Sudden cessation of operation of the refrigerator compartment or, conversely, endless freezing action is often indicated to failure of the thermostat. This small but critical element is responsible for maintaining the set temperature by opening and closing the electrical circuit of the compressor. If you notice that your refrigerator stops turning on or works without stopping, you cannot ignore this, as this threatens food spoilage and overheating of the motor.
Independent replacing the thermostat is a task quite feasible for a person who knows how to handle a screwdriver and understands the basics of electrical safety. Unlike complex freon or compressor problems, this does not require special vacuum equipment or welding skills. However, it is important to act carefully so as not to damage other components of the unit and to choose the right compatible part.
Before starting disassembly, you need to make sure that the problem lies in the thermostat, and not in the start relay or wiring. Equipment owners often make the mistake of buying a new spare part without preliminary diagnostics, which leads to unnecessary costs. In this article we will analyze all the nuances of the process, from troubleshooting to final testing of the system.
Diagnostics of thermostat malfunctions
The first sign of a malfunction thermostat is incorrect operation of the compressor. If the motor hums but does not start, or the refrigerator is silent, although there is voltage in the network, it is worth checking the control circuit. In modern models with electronic control, breakdown of the thermostat is less common, since there the control function is performed temperature sensor, but in classic mechanical systems this is the most common cause of failures.
For an initial check, you can perform the so-called "forced" switching on". To do this, you need to close the contacts coming from the thermostat directly. If after this manipulation the compressor starts working, then the problem is almost certainly in the temperature controller. If the motor is silent even when connected directly, you need to look for the reason deeper - in the starting relay or motor windings.
⚠️ Attention: Before any manipulations with electrical components, be sure to disconnect the refrigerator from the network! Even a short-term shorting of energized contacts can lead to electric shock or failure of the electronics.
It is also worth paying attention to indirect signs, such as freezing of the “coat” in the refrigerator compartment or, conversely, a complete lack of cold when the compressor is running. Mechanical thermostats often fail due to depressurization of the bellows tube or sticking contacts inside the housing. A visual inspection of the bellows for cracks or corrosion can give the answer without the use of instruments.
Preparation of tools and selection of spare parts
The success of the repair directly depends on the correct selection of components. Thermostats are not universal parts: they differ in length capillary tube, type of contacts, method of fastening and temperature range of operation. Buying the first part you come across in a store can lead to the fact that the refrigerator will not work correctly or the new part will burn out in a week.
To carry out the work, you will need a minimum set of tools, which are found in the garage of most men. Pay special attention to the safety and cleanliness of the workplace, since moisture or metal shavings cannot enter the electrical contacts. It is also recommended to prepare a multimeter for the final check of the continuity of the circuit.
The following is a list of necessary equipment for replacement:
- 🔧 Screwdrivers (phillips and flat) for removing panels and fastening terminals.
- 🔍 Multimeter or tester for continuity of the electrical circuit.
- 🧊 New thermostat, identical to the failed one.
- 🧤 Gloves to protect hands from sharp metal edges.
⚠️ Attention: The length of the capillary tube of the new thermostat must be no less than that of the old one. If the tube is shorter, you will not be able to properly place it in its normal place, and extending it is strictly prohibited. The excess length can be carefully twisted into a ring.
When choosing a new part, be sure to copy the markings from the old device. Even if visually they look the same, a difference in one symbol may mean different on and off temperatures. For two-chamber refrigerators, thermostats with two or three contacts are often used, and it is important not to confuse their purpose when connecting.
Removing the old thermostat
The process of removing the old temperature regulator depends on the design of your refrigerator. In most models Indesit, Atlant or Stinol the thermostat is located inside the refrigerator compartment, often hidden behind a plastic cover or lampshade. In some cases, access to it is possible only after removing the top panel of the case.
Start by removing the protective covers. Proceed with caution as the plastic becomes brittle over time and may crack if handled carelessly. Remember or take a photo of the order in which you disconnect the wires so that there is no confusion during reassembly. The color marking of wires does not always meet the standards, so a photograph is your best assistant.
☑️ Checklist before dismantling
After gaining access to the thermostat, you need to disconnect the regulator handle. Usually it can be easily removed by hand, but if it is stuck, you can gently pry it out with a flat-head screwdriver without using excessive force. Next, unscrew the screws securing the thermostat housing itself to the chamber wall or bracket.
The most delicate stage is removing the sensitive one capillary tube from the evaporator. It can be fixed in a special hole or pressed with a bracket. You cannot pull the tube sharply: inside it is filled with gas or liquid, and damage to its seal will make the part unusable. Carefully unscrew the fixing elements and smoothly pull the tube out of the seat.
