A sudden failure of a refrigeration chamber or compressor often causes panic, but in many cases the problem lies in a small but critical part - the start relay. It is this small element that is responsible for starting the engine, and if it fails, the refrigerator stops cooling or begins to make strange clicking sounds. Understanding how to remove a relay from a refrigerator can save you a significant amount of money on calling a technician and extend the life of your household appliances.
The replacement process does not require deep engineering knowledge, but does require compliance with safety precautions and care when working with electrical components. In this article we will analyze in detail the design of the trigger mechanism, consider the types of relays used in different models, and step by step describe the algorithm for dismantling and installing a new part. You don't need complex tools, just a basic DIY kit.
Before you start disassembling, it is important to make sure that the problem really lies in the relay, and not in the compressor or thermostat itself. Diagnostics starts with a visual inspection and listening to the operation of the unit. If you hear a buzzing noise followed by a clicking sound and then cutting off, this is a sure sign that the trigger is not doing its job. Next, we will look at what tools are required for the job.
Tools and safety measures during work
Any work with electrical appliances requires strict adherence to electrical safety rules. Before you start removing the relay, you must completely turn off the power to the refrigerator by unplugging the plug from the socket. Do not rely solely on the switch on the case, as it may not completely break the circuit. It is also worth preparing a workplace with good lighting in order to see small contacts and wire markings.
For dismantling you will need a minimum set of tools, which is usually found in every home. The main tool will be a flathead and Phillips screwdriver, as well as pliers for working with clamps. In some cases, you may need a multimeter to check the continuity of the circuit if you plan to diagnose the old part before disposal.
- 🛠️ A set of screwdrivers (flat and Phillips) for removing the casing and terminals.
- 🔌 Pliers or side cutters for carefully disconnecting the wires.
- 🧤 Dielectric gloves for protection against residual voltage.
- 📸 Smartphone for photographing the connection diagram before disassembling.
⚠️ Attention: Capacitors in the compressor power circuit can retain a charge even after being disconnected from the network. Do not touch live parts with your bare hands immediately after turning off the device; let the equipment stand for 10-15 minutes.
Work only with the external electrical part. If you see traces of melted wiring or smell a burning smell, this is a signal of a serious malfunction that requires professional attention.
Use multimeter will allow you to accurately determine whether there is an open circuit in the relay circuit. However, if you do not have experience working with electrical measuring instruments, it is better to limit yourself to a visual check and replace the part with a known good one, since the price of a new relay is usually low. Safety should be priority number one.
Diagnosis of a faulty start relay
Before removing the relay, you need to make sure the diagnosis is correct. The symptoms of a malfunction of this unit are quite specific and are rarely confused with other breakdowns. Most often, owners are faced with a situation where the engine tries to start, hums for a few seconds, then a loud click is heard and the unit goes silent. After some time, the cycle repeats.
Another sign is overheating of the compressor. If you touch the back wall of the refrigerator near the motor and feel that it is hot, although there is no cold in the chambers, this may indicate that the relay does not turn off the starting winding or cannot turn it on. In such cases thermal protection triggered, preventing engine combustion.
Visual inspection of the removed relay often shows clear signs of a malfunction. Inside the case there may be a charred coil, melted contacts, or even an insulation breakdown. If the relay emits a burning smell or a ringing sound is heard when shaken inside (like broken ceramic), its replacement is inevitable. Modern models often have markings that can be used to determine the type of malfunction.
Sometimes the problem lies not in the relay itself, but in sticking contacts or oxidation of the terminals. In such cases, cleaning the contacts can temporarily solve the problem, but it is better to make a complete replacement, since the life of the part has already been exhausted. Electromagnetic and posistor relays have different principles of operation, but the symptoms of their failure are similar.
Why does the relay fail?
A common cause of relay burnout is unstable voltage in the network or power surges. Natural wear of contacts and aging of insulation materials also lead to breakdowns. If the lights in your home flicker frequently, it is recommended to install a voltage stabilizer to protect all household appliances.
Types of starting relays and their design
Understanding the differences between the types of relays will help you choose the right replacement and avoid installation errors. Modern and old refrigerators use two main types of devices: electromagnetic and posistor (thermal). They are not always interchangeable, so it is important to know what is installed in your model.
Electromagnetic relays work based on the inductance of the coil. When current is applied through the winding, a magnetic field is created, which draws in the core and closes the contacts of the starting winding. When the engine speed reaches rated speed, the current drops, the core is released, and the starting circuit opens. Such relays were often installed in Soviet refrigerators and some Indesit or Ariston models.
Posistor relays (or thermal) work on the principle of changing the resistance of a semiconductor element (posistor) when heated. At the moment of switching on, the resistance is low, and the current flows to the starting winding. The posistor heats up, its resistance increases sharply, and the current practically stops flowing, turning off the starting winding. After cooling (which takes a few minutes), the relay is ready for operation again.
| Characteristics | Electromagnetic relay | Posistor (thermal) relay |
|---|---|---|
| Principle of operation | Magnetic field of the coil | Change in resistance when heated |
| Restart time | Immediately or after a short time | Cooling required (3-5 minutes) |
| Sensitivity | Sensitive to voltage surges | More resistant to surges |
| Typical application | Old models, single-phase compressors | Modern refrigerators, inverter systems |
When selecting a new part, pay attention to the compressor markings. Often the relay housing or refrigerator instructions will indicate what type of device is required. Using an unsuitable relay can lead to rapid failure of both the new part and the compressor itself. Universal relays exist, but their installation requires careful study of the connection diagram.
