How to correctly install the thermostat in the refrigerator: instructions with photos and diagrams

The thermostat is the “brain” of the refrigerator, which controls the temperature in the chambers, turns the compressor on and off. Incorrect installation or configuration of this device can lead to freezing of food, increased energy consumption, or even equipment breakdown. In this article we will look at how to independently replace or reconfigure the thermostat in refrigerators of different types - from Soviet "Biryusa" and "Atlant" to modern LG, Samsung and Indesit.

It is important to understand that the installation process depends on type of thermostat (mechanical or electronic), refrigerator model and even on where exactly the temperature sensor is located. We have collected proven connection diagrams, photos of work stages and advice from experts - so that you can cope without calling a specialist. If your refrigerator is still under warranty, it is better to contact a service center: independent repairs may void the warranty.

Before you begin, check whether the problem is really in the thermostat. Often malfunctions are disguised as a breakdown: this could be a freon leak, a clogged capillary tube, or a compressor failure. Read about how to diagnose a thermostat in the corresponding section.

How to check the thermostat before replacing

Before removing the old thermostat, make sure that it is really faulty. Here are the key signs of a breakdown:

• 🔴 The refrigerator does not turn on at all (there is no characteristic relay click when turning the thermostat knob).
• ❄️ The compressor works without stopping, but the temperature in the chamber does not drop to the desired level.
• 🌡️ In the freezer the chamber is too cold (the products are covered with an ice crust), and the main one is too warm.
• 🔊 The relay clicks are constantly heard, but the motor does not start.

For accurate diagnostics, you will need a multimeter. Unplug the refrigerator, remove the thermostat protective cover and check the resistance at its terminals. In operating condition at room temperature, the resistance should be 0 Ohm (closed circuit). If the device shows a break (OL), the thermostat must be replaced.

⚠️ Attention: In some models (for example, Samsung RL-33 or LG GA-B489) the thermostat is integrated into the electronic control unit. Replacing it requires soldering and programming - without experience, it’s better not to take risks.

If you don’t have a multimeter, you can check the thermostat using the “old-fashioned” method: take it out of the refrigerator, put it in the freezer for 15–20 minutes, and then connect a 220 V light bulb to its terminals via a plug. A working thermostat will close the circuit and the light will come on. But remember: this method is unsafe and is only suitable for mechanical regulators!

Types of thermostats: which one is suitable for your refrigerator

Thermostats are divided into two large groups: mechanical and electronic. The former are used in old and budget models (for example, Atlant MHM-170 or Indesit B18), the latter - in modern technology with a display (Samsung RB-30, Bosch KAN92VI20). They also differ in:

• 🔧 Type of fastening: on screws, latches or soldering.
• 📏 Length of the capillary tube: from 0.8 to 2.5 meters (it is important to choose one identical to the original!).
• 🔌 Number of contacts: usually 2–4 (for connecting a compressor, lamp, defrost mode).
• 🌡️ Temperature range: for example, -30°C…+10°C for freezers or 0°C…+15°C for main compartments.

To accurately select a thermostat, take an old regulator with you to the store or write down refrigerator brand i original part number (usually indicated on a sticker inside the camera or on the back wall). If you buy an analogue, check the compatibility by:

• 🔌 Connection diagram: number and location of terminals must match.
• 📏 The length of the capillary tube: if it shorter than the original, the sensor will not reach the evaporator.
• 🔧 Mounting type: for example, in Atlant the thermostat is mounted on screws, and in Indesit —on latches.

⚠️ Attention: In refrigerators with a system No Frost the thermostat is often combined with a defrost timer. Replacing it requires additional adjustment of defrosting cycles - without experience, it is better to entrust this to a specialist.

Preparation for installation: tools and safety precautions

To replace the thermostat you will need:

Disconnect the refrigerator from the mains and defrost it

Prepare screwdrivers (Phillips and flathead)

Prepare pliers and wire cutters

Wear dielectric gloves (for safety)

Prepare a new thermostat and heat-shrinkable tubes (for soldering)-->

Required unplug the refrigerator and wait until it is completely defrosted. Working with plugged-in equipment is deadly! Also:

• 🧤 Put on dielectric gloves —they will protect against accidental electric shock when checking circuits.
• 📸 Take a photo original connection of wires to the thermostat so as not to confuse them when reassembling.
• 🧼 Wipe your hands with alcohol - fat or moisture on the contacts can cause oxidation.

