phase and two-phase compressor?
The main difference is the connection diagram and the number of contacts. Two-phase compressors (often found on high-power models) require a relay capable of switching two windings simultaneously or in series. Installing the wrong type of relay will result in the motor either not starting or running on only one winding, quickly overheating.
Is it necessary to evacuate the system when replacing the relay?
No, when replacing the starting relay, the sealed circuit with freon is not broken. All work is carried out exclusively in the electrical part of the unit. Evacuation and charging with refrigerant are required only if copper tubes have been damaged as a result of careless actions.
How to determine the polarity of connecting the wires to the relay?
Most household refrigerators use alternating current, so the concept of polarity for connecting the supply wires to the relay is not critical - they work in both directions. However, it is important not to confuse the wires coming from the thermostat and from the power plug if their markings are not obvious. It is best to photograph the connection before removing it or use a multimeter to “test” the circuit.