A modern household refrigerator is a complex system where each link plays a critical role. However, it depends on thermostat how stably the given climate inside the chambers will be maintained. If the food begins to freeze or, conversely, quickly deteriorates, and the regulator knob turns without any visible result, then the problem most likely lies in the calibration or malfunction of this unit. In this article we will analyze in detail the design of the model K59which is widely used in refrigerators Atlant, Stinol and Indesit.
Independent adjustment requires some caution and understanding of the physical processes occurring inside the device. Incorrect actions can lead to the compressor working without stopping or, conversely, turning on too rarely. Thermostat K59 is a mechanical device that closes and opens an electrical circuit depending on the temperature of the sensing element. Before you take a screwdriver, you need to make sure that the problem is in the settings, and not in a freon leak or a breakdown of the relay itself.
It is important to understand that the factory settings are not always suitable for specific operating conditions. For example, if the refrigerator is in a warm kitchen or, conversely, in a cool pantry, the standard parameters may fail. Competent calibration allows you to adjust the operating range, making the unit more efficient. We will look at the process from preparing the tool to the final check of the system's functionality.
⚠️ Attention: Before starting any work on dismantling or adjusting the thermostat, be sure to disconnect the refrigerator from the power supply. Working with live electrical components is dangerous to life and health.
The operating principle and design of the thermostat
To properly configure K59 thermostat, you need to understand how it functions. Inside the housing there is a sealed system filled with gas or liquid (freon, freon), which is connected to a bellows. When the temperature in the chamber changes, the pressure within this system also changes, causing the bellows to contract or expand. This mechanical movement is transmitted to a lever mechanism, which opens the contacts.
The model K59 is distinguished by the presence of two main adjustment screws, access to which is usually hidden under a seal or plastic plug. One screw is responsible for setting the temperature range (shifts the entire operating schedule), and the second is responsible for the difference between the temperatures when the compressor turns on and off. It is these two parameters that are subject to adjustment during the maintenance process.
- 🔧 The bellows chamber is the main sensitive element that responds to changes in pressure.
- ⚡ Contact group is responsible for supplying voltage to the refrigerator compressor.
- ❄️ Capillary tube - a thin copper tube that transmits temperature from the evaporator to the thermostat.
It should be noted that the design K59 is quite reliable, but over time the springs may get tired, and contacts - burn. This results in a shift in actual temperatures relative to the position of the knob on the control panel. That is why a visual assessment of the position of the “1-2-3” knob is often not true, and an instrumental check is required.
⚠️ Attention: The capillary tube of the thermostat is very thin and fragile. If handled carelessly, it can easily be damaged, which will lead to failure of the entire device beyond repair.
How does the temperature differential work?
The differential is the difference between the temperature when the compressor turns on and off. For example, if the refrigerator turns off at -18°C and turns on at -12°C, then the differential is 6 degrees. A differential that is too small causes the compressor to start frequently, which is harmful for the engine, and a differential that is too large leads to large temperature fluctuations in the chamber.
Diagnostics before starting adjustment
Before making changes to the settings, it is necessary to conduct a thorough diagnosis. Blind adjustment can only make the situation worse. The first thing you need to do is rule out other faults, such as a loose door fit, wear on the seal, or simply overloading the chamber with warm products. If the refrigerator is working properly, but the temperature does not meet expectations, then it makes sense to touch thermostat.
For accurate diagnosis you will need an external thermometer, preferably digital, with a remote probe. Place the probe in a glass of water and place it in the center of the refrigerator compartment (for single-compressor models) or in the freezer compartment (for two-compressor models), depending on where the probe is installed. Leave the refrigerator to operate in normal mode for several hours so that the temperature stabilizes.
| Parameter | Normal value | Deviation |
|---|---|---|
| Temperature in the refrigerator | +2...+5 °C | Above +7 or below 0 °C |
| Temperature in the freezer | -18...-24 °C | Above -12 °C |
| Cycle duration | 10-20 minutes of operation / 20-40 minutes of standstill | Continuous operation or rare inclusions |
If the measurements show significant deviations, try turning the regulator knob one notch in the desired direction and wait a day. If the situation has not changed or the knob turns too easily (without a characteristic click), then intervention in the internal mechanics of the device will be required. It is also worth checking whether the capillary tube capillary tube has not moved from its mounting location on the evaporator, as this is a common cause of incorrect readings.
Necessary tools and preparation
For high-quality setup thermostat K59 will require a minimum set of tools, but they should be at hand. The main tool will be a Phillips and flathead screwdriver. A flathead screwdriver is needed to turn the adjusting screws, which often have small slots. It is important that the blade of the screwdriver exactly matches the size of the slot so as not to damage the screw head.
