A sharp increase in temperature in the refrigerator compartment or, conversely, the formation of an ice crust on products often indicate a failure of the thermostat. This small but critical component is responsible for maintaining the desired temperature by turning the compressor on and off at the right times. If you notice that the refrigerator works non-stop or does not turn on at all, most likely the problem lies precisely in the thermostat.
Replacing this part yourself is a very real task for a person who knows how to handle a screwdriver and a multimeter. However, it is important to understand that incorrect installation or choosing an incompatible model can lead to more serious damage to the cooling system. In this article, we will analyze in detail the process of diagnosing, selecting and installing a new regulator so that your refrigerator refrigerator will work again like new.
Before starting disassembly, you need to make sure the diagnosis is accurate. Often the symptoms of a faulty thermostat are confused with a freon leak or a compressor failure. If you are not confident in your abilities, it is better to turn to professionals, but if the decision is made, strictly follow the instructions below.
Diagnostics of a thermostat malfunction
The first step should always be a thorough check. A visual inspection rarely yields results, since the breakdown is electrical in nature. First you need to get to the thermostat itself by removing the protective panel in the refrigerator compartment or the top cover, depending on the design of your model. After removing the part, disconnect the wires and connect them directly to each other.
If, when you close the wires, the refrigerator starts working and gets cold, it means the circuit is working, and the problem is in the sensor. If the compressor is silent even when the circuit is closed, it is worth checking the starting relay or the motor-compressor itself. Also important is the state of the capillary tube, which transmits information about the temperature of the evaporator. Use a multimeter in dial mode to check the contacts. At room temperature, the contacts should be closed (for most models), and when the sensitive element is placed in cold water, they should open. Lack of response indicates the need for replacement. capillary tube, which transmits information about the evaporator temperature.
Use a multimeter in test mode to check the contacts. At room temperature, the contacts should be closed (for most models), and when the sensitive element is placed in cold water, they should open. Lack of response indicates the need for replacement.
⚠️ Attention: Before any manipulations with electrical components, be sure to disconnect the refrigerator from the power supply. Working with 220V voltage without proper qualifications is deadly.
Do not ignore signs of incorrect operation. If the refrigerator “threshes” without stopping, this not only leads to spoilage of food, but can also cause overheating of the compressor, which will require a major overhaul of the entire system.
Choosing the appropriate thermostat model
The spare parts market offers many options, but not all of them are interchangeable. The key parameter is the markings applied to the body of the old part. Even if visually the new thermostat looks identical, a difference in one symbol may mean a different temperature response range.
Pay attention to the length capillary tube. If it is too short, the sensor will not reach the desired control zone and the refrigerator will not work correctly. If it is too long, it will have to be carefully laid, avoiding kinks that can disrupt the circulation of gas inside.
Below is a table of correspondence between popular brands and their analogues, which will help you navigate your search:
| Original | Analog | Application | Features |
|---|---|---|---|
| Tam 133 | K 59 | Refrigerator compartment | Standard tube length |
| Tam 145 | K 50 | Freezer compartment | Lower threshold |
| Tam 112 | K 57 | Single chamber | Short tube |
| Ort 16 | K 56 | Universal | Specific stem |
When purchasing, be sure to check not only the number, but also the location contacts. In some models, the third contact is responsible for the warning light or defrost mode, and ignoring it will cause the indicator to stop lighting.
Necessary tools and preparation
For successful installation, you will need a minimum set of tools, which can be found in every home. The main thing is to prepare the workplace and provide good lighting, since the insides of the refrigerator are often hidden in hard-to-reach niches.
- 🔧 Screwdrivers (phillips and flat) for removing panels and terminals.
- 🔌 Pliers or pliers for working with wires.
- 🌡️ Multimeter for checking contacts.
- 🧤 Gloves to protect your hands from sharp metal edges.
Defrost the refrigerator completely in advance. Water may leak onto electrical components when removing the thermostat, so keep the chamber dry. Also prepare a container to collect melt water and a rag.
