Brand refrigerators Indesit have earned a reputation as reliable and durable devices, but even the highest quality equipment requires attention over time. One of the most vulnerable components in the cooling system is the start-up protection device, which is responsible for starting the compressor and protecting it from overloads. If your the refrigerator has stopped freezingand the motor hums, but does not start, or turns on for just a few seconds, the problem most likely lies in this component.
Self-diagnosis allows you to save time and money, since calling a technician to your home often costs more than the part itself. In this article, we will analyze in detail the device of the thermal relay, consider the symptoms of its malfunction and provide a step-by-step algorithm for testing using a multimeter. Correct diagnosis will help you understand whether only the relay needs to be changed or the problem lies deeper in the compressor itself.
Before taking active steps, It is necessary to understand that working with electrical appliances requires compliance with basic safety rules. Any manipulations with the electrical part of the refrigerator Indesit should be carried out only after the device is completely disconnected from the network. Ignoring this rule may result in electric shock or failure of the refrigerator's electronics.
⚠️ Attention: Before starting any diagnostic work, make sure that the refrigerator's plug is removed from the socket. The residual voltage in the capacitors can persist for several minutes, so let the equipment stand unplugged for at least 10-15 minutes.
Principle of operation and design of the trigger mechanism
To effectively test the part, you need to understand how it functions inside the system. In refrigerators Indesit most often, combined start-protective relays are used, which combine two elements in one housing: starting and thermal. Starting relay responsible for supplying voltage to the starting winding of the engine at the moment of start, helping the rotor to spin up.
The second component - a thermal protection relay - works on the principle of a bimetallic plate. When a current of normal strength passes through the motor windings, the plate remains straight and the circuit is closed. However, if an overload or jamming of the rotor occurs, the current increases sharply, the plate heats up, bends and opens the circuit, stopping the compressor to avoid burning out the windings.
Structurally, this device is a plastic case with terminals for connecting wires and internal contacts. Depending on the refrigerator model Indesit, the relay may have a different number of contacts and mounting form. Inside there is a spiral covering a bimetallic plate, which reacts to temperature changes depending on the current strength.
- 🔹 Bimetallic plate: the main sensitive element that opens the circuit when overheated.
- 🔹 Starting coil or posistor: an element that provides short-term connection to the second winding of the motor.
- 🔹 Contact group: moving and stationary contacts that switch electric current.
Typical symptoms of a relay malfunction
Determine that it is the thermal one that has failed relay, it is possible according to the characteristic signs of the operation of the refrigeration unit. Users often confuse a relay failure with a failure of the compressor itself, which leads to unnecessary costs. If you hear the motor struggling to start, making a clicking noise and then stopping, this is a classic sign of a problem in the starting circuit.
Another obvious symptom is the compressor housing at the bottom of the refrigerator becoming very hot. If, when you touch it with your hand (be careful, you can get burned), you feel that the motor is hot, but there is no cold in the chambers, it means that the protection is constantly activated, preventing the engine from reaching operating mode. In some cases, the relay may “stick” when turned on, which is even more dangerous, since the engine is running without protection.
Visual inspection can also provide a lot of information. If you remove the casing and remove the relay, it may show traces of soot, melted plastic, or a characteristic burning smell. Inside the case you can sometimes notice blackened contacts. However, the absence of external defects does not guarantee serviceability, therefore electrical check a multimeter is required.
Removing the start-protective device
The process of removing the relay in refrigerators Indesit is quite simple and does not require special tools other than a screwdriver and pliers. First you need to gain access to the compressor, which is located in a niche at the lower rear of the unit. Remove the cardboard or metal cover covering the engine compartment.
On the compressor you will see a black cylindrical or rectangular element to which the wires go. This is our desired device. It is put directly on the terminals of the motor windings. Before removal, it is recommended to photograph the wire connection diagram so as not to mix up the contacts during assembly, although often the design allows the relay to be installed in only one position.
Carefully disconnect the wire connectors if they are secured with terminals, or simply remove them from the contacts. Then, using a gentle rocking motion from side to side, remove the relay housing from the compressor studs. Do not use excessive force so as not to damage the copper tubes or motor leads.
☑️ Algorithm for removing the relay
Diagnostics with a multimeter: step-by-step algorithm
The most reliable way to check a thermal relay is to use a multimeter (tester) in resistance measurement mode (Ohm). If you don't have a multimeter, you can use a simple light bulb with a socket and two wires connected to a plug, but this method is less accurate and requires extra care. Let's consider a professional approach using a tester.
Switch the multimeter to continuity mode or resistance measurement to a limit of 200 Ohms. First of all, we check the thermal protection. Find the contacts going to the bimetallic strip (usually the input and output to the compressor). When cold (at room temperature), the resistance should be close to zero and the device should beep. If the device shows one (infinity), it means that the circuit is broken and the relay is faulty.
Next, we check the starting part. If a posistor is installed in the relay, its cold resistance should also be small (several ohms or tens of ohms). If the posistor is short-circuited or, conversely, has infinite resistance, it must be replaced. It is also important to check whether the relay is “piercing” into the housing. Touch one probe to any contact, and the other to the metal body of the relay - the device should not react.
