Has the refrigerator stopped freezing or, conversely, has the contents turned into an ice block? Most often, the culprit of such differences is a failed one thermostat. This small element is responsible for maintaining the set temperature inside the chambers by opening and closing the compressor power circuit. If it does not work correctly, the equipment either works without stopping, wearing out, or turns on too rarely, spoiling the products.
Independently replacing this component is a very real task for a person who knows how to hold a screwdriver and a multimeter. You don't have to call a professional to diagnose a simple breakdown if you have basic skills in handling electrical appliances. However, it is important to understand that thermostats different brands may have design differences that require a careful approach to installation.
In this article we will analyze the algorithm of actions that will allow you to safely remove the old sensor and install a new one. You will learn how to check the functionality of an element before purchasing, what tools you will need and what to pay special attention to during assembly. Correct completion of all stages guarantees a long service life of your refrigeration unit.
Diagnostics of thermostat malfunction
Before disassembling the refrigerator and buying new spare parts, you need to make sure that the problem lies precisely in thermostat. Symptoms may be similar to a broken compressor or start relay. If the compressor does not start at all, but the light inside the chamber is on, this may indicate an open circuit in the temperature sensor.
⚠️ Attention: Before any manipulations with the electrical part, be sure to disconnect the refrigerator from the network. Working with current requires compliance with safety precautions.
Carry out a simple test: turn the regulator knob to the extreme position (maximum cold) and listen. If after a while the compressor does not start, try lightly tapping the thermostat housing. Starting the engine after an impact indicates sticking of the contacts inside the mechanical thermostat.
For a more accurate check, use a multimeter in dial mode. Remove the terminals from the sensor contacts and connect the device probes to the terminals. At room temperature, a working thermostat should “ring”, indicating the presence of a circuit. If the appliance is silent, the element is faulty and requires replacement.
Necessary tools and preparation
To successfully replace the temperature controller, you will need a minimum set of tools that most craftsmen have in their home. The main thing is to prepare the workplace and provide good lighting, since some components may be located in hard-to-reach places.
You will need the following tools:
- 🔧 A set of screwdrivers (phillips and flat) for removing panels.
- 🔌 Pliers or pliers for working with terminals.
- 📏 Multimeter for checking the electrical circuit.
- 🧤 Gloves to protect hands from sharp metal edges.
- 📸 Phone or camera for recording the wiring diagram.
Pay special attention to the purchase new thermostat. They come with different capillary tube lengths and different response parameters. It is best to search for a spare part using the exact model of your refrigerator or the markings of the old sensor. An incorrectly selected element will lead to incorrect operation of the system.
☑️ Preparation for repair
Removing the old temperature controller
Removal process The thermostat depends on the type of refrigerator and the location of the sensor. In most models mechanical thermostats it is located inside the refrigerator compartment under a plastic cover or in the control unit. First you need to remove the decorative trim by unscrewing the fastening screws.
After removing the panel, you will see the regulator itself with a capillary tube going deep into the body. Carefully disconnect the electrical terminals. It is critical to remember the order in which the wires are connected. It is recommended to take a photo or mark the wires with a marker before disconnecting, so that during assembly you do not confuse phase and zero.
The most delicate part of the work is removing the sensitive tube. It can be fixed in a special hole in the chamber wall or pressed with a clamp. Proceed carefully, do not pull sharply, so as not to damage the thin copper tube or the wall of the evaporator. If the tube is frozen, allow the refrigerator to defrost completely.
⚠️ Attention: The capillary tube of the thermostat is filled with refrigerant and is very thin-walled. Any deformation or puncture will lead to gas leakage and complete inoperability of the new sensor.
What to do if the tube is stuck?
If the capillary tube cannot be removed, do not use force. Pour plenty of warm water (not boiling water!) over the exit area of the tube from a syringe or bulb. The ice will melt and the tube will come out freely. The use of metal objects for picking is prohibited.
Compatibility table and marking of thermostats
When choosing a replacement, it is important to focus not only on appearance, but also on technical characteristics. Different manufacturers use different marking systems, but the main parameters (on/off temperature, tube length) must be the same.