It is important to have electrical tape or heat shrink on hand. Although new parts are often supplied with caps, additional insulation of the connections never hurts, especially in conditions of high humidity inside the chamber.
☑️ Preparing for replacement
Removing the old thermostat
The removal process depends on the type of refrigerator. In models with a top cover (for example Atlant, Biryusa), you need to unscrew the screws securing the cover and carefully lift it to gain access to the assembly. In refrigerators with a crying system (for example, Indesit, Stinol), the thermostat is often located inside the chamber under a plastic cover.
Remove the temperature control knob. It may be a tight fit, so be careful not to break the plastic. Underneath there is usually a nut or screw that secures the thermostat housing. By unscrewing the fasteners, you can remove the housing from the seat.
The most crucial moment is removal capillary tube. It is attached to the evaporator with special clips. They need to be loosened carefully. Do not pull the tube sharply - it is very thin and breaks easily. Pull it out smoothly, following the channel.
⚠️ Attention: The capillary tube is filled with freon gas. If you damage it or the thermostat housing, gas will escape and the sensor will stop working. Do not use sharp objects to pick out the tube.
After removing the tube, disconnect the wires. It is best to mark them with a marker or take a photo before turning them off, so that when installing a new element you do not confuse the polarity.
Installation and connection of a new sensor
Installation of a new thermostat is carried out in the reverse order, but observing several nuances. Make sure the new sensing element has the same geometry. If the tube is longer, it can be carefully rolled into a ring, but the bend radius should not be less than 3-4 cm.
Insert the tube into the channel until it stops. It should fit snugly against the evaporator in the mounting area. Secure it with standard clips. Poor contact of the tube with the evaporator will lead to incorrect temperature readings and “lies” of the thermostat.
Connect the wires according to the diagram or marking made earlier. Usually the wires do not have a polarity, but it is important to connect the ground (if there is one) and the compressor power wire correctly. For reliability, crimp the contacts with pliers.
Connection diagram (standard):Pin 1-2: Compressor
Pin 1-4: Lamp (in some models)
Pin 3: Grounding housing
Install the thermostat housing in place and tighten the fixing nut. Do not overtighten the plastic; it may burst at low temperatures. Put the adjustment knob on and make sure it rotates freely.
What to do if the tube does not fit?
If the new capillary tube is longer than the old one, do not cut it! Carefully place the excess in a ring in the free space behind the back wall of the refrigerator, avoiding contact with moving parts of the compressor.
Setting up and testing operation
After assembly, turn on the refrigerator. The initial startup may take some time as the system needs to get up and running. Do not load the chamber with products during the first 2-3 hours of operation.
Set the regulator knob to the middle position (usually number 3 or 4). After 30-40 minutes, check the temperature inside the chamber using an external thermometer. It must correspond to the set value.
Pay attention to the operating cycle. The compressor must turn on and off at regular intervals. If the refrigerator runs non-stop, it is possible that the thermostat does not “see” the cold, and the tube does not fit well to the evaporator. If it doesn’t turn on at all, check the wire connections.
In some cases, adjustment is required with a screw on the thermostat itself (usually it is closed with a seal or plug). You should twist it very carefully, making no more than half a turn at a time, and waiting for the mode to stabilize.
Frequently asked questions (FAQ)
Is it possible to install a universal thermostat on any refrigerator?
Universal thermostats are suitable in 80% of cases, but it is important to consider the length of the capillary tube and the temperature range. For freezers, special low-temperature models are needed.
Why did the refrigerator start to freeze a lot after replacement?
Probably, the tube of the new thermostat is not immersed deep enough in the channel or is not pressed well against the evaporator. It is also possible that a thermostat with a different temperature range was selected.
How can you tell if the thermostat is faulty without a multimeter?
You can short the wires coming from the thermostat directly. If the refrigerator starts working, the thermostat is faulty. If not, the problem is in the compressor, relay or wiring.
Does the freon need to be recharged when replacing the thermostat?
No, the cooling system is sealed. The thermostat is an electrical device, and replacing it does not require opening the refrigerant circuit, unless you damaged the tube during installation.