The refrigerator has stopped freezing or, conversely, has turned food into ice block? In most cases, the culprit of such “whims” is the thermostat (thermostat). This small device is responsible for maintaining the set temperature by turning the compressor on and off at the right moments. If you notice that the equipment works without breaks or is silent for hours, do not rush to call a technician - often the problem can be solved with your own hands.
Understanding the principle of operation thermostat will help you avoid expensive repairs and extend the life of the unit. The device is a sensitive element that responds to changes in temperature inside the chamber and closes or opens the electrical circuit. A malfunction of this unit leads to disruption of the cooling cycle, food spoilage and increased energy consumption. In this article we will analyze all the stages of diagnostics and replacement of a part.
Signs of a malfunctioning thermostat
The first sign of a problem with temperature control is often uncharacteristic behavior of the compressor. If the motor hums continuously, without stopping for a minute, or, conversely, turns on extremely rarely, allowing the food to defrost, these are direct symptoms. It is also worth paying attention to the formation of a “snow coat” in the refrigerator compartment or, conversely, to the complete absence of cold when the engine is running.
In modern models with electronic control, failures can manifest themselves in the form of errors on the display, but in classic mechanical systems everything is much simpler. Thermoregulator it may simply stick in one position. Sometimes lightly tapping the regulator helps, but this is only a temporary measure. If the handle rotates too easily, without characteristic clicks, or, conversely, is jammed, the part requires replacement.
Pay attention to the following signs indicating a breakdown:
- ❄️ The compressor works non-stop, trying to gain temperature, but does not turns off.
- 🌡️ The temperature in the chamber is significantly higher or lower than that set on the regulator.
- 🔌 The device does not turn on at all, although the indicators are on and there is voltage in the network.
- 🧊 Ice freezes in the fridge compartment at the back wall, and in everything melts in the freezer.
Diagnostics before disassembly
Before grabbing a screwdriver, you must rule out other causes of the malfunction. Often, users mistakenly blame the thermostat when the problem lies in a freon leak or a compressor malfunction. First, make sure that the refrigerator is level, the doors close tightly, and the seal is not damaged. If everything is in order with the tightness, we move on to checking the electrical system.
The easiest method of initial diagnosis is to forcefully close the contacts. To do this, you need to disconnect the device from the network, remove the regulator knob and get to the terminals. If the compressor starts when the wires are shorted, it means that the motor itself and the start relay are working properly, and the problem is most likely in thermostat. If there is silence, the circuit breaks in another place.
⚠️ Attention: Carry out all work on diagnosing the electrical part only with the refrigerator completely disconnected from the network! Electric shock can be fatal.
For a more accurate check, you will need a multimeter. Switch the device to dial mode and check the thermostat contacts. In normal condition (at room temperature) the contacts should ring. If the multimeter is silent, the circuit is broken and the part is faulty. It is also worth checking whether the contacts have oxidized and whether there are traces of burning on them.
Tools and preparation for repair
Repair of the thermostat does not require complex professional equipment, but a certain set of tools must be prepared. First of all, you will need screwdrivers (Phillips and flathead), since fasteners in refrigerators are different. A knife for carefully removing plastic plugs and pliers will also be useful.
If you plan to not only remove the part, but also check it or replace it with an analogue, make sure that you have access to the markings of the old device. The part number is usually stamped on the body. To work with a capillary tube (a long copper tube coming from the thermostat), care will be required - it must not be bent or damaged.
Basic repair kit:
- 🔧 A set of screwdrivers of different sizes and shapes.
- 🔋 Multimeter or tester for checking circuits.
- 🧤 Gloves to protect hands from sharp metal edges.
- 📷 Smartphone for photographing the wiring diagram.
☑️ Preparing to replace the thermostat
The process of replacing the thermostat
Replacement thermostat is a procedure that requires care, but is quite accessible to the home handyman. Start by defrosting the refrigerator if there is a lot of ice in the compartment to prevent water from getting on the electrical contacts. Then remove the plastic cover that hides the regulator. In some models, for example Indesit or Stinol, the thermostat is located inside the chamber, in others, like Atlant, - outside.
Accurately disconnect the wires from the terminals. Here it is critical to remember or photograph the connection order. Even one incorrectly connected wire can cause a short circuit or incorrect operation. Remove the mounting screws holding the thermostat housing in place and remove it. Pay special attention to the capillary tube - it is very thin and fragile.
