Sudden stoppage of the compressor or characteristic clicks when trying to start are often the first signals of problems in the cooling system. Equipment owners Nord often encounter a situation where the engine hums but does not start, or turns on only for a couple of seconds before turning off. In most cases, the culprit for such unstable operation is the start-up relay, which is responsible for supplying voltage to the motor windings and protecting against overloads.
Before calling a technician or looking for a replacement for an expensive compressor, it is worth conducting an initial diagnosis of this small but critical element. Checking the relay It takes a little time and requires only basic tools available to the home handyman. Understanding the operating principle of this unit will allow you to save money on diagnostics and accurately determine whether you need to purchase a new part.
It is worth noting that in different models of refrigerators Nord, be it old Soviet versions or modern units, different types of starting devices can be installed. These can be induction, posistor or combined options. The exact type of relay is always indicated on the marking of the part body itself, and you must look for a replacement strictly according to this code, and not just according to the model of the refrigerator. Ignoring this rule can lead to repeated breakdown or even failure of the compressor itself.
Symptoms of a faulty starting relay
You can determine that the problem lies in the starting mechanism by a number of characteristic signs that appear during operation of the refrigeration unit. Most often, owners notice that the compressor begins to hum, trying to start, but after a few seconds there is a loud click and the motor goes silent. This cycle can be repeated at a certain interval until the thermal relay turns off the power completely to prevent overheating of the windings.
Sometimes the situation looks different: the refrigerator works, but does not reach the desired temperature, while the compressor works almost without interruption. This may indicate that the relay is stuck or the contacts are burnt, which is why the engine is not receiving enough momentum to reach operating speed. In some cases, the malfunction is accompanied by a specific smell of burning or melted plastic in the engine compartment area.
- 🔊 The compressor makes loud clicks when trying to start, but does not start itself.
- 🔥 The relay housing or adjacent wires have traces of melting or blackening.
- ⏱️ The motor works cyclically: it hums for a few seconds, then rests for a long time.
- ❄️ The refrigerator has stopped freezing, although the compressor is warm and trying to work.
⚠️ Attention: If you feel a persistent smell of burnt insulation, immediately unplug the refrigerator. Further attempts to turn on may result in a short circuit or fire in the wiring.
It is important to distinguish between symptoms of a relay malfunction and problems with the compressor itself. If after replacing the starting device the situation does not change, there may be a breakdown of the motor windings or jamming of the piston group. In such cases, simply replacing the relay will not help, and more serious repairs or replacement of the entire unit will be required.
Removing the relay for testing
To carry out high-quality diagnostics, it is necessary to remove the relay from the common circuit of the compressor. This process does not require sophisticated equipment, but does require compliance with safety precautions. The first step should always be to completely disconnect the refrigerator Nord from the electrical network. Do not attempt any electrical manipulation while the power cord is plugged in.
Get to the engine compartment, which is usually located at the lower rear of the chassis. You will need to remove the protective cover secured with screws or plastic clips. The front part of the compressor is often covered with a plastic cap, which must be carefully removed by first unscrewing the fixing clamp. Be careful not to damage the copper tubes and wire insulation.
The relay itself is placed directly on the compressor terminals and secured with a clamp or bracket. Carefully disconnect the wires suitable for the contact group, having first remembered or photographed their location. Then remove the retaining bracket and pull the relay off the compressor contacts. If the part is stuck or sits too tightly, do not use excessive force so as not to break the ceramic body or damage the motor leads.
☑️ Checklist before dismantling
After removal, carefully inspect the device body. The presence of cracks, traces of burning, soot or melted plastic clearly indicates the need for replacement. Even if the part looks intact on the outside, the internal contacts could have burned out, so a visual inspection is only the first stage of testing.
Visual inspection and initial diagnostics
Before picking up the multimeter, conduct a thorough visual analysis of the removed device. The internals of the relay may vary depending on the model, but the general principles remain similar. Shake the part near your ear: if a clear knocking or rattling sound is heard inside, it means that the mechanical parts are destroyed, and such a relay must be unconditionally replaced.
Pay attention to the condition of the contact group. If it is possible to carefully open the case (which is not always possible without damage), inspect the contacts for carbon deposits. Contacts that are blackened or covered with oxides create a high contact resistance, which prevents the engine from starting normally. However, in modern sealed cases Nord opening is often impossible, so rely on indirect signs.
Pay special attention to the posistor (if we are talking about a posistor relay). This is a ceramic element that changes its resistance when heated. If chips, cracks or signs of overheating are visible on its surface, the functionality of the element is impaired. Induction relays, in turn, contain a coil and a movable core, the jamming of which also leads to failure.
Is it possible to restore an old relay?
Theoretically, by cleaning the contacts and restoring the mobility of the core, you can temporarily revive the device. However, practice shows that such relays do not work for long and often cause repeated breakdowns of the compressor, so replacing with a new product is a more rational solution.
Do not forget that visual integrity does not guarantee the serviceability of the electrical characteristics. Even a seemingly perfect relay may have an open circuit or short circuit. Therefore, we move on to instrumental testing using measuring instruments.
Checking a relay with a multimeter: step-by-step instructions
The most accurate diagnostic method is to “test” the contacts using a multimeter switched to resistance measurement mode (Ohm). Before starting work, make sure that the device is working properly and the probes are short-circuited (the reading should be close to zero). Position the relay so that the contact pins are accessible to the probes.
