A sudden increase in temperature in the refrigerator compartment or, conversely, excessive freezing of food at the rear wall often indicates a failure of the cooling control system. In refrigerators Posis, as in many other models, thermostat (or a thermostat) is responsible for temperature control. This small device monitors the temperature of the evaporator and sends a signal to the compressor to turn on or off.
If your refrigerator Pozis stops keeping cold or works without interruptions, ignoring the regulator settings, most likely the problem lies precisely in sensor Replacing this element yourself is a completely doable task for a person with basic skills in working with tools. The main thing is to observe safety precautions and strictly follow the algorithm of actions so as not to damage the freon circuit or wiring.
In this article we will look in detail at how to diagnose a malfunction, what tool to prepare and how to correctly replace the thermostat in various models of refrigerators Posis. A correctly selected and installed sensor will return the equipment to its previous efficiency and extend the service life of the compressor.
Signs of a malfunctioning thermostat
Before disassembling the equipment, you need to make sure that the problem lies in the thermostat. Thermoregulator is a mechanical one or an electronic switch that can fail for various reasons: contact wear, freon leakage from the bellows tube, or oxidation. The most obvious symptom is the failure of the compressor to start, even when the chamber is warm.
However, there are also the opposite situations when compressor hums continuously, not turning off for days. In this case, the contacts inside the sensor could “stick” in the closed position. It is also worth paying attention to the products: if everything melts in the refrigerator compartment, and, on the contrary, a “fur coat” forms in the freezer, this is a sure sign that the automation does not correctly read the evaporator temperature.
⚠️ Attention: If after defrosting the refrigerator worked normally, but after a couple of days the symptoms returned, the problem is highly likely to lie in the electrical part, and not in the moisture removal system.
Diagnostics can be carried out by short-circuiting the wires coming from the thermostat directly. If the compressor starts, it means the circuit is intact and the sensor is to blame. Electronic models Posis with a display are characterized by errors in the form of flashing indicators, codes for which can be found in the instructions.
Choosing the appropriate thermostat model
For successful repairs, it is critical to choose the right analogue. Thermostats for refrigerators Position can differ in length of the capillary tube, type of fastening and temperature range of operation. Installing an unsuitable sensor will lead to incorrect operation: either the refrigerator will turn on frequently or will not be able to reach the desired temperature.
The most common thermostats are the TAM and T-110 series. For example, for two-chamber models, sensors marked TAM-112 or TAM-133 are often used. It is important to consider that the length of the capillary tube should be sufficient to reach the mounting location on the evaporator, but not too long so as not to create creases.
Below is a table of the correspondence of popular models of thermostats for technology Pozis:
| Original / Analogue | Mounting type | Tube length (cm) | Application |
|---|---|---|---|
| TAM-112 | With lug | 0.73 | Single chamber, freezers |
| TAM-133 | With lug | 1.3 | Two-chamber (cold chamber) |
| T-110 | Without lug | 0.9 | Old models Position |
| K-59 | With lug | 1.6 | Analogue for some series |
Where can I find the markings of the old thermostat?
The markings are usually applied to the metal body of the sensor. To see it, you may need to carefully remove the plastic cover or pull the unit out of its seat without completely disconnecting the wires. Look for inscriptions like “TAM”, “Ranco”, “Danfoss” or “T-110”.
When purchasing, pay attention to the position of the contacts. They can be normally closed or open when heated. For refrigerators Posis thermostats are most often used, which open the circuit when the lower temperature limit is reached.
Necessary tools and preparation
You do not need complex industrial equipment to carry out the work. A set of household tools is enough. However, it is important to prepare your work area: provide good lighting and easy access to the back wall of the refrigerator. Before starting any manipulations be sure to disconnect refrigerator from the mains.
You will need:
- 🔧 Screwdrivers (phillips and flat) for removing panels and terminals.
- 🔪 A sharp knife or side cutters for carefully cutting the old tube (if necessary).
- 🧤 Gloves to protect your hands from sharp metal edges.
- 📸 Smartphone to photograph the wiring diagram before disassembly.
- 🧊 Ice pack or hair dryer (to check the operation of the new sensor).
☑️ Preparation for repair
It would be a good idea to prepare a multimeter if you want to accurately diagnose the contacts before replacing. Also have a container for water under you, since during defrosting, which precedes repair, a significant amount of condensate may leak out.