Install the new thermostat in the reverse order. Secure the case, connect the wires according to the photos taken earlier. The capillary tube of the new sensor must be placed in the same place where the old one was located so that it correctly reads the temperature. Often this requires removing the internal panel or protective casing.
| Refrigerator model | Thermostat location | Mounting type | Difficulty of replacement |
|---|---|---|---|
| Indesit C 132 | Inside the refrigerator compartment | Screws + latches | Medium |
| Atlant MHM-1700 | Outside, above the door | Screws | Low |
| Bosch KGS | Inside, left | Latch | High |
| Stinol 103 | Inside, canopy light | Combined | Medium |
What to do if the capillary tube is too long?
If the tube of the new thermostat is longer than the old one, it can be carefully twisted into a ring with a diameter of at least 5 cm. Do not twist the tube or bend it at an acute angle - this will disrupt the circulation of the refrigerant inside sensor, and it will stop working.
Configuring and testing operation
After installing the new part and assembling all the panels, the verification stage begins. Plug in the refrigerator and set the control knob to the middle position. Don't expect immediate results - it may take time for the compressor to start up, especially if there is some oil left in the system after it has been idle. For the first 10-15 minutes, just listen to the operation of the unit.
A normal cycle is considered to be one in which the compressor runs for about 10-20 minutes, and then rests for the same amount of time until the temperature in the chamber rises by several degrees. If the refrigerator gets cold and turns off, you’ve done it! If it is silent or hums continuously, you may need to fine-tune the screw on the thermostat housing, but this is a job for specialists.
It is important to check the tightness of the capillary tube connection. It should fit tightly to the evaporator or be in a special channel. If the temperature sensor “hangs” in the air of the chamber, it will show incorrect data and the operation cycle will be disrupted. Thermoregulator It must read the temperature of the surface of the evaporator or the air in its immediate vicinity.
⚠️ Attention: Do not set the minimum temperature immediately after replacement. Allow the system to return to operating mode for 4-6 hours, gradually lowering the degrees.
Common mistakes during self-repair
Self-repair is always a risk make a mistake that could cost more than calling a specialist. One of the most common problems is the incorrect selection of an analogue. Thermostats differ in the length of the capillary tube, the on/off temperature and the type of contacts. Installing the wrong part will result in the refrigerator either not turning off or not starting at all.
Another mistake is careless handling of the wires. When reassembling, users often forget to secure the terminals or do not properly clean the contacts, which leads to sparking and heating. It is also worth remembering that in some models the thermostat is connected to a light bulb, and an error in the connection will lead to the light in the chamber being constantly on, heating the food.
List of typical errors:
- 🚫 Ignoring the markings and installing a “similar” thermostat.
- 🚫 Damage to the capillary tube during installation (creases, kinks).
- 🚫 Failure to check the contacts with a multimeter before assembly.
- 🚫 Attempted repair without disconnecting the device from the power supply.
Is it possible repair the old thermostat?
In 99% of cases, thermostats are non-separable and cannot be repaired. Inside there is a sealed capsule with gas or liquid, and breaking its seal is fatal. Attempts to disassemble the case will only lead to final breakdown.
When is it better to turn to a professional
Despite the apparent simplicity, there are situations when getting inside the equipment yourself is a bad idea. If your refrigerator is under warranty, any attempt to independently open the seals will result in a refusal of service. Also, do not take risks if you are not confident in your skills in working with electricity.
Complicated cases arise when replacing the thermostat does not solve the problem. This may mean that the compressor itself is faulty, there is a freon leak, or the capillary system is clogged. Diagnostics of these units requires special equipment (pressure gauges, vacuum sealers), which the average user does not have.
Contact the service if:
- 👨🔧 After replacing the thermostat, the refrigerator did not work.
- 🔊 There is a strong noise, knocking or vibration when work.
- 💧 You noticed oily stains or traces of leakage inside the chamber.
- 📜 The equipment is still under warranty service.
How much does it cost to replace the thermostat in the service?
The cost is the price of the spare part itself and the work of a master. On average, including on-site repairs, repairs will cost 2,000–4,000 rubles, depending on the refrigerator model and region. The thermostat itself costs from 800 to 2000 rubles.
Is it possible to use a thermostat from another model?
Sometimes this is possible if the mounting dimensions, capillary tube length and temperature parameters match. However, it is better to look for the original spare part number or its full analogue indicated in the cross-reference.
Why does the refrigerator freeze too much after replacement?
Perhaps the capillary tube is not immersed deep enough in the evaporator or is not pressed well. Also, the cause may be incorrect adjustment of the screw on the new thermostat or a defective spare part itself.
How often should the thermostat be changed?
The service life of a thermostat is usually 5–10 years. It does not require scheduled replacement if it works correctly. Replacement is made only when signs of malfunction appear.