Step-by-step instructions: how to remove the relay
The process of dismantling the relay is quite simple if you act consistently and without haste. The first step should always be to completely unplug the refrigerator. After this, move the unit away from the wall to provide easy access to the rear panel. You will need space to work.
On the back wall of the refrigerator, at the bottom, you will see a casing that covers the compressor. It can be metal or plastic and fastened with latches or screws. Carefully remove the cover. You will see a view of the compressor, to which a small plastic or metal box is attached to the side or top - this is the starting relay.
☑️ Algorithm for removing the relay
The relay is placed directly on the contact group of the compressor (three pins forming a triangle). In some models, it is fixed with a metal bracket or clip, which must be carefully bent with a screwdriver. If there is no latch, the relay simply sits tightly on the contacts. Grab the relay body and remove it from the pins with light rocking movements from side to side.
A block with wires fits the relay. Before you finally remove the part, remember or take a photo of which wire is connected where. Usually the wires are color coded, but it's best to double check. Disconnect the block by pressing on the latches if there are any, or simply pulling if the connection is tight. Now the relay is completely in your hands.
⚠️ Attention: Do not use excessive force when removing the relay from the compressor pins. A sharp jerk can damage the contacts of the motor itself or tear off the wires, which will lead to more complex and expensive repairs.
If you plan to install a universal relay, carefully study the diagram supplied with it. The design of universal models may differ from the original, and it is important to correctly match the contacts. An error in the connection may result in a short circuit. Make sure that the new part matches the parameters of your compressor.
Installing a new relay and checking operation
Installing a new part is carried out in the reverse order of removal. First, connect the wire block to the new relay, following the color code or diagram you photographed earlier. Make sure that the connection is secure and the wires are not strained, so as not to create unnecessary voltage on the contacts.
Then carefully place the relay on the contact group of the compressor. It should fit tightly and without distortion. If there is a retaining bracket or clip, return it to its place. Make sure the relay is not loose and is securely fastened. After this, you can begin assembling the protective casing.
Return the compressor casing into place and secure it with screws or latches. Make sure that no wires are caught under fasteners or pinched by sharp metal edges. Now you can turn on the refrigerator. In the first seconds you will hear the motor running.
- ✅ The relay is securely fastened to the compressor contacts.
- ✅ The wires are connected according to the diagram and are not pinched.
- ✅ The protective cover is installed in its place.
- ✅ The refrigerator is plugged in and running.
Pay attention to the nature of the engine operation. It should operate smoothly, without buzzing or vibration. If you hear the same sounds as before the replacement, the problem may not be with the relay, but with the compressor itself or the turn-to-turn short circuit of the windings. In this case, more in-depth diagnostics will be required.
Checking for tightness and absence of leaks is also important, although when replacing the relay you did not touch the freon circuit. However, if you accidentally damage the pipes or connections during operation, this may result in a refrigerant leak. Visually inspect all connections for oil stains, which may indicate the release of freon.
Common mistakes and expert advice
When repairing refrigerators on their own, beginners often make mistakes that can negate all efforts. One of the most common is ignoring the relay type. An attempt to install a posistor relay instead of an electromagnetic one (or vice versa) without changing the connection diagram often leads to instantaneous combustion of the new part.
Another mistake is poor contact in the connecting block. If the wires are oxidized or not inserted all the way, heating will occur at the contact point, which will lead to melting of the plastic and repeated failure. Always clean the contacts and secure the connections tightly. Contact quality directly affects the durability of the repair.
Some craftsmen advise cleaning the contacts of the old relay with sandpaper and reusing it. This is a temporary measure that may help in an emergency, but is not a full-fledged repair. The resource of the restored relay will be minimal, and the risk of repeated failure is very high. It is better to immediately install a new part.
⚠️ Attention: Technical characteristics of compressors and relays may vary depending on the manufacturer and year of manufacture of the refrigerator. Always check the markings on the new part with the data on the nameplate of your refrigerator or in the technical documentation.
It is also important not to mix up the wires when connecting. In a three-contact group, mixing up the start and run windings can result in the compressor humming but not starting, or starting in the opposite direction (which is often impossible for refrigeration compressors due to the design of the valves). Pay close attention to the color marking.
FAQ: Frequently asked questions
Is it possible to replace the relay with a universal one if the original is out of production?
Yes, you can. Universal relays (for example, PTC series or universal electromagnetic) are suitable for many compressor models. The main thing is to correctly select the compressor power range and start type (RSIR, RSCR, etc.), and also correctly connect the wires according to the diagram supplied with the universal relay.
Why did the new relay burn out immediately after installation?
There may be several reasons: the wrong type of relay, an error in connecting the wires, a short circuit in the compressor itself (turn-to-turn short circuit of windings) or voltage surge in the network. It is also possible that the compressor is “jammed” and it consumes too much current, which melts the relay.
How much does it cost to replace the relay in a service center?
The cost consists of the price of the part itself and the work of the technician. The part itself is inexpensive, but a specialist visit and diagnostics can cost significantly more. Replacing yourself allows you to save on work if you are confident in your abilities.
How to understand that it is the compressor that has burned out, and not the relay?
If, after replacing a working relay, the compressor still does not start, the machine hums and knocks out, or if the resistance of the windings, measured with a multimeter, shows an open circuit (infinity) or a short short circuit (zero or very small), most likely the compressor itself is faulty. Another sign may be the absence of a characteristic click when turned on, if the relay is working properly.
Is it necessary to release freon to replace the relay?
No, it is not necessary. The start relay is located on the external electrical part of the compressor and is not connected to the internal refrigerant circuit. The relay is replaced without breaking the tightness of the cooling system and without refilling with freon.