Many owners of household appliances are faced with a classic dilemma: the food in the chamber begins to deteriorate faster than usual or, conversely, becomes covered with an ice crust. At this moment, the eye falls on the rotary knob with numbers from 1 to 5 (or to 7) inside the refrigerator compartment. Intuitively, it seems that the higher the number, the “colder” it is, but how exactly does this affect the operation of the compressor and is it worth pursuing the maximum values? Understanding the logic of operation thermostat is the key to the long life of your unit and the safety of products.
In this article we will analyze the principle of operation of a mechanical regulator, explain why manufacturers use this particular scale and how to correctly set the temperature depending on the time of year and chamber load. You will learn that number on the scale is not degrees Celsius, but a conditional cooling power, and incorrect settings can lead to compressor failure or defrosting of supplies.
Everyone who wants to avoid unnecessary costs for electricity and repairs needs to understand this issue. Users often make the mistake of setting the knob to maximum immediately after purchase or defrosting, without understanding what this creates on the system. Let's study in detail how this unit works and where the "golden mean" is. critical load on the system. Let's study in detail how this node works and where the "golden mean" is.
The principle of operation of a mechanical thermostat
A mechanical temperature controller, or thermostat, is a simple but reliable device that opens and closes an electrical circuit depending on the temperature inside cameras. When the air in the refrigerator heats above the set threshold, the contacts close, starting compressor. Once the desired temperature is reached, the circuit opens and the motor stops. The numbers on a scale from 1 to 5 are just markings of the position of the spring inside the thermostat.
It is important to understand that the number "1" corresponds to the weakest cooling mode, and the number "5" (or "Max") to the strongest. This does not mean that at “one” the chamber will be +10°C, and at “five” -20°C. This means that at the minimum value the compressor will turn on less often and work for less time, maintaining the temperature closer to the upper limit of the norm. At the maximum value, it will work practically without interruption, trying to achieve an unattainable ideal.
Inside the device there is a bellows (accordion) filled with refrigerant, which reacts to temperature changes. By turning the knob, you change the tension of the spring, which presses on the bellows membrane. The stronger the spring is tensioned (closer to number 5), the lower the temperature should drop inside the chamber, the gas pressure drops so much that the contacts open.
Deciphering the scale: what do the numbers from 1 to 5 mean?
Let us examine in detail what happens to the operation of the refrigerator at different positions of the regulator. This will help you make an informed decision about where exactly to turn the knob in your situation.
- ❄️ Position 1 (Minimum): The compressor rarely turns on. The temperature in the main chamber can fluctuate around +6...+8°C. This is an energy saving mode, but it can be dangerous for perishable products in the summer.
- 🌡️ Position 2-3 (Normal): Optimal mode for everyday work. The temperature is maintained in the range +3...+5°C. The compressor operates in normal mode, alternating work and rest.
- 🚀 Position 4-5 (Maximum): Aggressive cooling. The compressor runs almost constantly. The temperature can drop to 0°C and below, which leads to freezing of vegetables and milk in the main chamber.
- 🛑 Position 0 or Off: Complete shutdown of the power supply to the compressor. Used during defrosting or prolonged downtime.
Why can’t you just put the knob on “5” and forget? The fact is that the resource motor-compressor is limited by the number of switching cycles and operating time. Working at the limit leads to overheating of the windings and rapid wear of mechanical parts. In addition, in maximum power mode, the refrigerator consumes significantly more electricity.
There is a common misconception that in winter you need to set the regulator to minimum, and in summer to maximum. In fact, modern refrigerators are designed to operate in a wide range of ambient temperatures (room temperatures). However, if the room is very hot (above +30°C), the refrigerator may indeed not have enough power even at “five” to maintain the norm. In this case, it is better to reduce the temperature in the kitchen itself than to overload the equipment.
How to correctly set the temperature by season
External ambient temperature plays an important role in heat transfer. Although modern refrigerants and oils allow equipment to operate reliably, seasonal adjustments to settings can extend the life of the unit. In the summer, when the apartment is hot, heat removal through the condenser (the grille at the back) is difficult.
During the hot period, it is not recommended to immediately set the regulator to maximum. It is better to start with the value 3 and wait a few hours. If the food begins to thaw, you can smoothly move the knob to 4. A sharp jump in 5 will force the compressor to work non-stop, which is fraught with overheating and tripping of the thermal protection relay.
In winter, the situation is the opposite. If the refrigerator is in a cool room (for example, on an insulated balcony or in a corridor), where the temperature is below +16°C, the thermostat may “think” that it is already cold in the chamber and not turn on the motor. In this case, for single-compressor models, it is sometimes necessary to install the regulator closer to maximum valuesto force the cooling cycle to start, although this depends on the climate class of the equipment.
⚠️ Attention: If your refrigerator stops turning on in winter in an unheated room, the problem may not be in the regulator, but in oil solidification in the compressor or lack of pressure in the circuit. Do not try to heat the compressor with a hairdryer - this may lead to a fire.
