If your refrigerator stops cooling, and the compressor either hums and clicks, or is silent, the problem often lies in the start-up relay. This small part is responsible for starting the engine and protecting against overloads. Replacing or diagnosing a relay is one of the most common procedures when repairing household appliances with your own hands, which does not require complex specialized equipment.
However, before starting any work, it is necessary to completely de-energize the unit. Working with live electrical components is fatal. After unplugging the power cord from the outlet, carefully move the refrigerator away from the wall, providing free access to the rear panel where the motor-compressor is located.
In this article we will look in detail at how to properly dismantle the relay without damaging the fragile contacts and tubes of the cooling system. You will learn how to determine the type of your device, what tools will be needed and what to pay special attention to so as not to damage an expensive compressor compressor
Diagnostics and signs of relay malfunction
Before removing the part, you should make sure that the problem is real in it. Often the symptoms of a relay malfunction are confused with a breakdown of the motor or thermostat itself. The main sign of failure of the starting mechanism is a characteristic click, followed by a hum that lasts a few seconds, after which there is a second click and silence.
If you hear this cycle repeating every few minutes, it means that the motor windings are trying to start, but the relay cannot close the starting winding circuit or it immediately opens the contacts due to a false operation of the protection. In some cases, the relay may “stick” and the compressor operates continuously without turning off, which leads to overheating and the formation of an ice coat in the chamber.
For an initial check, you can use a multimeter in continuity mode. The integrity of the coil and contacts is checked without removing the part, but a more accurate result is obtained by visual inspection after dismantling. There should be no traces of burning, plastic melting or contact oxidation inside the case.
⚠️ Attention: If the compressor makes a loud metallic knock or hum when you try to start, and then clicks, do not try to turn on the refrigerator repeatedly. This can lead to a wedge of the piston group and final breakdown of the motor.
Necessary tools and workplace preparation
To successfully complete the task of dismantling the relay, you will need a minimum set of tools. The main thing is to ensure that the work area is well lit, since the back of the refrigerator is often dark and covered in dust. Prepare a flathead and Phillips screwdriver, as well as needle-nose pliers.
Be sure to have an ice container or a rag ready, as condensation or oil may drip when removing the compressor casing. It would also be a good idea to have on hand WD-40 or a similar solvent if the contacts are heavily oxidized, although chemicals are rarely required when removing a relay.
It is important to organize the workplace so that nothing interferes with movement around the refrigerator. Remove carpets; children and pets should not be in the work area. It is better to put all removed screws and small parts in a magnetic tray or a separate box so as not to lose them.
- 🔧 Screwdrivers (flat and Phillips) for removing the protective cover.
- 🔌 Pliers or pliers for working with terminals.
- 🧤 Dielectric gloves for additional safety.
- 🔦 Flashlight for illuminating hard-to-reach places.
Removing the compressor protective casing
Access to the relay is blocked by a metal or plastic casing that covers the back of the compressor. Depending on the refrigerator model (Indesit, Atlant, Beko), the method of attaching the casing may differ. It is usually fixed with screws or special latches.
If the casing is screwed on, unscrew all visible screws around the perimeter. Be careful: the metal can be sharp and the paint can peel, so work carefully. If a system of latches is used, they must be carefully pressed out with a flat screwdriver, trying not to damage the plastic, which could become brittle over time.
After removing the fasteners, the casing is moved to the side or removed upwards. Under it you will see a black compressor cylinder, copper tubes and the same relay placed on the contact group. Often the casing is covered with a layer of sticky dust, so immediately prepare the place where to put it.
⚠️ Attention: The copper tubes suitable for the compressor are very thin-walled and soft. Under no circumstances should you lean on them or bend them when removing the casing, otherwise the system will depressurize and repairs will become economically unfeasible.
Types of relays and features of their design
Before pulling the part, you need to understand what type of device you are dealing with. There are two main types of start relays used in modern and older refrigerators: inductive (positional) and thermal start (PTC). The method of their dismantling and the principle of operation depend on the type.
Induction relays operate on the basis of an electromagnetic field and are often marked RT or RTP. They are noisier and heavier. Thermal start relays contain a ceramic element that is heated by current and changes resistance; they are lighter, often marked RTK or MR.
What is the difference between a posistor and an induction one relay?
An inductive relay opens the contacts mechanically using a movable core when the engine picks up speed. A posistor (thermal relay) does this by changing resistance when heated, without having moving mechanical parts inside the ceramic element.