What to do if you don’t have a multimeter at hand?
You can assemble a simple test: a 220V light bulb in series with one of the probes. If the circuit is closed, the light will light up. Be extremely careful as you are working with dangerous voltage. This method is not recommended for beginners due to the risk of short circuit.
Particular attention should be paid to the condition of the contacts. Even if the device shows the presence of a circuit, oxidized or burnt contacts can create high contact resistance, which will not allow the engine to start. Visually clean contacts are a good sign, but a guarantee is provided only by replacing with a known-good analogue.
⚠️ Attention: Never attempt to test a relay located on a compressor while it is energized unless you have experience working with electricity. You can accidentally short-circuit the leads and damage the motor windings, which will lead to expensive repairs.
Table of values and possible faults
For ease of diagnosis, the measurement results can be systematized. Below is a table that will help you interpret your meter readings and determine the condition of the unit.
| Test Type | Normal Reading | Fault Indication | Probable Cause |
|---|---|---|---|
| Thermal protection (cold) | 0.1 - 2 Ohm (Sound) | ∞ (Unit on screen) | Bimetallic plate break |
| Trigger element (posistor) | 5 - 50 Ohm | 0 Ohm or ∞ | Short circuit or combustion of the posistor |
| Insulation (contact-housing) | ∞ (No reaction) | Any Ohm value | Insulation breakdown, life-threatening |
| Visual inspection | Clean contacts | Soot, melting | Overload, poor contact, sparking |
If your If the measurements coincide with the “Fault Indication” column, then the part requires replacement. Attempts to restore a burnt-out thermal relay, for example, by stripping the contacts or closing the circuit directly, are temporary and can lead to a fire or permanent breakdown of the compressor.
Replacement and selection of an analogue for the Indesit refrigerator
Selecting a new relay is a critically important step. Devices for refrigerators Indesit may differ in engine power, type of compressor (regular or inverter, although relays work differently on inverters) and connection diagram. There is always a marking on the body of the old relay, for example, PTM11L, R6 or 3394.
When purchasing, pay attention to the following parameters: voltage (usually 220-240V), frequency (50/60 Hz) and, most importantly, permissible current or motor power. Installing a relay with a lower current will lead to constant false shutdowns, and with a higher current, the protection will not work in a real accident.
The process of installing a new element occurs in the reverse order of removal. Push the relay onto the compressor studs until you hear a characteristic click or stop. Connect the wires strictly according to the photograph taken earlier. Make sure that the connectors fit tightly and do not loosen.
- 🔸 Compatibility: Make sure that the new relay is suitable for your series of compressors (Danfoss, Embraco, Aspera) that were installed on Indesit.
- 🔸 Orientation: Some relays are sensitive to the installation position (up arrow), check markings on the body.
- 🔸 Fixation: After installation, check whether the relay vibrates during operation, as vibration can cause false operation.
Frequent errors in diagnostics and repair
Many amateur craftsmen make typical mistakes that complicate repairs. One of the most common is an attempt to start the compressor by shorting the relay contacts directly, without installing new protection. This can lead to the fact that when the engine jams, the wiring in the wall or the compressor itself will burn out, since it will be left without protection.
The condition of the capacitor is also often ignored, if it is in the circuit (in some older models). If the capacitor has lost capacity, the engine may not start even with a working relay, creating a false impression that the starting device is broken. Always check the entire trigger circuit as a whole.
Another mistake is using inappropriate tools to strip contacts. A file or sandpaper may leave conductive dust or disrupt the geometry of the pad, causing poor seal. It is better to replace the unit immediately than to take risks.
⚠️ Attention: Technical characteristics of compressors and relays may vary depending on the year of manufacture and the specific model of the refrigerator. Always check the markings on the body of the part with manufacturers' catalogs or consultants of specialized stores before purchasing a replacement.
FAQ: Frequently asked questions
Is it possible to temporarily turn on a refrigerator without a thermal relay?
It is strictly not recommended. Unprotected operation may result in the compressor windings catching fire if it becomes jammed or overloaded. This is a fire hazard and can completely destroy an expensive unit.
Why does the new relay click, but the refrigerator does not start?
Possible reasons: the compressor itself is faulty (an interturn short circuit or wedge), the capacitor is faulty (if present in the circuit), or a relay with unsuitable current characteristics has been selected cutoff.
How to distinguish Indesit relays from relays of other brands?
Visually they may be similar, but the key difference is in the markings and current characteristics. Relays for Indesit often have a specific housing shape and contact arrangement, compressors installed on this equipment.
How long does a thermal relay last on average?
The service life depends on the stability of the voltage in the network and the frequency of on-off cycles. On average, a high-quality relay lasts 5-10 years, but power surges can shorten this period to 1-2 years.
Do you need to wait after a shutdown before turning it back on?
Yes, definitely. After the compressor is switched off, a minimum of 5-10 minutes must pass before restarting. This time is necessary to equalize the pressure in the system and cool the bimetallic plate of the relay, otherwise it may not work correctly or damage the engine.