Where is the thermal relay in the refrigerator: search and replacement

If your refrigerator has stopped freezing, and the compressor is either silent or hums for several seconds and then stops, the problem often lies in the engine starting system. In most cases, the culprit of the malfunction is start-up protection relay. This small but critical element is responsible for supplying voltage to the electric motor windings and protecting against overloads. Understanding where exactly it is located is the first step to restoring the functionality of household appliances.

You don’t have to be a professional craftsman to find this unit. The design of most refrigeration units, be it Indesit, Atlant or LG, provides access to the compressor and its attachments. However, without knowing the exact location, a lot of time can be lost or fragile tubes can be damaged. In this article we will look in detail at how to find a relay, what it looks like and why it fails.

⚠️ Attention: Before starting any work to find or replace parts, be sure to disconnect the refrigerator from the electrical network. Working with live electrical equipment is life-threatening.

Design and purpose of a start-up protection deviceTo effectively search for a part, we need to understand what exactly we are looking for. In everyday life, a thermal relay is often confused with a starting relay, but in modern refrigerators they are combined into a single housing, which is correctly called start-protective relay. Inside this plastic or carbolite housing there are two main systems: a starting system, which briefly supplies current to the starting winding of the motor, and a thermal one, which breaks the circuit when the permissible current is exceeded.

The principle of operation is based on the physical properties of materials. The trigger mechanism often uses a posistor or electromagnetic coil, and the thermal mechanism often uses a bimetallic plate. When the compressor consumes too much energy (for example, when it seizes), the plate heats up, bends and opens the contacts. This prevents the motor windings from burning out. The thermal release point is usually set to a current that is 20-30% higher than the rated operating current of the motor.

The location of this unit is always related to the compressor, since it must be in direct contact with its terminals or in close proximity to ensure proper operation. In older models, the relay could be located separately, but in modern technology, such as Bosch or Electrolux, a compact arrangement “on the shaft” is used.

The typical location of the relay on different models of refrigeratorsThe answer to the question “where is the thermal relay located” is almost always the same: on the compressor casing. The compressor is a black metal "cylinder" located at the bottom rear of the refrigerator. The relay is placed directly on the side pins (winding terminals) of the motor. However, access to it may differ depending on the design of the housing.

In classic models with an open compressor compartment (often found in Atlant or old ZILs), access to the relay is not limited in any way. Just move the refrigerator away from the wall and you will see a black motor, and on the side or top of it there is a plastic box with suitable wires. This is the required unit.

In models with a closed base (for example, many Samsung, LG, Whirlpool), the compressor is hidden behind a decorative panel or metal cover at the bottom of the rear wall.

• 🛠️ You will need to remove the back metal cover by unscrewing several screws around the perimeter.
• 🔍 Sometimes it is necessary to remove the plastic casing that covers the compressor compartment itself.
• 💡 In some cases, access is only possible after removing the lower decorative panel at the front (base).

📊 What problem did you encounter when searching for the relay?

The relay is easily accessible from the back

You need to remove the covers

The compressor is sealed in foam

I can’t find the compressor

Visual identification: what the relay looks likeHaving found the compressor, you will see that a plastic or black carbolite element approaches its terminals, from which a bundle of wires comes. This is start-up protection relay. It can have different shapes: rectangular, cylindrical or drop-shaped, depending on the manufacturer (Danfoss, Secop, Embraco).

The body color is most often white, gray or black. The side surface is usually marked with the part number, voltage (220V) and operating current. It is these parameters that are important when selecting a replacement. If the relay has a metal casing, it most likely belongs to older models or industrial units.

⚠️ Attention: Do not try to remove the relay by force. It is held on the compressor terminals by a tight fit and is sometimes secured with a metal bracket or plastic retainer. A sudden movement can break the ceramic terminals of the compressor.

Removal is often required. carefully pry up the retainer or remove the metal frame-holder. The wires can be assembled into a bundle or go separately to the thermostat and plug.

Dismantling instructions for diagnosticsIf you find a suspicious element, it must be removed for visual inspection or “testing” with a multimeter. The dismantling process requires care, since the contacts inside may be damaged. oxidized, and the plastic becomes brittle over time.

First, take a photo of the location of the wires so as not to mix up the contacts during assembly. Then, holding the relay body with one hand, gently rock it from side to side with the other, pulling it off the compressor contacts. If the metal bracket is in the way, you need to bend it with a screwdriver.

☑️ Check before. by removing the relay

Disconnect the refrigerator from the outletRemove the protective cover of the compressorTake a photo of the connection diagramInspect the wires for melting

Done: 0 / 4

After removing the relay, it is often discovered that the internal chamber where the compressor contacts enter is blackened or melted. This is a sure sign of overheating and poor contact. The internal mechanism (posistor or coil) may crumble when shaken, which clearly indicates a malfunction.

Compatibility table and symptoms of malfunctionUnderstanding the symptoms. helps to quickly diagnose the problem. Below is a table that helps to compare the behavior of the refrigerator and the state of the relay.

Symptom	Probable cause	Relay condition
Beeps for 5-10 seconds and clicks	Sticking of contacts or breakdown of a posistor	Black soot inside, burning smell
Silent, no light	Thermal protection broken	No circuit bell on the multimeter
The refrigerator rarely turns on	False activation of the protection	The bimetallic plate is deformed
The compressor is hot	The protection does not turn off	The contacts are welded to each other

Can the relay be repaired?

It is not economically feasible to repair the start-protection relay. The cost of the new device is low, and the reliability after opening the sealed case will be low. It is better to make a complete replacement.

If the compressor is old and has an interturn short circuit, it will consume increased current, burning new relays one after another.

The nuances of installing a new componentWhen installing a new one start-up protection relay it is critically important to observe orientation. There is always a marking on the case: UP (top) or an arrow pointing up. If you install the relay upside down, gravity will not allow the mechanism to work correctly, and the protection will not work at the right time, which will lead to the compressor burning out.

When connecting wires, refer to the photograph or color marking you took earlier. Terminal blocks are usually used, but some models may have wires twisted and insulated with heat shrink. After assembly, turn on the refrigerator and listen: the startup should be confident, without buzzing and repeated clicks.

What is the difference between a posistor relay and an electromagnetic one?

A posistor relay uses a ceramic element that changes resistance when heated, and has no moving parts in the starting circuit. Electromagnetic uses a coil and a core that is drawn in by current. PTC posistors are more common in modern technology.

Why does the relay heat up during operation?

Slight heating of the housing is acceptable, since current passes through it. However, if the body chars or melts, it means that either the relay is selected incorrectly (the wrong current), or the compressor is faulty and consumes too much current.

Is it possible to start a refrigerator without a relay?

You can start the engine briefly by applying voltage directly to the working and starting windings, but this is dangerous and requires skill. Operating the refrigerator without protection is strictly prohibited - this will lead to a fire or failure of the compressor.

Where to buy a suitable relay?

You need to look for it by the markings on the body of the old device. The article number usually consists of an alphanumeric code (for example, 117N0011). It is better to buy in specialized stores of spare parts for household appliances.

What to do if the new relay does not fit the shape?

The main thing is the compliance of the electrical characteristics (current, voltage) and the connection diagram. If the shape is different, you may need an adapter frame or careful modification of the mounting location, but this should be done by a specialist.