Sudden cessation of operation of the refrigerator or its inability to maintain the set temperature is often indicated to failure of the starting relay. This small but critical component is responsible for starting the compressor engine and its subsequent operation as normal. If you are faced with the fact that the engine hums, but does not start, or turns on only for a few seconds, the problem with a high degree of probability lies precisely in the starting device.
Independently replacing the relay is a real task for the owner of the equipment, allowing you to save on calling a technician and expensive repairs. In refrigerators Nord (including popular models Nord 239, Nord 101, Nord 507-011), the design of the starting unit is quite standardized, which simplifies the diagnostic process. However, before starting any work, it is necessary to strictly observe safety precautions and completely de-energize the unit.
In this article we will analyze in detail the algorithm of actions that will allow you to determine the malfunction, select the correct analogue and correctly connect the new element. Important to understandthat electric current is dangerous, therefore all manipulations within the electrical circuit are carried out only with the plug removed from the socket. Ignoring this rule may result in electric shock or damage to the electronics.
Diagnostics of a faulty starting relay
The first sign of problems with the starting mechanism is a characteristic sound: the compressor tries to start, there is a click, a hum, but after 5-10 seconds the engine stops again. Often after this, the thermal protection relay is triggered, and restarting is possible only after cooling. If you hear such sounds, this is a good signal to check the trigger element. In normal condition, the refrigerator operates cyclically, without sudden interruptions and extraneous clicks.
For the initial check, it is not necessary to immediately disassemble the unit. Pay attention to the temperature of the compressor housing. If it gets very hot, but the cold does not accumulate in the chambers, it means that the engine does not go into operating mode. It is also worth listening: if the relay makes a cracking sound when shaken (in the off state), it means that its internal contacts are damaged or burnt. Visual inspection Often provides more information than long measurements with a multimeter.
More accurate diagnostics can be carried out by removing the relay and checking its integrity. In some cases, the starting coil winding may have a break, which cannot be determined by ear. If you have a multimeter, test the contacts: the resistance should correspond to the rating data for the specific model. Lack of resistance or, conversely, a short circuit indicates the need for urgent replacement.
⚠️ Attention: If after replacing the relay the compressor continues to hum and does not start, the problem may lie in the motor itself (jamming) or in broken windings. In this case, further operation may lead to engine combustion.
Required tools and safety measures
Before starting repairs, you must prepare a minimum set of tools. You will need a flathead and Phillips screwdriver to remove the compressor protective cover and clamps. It would also be a good idea to have pliers on hand to carefully remove the terminals and a multimeter to check the circuit. All tools must be dry and in good working order to avoid accidental short circuits.
The main rule is complete disconnection from the power supply. It is not enough to simply turn off the refrigerator with a button, if there is one; you need to unplug the cord from the outlet. After this, it is recommended to wait 10–15 minutes for the capacitors to discharge and the compressor to cool down. This will reduce the risk of burns and electric shock. It is better to work in good light, using a flashlight or portable lamp.
To protect your hands from sharp metal edges and possible residual oil, use work gloves. If the relay shows signs of heavy carbon deposits or plastic melting, it is better to work with it in a ventilated area, since when heated, some materials can emit unpleasant odors. Cleanliness of the workplace also important: dust and moisture should not get inside the electrical contacts.
☑️ Preparation for repair
Removing the old compressor relay
The removal process begins with access to the compressor, which is usually located in the lower rear part of the refrigerator. Remove the protective cardboard or metal panel covering the engine compartment. On some models Nord it may be necessary to remove the rear panel completely if access from below is limited. Be careful not to damage the refrigeration circuit tubes.
On the compressor housing you will see a plastic box - this is the start relay casing. It is secured either with latches or a clamp. Carefully bend the latches or loosen the clamp, then remove the cover. Inside you will see the wires going to the relay contacts, and the block itself, put on the compressor rod. Remember or take a photo the order of connecting the wires before disconnecting.
To remove the relay, you need to carefully pull it down, removing it from the pins of the compressor. Sometimes it can sit tight due to oxidation or heat. Do not use excessive force to avoid breaking the plastic clips or damaging the compressor terminals. If the relay has additional grounding or fan connection wires, they must also be disconnected, having first noted the position.
⚠️ Attention: Never try to remove the relay by jerking upwards or sideways - this can lead to breakage of the copper tubes of the compressor, which will require complex and expensive repairs with refilling with freon.
What to do if the relay stuck?
If the relay cannot be removed by hand, you can carefully pry it with a flat screwdriver at the junction with the compressor housing, but you must act extremely carefully so as not to damage the terminals. Sometimes a slight rocking from side to side helps.
Connection diagram and contact marking
Correct connection of the relay is the key to successful repair. A connection diagram is often printed on the inside of the cover or on the relay body itself. Contacts are marked with letters or numbers. The main designations that you will come across: C or R (Common/Run - general), S (Start - starting) and R (Run - working). Some circuits use marking L (Line) for the phase.
