A sudden stop in the operation of refrigeration equipment often takes you by surprise, especially when there are perishable products in the chambers. For equipment owners Nord one of the most common causes of compressor failure is the failure of the start-up relay. This small but critical element is responsible for starting the engine and protecting it from overloads, so its serviceability directly affects the service life of the entire unit.
Independent replacement of this part does not require deep knowledge in electronics, but requires strict adherence to safety precautions and sequence of actions. If you notice that the engine hums but does not start, or turns on for a few seconds and immediately stalls, the problem most likely lies in the starting system. In this article, we will look in detail at how to correctly diagnose a breakdown and connect a new relay to your refrigerator.
Diagnostics of a faulty start relay
Before you start disassembling the unit and purchasing new components, you need to make sure the diagnosis is correct. Start relay is an electromechanical switch, which supplies current to the starting winding of the compressor only at the moment of start. If the contacts inside the device burn or stick, the motor does not receive the necessary impulse to rotate the shaft.
The first sign of a malfunction is often a characteristic click that is heard every few minutes. The compressor tries to start, hums, but then there is a click and the sound stops. This triggers thermal protection, since the current in the windings increases, but there is no rotation. It is also worth paying attention to the appearance of the relay itself: if melting, cracks or traces of burning are visible on the plastic case, its replacement is necessary without additional testing.
For more accurate diagnostics, you can use a multimeter. In normal condition, the resistance between the contacts should be close to zero (closed) or correspond to the parameters specified in the technical documentation. If the device shows an open circuit where there should be a contact, or vice versa - a short circuit in the off state, the part is faulty.
- 🔊 The compressor hums for 5-10 seconds, followed by a click and complete silence.
- 🔥 Traces of thermal effects or blackening are visible on the relay body.
- ❄️ The refrigerator has stopped freezing, although the light inside is on.
- ⚡ When checking with a multimeter, the lack of conductivity on the working contacts is recorded.
⚠️ Attention: If after replacing the relay the compressor continues to behave in the same way, the problem may be deeper - perhaps the motor itself is jammed or the wiring is faulty. In this case, further operation without a master is dangerous.
Preparation of tools and safety measures
Any work with electrical appliances begins with ensuring safety. Disconnection from the network is the first and immutable rule. Even if you think you won't hit anything, the risk of electric shock when working on live internal components is too great. Unplug the power cord from the outlet and make sure that access to it will not be blocked by furniture during the repair process.
To carry out the work you will need a minimum set of tools. In most cases, a Phillips and flat-head screwdriver, as well as pliers, are sufficient. If you need to clean contacts or wires, prepare fine sandpaper. It would also be a good idea to prepare a container for water to defrost ice if it has formed on the evaporator due to equipment downtime.
The workplace should be well lit. The back wall of the refrigerator Nord is often covered with a layer of dust, so it is recommended to immediately prepare a vacuum cleaner or dry rag to clean the area around the compressor. This will not only improve visibility, but also prevent dirt from getting inside the electrical connections.
☑️ Preparation for repair
Therefore, all connections must be made securely, without twists or weak fixation. Any spark in the area of possible refrigerant vapors (although the likelihood of their leakage when replacing the relay is minimal) is theoretically undesirable, so avoid creating an open fire near the unit.
Removing the old relay
The process of removing a faulty part in refrigerators Nord usually does not cause difficulties, since the design compressor compartment is quite standardized. First you need to remove the rear metal cover that blocks access to the motor. It is usually secured with four screws around the perimeter or with latches that need to be carefully pressed out.
After removing the cover, you will see a black cylindrical or square compressor. There is a box on its side or bottom (depending on the model) - this is our desired relay. Wires from the network and from the engine itself are suitable for it. Before removing the part, it is strongly recommended to photograph the connection diagram or sketch the location of the wires so that there is no confusion when installing a new element.
Removal is carried out by disconnecting the terminal block. In some models Nord the relay is simply put on the three pins of the compressor and secured with a spring clip or plastic holder. If the wires fit through the connector, it must be carefully removed by pulling the body of the chip, and not the wires themselves, so as not to break them at the base.
What to do if the terminals are stuck?
If the terminal block cannot be removed by hand, do not use excessive force. Try gently rocking it from side to side. As a last resort, you can use pliers, but be very careful not to damage the compressor contacts.
Sometimes the old relay may be secured with a metal frame. In this case, you will need pliers to release the fixation tendrils. After releasing the fasteners, the part is easily removed from the pins. Inspect the compressor pins: if there are oxides or carbon deposits on them, they should be carefully cleaned before installing a new relay.