Also, do not forget to prepare a multimeter to check the integrity of the contacts. In some cases, you may need a hair dryer to defrost ice if access to the thermostat is blocked by ice. It is better to carry out work in good lighting, since the adjusting screws are located in hard-to-reach places and are small in size.
- 🔌 Multimeter - to check the contacts are closed.
- 📏 Thermometer - to monitor the actual temperature in camera.
- 🔦 Flashlight - to illuminate the thermostat installation location.
Before starting work, free access to the thermostat. In most refrigerator models, it is located inside the refrigerator compartment, under a plastic panel or directly on the temperature control knob. Carefully remove the protective covers, being careful not to break the plastic latches, which become brittle from the cold.
Step-by-step instructions for setting up K59
Thermostat setting process K59 is divided into two stages: adjusting the temperature range and adjusting the differential. The thermostat housing usually has two holes for screws. One of them (often marked or located closer to the edge) is responsible for shifting the temperature curve. Rotating this screw clockwise lowers the temperature in the chamber (the compressor will turn off at lower values), counterclockwise - increases it.
The second screw regulates the stroke length of the bellows rod, which affects the difference in the on and off temperatures. By tightening it, you reduce the differential (the refrigerator will turn on more often, but for a shorter time), by unscrewing it, you increase it. Be careful: each turn of the screw should be minimal, no more than 1/8 or 1/4 turn. After each change, you need to give the refrigerator time (at least 30-40 minutes) to stabilize the mode.
- Remove the temperature control knob and the protective pad.
- Find the two adjustment holes on the thermostat body.
- Use a marker to mark the original position of the screws to be able to return to the factory settings.
- Turn the range screw 1/4 turns in the desired direction.
- Turn on the refrigerator and check the temperature after 2-3 hours of operation.
If, after adjusting the range, the temperature in the chamber has become acceptable, but the compressor turns on too often or rarely, proceed to adjust the differential. The ideal mode is when the refrigerator operates approximately 30-40% of the total time. This ensures optimal temperature conditions and saves compressor life.
☑️ Setting checklist
Typical errors and ways to eliminate them
One of the most common mistakes is trying adjust thermostat without first defrosting the refrigerator. If there is a “coat” of ice on the evaporator, the temperature-sensitive element will read the wrong temperature and all your adjustments will go down the drain. Always start by completely defrosting the unit within 10-12 hours.
Another mistake is sudden and strong rotation of the adjusting screws. The thermostat mechanism K59 is sensitive, and even half a turn can change the temperature in the chamber by 3-5 degrees. If you unscrew the screw too much, you may break the system's seal or break the threads. Act gradually, recording each step.
⚠️ Attention: If after adjustment the compressor stops turning off completely, immediately turn off the refrigerator. This can lead to overheating of the motor and fire. Return the screws to their original position and repeat the procedure with smaller increments.
Also, users often confuse adjusting the thermostat with adjusting the damper (if there is one) or the fan. In models with a No Frost system, different sensors may be responsible for the temperature, but K59 thermostat usually it controls the compressor operating cycle. Make sure that you are setting up the correct unit.
Checking the results and final assembly
After you have made the necessary manipulations with the screws, you need to carry out a final check. Set the control knob to the middle position (usually number 3 or 4) and leave the refrigerator to operate for 12-24 hours. At this time, do not open the door unless absolutely necessary, so as not to disturb the temperature.
Use an external thermometer for control. If the temperature in the main chamber is kept within +2...+5 °C, and in the freezer (if available) is normal, then the adjustment was successful. The compressor should turn on and off with a characteristic click, without buzzing or vibration.
- ✅ The temperature in the chamber is stable throughout the day.
- ✅ The compressor operates cyclically and not continuously.
- ✅ There is no excessive freezing of the rear walls.
If all parameters are normal, you can assemble the structure in the reverse order. Install the protective covers, the regulator handle and make sure that nothing prevents the door from closing. The thermostat adjustment K59 is completed, and your refrigerator is ready for full operation again.
What to do if the adjustment screw scrolls in vain?
If the screw scrolls without resistance and without changing the operating parameters of the refrigerator, The spline on the screw head may be broken or the internal rotation transmission mechanism may be damaged. In this case, adjustment is impossible; the thermostat must be replaced with a new one. Attempts to fix the screw with glue or other methods are ineffective and dangerous.
Is it possible to replace the K59 with a thermostat from another manufacturer?
Yes, thermostats K59 are often interchangeable with analogues from Tam, Ranco or Ortobal, but it is important to consider the length of the capillary tube, the location of the contacts and overall dimensions. An incorrectly selected analogue may not be suitable for mounting or have a different temperature response range.
How often should the thermostat be changed?
Thermostat service life K59 usually 5-10 years depending on the intensity of use refrigerator. A scheduled replacement is not required, they change it only when malfunctions occur: the refrigerator has stopped freezing, does not turn off or turn on.