In refrigerators Nord the following configuration is most often used: the three pins on the compressor form a triangle. The top pin is the common wire, the bottom left is the starting winding, the bottom right is the working winding. The relay is placed on these pins in a strictly defined way; it usually cannot be turned over due to the shape of the seat. However, the wires going to the relay may have been mixed up during previous repairs.
If you are installing a universal relay (for example, RTK-1, RTK-1-3, PZR), it is important to pay attention to the orientation. The case often has an arrow UP or an inscription TOPthat should look straight up. Violation of the orientation will result in the ball inside the relay not performing its function and the compressor will not start. Installation accuracy is critical here.
Below is a table of contact correspondence for common types of relays used in Nord technology:
| Relay type | Contact 1 (General) | Contact 2 (Start) | Contact 3 (Work) |
|---|---|---|---|
| RTK-1 / RTK-1-3 | Upper (L) | Left (S) | Right (R) |
| PZR (China) | Top | Left | Right |
| 17.500.59.010 | Central | Side 1 | Side 2 |
Installing and connecting a new relay
The process of installing a new relay is the reverse of dismantling, but requires increased care. First, make sure that the new device fully matches the dimensions and type of mounting. Insert the relay onto the compressor pins as far as it will go. It should fit tightly, without any play. If you are using an adapter block (often included with universal relays), first assemble the structure on the table, check the reliability of the contacts, and then put it on the compressor.
Connect the wires to the appropriate terminals. If the wires have male terminals, they should fit tightly into the relay sockets. If the wires are simply stripped, use screw terminals or reliable twists with insulation (although twists in household appliances are a temporary solution, it is better to use original terminals). Insulation The connection points should be perfect to prevent sparking.
Check that the wires are not touching hot compressor parts or sharp metal edges. If necessary, secure them with plastic ties or standard holders. After this, install the relay protective cover and secure it with a clamp or latches. Make sure the lid sits flat and covers all live parts.
⚠️ Attention: Compressor specifications and relay compatibility may vary depending on the year of manufacture of the refrigerator. Always check the markings on the motor nameplate with the data in the manufacturer's technical documentation.
Checking operation after replacement
After assembly, you can start testing. Plug in the refrigerator. In the first seconds you can hear a quiet hum, which after 1-3 seconds should turn into a smooth hum of a working compressor. If there is a click and silence, turn off the device immediately. This means that the relay did not work, the contacts do not close, or the problem is deeper (for example, in the windings).
Pay attention to the indicators (if any) and listen to the operation of the unit for 15–20 minutes. The compressor should not overheat (case temperature up to 70–80°C is acceptable, but not higher). After 30–40 minutes of operation, check the freezer: cold should appear there, and frost should appear on the evaporator. Successful startup and a stable temperature increase indicate that the work was done correctly.
If the refrigerator is working normally, put the back panel in place. Do not leave the engine compartment open for long periods of time as this will interfere with air circulation and allow dust to accumulate. In the future, it is recommended to visually inspect the relay once a year and clean the condenser from dust in order to extend the service life of the equipment.
Frequent errors and advice from experts
One of the most common errors is ignoring the state of the capacitor. In some circuits, a capacitor is connected in parallel with the starting winding, which helps to shift the phase. If it is swollen or has lost capacity, even a new relay will not help start the compressor. Therefore, when replacing a relay, always check the capacitor, especially in older models Nord.
Another mistake is using a relay with an inappropriate current characteristic. Installing a relay that is too powerful on a weak compressor may result in it not turning off the starting winding, which will cause overheating and engine burnout. Conversely, a weak relay on a powerful motor will burn out instantly. Always focus on the marking rated current.
Masters also advise not to skimp on the quality of parts. Cheap Chinese analogues can last only a couple of months. It is better to purchase an original relay Nord or a proven analogue from well-known brands (Danfoss, Secop). This will ensure long and reliable operation of the refrigerator without the need for repeated repairs.
Is it possible to use a relay from another brand?
Yes, you can, if the electrical characteristics (current, voltage) and geometric dimensions of the seat match. Universal relays are often equipped with adapters for different types of compressors.
Why did the old relay burn out?
Most often the reason is frequent power surges in the network, natural wear of the contacts, or jamming of the compressor. Also, the cause may be poor contact at the junction of the wires.
Is it necessary to defrost the refrigerator before replacing?
It is not necessary to specifically defrost it to replace the relay if access to the compressor is free. However, if there is a lot of ice in the chamber and there is a risk of water getting on the electrics when the unit is tilted, it is better to defrost it.
How much does it cost to replace the relay?
The cost of the relay itself varies from 300 to 1500 rubles depending on the model. The work of a master will cost about the same amount, so independent repairs are economically profitable.