The situation when the refrigerator stops freezing, and the compressor either hums but does not start, or clicks and goes silent after a couple of seconds, often indicating a failure of the start-up relay. This small but critical element is responsible for supplying a starting pulse to the motor winding and protecting against overheating. If you notice such symptoms, self-diagnosis and, possibly, replacing the relay can bring the equipment back to life without calling a technician.
Before starting disassembly, you must clearly understand that the work will be done with electrical equipment. Safety is priority number one. In this article we will analyze in detail the process of dismantling the relay, consider the differences between induction and posistor models, and also point out subtleties that will help avoid damage to the contacts or the compressor itself. Dismantling usually does not require a complex tool, but requires care and adherence to the sequence of actions.
The success of the operation largely depends on proper preparation of the workplace and understanding of the unit structure. Do not rush to pull off parts if they are stuck or clamped with clamps. We will consider an algorithm of actions that is suitable for most household refrigerator models, including popular brands like Indesit, Beko, Atlant and Stinol. A correctly performed removal procedure will allow you to visually assess the condition of the contacts and decide on further actions.
⚠️ Attention: Before starting any work on removing the relay, be sure to disconnect the refrigerator from the power supply! Unplug the plug from the socket. Working with live electrical wiring is deadly.
Diagnostics and signs of relay malfunction
An understanding of what exactly has failed comes even before disassembly begins. If the compressor tries to start, makes a loud click, hums for a few seconds, then clicks again and becomes silent, this is a classic symptom. At this moment starting relay cannot close the starting winding circuit or, conversely, does not open it in time. Also, a malfunction may be indicated by strong heating of the compressor housing in the absence of cold in the chambers.
Sometimes the relay does not fail completely, but works intermittently. In such cases, the refrigerator may be silent for a long time, and then suddenly start. This indicates that the inside contacts has been burnt or oxidized, creating a high contact resistance. Another option is a malfunction thermal release, which prematurely breaks the power circuit, preventing the engine from gaining speed.
For an initial check, you can carefully remove the back cover (if there is one) and listen to the operating unit. If you hear a hum, but the shaft does not spin, and after 5-10 seconds you hear a shutdown click, the problem is almost certainly in the starter or the motor itself. It is important to distinguish this from the situation when the compressor hums smoothly and for a long time, but does not start - there may already be a jamming of the mechanical part, and replacing the relay will not help.
Necessary tools and preparation
In order to remove the relay, you do not need a whole arsenal of plumbing tools. In most cases, a minimum of equipment that can be found in every home is sufficient. The main thing is to ensure good access to the compressor, which is usually located at the lower rear of the unit. Sometimes this requires moving the refrigerator away from the wall, which requires physical strength or an assistant.
You may need the following tools:
- 🔧 Screwdriver (Phillips or flathead) - to remove the protective cover if it is secured with screws or latches.
- 🧤 Pliers or pliers - for carefully removing fixing brackets or clamps if they are rusty.
- 🧼 Dry rags - for wiping contacts and removing dust from the compressor.
- 📸 Smartphone - to photograph the wiring diagram before removal.
Pay special attention lighting. The compressor niche is often dark, so use a flashlight to avoid damaging fragile plastic parts or wires. Also make sure that the floor under your feet is dry to prevent slipping when working with a heavy machine. If traces of oil are visible on the compressor, it is better to remove them immediately so that your hands do not slip on metal parts.
☑️ Ready for repair
Types of starting relays and their features
Before you start dismantling, it is useful to know what type of device you have matter. This affects how it is attached and how it behaves when it malfunctions. In modern and not very old refrigerators, two main types are most often found: induction (electromagnetic) and posistor (thermal). They can be distinguished by their appearance and number of contacts.
Induction relays, often labeled as RTP, RT, R-1, have a more complex internal structure with a coil and a movable core. They are position sensitive: on their body there is an arrow or the inscription “UP”, indicating that the relay must be positioned strictly vertically. Posistor analogs (for example, RTK) are more compact, do not have moving mechanical parts inside and work by changing the resistance of the ceramic element when heated.
It is important to understand that that the interchangeability of these devices is limited. You cannot simply replace an induction relay with a posistor relay without changing the connection diagram, since they have a different operating principle and number of pins. Below is a table that helps you quickly identify the type of device by markings and external features.
| Relay type | Characteristic markings | Number of contacts | Position sensitivity |
|---|---|---|---|
| Induction | RTP, RT, R-1 | Usually 3 or 4 | High (vertical only) |
| Posistor | RTK, 17.500 | Usually 3 | Low (works in any position) |
| Combined | RT-X, 11730 | 3 or 4 | Depends on the model |
| Electronic | Without mechanics | Miscellaneous | Not sensitive |
Can I use a relay from another refrigerator?
The use of a relay from another model is possible only if the markings, number of contacts and type (induction/posistor) completely match. Otherwise, there is a high risk of burning the compressor.
The process of removing the protective casing
Access to the relay is covered by a protective plastic or metal casing that covers the back of the compressor. Removing this element is the first physical stage of the work. Depending on the refrigerator model, the casing can be attached with screws, latches, or simply held in place by a tight fit on rubber shock absorbers. Be careful, the plastic becomes brittle over time.