Removing the old thermostat
The process of removing the sensor depends on the design of your refrigerator Position. In most models, the thermostat is located inside the refrigerator compartment, under a plastic cover, or on the back wall outside. If the regulator is hidden inside, carefully pry up the plastic panel with the temperature adjustment knob.
After removing the decorative trim, you will see the thermostat block itself. Unscrew the mounting screws and carefully remove the housing. Here it is important to be extremely careful with capillary tube. It is very thin and fragile, filled with freon gas. Any damage to the tube will render the new sensor inoperative, as the gas will evaporate.
⚠️ Attention: Under no circumstances pull the tube with force! It may burst at the very base of the evaporator. If the tube is stuck to the metal, carefully trim the insulation or use a defrosting liquid, but do not use brute force.
Disconnect the electrical wires. It is best to mark them with a marker or take a close-up photo so that when connecting a new element you do not confuse the polarity or grounding. In some models, the wires are simply inserted into the terminals, in others they are soldered or clamped with screws.
After disconnecting all elements, remove the old thermostat. If the capillary tube was secured to the evaporator with a staple or tape, carefully release it. Now you can begin installing a new part.
Installation of a new thermostat and assembly
Installation of a new one thermostat is carried out in the reverse order of dismantling. Insert the capillary tube into the technological hole at the same depth at which the old one stood. Secure the tube with a standard bracket or heat-resistant tape so that it fits tightly to the surface of the evaporator. Poor contact will lead to a delayed response of the sensor.
Connect the electrical wires according to the photographs or markings taken previously. Make sure the terminals are tight and not loose. If there is a grounding contact on the thermostat body, its connection is mandatory for safe operation.
Fix the thermostat block in the niche and return the plastic decorative cover to its place. Make sure that the adjustment knob rotates freely and does not touch the body. Now you can plug in the refrigerator.
After assembly, let the refrigerator run idle (without food) for 2-3 hours. This will allow the system to enter mode and make sure that the compressor turns off when the set temperature is reached.
Checking operation and setting
The first cycle of operation is the most important. Listen to the compressor start. It should work some time after turning it on (or immediately if the camera is warm). Then wait until the temperature drops to normal and make sure the motor is turned off. The click should be distinct.
If the refrigerator Position turned off, but after 5-10 minutes it turned on again, although the food has not yet cooled down, perhaps the sensitivity of the new sensor is too high or the tube is not installed tightly. In models with a mechanical regulator, you can try tightening the screw under the handle (if it is available and there is calibration equipment), but in domestic conditions it is better to simply check the tightness of the tube.
- ✅ The compressor turns on and off cyclically - the replacement was successful.
- ❌ Compressor does not turn on - check the connection of the wires and the integrity of the contacts.
- ❌ The compressor does not turn off - check the fit of the capillary tube or compliance with the thermostat model.
Do not completely load the chamber with products until the first full cooling cycle is completed. This will give a false impression of the system's operation. It is better to put several bottles of water for temperature inertia.
⚠️ Attention: The characteristics of thermostats may vary slightly depending on the batch and manufacturer. If the new sensor behaves strangely, let the refrigerator run for a day. Sometimes it takes time to stabilize the pressure in the system and “grind in” the contacts.
In conclusion, it is worth noting that timely replacement of the thermostat saves the compressor from overload. A motor running non-stop will quickly fail, and repairs will cost much more than replacing a penny sensor.
Is it possible to replace the thermostat with an analogue from another company?
Yes, you can. The main thing is that the main parameters coincide: the type of contacts (normally closed/open), the temperature range of operation and, preferably, the length of the capillary tube. Chinese analogues are often cheaper, but may be inferior in durability to the original Danfoss or Ranco.
Why does the new thermostat click, but the refrigerator does not turn on?
If there is a click, then the mechanics are working. The problem may be with the compressor start relay, the motor itself, or a broken wiring between the thermostat and the motor. It is necessary to test the circuit with a multimeter.
Is it necessary to defrost the refrigerator before replacing?
Yes, definitely. The presence of ice on the evaporator will make it difficult to access the capillary tube mounting and can lead to damage to fragile elements during dismantling. Complete defrosting will take at least 10-12 hours.
How to understand that the thermostat is “lying”?
For this you need an external thermometer. Place it in the chamber and set the regulator to the middle position. If the thermometer readings are very different from what the refrigerator “feels” (it does not turn off or turns off too early), the sensor is faulty or its calibration screw is knocked out.