If your refrigerator has a thermostat sealed (for example, in models Liebert or Electrolux), replacement will require soldering iron a power of 40–60 W and solder. Do not use acidic fluxes - they will corrode the contacts. It’s better to take rosin or alcohol-based flux.

Step-by-step instructions: how to remove the old thermostat

The dismantling process depends on the refrigerator model. We will analyze the two most common options: with mechanical regulator (for example, in Atlant or Stinol) and with electronic unit (as in Samsung or LG).

Option 1: Mechanical thermostat (single-chamber and double-chamber refrigerators)

In most models, the thermostat is located inside the refrigerator compartment, under a plastic panel or temperature control knob. To remove it:

1. Unscrew the screws securing the plastic panel (usually they are hidden under the plugs).
2. Carefully remove the panel without damaging the capillary tube of the thermostat - it is thin and fragile!
3. Disconnect the wires from the thermostat terminals. If they are secured with screws, loosen them with a screwdriver. If it is on the latches, pry it off with a flat screwdriver.
4. Unscrew the thermostat itself (usually it is held on by 2-3 screws).
5. Remove the capillary tube from the mounts. Be careful - it is filled with freon!

In some models (for example, Biryusa-18) the thermostat is mounted outside, on the back wall. In this case, you will have to remove the compressor protective casing.

Option 2: Electronic thermostat (No Frost and inverter models)

In modern refrigerators, the thermostat is often built into electronic control unit, which located:

• 🔹 On the top panel inside the chamber (for example, Samsung RL-33).
• 🔹 At the back, next to the compressor (LG GA-B489).
• 🔹 Under the freezer compartment (Bosch KAN58A50).

To get it:

1. Remove the cover of the control unit (it can be secured with latches or screws).
2. Disconnect the power and sensor connectors. Remember their location!
3. Remove the block from the grooves. In some models, it is soldered to the board. you will need a soldering iron.

⚠️ Attention: In refrigerators with inverter compressor (for example, Samsung Digital Inverter) the electronic thermostat is connected to the control board. Replacing it without flashing it can lead to errors E1 or E2 display.

Installing a new thermostat: connection diagrams

Now we move on to the most important stage - connecting the new thermostat. Important: if the length of the capillary tube of the new thermostat differs from the original by more than 10 cm, it cannot be used - this will lead to incorrect temperature readings.

Connection diagram for mechanical thermostats

In most cases, a mechanical thermostat has 3-4 terminals:

• 1 and 2 — power supply (220 V).
• 3 — output to the compressor.
• 4 (if any) — lighting lamp or defrost mode.

Standard connection diagram:

~220V
│
├───┬─── Terminal 1 (phase)
│   │
Thermostat Compressor
│   │
├───┴─── Terminal 3
│
└─────── Terminal 2 (zero)

If your refrigerator has 4 terminals, the fourth is usually goes to the lamp. Check this according to the diagram on the thermostat body or in the instructions for the refrigerator.

Scheme for electronic thermostats

Electronic thermostats are connected through connectors. The main thing is not to mix up the wires:

• 🔴 Red - power supply (+12 V or +5 V).
• 🔵 Blue/black —ground (GND).
• 🟢 Green/yellow —signal from the temperature sensor.
• 🟡 Yellow —control compressor.

Models No Frost may additionally have wires for:

• 🔹 Defrost timer (DEF).
• 🔹 Fan (FAN).
• 🔹 Additional evaporator sensor.

⚠️ Attention: In refrigerators LG with a system Smart Inverter the thermostat is connected to the board via CAN bus. Incorrect connection can damage the entire unit control!

After connecting, check:

• 🔌 Are all wires tightly seated in the terminals/connectors.
• 📏 Capillary the tube is not kinked and does not touch hot parts (compressor, condenser).
• 🔧 The thermostat mounting screws are tightened all the way, but not overtightened.

