An unexpected stop of the compressor is always stressful for the owner of the refrigerator, because food supplies and a comfortable atmosphere in the kitchen are at risk. If you hear a click followed by the hum of the motor, but the start does not occur, or the compressor is completely silent, most likely the problem lies in the starter. Refrigerator relay Danfoss is one of the most common components in household appliances, and its proper replacement can bring the unit back to life without calling a technician.
In this article we will analyze in detail the process of diagnosing and installing a new element, paying special attention to electrical safety and the correct selection of spare parts. Danfoss Company produces reliable components that are used in many brands, including Indesit, Ariston, Stinol and others. Understanding the operating principle of this unit will help you avoid common mistakes during repairs.
Before starting any work, you must completely turn off the power to the refrigerator by unplugging the plug from the socket. Failure to do so may result in serious electrical injury or damage to the control electronics. We will consider not only the mechanical installation, but also the nuances of checking the motor windings, which is a critical step.
Diagnostics of a faulty starting relay
Before buying a new part, you should make sure that the problem is in it, and not in the compressor or wiring itself. An external inspection often helps to identify obvious signs of overheating, such as blackening of the plastic, melting of contacts, or the presence of carbon deposits. If starting relay has visible damage, its operation is impossible and requires immediate replacement.
However, the absence of external defects does not guarantee the serviceability of the device. Often the inductor inside breaks or the contacts stick, which is not visually noticeable. For accurate diagnostics, you will need a multimeter configured for continuity or resistance measurement mode. The resistance of a working coil is usually several tens of Ohms, while a break will show infinity.
⚠️ Attention: If after replacing the relay the refrigerator does not start again or the machine in the panel knocks out, immediately stop trying to turn it on. This may indicate an interturn short circuit in the compressor windings, which requires professional intervention.
It is also worth paying attention to the nature of the sound when trying to start. A dull hum that turns into a click after a few seconds is a classic symptom of a faulty trigger mechanism or a jammed piston group. In some cases, the thermostat or control board may be the culprit, so a comprehensive approach to diagnostics is required.
Checking the integrity of the thermal protection, which is often built into or located next to the relay housing, is also an important step. Thermal relay should ring short when cold. If the circuit is broken even at room temperature, the protection has burned out and requires replacement along with the starting element.
Selection of a compatible Danfoss relay model
The world of refrigeration technology is diverse, and even within the same brand, different types of compressors can be used. Danfoss relay are available in various modifications, which differ in power, type of connection and housing design. An error in choosing a part can lead to the new component burning out in the first seconds of operation or not being able to start the engine.
On the body of the old relay there is always a marking containing the model code, mains voltage and permissible current range. The most common series for household refrigerators are 101N00xx and 101N01xx. It is important to rewrite these numbers verbatim before going to the store or placing an order online.
There is a division into relays for single-phase compressors with a starting winding and for models with a capacitor start. Installing the wrong type will lead to incorrect operation of the motor: it will either not start or will work on only one winding, quickly overheating. Therefore, checking with technical documentation or a compatibility table is mandatory.
If the original model cannot be found, you can use universal analogues, but they require more fine-tuning. Universal relays they often have an adjusting screw or a set of contacts for different powers, which requires additional knowledge during installation. It is best to look for an exact analogue using the manufacturer's code.
Necessary tools and safety measures
To successfully complete the replacement, you will need a minimum set of tools that most home craftsmen will have. The main tool will be a flathead and Phillips screwdriver for removing the back cover of the refrigerator and dismantling the compressor casing. You may also need pliers with insulated handles.
A multimeter is indispensable for diagnosing and checking contacts. Without it, it is impossible to guarantee the serviceability of the new part and the absence of problems with the motor windings. If you do not have this device, purchasing it or borrowing it from friends will significantly increase the chances of a successful repair.
☑️ Preparation for repair
Safety comes first. Working with live electrical appliances is strictly prohibited. Even after unplugging, capacitors may still have a residual charge, so do not touch live parts with your bare hands without first discharging them (if applicable to your particular circuit).
In addition, the compressor is a sealed unit filled with refrigerant under pressure. Never cut through copper pipes or drill into the compressor housing. Mechanical damage to the cooling system will lead to a freon leak and will require an expensive refill from a specialist.
Step-by-step instructions for replacing the relay
The replacement process begins with access to the compressor, which is usually located in the lower rear part of the refrigerator. Remove the protective cover by unscrewing the mounting screws or releasing the latches. You will see a view of the black “tank” of the compressor with the corresponding tubes and electrical box.
