A situation where the refrigerator stops starting or makes a loud click and then hums, but does not produce cold, often indicates a faulty start relay. This small device is responsible for sending a pulse to the compressor motor windings, allowing it to start. Owners of household appliances often face a problem: original spare parts are not available for sale, they are unreasonably expensive, or they will have to wait weeks for delivery. A logical question arises: is it possible to install an analogue and what exactly is suitable for your model?
In most cases replacement is possible, since the operating principle of these devices is unified. However, mechanical matching of sizes is only half the success. It is critical to consider the electrical specifications, compressor type, and mounting method. An incorrectly selected part can lead to repeated burnout or, worse, to failure of the motor-compressor itself, the repair of which will cost much more.
In this article we will look in detail at what types of relays exist, how to select a replacement using the correspondence tables, and whether it is possible to temporarily start the unit without purchasing a new part. You will learn what parameters to pay attention to first and how to avoid common mistakes when doing DIY repairs.
⚠️ Attention: All work on replacing the electrical components of the refrigerator must be carried out strictly with the power disconnected from the mains. Residual voltage in capacitors can be dangerous, so let the equipment stand turned off for 10-15 minutes before starting disassembly.
Types of starting relays and their features
To understand how to replace a failed part, you must first determine the type of device installed in your refrigerator. In household appliances, two main types are most often found: electromagnetic (starting) and thermal (starting). The former work on the principle of retracting the core when starting current, the latter - on heating a bimetallic plate, which opens the circuit when a certain temperature or current is reached.
Modern models, especially with inverter compressors or systems No Frost, can be equipped with more complex electronic control modules, where the start function is built into the common board. However, in the classic Atlant, Biryusa, Indesit or Stinol refrigerators, mechanical relays predominate. Electromagnetic relay usually has a vertical arrangement and one contact, and a thermal one has a horizontal arrangement and three contacts, although there are exceptions.
It is also important to distinguish between the mounting method: two pins, three pins or on a special frame. If you try to put a horizontally mounted relay in place of a vertical one, the mechanism simply won't work due to gravity. Inside the case there may be a coil with a movable core or a bimetallic “tablet”.
Criteria for selecting an analogue: voltage and current
When looking for a replacement, the main guideline is the marking on the body of the burnt part. Even if you do not find the exact model with the same name, you can choose an analogue based on the technical characteristics. First of all, look at the operating voltage: for household refrigerators, this is usually 220-240 V at frequency 50 Hz. Installing a 110 V relay in a 220 V network will lead to instant combustion.
The second and most important parameter is the starting current. It is measured in amperes and indicates the maximum current value at which the relay is still able to open the circuit (for thermal) or close the starting winding (for electromagnetic). The current range usually varies from 1.0 A to 2.5 A. If you install a relay with a lower current, it will constantly click, preventing the motor from accelerating. If it is large, it may not turn off the starting winding, which will cause overheating and combustion of the engine.
Pay attention to the diameter of the compressor shaft and the distance between the contacts. In some cases, the seats may differ by millimeters, which will require slight modification of the housing or the use of an adapter frame. Universal relays They are often equipped with a set of adapters, which simplifies installation on different types of compressors.
Compatibility table and popular analogues
There are many manufacturers on the spare parts market that produce compatible components. Brands such as Danfoss (now Secop), Start, PZR, RCT and PTCproduce products that can be interchanged with each other, subject to the conditions for current and type of fastening. Below is a table to help you navigate the analogues for common models.
| Original / Model | Type | Starting current (A) | Possible analogue | Note |
|---|---|---|---|---|
| RT-21 (Atlant) | Starting | 2.1 - 2.5 | PZR 21-118, RCT 21 | Vertical, 1 contact |
| RTK-1 (HK) | Starting protection | 1.3 - 1.6 | PTC 14-60, 33.6 | Horizontal, 3 contacts |
| Danfoss 101L0011 | Starting | 1.1 | PZR 11-118 | For low-power compressors |
| Start-103 | Combined | 2.5 | RCT 25 | Universal, requires checks |
When using a table, remember that the numbers in the title often (but not always) indicate the current strength. For example, in marking RT-21 the number 21 can mean a series, but often correlates with a current of about 2.1-2.2 Amperes. Always check the data with documentation or datasheets for a specific series of compressors.
If you do not find your relay in the list, search by the compressor catalog number. The manufacturer and model are always indicated on the motor nameplate located on the casing. Using this data, you can find an official relay compatibility card on the Internet. Chinese universal relays Often have a wide range of operating currents, which makes them popular, but less reliable in the long term.
⚠️ Attention: Do not use relays with a large current reserve “just in case”. If the relay is designed for 3.0 A, and the motor needs 1.5 A, if the rotor jams, the relay will not turn off in time, and the motor windings will burn out.
