How to choose and replace the thermostat for the refrigerator

The refrigerator has stopped freezing or, conversely, turned food into ice blocks? In most cases, the culprit of these troubles is a failed thermostat. It is this small device that is responsible for maintaining the set temperature inside the chambers, turning the compressor on and off as needed. Without it, normal operation of the refrigeration unit is impossible.

Choosing the right spare part is not just buying a “similar” part, but a precise engineering task. Incorrectly selected thermostat can lead to incorrect operation of the compressor, freezing of the evaporator, or even food spoilage. In this article, we will analyze in detail what parameters you need to pay attention to so as not to make a mistake when ordering.

Independent diagnostics and replacement require care, but it is quite within the capabilities of a home craftsman. The main thing is to understand the principle of operation of the device and know how different models of regulators are marked. Let's figure out what exactly you need to look for first.

Operating principle and types of thermostats

A thermostat, or thermostat, is an electromechanical device that responds to changes in temperature. Inside its sensitive system is a bellows (corrugated metal container) filled with refrigerant (freon). When heated, freon expands, the pressure in the bellows increases, which opens the electrical contacts and stops the compressor.

When the temperature in the chamber rises, the pressure drops, the spring closes the contacts, and the cooling cycle resumes. There are also electronic analogues, but 90% of household refrigerators use mechanical models. They are reliable, cheap and easy to replace.

It is important to distinguish thermostats by the type of fastening and the length of the capillary tube. The capillary tube is a thin copper conductor that is inserted into evaporator or attached to it externally; It is this that transmits the temperature from the camera to the sensor itself. Incorrect selection of the length of this tube will make replacement impossible without modifications.

The regulators are also divided according to the operating temperature range. The refrigerator compartment requires certain response parameters, while the freezer compartment requires completely different ones. Installing a thermostat from the freezer into the main compartment will result in food simply rotting because the temperature will remain too low.

Key parameters when choosing a part

The first thing you need to do before going to the store or ordering online is to remove the old thermostat and study its markings. The part number is usually stamped on the metal housing. This code is the easiest way to find an analogue. However, if the number is erased or the part is unavailable, you will have to select an analogue based on technical characteristics.

Pay attention to the number of contacts. Standard household thermostats have three terminals, but there are models with two or four. If you buy a device with an extra contact, it's not a big deal - it will simply remain unused. But if there are not enough contacts, the circuit will not work.

The length of the capillary tube is a critical parameter. It varies from 0.5 to 3 meters. If the tube is too short, you simply will not be able to connect the sensor to the evaporator. If it is too long, you will have to carefully twist the excess so that it does not interfere with installation.

• 🔍 Marking: look for codes starting with TAM, K, DANFOSS, RANCO.
• ❄️ Temperature range: for the refrigerator compartment, usually from -10 to +10°C, for the freezer - up to -25°C.
• 📏 Geometry: tube length, contact arrangement and housing shape.

⚠️ Attention: Never bend the capillary tube at an acute angle or too close to the sensor body. This can lead to a crease and leakage of freon, which will completely disable the thermostat.

Decoding of markings and brand compatibility

The market is dominated by thermostats from several manufacturers, whose products are often interchangeable. The most popular brands are Danfoss (formerly Ranco) and Klixon. Knowing the markings of one, you can often find a direct analogue of the other. For example, the TAM series often corresponds to the K series.

For refrigerators Indesit and Ariston thermostats labeled TAM 133 or similar are most often used. In models Atlant there are regulators TAM 133, TAM 145. Refrigerators LG and Samsung are often equipped with sensors of the K59 series or their analogues from Danfoss.

The following is a table of correspondence between popular thermostat models for various brands of refrigerators:

When selecting an analogue, it is important to consider not only the brand, but also the specific series of the refrigerator. Sometimes within the same manufacturer different types of regulators may be used depending on the year of manufacture.

Instructions for diagnostics and replacement

Before buying a new one part, make sure that the problem is in the thermostat. A symptom of a malfunction may be the continuous operation of the compressor (the refrigerator does not turn off) or its complete refusal to turn on. Another sign may be the absence of a click when turning the regulator knob.