You can visually distinguish them by shape and weight. Induction ones often look like chunky black boxes, while thermal ones can be smaller and lighter. Also pay attention to the markings on the body - it will tell you which analogue to look for in case of replacement.
| Relay type | Principle of operation | Characteristic sound | Marking |
|---|---|---|---|
| Induction | Electromagnetic | Loud click | RT, RTP, RN |
| Thermal starting (PTC) | Thermal (posistor) | Quiet or no sound | RTK, MR, 33N |
| Combined | Heat + Electric | Average | RTK-X |
The process of disconnecting the relay from the compressor
The process of removing the relay itself requires accuracy and understanding of the fastener design. The relay is placed on three contact pins coming out of the compressor housing and is additionally secured with a metal bracket or strip. First you need to release the retaining element.
Find the metal strip that presses the relay to the motor housing. It can be secured with a screw or simply snapped into place. If there is a screw, unscrew it. If the bar is held on by a spring or latch, gently press it out with a screwdriver. After this, the relay should be free to move, but still sit on the contacts.
Now take the relay by the body (not by the wires!) and remove it from the pins with a rocking motion from side to side. Do not pull sharply upward, so as not to break the plastic contacts inside the relay itself or damage the compressor leads. If the relay is tight, you can slightly help yourself with a flat screwdriver by prying up its base, but very carefully.
☑️ Algorithm for removing the relay
After removing the relay, wires depart from it, connected to a common terminal block or directly. To finally remove the part for inspection or replacement, you must disconnect these wires. They are usually held on by clips or fit tightly over the contacts. Use pliers to tighten the terminals, holding the wire at the base.
Typical mistakes during dismantling
One of the most common mistakes is the use of excessive force. If the relay cannot be removed, it means that you have not completely released the retaining bracket or have not understood the principle of its fastening. A jerk can lead to breaking off the compressor contact pins, which will require complex repairs with flaring and welding.
Another mistake is ignoring the condition of the wires. Old insulation on refrigerator wires often becomes oaky and cracks. If handled carelessly, the insulation can be damaged, which will lead to a short circuit to the housing the next time you turn it on. Always check the integrity of the insulation before installing a new relay.
Also, beginners often forget to clean the compressor contacts before installing a new part. Oxides and carbon deposits on the pins can cause poor contact and repeated failure. Clean the pins with fine sandpaper or an eraser until they shine.
⚠️ Attention: Never check the operation of the relay by connecting it to the compressor without a protective casing and outside the refrigerator body if you are not sure of your actions. This can lead to electric shock, since the contacts are under high voltage.
Checking the removed relay and choosing a replacement
After the relay has been removed, it can be checked. Shake the PTC relay near your ear: if something rattles inside, the ceramic element has crumbled and the relay needs to be replaced. The induction relay is checked by testing the contacts: in the initial position the circuit must be open, and when voltage is applied (which is difficult to do at home without a test bench) it must be closed.
When purchasing a new relay, matching the parameters is critically important. They must match the power and type of compressor of your refrigerator. Markings on the case (for example, 1/4 HP or 1/5 HP) indicate the power for which the device is intended. Using a relay with an unsuitable power range will either result in engine failure or burnout.
Installation is carried out in the reverse order: first, the wires are put on the relay contacts, then the relay is put on the compressor pins all the way, and only then is it fixed with a metal strip or screw. Make sure that the relay sits tightly and does not loosen.
- 🔍 Check the integrity of the ceramic element inside the relay.
- ⚡ Test the contacts with a multimeter for a break.
- 🧹 Clean the contact groups before reassembling.
- 📝 Compare the markings of the old and new relays.
Is it possible to install a relay from another refrigerator model?
Installation of a relay from another model is possible only if the electrical parameters (rated current, power) and the geometric dimensions of the seat completely match. However, it is better to look for an original analogue or a universal relay with an adjustable power range to avoid the risk of the compressor breaking down again.
Why does the relay burn out repeatedly (constantly)?
If the new relay burns out soon after replacement, the reason is most likely not in it. The problem may be in the compressor itself (turn-to-turn short circuit of the windings, wedge), in a malfunction of the thermostat (which does not allow the compressor to rest), or in power surges in the network. In such cases, in-depth diagnostics of the motor is required.
Is it necessary to change the relay if the refrigerator works, but clicks?
If the refrigerator is cold, the cooling cycle is observed, but a loud click is heard when starting, this may be a sign of aging of the relay. It still works, but the contact has already been broken. Replacing in this case will extend the life of the compressor, since poor contact causes sparking and heating, but there is no urgency if the temperature in the chamber remains the same.
Relay service life
On average, a start-up relay lasts from 5 to 10 years, but with frequent power surges or overheating of the compressor, it can fail much earlier. Preventive replacement every 10 years is considered a good practice for old refrigerators.