Sudden stop of the compressor or characteristic clicks when trying to start the refrigerator Nord often indicate a malfunction in the electrical circuit of the engine. It is the starting relay that is responsible for supplying the starting pulse necessary to accelerate the rotor, and its failure leads to complete inoperability of the unit. The owner may be faced with a situation where the motor hums but does not start, or turns on only for a few seconds, after which the thermal protection is triggered.
Diagnostics of this component is one of the most affordable types of repairs that can be performed at home without calling a technician. Understanding the operating principle and having a basic set of tools will allow you to quickly determine the cause of the breakdown and restore the functionality of household appliances. In this article we will analyze in detail the algorithm of actions for checking relays on models Nord of various series.
The principle of operation and the role of the relay in the starting system
The starting relay in refrigerators Nord performs the function of an automatic switch that supplies voltage to the starting winding compressor only at the moment of start. As soon as the engine reaches the required speed, the relay opens the starting winding circuit, leaving only the main winding running. This mechanism is critically important, since long-term supply of current to the starting winding can lead to its burnout.
Depending on the model and year of manufacture, refrigerators Nord can use two main types of devices: induction (electromagnetic) and posistor (thermal). Induction relays operate by using a magnetic field created by current in the main winding, which draws in the core and closes the contacts. The posistor options use the property of the material to sharply increase resistance when heated, which actually breaks the circuit after the element warms up.
Malfunction any of these components leads to the fact that the compressor cannot reach operating mode. If the relay “sticks” in the closed state, the starting winding burns out. If the contacts do not close at all, the engine only hums, trying to start. Understanding the type of your device is the first step to successful diagnosis.
⚠️ Attention: Before starting any diagnostic work, be sure to disconnect the refrigerator Nord from the electrical network. Working with electrical appliances under voltage is prohibited and dangerous to life.
It is worth noting that the life of the starting relay is limited by the number of on and off cycles. Over time, the contacts may oxidize or burn, which will increase the resistance and disrupt the normal operation of the unit. That is why checking the condition of the contacts is a priority when servicing equipment.
Visual diagnostics and external signs of malfunction
The first stage of testing should always be a thorough visual inspection. Often external signs can indicate a problem faster than instrumental diagnostics. You will need to remove the rear protective cover of the compressor and dismantle the relay unit itself, which is usually attached to the side pins of the compressor or secured with a clamp.
Pay attention to the condition of the plastic case. If you see traces of soot, melting, or smell a strong smell of burnt insulation, this is a sure sign that a short circuit or overheating has occurred inside. Deformation of the housing often indicates that the thermal protection did not work correctly or the component was subjected to extreme loads.
Also It is important to inspect the contacts for oxidation. A greenish or black coating on the terminals increases resistance and prevents the normal flow of current. If the relay looks intact on the outside, but the refrigerator does not start, you need to move on to a deeper check using measuring instruments.
Why does the relay get hot?
During normal operation, the starting relay may heat up, but should not be hot to the touch. Excessive heating often indicates that the compressor is drawing too much current (turn-to-turn short circuit) or the relay itself has internal resistance due to burnt contacts.
Also check the integrity of the wires going to the relay. Often, vibration of the compressor leads to chafing of the insulation or tearing off of contacts. Make sure that the connectors are tightly in place and have no signs of corrosion.
Necessary tools for checking the relay
For high-quality diagnostics, you will need a minimum set of tools that most home craftsmen can find. The main device will be a multimeter (tester), which allows you to measure resistance and check the integrity of the circuit. Without this device, an accurate check is impossible, since it is impossible to determine the internal state of the contacts “by eye.”
In addition to the multimeter, prepare the following tools:
- 🔧 Screwdrivers (flat and Phillips) for removing protective covers and dismantling clamps.
- ✂️ Pliers or pliers for carefully removing the terminals if they are too tight.
- 🧹 Fine-grained sandpaper for cleaning the contacts in case of slight oxidation.
- 📱 A smartphone with a camera to photograph the connection diagram before disassembling.
Make sure your multimeter is working properly and has charged batteries. To test the relay, you will need to switch the device to resistance measurement mode (Ohm). Measurement limit usually selected in the range of up to 20 kOhm, although for most tests a range of up to 200 Ohm is sufficient.
It is important to use a tool with intact insulation on the probes. Damaged insulation can lead to a short circuit during testing or inaccurate readings (incorrect readings) due to current leakage through the hands of the master.
Step-by-step instructions for removal and disassembly
The process of dismantling the start relay on refrigerators Nord enough standardized, but requires accuracy. First, remove the back metal or plastic panel at the bottom of the refrigerator that covers the compressor. It is usually secured with bolts or latches.
After gaining access to the compressor, you will see a black cylindrical motor tank, to which a small plastic block is attached to the side or top - this is our relay. It is put on three contact pins coming out of the compressor housing. Carefully remove the fixing clamp or bracket, if present.
Remove the relay strictly vertically or with a slight rocking, trying not to jerk the wires sharply. Inside the relay housing is the switching mechanism itself and, often, a thermal protection relay. Disassembling the plastic relay case itself is done by snapping the latches with a flat screwdriver.