Adjusting the thermostat after installation

After replacing the thermostat, you need a refrigerator calibrate. This is especially important for mechanical models, where accuracy depends on the position of the capillary tube and spring settings.

For mechanical thermostats

Plug in the refrigerator and follow these steps:

1. Install thermostat knob to position 2–3 (medium temperature).
2. Place the outdoor thermometer in the refrigerator compartment (next to the sensor).
3. After 2-3 hours, check the temperature. It should be within the range. +3°C...+5°C.
4. If the temperature is too high or low, adjust the tension of the thermostat spring (it is located under the protective cover).

In models Atlant and Stinol for calibration used adjustment screw on the thermostat housing. Turning clockwise increases the compressor shut-off temperature (the refrigerator will work longer), counterclockwise - decreases it.

For electronic thermostats

In refrigerators with a display, the setting is performed via service menuFor example, in Samsung you need to:

1. Press and hold buttons Freezer + Fridge 5 seconds.
2. In the menu, select item Calibration (calibration).
3. Set temperature offset (usually 0 or +1).
4. Save settings and reboot refrigerator.

In models LG with Smart ThinQ calibration can be performed automatically through a mobile application.

Common mistakes and how to avoid them

Even experienced technicians sometimes make mistakes when installing a thermostat. Here are the most common ones and ways to avoid them:

• 🔌 Messed-up wires: if you connect the phase and zero incorrectly, the thermostat will burn out. multimeter!
• 📏 Incorrect position of the capillary tube: it should fit tightly to the evaporator, but not touch its walls (otherwise there will be a false positive).
• 🔧 Overtightened mounting screws: this can deform the housing thermostat and disrupt its operation.
• 🌡️ Lack of calibration: without adjustment, the new thermostat can maintain the temperature +10°C instead +4°C.
• 🚫 Ignoring the leak test: if after replacement the refrigerator does not cool, the capillary tube may be damaged.

If after installing the thermostat refrigerator:

• 🔴 Does not turn on: check the fuse, power circuit and correct connection.
• ❄️ Freezing: reduce the temperature setting or calibrate the thermostat.
• 🌡️ Does not cool: possibly the compressor is faulty or there is a freon leak.

What to do if the new thermostat does not work?

1. Check the voltage at the terminals (should be 220 V).

2. the tube is not damaged.

3. Test the thermostat with a multimeter - in the closed state the resistance should be 0 Ohm.

4. If the thermostat is working, the problem may be in the compressor relay or control board.

FAQ: Answers to frequently asked questions

Is it possible to replace a mechanical thermostat with an electronic one?

Technically, yes, but this will require altering the electrical circuit of the refrigerator. In most cases, it is easier and cheaper to install a mechanical analogue. Electronic thermostats are only suitable for models with an appropriate control board (for example, Samsung or LG c). display).

How to check the thermostat without a multimeter?

You can use a 220 V light bulb: connect it in series to the terminals of the thermostat and place it in the freezer. If after 15-20 minutes the light comes on, the thermostat is working. But this method is not safe and does not work 100%. accuracy!

How much does it cost to replace a thermostat in a service center?

The price depends on the model of the refrigerator and the type of thermostat:

• Mechanical thermostat: 1,500–3,000 ₽ (with work).
• Electronic thermostat: 3,000–6,000 ₽.
• Replacement in refrigerators No Frost or with an inverter compressor: up to 8,000 ₽.

Independent replacement will cost only cost of the part (from 800 ₽).

Why does the new thermostat click, but the compressor does not start?

Probable reasons:

• Faulty start relay compressor.
• Burned out compressor (check its windings with a multimeter).
• No power to compressor (check the wires and fuse).

The thermostat in this case is working - the problem is in the motor power supply circuit.

Is it possible to install a thermostat from another refrigerator model?

It is possible if:

• It matches mounting type (screws/latches).
• Identical capillary tube length (tolerance ±10 cm).
• Suitable connection diagram (number and purpose of terminals).

For example, a thermostat from Atlant is suitable for Pozisif they are of the same generation. But for No Frost you only need an original thermostat.