A decrease in refrigeration capacity or, conversely, excessive freezing of products often indicates a malfunction of the temperature control system. In most cases, the culprit of such anomalies is thermostat, which ceases to correctly read the data inside the camera. This device is responsible for turning the compressor on and off, maintaining the temperature regime specified by the user.
If your refrigerator Indesit or Atlant started working without interruptions, forming an ice coat, or stopped turning on altogether, diagnostics are necessary. Often it is enough to simply replace this component to return the unit to functionality. Independent removal of the thermostat requires a minimum set of tools and basic knowledge about the design of household appliances.
It is important to understand that before starting any work, the unit must be completely disconnected from the power supply. Failure to comply with this rule may result in electric shock, as there are high voltage live parts inside the housing. Further actions depend on the type of your refrigerator: single-chamber or double-chamber, since the location of the sensor will be different.
Principle of operation and types of thermostats
A thermostat is a mechanical or electronic device that opens and closes an electrical circuit depending on the ambient temperature. Classic models use bellows tubefilled with freon or other refrigerant. When the temperature in the chamber changes, the pressure inside the tube changes, affecting the membrane and switching contacts.
Modern models of refrigerators Liebherr or Bosch can be equipped with electronic sensors, but mechanical regulators are still widespread due to their reliability. A mechanical thermostat usually has an adjustment handle located inside the chamber or on the outer panel of the housing. Electronic analogues transmit data to the central control module.
The difference between mechanics and electronics
Mechanical thermostats make a characteristic click when switching, electronic thermostats operate silently.
When a mechanical element fails, sticking of contacts or loss of tightness of the bellows is often observed. As a result, the compressor either does not receive a start signal or runs continuously. Understanding the type of regulator installed in your unit will help you choose the right spare part and plan the progress of work.
- 🔧 Mechanical thermostats are controlled by the physical expansion of gas in a capillary tube.
- 💻 Electronic sensors use thermistors to transmit a signal to the board.
- ❄️ B In two-chamber models, the sensor usually controls the temperature of the evaporator.
- 🏠 In single-chamber refrigerators, the thermostat tube often comes into contact with the chamber air.
Necessary tools and preparation for work
In order to safely and efficiently remove the thermostat, you will need to prepare a workplace and a minimum set of tools. You do not need complex diagnostic tools if you are already sure that this particular unit is faulty. However, to check a new element, a multimeter may be useful multimeter.
The main task is to provide access to the place where the regulator is attached. Depending on the design of the refrigerator Stinol or Nord, you may need to remove the top cover, decorative panel or lampshade. All actions should be performed carefully so as not to damage the plastic latches.
☑️ Tools for replacement
Be sure to free up space around the refrigerator to be able to move freely. Prepare a container for defrosting in advance if you need to completely defrost the unit before starting work. Cleanliness and order in the workplace will prevent the loss of small fasteners.
- 📏 Screwdrivers of various sizes for dismantling panels.
- 🔌 Multimeter for checking the integrity of contacts.
- 🧤 Gloves to protect hands from sharp metal edges.
- 💡 Flashlight or headlamp for working in the depths of the case.
Diagnostics of thermostat malfunction
Before disassembling the refrigerator, you should make sure that the problem lies in the thermostat. A characteristic sign of a malfunction is the absence of a characteristic click when turning the regulator knob. If the refrigerator is silent and does not respond to changes in the position of the handle, the probability of the thermostat failure is high.
For a more accurate diagnosis, you can use the exclusion method. If the compressor is working properly and operates from a direct voltage supply, but does not turn on through the thermostat, then the circuit is broken. It is also worth checking whether the “fur coat” on the evaporator is frozen, which could block the sensitive element.
⚠️ Attention: If after defrosting the refrigerator worked normally, but after a couple of days the problem returned, most likely the thermostat has lost calibration or tightness.
Checking with a multimeter in dial mode allows you to accurately determine the condition of the contacts. When the handle is turned to its extreme position, a sound signal should be heard, indicating that the circuit is closed. The absence of a signal indicates the need to replace the component.
Step-by-step instructions: how to get to the thermostat
The process of removing the thermostat varies depending on where it is located: inside the refrigerator compartment or outside on the body. In single-chamber models, access is usually through a lighting lamp or a special hole in the chamber wall. In two-chamber units Electrolux the sensor is often hidden behind a decorative trim.
First you need to remove the temperature control knob. It can simply be removed by hand or fixed with a screw under a decorative plug. After removing the handle, access to the fastening elements of the thermostat itself opens.