Carefully remove the plastic box covering the electrical contacts. Inside you will see wires leading from the mains and thermostat to the relay and thermal protection contact group. Connection diagram may differ depending on the model, so it is strongly recommended to take a photo before disconnecting any wires.
The relay itself is put on the pins of the compressor and fixed in a metal frame or plastic holder. Loosen the frame fasteners, if any, and carefully pull the relay down, releasing the contacts. Be careful not to damage the thermal protection wires, which are often attached to the relay body or with a clamp on the pipe.
⚠️ Attention: When removing the old relay, proceed without sudden jerks. The contacts can be oxidized or “stick”, and excessive force can break the wires going to the compressor windings, which will complicate repairs.
Install the new part, observing the top-bottom orientation indicated on the housing (often there is an arrow or the inscription TOP). Push the relay onto the pins as far as they will go, making sure they fit into the contact sockets. Then return the fixing frame to its place and connect the wires according to the photograph or diagram taken earlier.
Connection diagrams and pinouts
Correct connection of the wires is the key point of repair. The compressor has three terminals: common (C), starting (S) and working (R). The Danfoss relay is designed to automatically connect the starting winding only at the time of start and disconnect it when the speed is up.
Usually the wires are connected as follows: the common wire (often white or black) goes to contact C, the phase wire through the thermostat goes to contact R, and the starting winding is closed inside the relay. However, the color marking of the wires may vary depending on the manufacturer of the refrigerator.
| Contact on the compressor | Designation | Function | Wire color (approximate) |
|---|---|---|---|
| Common | C | General input power supply | White / Black |
| Run | R | Working winding | Red / Brown |
| Start | S | Start winding | Blue / Green |
| Ground | - | Chassis grounding | Yellow-green |
If you are using a universal relay, it is important to correctly determine which contact to connect where. Such models are often marked 1, 2, 3 or L, S, R. An error in the connection can lead to the compressor humming, but not spinning, or starting to heat up.
What do the numbers on the relay contacts mean?
On a Danfoss relay the numbers usually mean: 1 - phase input, 2 - starting winding, 3 - working winding. However, always check the diagram on the case of your specific model, as standards may differ.
After connecting all the wires, check the contact tightness again. They should not wobble or spark. Weak contact will lead to heating and melting of the plastic, which will cause repeated breakdowns in a short time.
Checking operation and possible errors
After assembling the entire electrical part, do not rush to close the back cover of the refrigerator. Plug in the unit and listen. There should be a confident click from the relay, followed by the smooth hum of the operating compressor. If you only hear a hum without starting, turn off the device immediately.
Pay attention to the behavior of the thermal protection. If the compressor starts, but after 10-20 seconds it clicks and turns off, the thermal protection may be tripping. This may be a sign that a relay has been selected with the wrong response current or that there are problems with the motor itself.
A common mistake is to ignore the condition of the capacitor, if it is provided for in the design. Starting capacitor helps the engine gain speed, and if it is swollen or loses capacity, even a new relay will not be able to start the refrigerator. Check it visually and with a device.
It is also worth checking the integrity of the wires going to the relay. Often, due to vibration or heat, the insulation cracks and a short circuit occurs to the housing. A visual inspection and “continuity” of the wires will help eliminate this factor.
Frequently asked questions and answers (FAQ)
Is it possible to replace a Danfoss relay with a universal analogue?
Yes, this is possible, but it requires careful selection of the current and power of the compressor. Universal relays often have switchable contacts for different powers, which must be configured correctly. However, the original is always preferable in terms of reliability and service life.
Why does a new relay burn out after a few days?
There may be several reasons: incorrectly selected power, poor contact in the terminals, a malfunction of the compressor itself (turn-to-turn short circuit) or problems with the voltage in the network. It is also worth checking the thermal protection.
How to determine whether the relay or the compressor is faulty?
You need to test the compressor windings with a multimeter. If there is resistance between the contacts and it is not zero or infinity, and there is no breakdown to the housing, most likely the motor is alive, and the problem is in the relay. If the windings ring short or to the housing, the compressor is faulty.
Is it necessary to change the thermal protection together with the relay?
It is recommended to change them in pairs, especially if the old protection has traces of heating or is more than 10 years old. Thermal protection is inexpensive, but ensures safety and prevents the new relay from burning out when overheated.