Below is a table of correspondence between popular models of thermostats for different brands of refrigerators:
| Original (Marking) | Analogue (Replacement) | Refrigerator brand | Tube length (cm) |
|---|---|---|---|
| TAM-133 | K-59 L1958 | Atlant, Indesit | 75-100 |
| TAM-125 | K-50 L1958 | Biryusa, Stinal | 75-100 |
| TAM-145 | K-57 L1958 | Freezers | 100-120 |
| 17D28 | K-56 L1958 | Electrolux, Zanussi | 75-100 |
Pay attention to control rod color. Often it indicates a temperature range: red, blue or black. Setting the thermostat to the wrong range will result in the refrigerator either undercooling food or operating in continuous freezing mode. Always check the parameters with the documentation.
Installation and connection of a new sensor
Installation of a new one thermostat is carried out in the reverse order of dismantling. Insert the sensing tube into the hole as far as it will go. It should enter freely, without effort. If a clamp is used, secure the tube so that it fits tightly to the surface of the evaporator for correct temperature reading.
Connecting electrical wires requires maximum concentration. Use photos or notes you took earlier. Typically, thermostats have three contacts: one common and two working (for the compressor and for the lamp/defrost). If there are two contacts, then the circuit is simpler: the circuit breaks on one of them.
After connecting the terminals, make sure that they fit tightly and do not loosen. Poor contact will result in sparking, heating and possible melting of the plastic. Assemble the body, install the decorative trims and the regulator knob in place. Make sure that the handle rotates freely and does not touch adjacent elements.
It is important to correctly position the thermostat housing inside the niche. It must not touch vibrating parts or hot surfaces. Securely fasten all screws to avoid rattling when the compressor is running.
Checking functionality and setting
After assembly, turn on the refrigerator. In the first minutes of operation, listen to the sounds: the compressor should start working. If the engine hums but does not start, the problem may be in the start relay, not the thermostat, or the electrical assembly is not assembled correctly.
Let the equipment idle (without food) for several hours. Check if the compressor switches off when the set temperature is reached. Mechanical models are characterized by a clear click when the contacts open. If the refrigerator turns off, it means cooling cycle it is working correctly.
Adjust the regulator knob to the middle value (usually the number 3 or 4). After 2-3 hours, check the temperature in the chamber using an external thermometer. The optimal range for the refrigerator compartment is from +2 to +5 degrees Celsius. If necessary, adjust the position of the handle.
⚠️ Attention: Do not load the refrigerator with food immediately after turning it on. Let it return to operating mode for 4-6 hours to stabilize the temperature background and check the switching cycle.
Common mistakes when replacing a thermostat
Beginners often make mistakes that negate all the work. One of the most common is incorrect installation of the capillary tube. If it is not fully inserted into the channel or dangles in the air, the sensor will respond to the temperature of the air in the chamber, and not to the temperature of the evaporator, which will lead to constant on and off.
Another mistake is ignoring grounding. If your thermostat has a ground pin (usually marked with a ground symbol), it must be connected. This ensures the safe operation of the electrical appliance and protects against electric shock in the event of an insulation breakdown.
Also, you should not use thermostats with a longer tube, “twisting” the excess into a ring. This changes thermal performance and may cause failure. If the tube is too long, it can be carefully laid like a snake in free space, but not bent at an acute angle.
Can a universal thermostat be used?
There are universal models with adjustable tube length. They can be used as a temporary solution, but they are often less accurate and durable than original spare parts designed specifically for your refrigerator model.
FAQ: Frequently Asked Questions
Is it possible to repair an old thermostat or just replace it?
At home, repairing a thermostat is not possible. This is a sealed unit filled with filler gas. Opening the case will lead to depressurization and loss of operating properties. The only solution is a complete replacement with a new element.
Why does the new thermostat click, but the refrigerator does not turn on?
This may indicate a malfunction of the compressor start relay or the motor itself. A clicking sound means the circuit is complete but no current is reaching the engine or the engine cannot start. Also check the tightness of the contacts on the terminals.
How often should you change the thermostat?
The service life of the thermostat is usually 5-10 years. However, with frequent power surges or mechanical stress, it may fail earlier. Scheduled replacement is not required, they are changed only when malfunctions occur.
Does the length of the capillary tube affect the operation of the refrigerator?
Yes, the length of the tube affects the speed of the sensor response. A tube that is too short will not reach the control zone; a tube that is too long may bend and become damaged. Try to select an analogue with a length close to the original (a tolerance of +/- 10-15 cm is usually acceptable with careful installation).
What to do if the regulator handle does not fit the new rod?
Sometimes the thread or diameter of the rod may differ even for compatible models. In such cases, you can carefully move the plastic rod from the old regulator to a new one, if the design allows, or select a suitable handle from the repair kit.