A sudden stop in the operation of the refrigerator compartment or characteristic clicks, after which the compressor is silent, often indicate a problem in the engine starting circuit. In most cases, the culprit in this situation is start relay a small but critical unit responsible for supplying voltage to the motor windings at the time of start. If this element fails, the refrigerator stops cooling, and the food begins to deteriorate, requiring immediate intervention.
Diagnostics of this part does not always require calling a specialist, since in many models it can be checked independently with basic knowledge and a simple tool. Relay can be electromagnetic or thermal, and the principle their checks will be slightly different, but the general algorithm of actions remains similar. Understanding exactly how this mechanism works will help you avoid unnecessary expenses on repairs or purchasing a new unit.
Before you start disassembling, you need to make sure that the problem lies in the electrical part, and not in voltage surges in the network or a blown fuse. In this article, we will look in detail at how to remove and check the refrigerator start relay, what tools you will need for this, and what nuances you should pay special attention to in order not to damage the compressor.
⚠️ Attention: Before starting any diagnostic work or replacing parts, be sure to disconnect the refrigerator from the electrical network. Working with live electrical wiring is deadly!
The principle of operation of the start relay in the refrigerator
The start relay is an automatic switch that is activated when the compressor is turned on. Its main task is to briefly apply voltage to the starting winding of the motor in order to create the necessary torque to rotate the rotor. As soon as the engine reaches the required speed (usually in a split second), the relay opens the starting winding circuit, and the motor continues to operate on the working winding.
In modern refrigerators, two types of these devices are most often found. Electromagnetic relays they close the contacts due to the magnetic field created by the current flowing through the coil at start. Thermal relays, in turn, use a bimetallic plate that bends when heated by current and opens the circuit. There are also combined models that combine the functions of protection against overheating and a trigger mechanism.
Understanding the type of your relay is important, since the method for testing it depends on it. For example, in electromagnetic models a key role is played by the movable core, which must move freely, and in thermal conditions - the state of the bimetallic plate and contacts. If the mechanism sticks or the contacts oxidize, the engine does not receive a starting impulse.
Why does the relay fail?
The main causes of failure are voltage surges in the network, contact wear due to frequent on-off cycles, and overheating of the compressor. Often the relay burns out when trying to start a “jammed” compressor, when the current in the starting winding reaches critical values.
External signs of a malfunction of the starting relay
You can determine that the problem lies in the starting relay by the characteristic signs that appear when the refrigerator is operating. Most often, the user hears repeated clicks at intervals of several seconds or minutes. This means that the automation is trying to start the compressor, the relay clicks, but the engine does not start, and the protection is triggered.
Another obvious symptom is the situation when the compressor starts to hum, but after a few seconds there is a click and it goes silent. At this point, the refrigerator is not cooling, and there is no heating on the rear grille (condenser). If the compressor itself is hot, but the relay is cold or, on the contrary, has melted, this is a sure sign of its malfunction.
- 🔊 Frequent clicks are heard from the back of the refrigerator, but the motor does not start.
- 🔥 The compressor heats up, hums for a few seconds and turns off.
- ⚡ Traces of melting, soot or black deposits are visible on the relay body.
- ❄️ The refrigerator has stopped freezing, although the indicators are on.
It is important to distinguish a relay failure from a malfunction of the compressor itself. If after replacing the relay the situation does not change and the engine still does not start or there is a “pull-in” hum, the problem may be an inter-turn short circuit of the motor windings or its mechanical jamming. In such cases, simply replacing the relay will not help.
Preparation for diagnostics: tools and safety
To properly check the start relay of the refrigerator, you will need a minimum set of tools that any home craftsman usually has. The main device will be multimeter (tester), which allows you to measure the resistance of the circuit and check for short circuits. Without this device, diagnostics will be only speculative.
You will also need pliers or pliers to carefully remove the terminals, a screwdriver to remove the protective cover of the compressor, and possibly a knife to clean the contacts if they are oxidized. Before starting work, make sure that you are in a well-lit area and have sufficient room to maneuver at the rear wall of the unit.
☑️ Tools for testing relays
Do not forget about safety precautions. In addition to disconnecting from the network, it is recommended to discharge the capacitors if they are in the circuit, although in modern models starting relays often do not have energy storage devices. Work with dry hands and use tools with insulated handles to eliminate the risk of electric shock.
⚠️ Attention: If insulation damage is visible on the wires or relay housing, do not plug in the refrigerator even for a short time to check. This can lead to a short circuit or fire.
Step-by-step instructions: how to remove and test the relay
The diagnostic process begins with removing the compressor protective casing, which is usually secured with latches or screws. After removing the cover, you will see a black cylindrical or rectangular block placed on the compressor rod - this is the start relay. Carefully disconnect the wires, having first memorized or photographed their connection diagram so as not to mix up the contacts during assembly.