If the thermostat is located inside the chamber, carefully remove the plastic casing. Be careful with the wires going to the light bulb if it is located nearby. At this point, the capillary tube of the thermostat can be secured to the wall or evaporator using clips or glue.
- 🔩 Remove the decorative plugs and unscrew the visible fastening screws.
- 🧊 Carefully bend the plastic clips without breaking them.
- 💡 Disconnect the wires from the lighting lamp if they interfere with access.
- 🔍 Inspect the place where the capillary tube is attached for signs of corrosion.
Removing the old thermostat
The most critical step is removing the sensitive capillary tube. It is very thin and easily damaged if handled carelessly. Damage to the tube will cause refrigerant to leak from the bellows, causing the new thermostat to fail immediately. It is strictly forbidden to pull on the wires or the tube itself.
You need to find the place where the tube is fixed to the evaporator or chamber wall. Often it is fixed in a special groove or pressed with a metal bracket. Carefully release the tube, helping yourself with pliers if the bracket is rusty, but trying not to deform the evaporator itself.
After freeing the tube, you can proceed to disconnecting the electrical wires. Before doing this, be sure to remember or photograph the connection diagram. In thermostats from different manufacturers, the color of the wires and the location of the terminals may differ. It is not recommended to bite off the wires - it is better to carefully disconnect them from the contact group.
Remove the thermostat body from the niche. If it gets stuck, do not use excessive force to avoid crumbling the foam insulation. In some refrigerator models Samsung or LG partial disassembly of the internal lining may be required to allow the unit to come out freely.
Installing a new regulator and checking operation
Installation of a new thermostat is carried out in the reverse order of dismantling. First of all, it is necessary to correctly lay the capillary tube. It should follow the trajectory of the old sensor and fit tightly to the evaporator at the mounting location. It is unacceptable for the tube to touch sharp metal edges or be in a tense state.
Connect the electrical wires according to the diagram or photograph made earlier. Make sure the contacts are firmly seated on the terminals and are not loose. Poor contact can lead to sparking and melting of the plastic, which will create a fire hazard.
Fix the thermostat housing in the niche and reinstall the adjustment knob. Make sure the handle rotates freely and has full travel from minimum to maximum. After assembling all the panels, you can connect the refrigerator to the network.
| Parameter | Normal value | Fault symptom |
|---|---|---|
| Contact resistance | 0 Ohm (closed) | Infinity (open) |
| Reaction to cold | Opening the circuit | Contacts do not open |
| Tightness tubes | Full | Traces of oil, smell of freon |
| Handle stroke | Smooth, with clicks | Sticking, no click |
It is better to control the first start after replacement. Let the refrigerator run for several hours and check if it returns to normal and if the compressor turns off. The temperature in the chamber must stabilize in accordance with the set value.
Frequent replacement errors and safety measures
One of the most common mistakes is incorrect installation of the capillary tube. If it does not fit tightly to the evaporator, the thermostat will “lie”, reading the temperature of the air, not the surface. This will lead to improper operation of the unit and damage to the products.
Also, technicians often forget to check the tightness of the new thermostat before installation. Even a microscopic crack in the tube will render the device inoperable. Visual inspection and accuracy during installation are the key to success.
⚠️ Attention: Do not use glue that is not intended for low temperatures to secure the tube. Ordinary glue can lose its properties in the cold and the tube may come loose.
If you are not confident in your abilities or are afraid of damaging the cooling system, it is better to turn to professionals. Repairing a refrigerator is a delicate process, and a mistake can cost more than calling a repairman. However, if you follow the instructions, replacing the thermostat is quite within the capabilities of a home handyman.
Is it possible to replace the thermostat with an analogue from another manufacturer?
Yes, you can often use universal thermostats or analogues from other brands if the mounting dimensions, capillary tube length and electrical parameters are the same. However, it is better to look for an original spare part or a proven analogue recommended for your model.
Why does the new thermostat click, but the refrigerator does not turn on?
This may indicate a malfunction of the compressor start relay, the compressor itself, or a break in the wiring. In this case, the thermostat properly closes the circuit, but the current does not reach the engine or the engine cannot start.
How to determine that the capillary tube is damaged?
If the tube is damaged, gas may escape from it, and sometimes (not always) traces of oil appear. The surest way is to check the thermostat with a multimeter when cooling: if the contacts do not open even in extreme cold, the seal is broken.
Is it necessary to defrost the refrigerator before replacing it?
Yes, complete defrosting is required. Ice can prevent access to components, and working with electrical equipment in a damp environment is dangerous. In addition, the ice crust on the evaporator will not allow the sensitive tube to be installed correctly.