To check, you can close the thermostat contacts (after disconnecting the refrigerator from the network!). If the compressor starts working after closing the contacts, then there is a problem with the thermostat. If not, you need to look for the cause in the start relay or the compressor itself.

The replacement process requires compliance with safety precautions. Be sure to turn off the power to the appliance before starting work. Remove the regulator knob, remove the plastic cover and get to the metal thermostat housing.

Carefully disconnect the wires, remembering or photographing their location. Unscrew the mounting screws and remove the thermostat. Pay special attention to removing the capillary tube from its seat in the evaporator - do it without sudden jerks.

Install the new thermostat in the reverse order. Make sure that the tube fits snugly around the evaporator (if it is attached externally) or is inserted correctly inside. Secure the case, connect the wires according to the diagram and install decorative elements.

⚠️ Attention: If your refrigerator is equipped with a No Frost system, access to the thermostat may be hidden behind plastic panels inside the chamber. Be careful when removing the plastic so as not to break the latches.

Common mistakes during selection and installation

One ​​of the most common mistakes is ignoring the temperature range. Users often place a thermostat from the freezer into the refrigerator compartment. As a result, the temperature in the main chamber drops to -5...-10°C, the food freezes, and the compressor is overloaded.

Another mistake is an attempt to shorten the capillary tube. This is strictly forbidden. The tube is filled with freon under pressure, and any violation of its tightness or volume will lead to incorrect operation or breakdown. If the tube is long, it can be carefully wound into a ring, but not cut.

Incorrect connection of wires is the third most common problem. Even if the connectors are the right size, they may not match the diagram. Always check the electrical diagram of your refrigerator or the color coding of the wires of the old thermostat.

What happens if you mix up the wires?

If you mix up the wires, you can cause a short circuit when you turn on the refrigerator. In the best case, the fuse or start relay will burn out, in the worst case, the compressor winding will burn out or the wiring will catch fire. Always double check the circuit before applying voltage.

It is also worth mentioning the problem of “underloading” of the contacts. If the thermostat is not installed tightly or its sensing element is in poor contact with the evaporator, the temperature readings will be distorted. The refrigerator will “think” that the chamber is warmer than it actually is and will work non-stop.

Replacement cost: or a technician?

Replacing the thermostat yourself means saving money on calling a technician. The cost of the device itself usually varies from 500 to 1500 rubles, depending on the model and manufacturer. Original spare parts may cost more, but high-quality analogues (for example, Danfoss) are often not inferior to them in reliability.

The services of a technician to replace a thermostat cost on average 1,500–3,000 rubles plus the cost of the part. If you do not have experience working with electrical appliances or are afraid of damaging fragile elements of the internal lining, it is better to entrust the work to a professional.

However, if the refrigerator is under warranty from the manufacturer, any independent repair will lead to loss of warranty. In this case, the only correct solution would be to call an authorized specialist.

FAQ: Frequently asked questions

Is it possible to install a thermostat with a longer capillary tube?

Yes, you can. The excess tube must be carefully wound into a ring with a diameter of at least 5 cm and secured in the free space of the housing so that it does not vibrate or become damaged. The main thing is not to break the tube.

Why does the new thermostat click, but the refrigerator does not turn on?

This may indicate a malfunction of the compressor start relay, a problem with the compressor itself, or incorrect connection of the wires to the new thermostat. It is also worth checking the presence of voltage in the outlet.

How to understand that the thermostat is “lying”?

If the food in the refrigerator is clearly freezing or, on the contrary, spoiling, although the regulator knob is in the middle position, most likely the thermostat calibration is broken. An accurate check can only be carried out using an external thermometer.

Will a thermostat fit from a single-chamber refrigerator to a two-chamber one?

Only if the temperature range and the length of the capillary tube match. However, structurally they may differ in the method of fastening. It is better to select a part specifically for your type of refrigerator.