Remove the relay from the compressor rod. It may fit tightly, so be careful not to damage the ceramic insulators or contacts. Inspect the device externally: there should be no cracks, traces of burning or melted plastic. If the housing is damaged, the relay definitely requires replacement, even if the electrical parameters are normal.
Next, we proceed to an electrical test using a multimeter. Switch the device to resistance measurement mode (Ohms). For an electromagnetic relay, connect the probes to the coil contacts. If the device shows a break (infinity) or, conversely, zero (short circuit), the part is faulty. The normal coil resistance is usually several tens of Ohms.
Normal coil resistance values: 20-60 OhmsSign of a break: 1 or OL on the multimeter screen
Sign of a short circuit: 0 Ohm
Thermal relays are checked by checking the continuity of the circuit between the input and output contacts. When cold, the circuit should be closed (resistance close to zero). If the multimeter shows a break, it means that the bimetallic plate has already worked and does not return to its original position, or the contacts have burned out. Also check that there is no short to the housing.
Table of typical faults and methods for eliminating them
For the convenience of systematizing possible problems, we present a table that will help you quickly identify a malfunction based on measurement results and external signs. This will allow you to make the right decision about repairing or replacing the unit.
| Symptom / Indicator | Probable cause | Check method | Solution |
|---|---|---|---|
| Coil break (infinity) | Electromagnet winding burnt out | Measuring resistance with a multimeter | Replacing the relay |
| Short circuit (0 Ohm) | Short circuit turns or contacts | Measurement of resistance | Replacement of the relay |
| Contacts do not ring | Soot or oxidation of contacts | Visual inspection and continuity testing | Cleaning or replacement |
| The relay gets hot during operation | Incorrect operation or overload | Tactile temperature check | Checking the compressor |
| Knocking inside case | Destruction of the mechanical part | Shaking the device | Replacing the relay |
It is worth noting that in some cases you can try to clean the contacts if they are simply burnt. To do this, carefully open the case (if possible without destruction) and go over the contacts with fine sandpaper or a file. However, given the low cost of new parts, it is often more advisable to completely replace the unit replacement of the unit.
If after replacing the relay the refrigerator started working, but after some time the symptoms recurred, the problem may be deeper. Perhaps the compressor itself has increased starting winding resistance or mechanical defects, causing it to draw too much current, burning out the new relay.
Can a universal relay be used?
There are universal starting relays with three contacts that fit many compressor models. They often come complete with adapters. However, it is best to look for an original analogue by the markings on the body of the old device.
Replacement of the starting relay and final check
If diagnostics confirm a malfunction, you need to purchase a new element. When choosing, pay attention to the markings, compressor power and type of refrigerant, as these parameters affect the characteristics of the relay. Installation is carried out in the reverse order of removal: first we put the relay on the rod, then we connect the wires according to the previously made diagram or photograph.
Pay special attention to the correct connection of the wires to the contacts. By mixing up phase and zero or the contacts of the starting and working windings, you risk burning the new element or damaging the compressor. Make sure that the terminals are tight and not loose, and that the relay block itself is securely fixed to the compressor.
After assembly, turn on the refrigerator. In the first seconds, listen: the engine should start confidently without long clicks. After 10-15 minutes of operation, check the heating of the condenser grille at the back - it should begin to warm up. If everything went well, you can install the protective cover and push the refrigerator into place.
⚠️ Attention: Do not leave the refrigerator with the compressor compartment open for a long time. This can lead to dust getting on the contacts and disrupting heat transfer.
Frequently asked questions (FAQ)
Is it possible to start a refrigerator without a starting relay?
Theoretically, you can start the engine by applying voltage to the starting winding manually through a button, but this requires qualifications and dangerous. It is strictly forbidden to operate a refrigerator without a relay: the motor will not be able to reach operating mode, will overheat and quickly burn out, or will constantly trip the circuit breaker.
How much does a starting relay cost and is it difficult to find?
The cost of a relay varies from 500 to 2000 rubles depending on the model and manufacturer. You can find them in spare parts stores for household appliances or online markets, knowing the exact model of the refrigerator or the marking of the old relay. Universal analogues are cheaper and available almost everywhere.
Why does a new relay burn out immediately after installation?
If a new relay burns out almost instantly, the reason is almost always a malfunction of the compressor itself (an interturn short circuit, jamming of the piston group) or problems with wiring and power surges in the network. In this case, diagnostics of the motor by a refrigeration technician is required.
Is the relay different for Indesit and Atlant refrigerators?
Yes, the design and electrical parameters of the relay for different brands may differ. For example, Indesit often uses relays made in Italy (Clixon), and Atlant - domestic or Chinese analogues. It is important to select a part by catalog number or full technical specifications, and not just by brand.
How to extend the life of the starting relay?
To extend the life of the relay, it is recommended to use a voltage stabilizer if there are surges in your network. It is also important to ensure good ventilation of the rear wall of the refrigerator so that the compressor does not overheat, since high temperatures negatively affect the operation of thermal protection elements.