If you see screws, carefully remove them with a suitable screwdriver. Do not use excessive force to avoid stripping the threads or crumbling the plastic. If there are no fasteners, inspect the perimeter of the casing. It is often secured with a metal "U" shaped bracket that wraps around the casing and presses it against the compressor housing. This bracket needs to be pryed off with a flat screwdriver and removed.
In some cases, especially on older models, the casing can simply be put on top and held in place by friction. In this case, you need to gently pull it down or to the side (usually down), while holding the compressor with your other hand. Do not pull sharply so as not to damage the wires suitable for the relay or the copper tube that may be running nearby.
How to properly remove the relay from the compressor
After removing the casing, you will see a view of the compressor with a relay attached to its end. It can be installed directly on the motor terminals or connected to them through a short block. The most common option is that the relay is placed directly on the three pins coming out of the compressor housing. To remove it, you need to act confidently, but without jerking.
Grab the relay with your hand by the body (not by the wires!) and try to pull it down with rocking movements from side to side. It may sit very tightly due to oxidation of contacts or vibration during operation. If you can’t remove it by hand, you can carefully use pliers, but be sure to go through a layer of fabric so as not to split the plastic body of the device. Contact The inside may be stuck, so some effort will be required.
If the relay is connected to the compressor through an intermediate terminal block, you first need to disconnect it. Sometimes the block is additionally secured with a metal clamp or clip. Remove the clamp, move the block to the side and only then remove the relay itself. Remember that the wires from the thermostat and the network are suitable for the relay - do not pull on them, so as not to break the soldering inside the compressor housing.
⚠️ Attention: Never try to remove the relay by pulling on the wires that go to it! This will lead to broken wires and the need to restore the wiring, which will complicate repairs.
Checking contacts and visual inspection
Once the relay is in your hands, conduct a thorough visual inspection. Shake the device near your ear: if a ringing or knocking sound is heard inside, it means that the mechanical part is destroyed or the core has fallen off - such a relay is definitely faulty. PTC models must be monolithic and not make sounds when shaken.
Inspect the mounting holes and contact pads. They must be clean, without traces of soot, black soot or melted plastic. The presence of a burning smell is a sure sign that a short circuit or overheating has occurred inside. If the contacts are blackened, you can try to clean them with fine sandpaper, but this is a temporary measure: reliability such contact will be low.
Pay attention to the condition of the springs and moving elements (if the relay is inductive). The spring must be intact and elastic, and the movable core must move freely inside the coil. Core sticking is a common reason why the relay does not open the starting winding, which leads to motor burnout. Also check the integrity of the ceramic posistor: there should be no cracks or chips on it.
Installation of a new relay and assembly
Installation of a new device is carried out in the reverse order of removal. First of all, make sure that the new relay has the same markings and wiring diagram as the old one. Align the holes on the relay with the pins on the compressor. It is important to orient the device correctly: the top and bottom should correspond to the markings on the case (usually "UP" or an up arrow). If the polarity or orientation is reversed, the inductive relay will not work.
Push the relay all the way until it sits tightly on the terminals. Make sure that the wires are not pinched between the relay housing and the compressor or touching hot parts. If a retaining bracket or clamp was used, return it to its original location. Then put on the protective cover and secure it with screws or latches. Check that all the wires are laid neatly and do not dangle.
After assembly, do not rush to immediately plug in the refrigerator. Let the device sit for 10-15 minutes, especially if you held it in your hands for a long time or the room was cold. This is necessary to stabilize the temperature of the internal components. Only after this can you turn on the unit and check the first start: the compressor should start on the first try and run smoothly, without buzzing or clicking.
What to do if the new relay does not fit in size?
Sometimes it happens that the analogue has a slightly different size of mounting holes. If the difference is insignificant, you can carefully widen the holes in the relay housing with a hot awl or drill, but you must act extremely carefully so as not to damage the insides. If the design is fundamentally different, it is better to look for an original spare part.
Is it possible to repair an old relay?
Theoretically, an induction relay can be disassembled (by carefully lifting the cover), cleaned the contacts and reassembled. However, the tightness and reliability of such repairs are questionable. PTC relays cannot be repaired, as they are a monolithic unit. Considering the low cost of new parts, repairing an old relay is most often impractical.
Why did the new relay burn out?
If after replacing the relay it fails again, the reason may be deeper. Often the compressor itself is to blame: an interturn short circuit in the windings leads to increased current consumption, which melts the relay contacts. The problem may also be a faulty thermostat, which does not allow the compressor to rest, causing it to constantly overheat.
How to distinguish a relay malfunction from a compressor breakdown?
The simplest way is to “ring” the compressor windings with a multimeter. If the resistance between the contacts is infinitely high (open) or close to zero (short circuit), then the compressor is faulty. If the windings are intact and the refrigerator does not start, most likely the problem is in the relay or the starting capacitor.
Does it need to be replaced with the starting capacitor along with the relay?
If your refrigerator model has a separate starting capacitor (black cylindrical element), it is also recommended to check or replace it preventively, especially if the relay burned out due to power surge. An old capacitor may have a changed capacity, which will make it difficult to start the engine even with a new relay.