First check the continuity of the circuit between the input and output contacts. Depending on the type of relay, resistance should either be absent (open) or minimal (short) in a certain position. PTC relays are characterized by the presence of resistance in the range from 20 to 60 ohms between certain contacts at room temperature. If the device shows infinity where there should be resistance, or zero where it should not be, the part is faulty.
Check the inductance coil (for inductive relays). The winding resistance is usually several ohms. If the multimeter shows one (infinity), it means that there is a break in the winding and no current will flow through it. Also check that there is no short circuit to the case: none of the contacts should “ring” to the metal case or fasteners.
| Relay type | Normal resistance | Fault symptom | Action |
|---|---|---|---|
| Posistor | 20–60 Ohm | Infinity or 0 Ohm | Replacement |
| Induction | Several Ohms (coil) | Winding break | Replacement |
| Thermal | Minimum (bimetal) | No contact | Replacement |
| Combined | Depends on circuit | Inconsistency with the circuit | Replacement |
When checking, it is important to take into account that the posistor changes its properties after heating. If you just tested the relay and it got hot from your hands or previous tests, let it cool for 15-20 minutes before testing it again. A “hot” posistor may show high resistance, which is normal for it in a warm state, but is mistakenly perceived as a breakdown.
Compatibility and marking table
When looking for a replacement for a refrigerator Nord it is important to focus not only on the model of the refrigerator, but also on the marking of the relay itself. Compressor manufacturers (for example Danfoss, Secop, Atlant) use standard designations that may differ from the refrigerator brand name. An incorrectly selected relay may not start the engine or quickly burn out.
Pay attention to the location of the contacts. They can be vertical, horizontal, or have a specific configuration (for example, 3 contacts in a row or a triangle). The type of shank and the method of attachment to the compressor are also important. In some cases, a slight modification of the seat or the use of adapters is required.
- 🏷️ RT — a series of relays for Danfoss/Secop compressors (often found in old Nords).
- 🏷️ PTC — designation of posistor elements, often included with a thermal relay.
- 🏷️ RS — a series of relays for compressors from various manufacturers, including Atlant.
Always check the electrical characteristics: rated current, voltage and type of refrigerant. Using a relay designed for a lower current will lead to its rapid burnout, and using a relay designed for a higher current will result in a lack of compressor protection. If you are in doubt about the choice, it is better to consult with a specialist or find an exact analogue using the catalog number.
⚠️ Attention: Technical characteristics of compressors and compatible relays may vary depending on the year of manufacture and the specific modification of the refrigerator. Always check the data on the nameplate of your device before purchasing spare parts.
Frequent errors in diagnostics and replacement
One of the common mistakes is trying to replace the relay without checking the compressor itself. If the motor has an interturn short circuit or is jammed, the new relay will burn out almost instantly, creating the illusion of a defective part. Therefore, if after replacement the situation repeats, it is necessary to check the motor windings for breakdown and resistance.
Another mistake is ignoring the condition of the contact block on the compressor itself. The contacts on the motor terminals may oxidize or burn, resulting in a poor connection even with a new relay. Before installing a new part, be sure to clean the contacts on the compressor with fine sandpaper or a file, if necessary.
Also, craftsmen often forget about the thermal protection relay, which can be paired with the starting one. If the starting device is working properly, but the refrigerator still knocks out after a couple of seconds, it is possible that the thermal release is faulty. In some models they are combined into one unit, in others they go separately.
Why does a new relay burn out immediately after installation?
Most often this happens due to a compressor malfunction (short circuit of the windings), incorrect selection of the relay type (wrong current or configuration) or poor contact in the circuit, causing sparking and heating.
Do not try to “collectively farm” temporary solutions, for example, short-circuiting the contacts directly. This removes the engine protection, and if there is a starting overload, the compressor may burn out irrevocably, which will make repairs economically impractical. The reliability of the refrigerator Nord directly depends on the quality of the installed components.
FAQ: Frequently asked questions
Is it possible to start a refrigerator without a relay?
Technically, you can start the compressor by applying voltage directly to the working and starting windings using a button or a capacitor, but this is a temporary diagnostic measure. Long-term operation without a starting and thermal relay is prohibited, since the engine will burn out at the first overheat or attempt to restart under load.
Where can you find the relay markings on the Nord refrigerator?
The markings are on the relay body itself, which is attached to the compressor terminals in the engine compartment. This information is usually not indicated on the refrigerator body or in the instructions, since the manufacturer can equip the same model with different compressors.
How much does it cost to replace a relay and is it difficult to do it yourself?
The cost of the relay itself varies from 300 to 1500 rubles, depending on the type and manufacturer. Replacement takes 15-30 minutes and requires only a screwdriver and a multimeter. The difficulty is minimal if you have basic electrical and tool skills.
Why does the relay click, but the refrigerator does not turn on?
The click means that the thermal relay is opening the circuit due to an overload. This happens if the starting relay does not start the motor, and the current in the windings increases to a critical value. The reason could be either the starting relay itself, or a malfunction of the compressor or low voltage in the network.
Can a universal relay be used for Nord?
There are universal kits (for example, SUPTECH) that are suitable for many types of compressors. They are often sold with a set of adapters for different mounting positions. The main thing is to choose the right current characteristic that matches the power of your compressor.