Installing a new thermostat
Installation of a new temperature control element is carried out in the reverse order of dismantling. First of all, install the capillary tube into the evaporator. The immersion depth and bending angle must correspond to the original. If the tube is too long, carefully roll the excess into a ring with a diameter of at least 5 cm so as not to pinch it and disrupt the circulation of the refrigerant inside.
Fix the thermostat housing in its original place. Make sure it fits snugly and does not wobble, as vibrations from the compressor can loosen the mount over time. Pay special attention to connecting the wires: use the diagram that you photographed earlier, or the markings on the terminals of the new device.
| Type of contacts | Wire color (usually) | Function | Note |
|---|---|---|---|
| 2 contacts | Red, Black | Compressor on/off | Standard circuit |
| 3 contacts | Red, Black, Orange | Compressor + Lamp/Fan | Third contact often for signal |
| Ground | Yellow-green | Safety | Connects to the case |
After connecting all the wires, install the temperature control knob in place. Make sure it rotates freely and locks into position. Don't forget to replace all removed decorative panels and lampshades. Only after complete assembly can you proceed to testing.
What to do if the capillary tube does not fit?
If the tube of the new thermostat is longer than the old one, under no circumstances cut it or bend it at an acute angle. Carefully place the excess in the free space behind the back wall of the refrigerator compartment or roll it into a ring next to the evaporator, securing it with tape so that it does not vibrate.
System setup and testing
After installing a new thermostat, you need to check that it is working correctly. Plug in the refrigerator and set the control knob to the middle position. After some time (usually 15-30 minutes) the compressor should start. If this does not happen, turn the knob all the way in the direction of maximum cold - this will help “rock” the system if the contacts are tight.
The criterion for correct setting is the cyclic operation of the unit. The refrigerator should gain temperature, turn off, then, after the temperature inside the chambers rises, turn on again. The operating and downtime time depends on the product load and the ambient temperature, but the cycle must be stable.
⚠️ Attention: If, after replacing the thermostat, the refrigerator operates continuously for more than 2-3 hours without shutting down, this may indicate an incorrect setting or a defect in the new spare part. Long-term operation without interruption is dangerous for the compressor.
To accurately check the temperature inside the chamber, you can use an external thermometer by placing it in a glass of water in the center of the refrigerator. The readings must correspond to the established regime. If the temperature does not stabilize even after several cycles, you may need to recalibrate or check the system for leaks.
Common mistakes when replacing
One of the most common mistakes is ignoring the tightness of the bellows. If installed carelessly, you can accidentally damage the thin tube with the sharp edge of the housing or a tool. Even a microscopic crack will lead to the leakage of sensitive gas, and the thermostat will stop responding to temperature changes, believing that the chamber is always “warm.”
Another error is the incorrect location of the end of the capillary tube in the evaporator. If it touches the chamber wall too weakly or, conversely, too strongly, the temperature readings will be distorted. This will lead to frequent turning on of the motor or, conversely, to defrosting of food. Accurate positioning according to the factory diagram is critical.
Also, novice craftsmen often forget to check the reliability of the contact in the terminal block. Poor contact causes sparking, heating and eventual melting of the plastic. Be sure to tighten the screws securing the wires, but without fanaticism, so as not to strip the threads in the soft metal of the terminals.
You should also not forget about cleanliness. Moisture or dust that gets inside the thermostat mechanism can disrupt the operation of the contacts. Always carry out work in a dry room and try not to touch the internal parts of electrical components with your hands unless necessary.
FAQ: Frequently asked questions
Is it possible to replace the thermostat with an analogue with a different marking?
Yes, it is possible if the main parameters match: the length of the capillary tube, the number of contacts, the diameter threads and temperature range. However, it is better to look for a complete analogue by catalog number to avoid problems with setup.
Why does the refrigerator not turn off after replacing the thermostat?
This can be caused by several reasons: the thermostat is incorrectly configured, the capillary tube is not fully immersed, the new thermostat itself is faulty, or there is a freon leak. Also check the tightness of the door.
How much does it cost to replace a thermostat in a service?
The cost consists of the price of the spare part and the work of the technician. On average, the price of a part ranges from 1000 to 3000 rubles, and the work will cost another 1500-2500 rubles, depending on the region and the complexity of access to the unit.
Do you need to defrost the refrigerator before replacing?
Full defrosting is not necessary if access to the thermostat is in top of the camera. However, if ice interferes with access or there is a risk of water getting on the electrical contacts, it is better to defrost the refrigerator in advance.