Sudden stoppage of the refrigerator and defrosting of food is a situation familiar to many owners of household appliances. Often the cause of a breakdown is the failure of the starting or protective relay, which is responsible for starting compressor. Replacing this element yourself allows you to save a significant amount on calling a technician if you approach the matter with care and knowledge. However, before proceeding with disassembly, you need to make sure that the diagnosis is correct.
The replacement process does not require complex professional equipment, but it is critical to follow safety precautions and sequence of actions. Electric current and the refrigerant inside the system requires careful handling. In this article, we will look at how to determine the malfunction, choose the right part and connect the relay correctly so that your refrigerator works like new again.
Diagnostics of a faulty start relay
The first sign of a problem with the relay is a characteristic sound: the refrigerator hums, trying to start, but after a few seconds a click is heard and the engine stops. This indicates that starting winding receives voltage, but the engine cannot reach operating speed, and the thermal protection is triggered. Sometimes the compressor may not make any sounds, remaining absolutely quiet, which also indicates a break in the control circuit.
For accurate diagnosis, it is necessary to remove the relay from the compressor housing. It is usually covered with a plastic cover on the back of the unit. After removing the casing, you will see a box placed on the motor rod. A visual inspection may reveal traces of burning, melted plastic, or the characteristic smell of burnt wiring. If the device looks intact outwardly, you will need to ring it with a multimeterether.
⚠️ Attention: Before starting any diagnostic work, be sure to disconnect the refrigerator from the power supply. Working with live electrical wiring is deadly.
Checking with a multimeter can reveal broken internal contacts or sticking. In normal condition, the coil resistance should be close to zero, and the contacts should close at a certain position. If the device shows infinite resistance or, conversely, a short circuit where it should not be, the part must be replaced.
Selecting a suitable relay for replacement
Selecting a new component is a critical stage, since there are no universal solutions for all models. Relays differ in the type of compressor (linear or inverter), motor power and mounting method. The most reliable way to select an analogue is to find the markings on the body of the old part. Usually this is an alphanumeric code, for example PTC-123 or R-600a.
If the marking is erased or unreadable, you can use compatibility tables or select a device based on motor power. It is important to consider that for different refrigerants (freon R134a or R600a) different types of starters can be used. An incorrectly selected relay will either lead to instantaneous combustion of the new element or the inability to start the compressor.
There are two main types of devices: electromagnetic and posistor (PTC). Electromagnetic ones work by changing the current in the winding, while posistor ones use the thermal effect of resistance. They are not always interchangeable, so when buying a new part, be sure to check the type with the original.
Preparation of tools and workplace
For a successful replacement, you will need a minimum set of tools, which is found in the home of most craftsmen. The main requirement is cleanliness and dryness in the work area. Moisture or metal shavings getting inside the electrical part of the compressor can cause a short circuit.
You will need the following tools:
- 🔧 Screwdriver (Phillips or flathead) to remove the back cover.
- 🔍 Multimeter to check contacts.
- 🧤 Dielectric gloves for safety.
- 🧹 Dry rags for cleaning contacts.
- ✂️ Pliers or side cutters (if stripping of wires is required).
Organize good lighting of the work area. The back of the refrigerator is often covered with dust, which is best removed with a vacuum cleaner or a dry cloth. This will prevent dirt from getting into the ventilation holes and onto the contacts of the new relay.
☑️ Ready for repair
Removing the old starting relay
The removal process begins with dismantling the compressor protective casing. It is usually secured with latches or screws. Be careful, the plastic may become brittle after prolonged use. After removing the cover, you will see a black cylindrical compressor housing with protruding tubes and an electrical part on the side.
The relay is placed directly on the three contact pins of the compressor. In some models it is additionally secured with a metal bracket or plastic clip. Carefully remove the retainer, if there is one, and wiggle the relay from side to side to release it from the pins. You should not make sudden movements so as not to damage the motor contacts.
Pay attention to the orientation of the part. On the relay body there is often an arrow indicating the direction UP (up), or an inscription TOP. This is important for proper installation of the new element. Also check the condition of the wires going to the relay: they should not be frayed or melted.
⚠️ Attention: Do not use excessive force when removing the relay. If it cannot be removed, check whether you forgot to remove the fixing bracket or clamp.
Connection diagram and installation of a new relay
Installation of a new relay is carried out in the reverse order of dismantling. The main rule is the coincidence of contacts. The pins on the compressor and the holes in the relay must match in diameter and location. Typically, a circuit with three contacts is used: two for the starting winding and one for the working winding, plus grounding.
The table below will help you understand the standard marking of contacts on various types of relays:
| Designation | Contact function | Wire color (standard) | Location |
|---|---|---|---|
| C (Common) | General contact | Red or White | Central or top |
| R (Run) | Working winding | Blue or Green | Side |
| S (Start) | Start winding | Black or Yellow | Side (opposite) |
| GND | Grounding | Yellow-green | On the body |
Push the new relay onto the compressor pins until it stops. It should fit tightly and not wobble. If a retaining bracket is used, reinstall it. Then connect the wires to the relay terminals according to the color coding or diagram that can be drawn on the inside of the cover.
After connecting all the wires, check again for the reliability of the connections. Wires should not touch hot parts of the compressor or sharp metal edges. Lay the cable route so that it does not interfere with the vibration of the motor during operation.
What to do if the new relay does not fit in shape?
Sometimes manufacturers change the design of the relay, leaving the electrical parameters the same. In such cases, you can carefully re-solder the wires from the old relay to the new one, observing the color coding. The main thing is to preserve the electrical connection diagram. If you do not know how to solder, it is better to contact a specialist.
Checking performance and startup
Before closing the back cover, it is recommended to conduct a test run. Plug in the refrigerator and listen. The compressor should start with a characteristic hum, without any extraneous clicks or buzzing. After 10-15 seconds, work should become quiet and uniform.
Check the heating of the new relay. After 5-10 minutes of operation, it may warm up slightly, but should not heat up to temperatures dangerous to touch. If the relay is hot or a cracking noise is heard, immediately unplug the appliance. This may mean incorrect selection of the part or an installation error.
If everything went well, install the rear protective panel in place and secure it with screws. Make sure there are no gaps between the panel and the cabinet that could allow dust or insects to enter. Now the refrigerator is ready for full operation.
Why does the relay burn out again after a short time?
Repeated combustion of the relay often indicates a deeper problem. This may be wear and tear on the compressor itself (turn-to-turn short circuit of the windings), power surges in the network, or a malfunction of the thermostat. In such cases, simply replacing the relay will only give a temporary effect.
Is it possible to use a relay from another brand of refrigerator?
Yes, you can, if the electrical characteristics (power, type of compressor, voltage) and geometric dimensions of the seats match. The brand of the refrigerator manufacturer is secondary, the main thing is the parameters of the motor and relay itself.
Is it dangerous to change the relay on an inverter compressor yourself?
Yes, it is dangerous and difficult. Inverter systems are controlled by electronic boards rather than simple start relays. An attempt to intervene without special knowledge and equipment can lead to the failure of expensive electronics. It is better to trust such cases to professionals.