The influence of chamber loading on the operation of the regulator
A full refrigerator and an empty refrigerator behave differently. Air has a low heat capacity, so in an empty chamber the temperature jumps quickly: they opened the door - warm air came in, closed it - the thermostat detected the heating and turned on the motor. Products, especially those containing water, serve as excellent cold accumulators.
If you have just loaded a large amount of room temperature products into the chamber (for example, brought from the store), it makes sense to temporarily increase the cooling power. Move the regulator knob to value 4 or use mode Super Cool (if it is in electronic form, then for mechanics - just turn the knob). This will help cool a lot of food faster.
After the food has cooled (usually after 6-10 hours), be sure to return the regulator to the normal position (2-3). If you leave high power at full load, the food at the back wall may freeze, and the compressor will spend extra energy to maintain excess cold.
☑️ Checking the correct setting
Typical errors when setting the thermostat
One One of the most common mistakes is trying to “deceive” an aging refrigerator. If the equipment has become worse at keeping the cold (the seal is worn out, the condenser is dirty, the freon is gone), users often turn the knob, thinking that this will correct the situation. This may help for a while, but ultimately leads to combustion 5, thinking that this will fix the situation. This may help for a while, but ultimately leads to burnout. compressor.
Another mistake is constantly “playing” with the regulator. There is no need to turn the knob back and forth every hour, expecting instant results. The thermostat has inertia. After changing the position of the handle, 4 to 8 hours must pass for the temperature to stabilize and the result to be assessed.
Also, users often ignore the position of the products relative to the sensor. If you put a bag of warm soup directly opposite the air outlet or next to the temperature sensor (usually a capillary tube going inside the chamber), the refrigerator will “think” that the chamber is hot and work for wear, even if the handle is on 2.
th>Possible cause (settings)
| Symptom | Recommended action | |
|---|---|---|
| Food freezes at the back wall | The regulator is turned to the maximum (4-5) | Reduce the value to 2-3 |
| The chamber is warm, food deteriorate | The regulator is at minimum (1) or there is a malfunction | Increase the value, check the seal |
| The refrigerator hums continuously | High load or Max mode | Reduce the setting, check the rear ventilation |
| Frequent switching on/off | The setting is too low or poor contact | Check the tightness of the door closure |
Why can’t you keep the refrigerator at maximum all the time?
Constant operation at the power limit leads to the fact that the refrigerant does not have time to completely evaporate and return to the compressor in the form of gas. Liquid freon causes water hammer, which physically destroys the compressor valves. In addition, constant overheating of the windings leads to destruction of insulation and interturn short circuit.
When the regulator no longer helps: signs of malfunction
There are situations when turning the knob from 1 to 5 is pointless. If you turn the regulator to the maximum, and the refrigerator is silent and does not cool, or vice versa - it is at a minimum, but freezes so much that the door freezes, most likely the thermostat itself has failed. Mechanical thermostats lose elasticity over time. The spring stretches, the bellows poisons, the contacts burn out. In this case, the position of the handle ceases to correlate with the actual temperature inside. The characteristic click when turning the handle may become quieter or disappear altogether, which indicates mechanical destruction of the unit. thermostat.
Mechanical thermostats lose elasticity over time. The spring stretches, the bellows poisons, the contacts burn out. In this case, the position of the handle ceases to correlate with the actual temperature inside. The characteristic click when turning the handle may become quieter or disappear altogether, which indicates mechanical destruction of the unit.
Another sign is the absence of a characteristic shutdown click. The refrigerator freezes until a “fur coat” forms on the evaporator, but the compressor does not stop. This means that the contacts inside the thermostat are “stuck” or the mechanism is stuck in a closed state. In such cases, replacement of the part is required.
⚠️ Attention: Before replacing the thermostat, be sure to disconnect the refrigerator from the power supply! Working with live electrical components is dangerous. If you are not confident in your skills, contact a specialist.
FAQ: Frequently Asked Questions
What happens if you set the regulator to 0?
Position 0 (or Off) means full opening of the electrical circuit. The compressor will not receive power and will not turn on. The light in the refrigerator will be on (if there is a separate lamp), but there will be no cold. This mode is used for defrosting or long-term shutdown of equipment.
Why are there no degrees Celsius on the regulator?
Mechanical thermostats are calibrated in conventional units, since they respond not to absolute temperature, but to pressure differences. Accurate calibration in degrees for mechanics is complex and expensive, so manufacturers use a scale from “weak” to “strong,” which is more understandable to the user.
Is it possible to replace a mechanical regulator with an electronic one?
Theoretically it is possible, but this requires a deep rework: installing a new sensor, controller and, possibly, changing the compressor control circuit. For older models this is not economically feasible. It’s easier to buy a new mechanical thermostat that fits the fitting dimensions.
How often do you need to change the regulator settings?
Ideally, having selected the optimal position (usually in the middle of the scale), you no longer need to touch the regulator. Adjustment is required only when there is a sudden change in conditions: the onset of extreme heat, a full load of warm food, or, conversely, the refrigerator has been left half-empty for a long time.