Temporary solutions and emergency start
There are situations when the refrigerator is needed “right now,” and no spare parts. There is a method to temporarily start the compressor by bypassing the relay, but it requires extreme caution and an understanding of the risks. The essence of the method is to manually apply voltage to the starting winding at the moment of start. This allows you to start the motor, after which the starting winding is turned off, and the refrigerator operates on the main one.
This will require a piece of wire with a plug and a button (or simply closing the contacts with a screwdriver with an insulated handle for a split second). The circuit is simple: the phase is constantly supplied to the working winding, and to the starting winding - briefly at the moment of switching on. As soon as the motor picks up speed (after 1-2 seconds), the starting winding circuit must be immediately broken.
Temporary connection diagram
Connect one wire from the plug directly to the contact of the working winding (usually the bottom or left). Pass the second wire from the plug through the button to the contact of the starting winding (top). Press the button, plug the plug into the socket. When the compressor hums, release the button. If you release it too late, the winding will burn out. If it’s early, it won’t start.
This method is absolutely not suitable for constant use. It deprives the compressor of protection against overheating and restarts. In addition, if the network voltage is unstable, the motor may not start the first time, which will lead to humming and overheating. Use this method only for diagnosing or evacuating products.
Instructions for replacing the relay with your own hands
If you have decided on an analogue and purchased a new part, you can proceed with the replacement. The process does not require a complex tool, but it does require accuracy. First, remove the back cover of the refrigerator at the bottom where the compressor is located. You will see a black metal “tank” - this is the motor-compressor, and a plastic box is attached to its end or side.
Remove the retaining bracket or plastic holder holding the relay. Carefully pull the relay housing down, releasing the compressor contacts. Pay attention to the position of the parts: which side was on top, how the contacts are oriented. Before installing a new element, it is recommended to blow out the compressor pipes to make sure that it is not clogged with wear products.
☑️ Checklist before installation
Install the new relay in place of the old one, observing the correct orientation (arrow "UP" or "Top" should face up). Put on the fixing bracket. Reconnect the wires to the terminals if they were disconnected. Plug in the refrigerator and listen: there should be a click, a hum, and the motor should start. After a few seconds, the hum should become even and quiet.
⚠️ Attention: If, after replacing the relay, the compressor hums but does not start, or starts and immediately stalls, turn off the device immediately. Perhaps the compressor itself is faulty (an interturn short circuit or a wedge), and a new relay will not help here, but will only burn out.
Why the relay burns out: analysis of the reasons
Simply replacing the part is half the battle. It is important to understand why the previous one failed so that the situation does not repeat itself in a month. The main reason for the start relay burning out is current overload. This can happen due to frequent power surges in the network when the motor tries to start at the wrong moment.
Another common reason is loss of tightness of the compressor casing or the relay itself. The penetration of moisture, condensation or aggressive cleaning agents into the plastic case leads to oxidation of the contacts and disruption of the bimetallic plate. Also, the relay can fail due to the natural aging of materials: the plastic crumbles, the spring weakens.
If you have a relay type RTK or RT, make sure the contacts are clean. Sparking inside the case chars the contact pads, increasing resistance. As a result, the relay begins to heat up and eventually melts. Regular maintenance and checking the tightening of the terminals can extend the life of the device.
Frequently asked questions (FAQ)
Is it possible to install a relay with a higher current if a smaller one is not available for sale?
Short-term - possible, but with risk. If the difference is 0.1-0.2 A, this is acceptable. If you set the relay to 3.0 A instead of 1.3 A, the overload protection will not operate and the compressor may burn out. It is better to wait for the required part or use a universal relay with an adjustable range.
Why does the new relay click, but the refrigerator does not turn on?
This indicates that the starting pulse is supplied, but the motor cannot turn over. Reasons: a jammed compressor (piston group wedge), broken windings inside the motor, or critically low voltage in the network. It is also possible that the relay is not the right type (for example, for a single-phase motor a three-phase one was installed or vice versa).
Where can you find the current marking if it is erased on the body?
Look at the marking on the nameplate of the compressor itself (metal sticker on the “barrel”). The recommended relay type or maximum current (LRA - Locked Rotor Amps) is often indicated there. You can also find the compressor model on the Internet and look at the required starting device in the specification.
Is the relay different for refrigerators with one compressor and for two-compressor ones?
In principle, no, if the power of the compressors is similar. However, dual-compressor models (for example Indesit or Stinol) often use more compact relays due to limited space. It is important to take into account the dimensions and shape of the case so that the part fits into its normal place.
How much does it cost to replace a relay in a service compared to doing it yourself?
Independent replacement will cost the cost of the part (from 300 to 1500 rubles depending on the model). The service will add to this amount the cost of calling a specialist and work (usually from 1000 to 2500 rubles). If you have minimal skills and tools, self-repair is economically feasible.