☑️ Dismantling the relay
When disassembling, be careful: inside there may be a movable core or a ceramic posistor, which can be easily lost or broken. Place all small parts in a separate container. If the relay is monolithic and cannot be disassembled without destroying the housing, it is checked only by external methods or replaced immediately.
Diagnostics with a multimeter: resistance measurements
The most reliable way to check is to test the windings and contacts with a multimeter. First you need to determine which contacts are responsible for what. Usually there is a marking on the relay body, but if there is none, you can rely on the standard diagram: two contacts go to the main winding, one to the starting winding, plus thermal relay contacts.
Connect the multimeter probes to the input and output contacts of the relay. In normal condition (when the relay is not energized and not heated), the resistance between certain contacts should be close to zero (closed circuit), and between others - infinity (open circuit). If the device shows infinity where zero should be, it means the contacts are oxidized or broken.
Pay special attention to checking the posistor (if you have a thermal relay). At room temperature it should have low resistance. If the multimeter shows an open or very high resistance, the element is faulty and needs to be replaced. For inductive relays, it is important to check the coil for an open circuit.
| Test type | Normal readings | Malfunction symptom | Action |
|---|---|---|---|
| Coil integrity | Low resistance (Ohm) | Infinity (∞) | Replacing the relay |
| Contacts at rest | Closed (0 Ohm) or Open | Inconsistency with the diagram | Cleaning or replacement |
| Posistor | Low resistance | High resistance | Replacing the posistor |
| Thermal protection | Closed (0 Ohm) | Open (∞) | Checking the compressor |
If after testing it turns out that the relay is working, the problem may lie in the compressor itself or the wiring. However, in 80% of cases when the refrigerator hums and clicks, the culprit is the starting device. The critical indicator is the complete lack of reaction of the contacts to the relay flip (for inductive models) - this guarantees a breakdown.
Replacing the start relay: selection and installation
If the diagnostics confirm a malfunction, the relay must be replaced. You need to buy an analogue that strictly matches the power of your compressor. On the body of the old relay there is always a marking, for example R600a or indicating the power in watts (W) or horsepower (HP). The power of the new relay should be equal to or slightly higher (but not more than 20%) of the power of the old one.
Installation is carried out in the reverse order of removal. Push the new relay onto the compressor pins as far as it will go. Make sure it fits snugly and doesn't wobble. If necessary, use a new clamp, as the old one may have lost its elasticity. Connect the wires to the terminals according to the photograph taken earlier.
After assembly, do not rush to close the back panel. Plug in the refrigerator and listen. The compressor should start with a characteristic sound, run for a while and turn off when the set temperature is reached. If the startup was successful and there are no extraneous sounds, you can fix the panel.
⚠️ Attention: Never install a relay with less power than required. This will lead to instant combustion of the new part and possible damage to the compressor windings.
In some cases, it is possible to temporarily install a relay with a slightly higher power, but this is not recommended on a permanent basis, since the cut-off moment of the starting winding may change. The ideal option is to search for an original component or a high-quality universal analogue from trusted brands like Danfoss or Indesit (compatible models).
Common mistakes when repairing yourself
When repairing refrigerators Nord Newbies often make common mistakes that can aggravate the situation. One of the most common is an attempt to clean the contacts with sandpaper without subsequent degreasing. Remaining dust and abrasive can cause a short circuit inside the housing.
Another mistake is ignoring the thermal relay check. They often change the starting part, forgetting that the thermal protection could also fail. As a result, the new component quickly burns out due to overload. Always check the entire assembly.
It is also a mistake to assume that any relay will fit any refrigerator. Differences in the geometry of the fastening and the location of the contacts may lead to the fact that you simply cannot install the part, or it will short out on the compressor housing. Compatibility is a key parameter when purchasing.
Do not forget that working with refrigeration equipment requires care. If you are not sure of your actions at any stage, it is better to stop and consult with a specialist so as not to damage the expensive compressor.
FAQ: Frequently asked questions
Is it possible to start a Nord refrigerator without a starting relay?
Theoretically, you can start the engine by applying voltage to the starting relay winding by hand, but doing this is strictly not recommended. Without a relay, the engine will not turn off the starting winding, which will lead to its rapid combustion. This is an emergency testing method, and not a method of operation.
How much does a starting relay for a Nord refrigerator cost?
The cost of universal starting relays varies from 300 to 800 rubles, depending on the manufacturer and power. Original components can cost more, up to 1,500 rubles. The price is small compared to the cost of calling a technician.
Why does a new relay immediately burn out after installation?
This may indicate a malfunction of the compressor itself (turn-to-turn short circuit of the windings), problems with the wiring, or incorrect selection of relay power. Also, the cause may be a power surge in the network or poor contact in the socket.
How to distinguish a thermal relay from an inductive one?
A thermal relay (posistor) usually has a more compact plastic case and contains a ceramic element inside. An inductive relay is often heavier, contains a copper coil and a movable core, and may have a more complex system of levers inside.