Connection diagram and installation of a new relay
Installing a new starting relay requires attention to the markings. On the body of a new part there are always symbols: Run (working winding), Start (starting winding) and Common (common contact). These designations must strictly correspond to the location of the pins on the compressor of your refrigerator Nord.
The most important point is the orientation of the part. The relay is sensitive to its position in space, as evidenced by the arrow UP or the inscription TOP on the body. She should look straight up. If you install the relay upside down, the mechanism will not operate correctly and the compressor will either not start or burn out. This is critical errorwhich beginners make by ignoring the markings.
The installation process is as follows: first, the relay is put on the compressor pins until there is a characteristic click or a tight fit. Then, if the model requires it, it is fixed with a metal bracket. Only after this are the wires connected. If you have not photographed the circuit, be guided by the colors of the wires, which are often (but not always) standardized: brown or black - phase, blue - zero, yellow-green - ground.
| Marking on the relay | Contact function | Wire color (standard) | Location on the compressor |
|---|---|---|---|
C or L |
General (Line) | Brown / Black | Bottom left (conditionally) |
R |
Working winding (Run) | Blue / White | Bottom right |
S |
Start winding (Start) | Red / Green | Upper |
⏚ |
Grounding | Yellow-green | On the body |
After connecting all the wires, check the reliability of the connections again. They should not dangle or come off easily with a slight tug. Make sure that the wires do not touch hot parts of the compressor or sharp edges of the metal casing, which could cause the insulation to melt in the future.
Checking system performance
Once the new relay is installed and all wires are connected, you can proceed to testing. Do not rush to immediately load the refrigerator with food. Plug in the unit and listen. Start-up should occur almost instantly or within 1-2 seconds after the characteristic click of the relay.
Normal operation is characterized by a smooth, monotonous hum of the compressor. If you hear strong vibration, knocking or repeated clicking noises without the engine starting, unplug the appliance immediately. This is a signal that either the relay is selected incorrectly (does not match the power or type), or the problem lies in the compressor itself.
Pay attention to the temperature of the relay housing during operation. It may get slightly warm in the first few minutes, which is normal, but if it becomes scalding hot, it's a sign of overload. Also check whether the evaporator inside the chamber begins to cool - the first signs of cold should appear after 10-15 minutes of operation.
- ✅ The compressor started the first time and runs smoothly.
- ✅ There are no extraneous sounds, except for the quiet hum of the motor.
- ✅ Relay housing warm, but not hot.
- ✅ After 20 minutes, a decrease in temperature is felt in the refrigerator compartment.
⚠️ Attention: If the new compressor or relay makes an unusually loud noise in the first minutes of operation, let the equipment run for 10-15 minutes. Sometimes it takes time to pump the oil and equalize the pressure in the system.
Typical connection errors
One of the most common mistakes is ignoring the type of refrigerant and the corresponding relay. Refrigerators Nord of different years of production could be filled with R12, R134a or R600a freon. Relays for them may differ in starting current characteristics. Installing a relay from a model with a different refrigerant can lead to rapid failure of the new part.
Another common problem is poor contact in the terminal block. If the wires are not inserted completely or are oxidized, heat will begin to be generated at the connection. Over time, this leads to melting of the plastic and, in the worst case, to a short circuit. Always check the tightness of the wires.
Some craftsmen try to “revive” an old relay by stripping the contacts or tapping. This is strictly not recommended. The resource of the starting device is limited, and after the first signs of malfunction appear, its internal structure is already damaged. Reinstalling such a relay is only a temporary measure that may cost you a burned out compressor.
Frequently asked questions (FAQ)
Is it possible to install a relay from another brand of refrigerator on Nord?
Yes, this is possible if the electrical parameters (starting current, voltage) and the geometric dimensions of the landing pins match. However, it is better to look for relays specifically designed for compressors installed in equipment Nord (often these are Danfoss models or their analogues).
Why does a new relay burn out after a few days?
There may be several reasons: incorrect orientation during installation (not according to the UP mark), excessive voltage in the network, malfunction of the compressor itself (turn-to-turn short circuit) or the use of a low-quality analog relay.
Do you need to wait after turning on the refrigerator before restarting?
Yes, if you turned off the refrigerator, it is recommended to turn it on again no earlier than 5-10 minutes later. This is necessary to equalize the pressure in the system and cool down the thermal protection, otherwise the compressor may not start or go into protection.
How to distinguish a starting relay from a protective one?
Modern refrigerators Nord often use a combined unit, where the starting and thermal protective relays are combined in one housing. If they are separated, then the starting one is usually larger in size and is attached directly to the pins, and the thermal (protective) one is put on the compressor housing or connected in series in the circuit.