Refrigerators of the brand Stinol have remained popular for many years due to their reliability and maintainability. However, any mechanism is subject to wear, and often the temperature control system is the first to fail. Understanding how it works Thermostat of the Stinol refrigeratoris a key skill for the owner who wants to independently diagnose the problem without calling a technician.
The thermostat is the “brain” of the climate control in the chamber, which makes the decision to start or stop the compressor. If this unit does not function properly, food can either defrost or turn into an icy monolith. In this article we will analyze in detail the internal structure of the sensor, methods for checking it and features of replacement in various models of equipment.
Design features of Stinol thermostats
Most models of refrigerators Stinol, such as series 101, 102 and 103, use mechanical thermostats of capillary type. The main element here is the bellows - a sealed corrugated chamber filled with a gas or liquid with high volatility (often freon or freon). When the temperature in the evaporator increases, the substance inside the bellows expands, creating pressure on the movable rod.
This rod mechanically opens or closes electrical contacts, supplying power to the compressor motor. It is important to understand that the thermostat does not measure temperature directly in degrees, but reacts to a physical change in the volume of the working fluid. The design also includes an adjustment spring, the force of which can be changed by rotating the control knob inside the chamber.
⚠️ Attention: The capillary tube of the thermostat is very thin and easily bent. When installing a new sensor, make sure that the bending radius of the tube is not less than 30 mm, otherwise the seal will be broken and the device will stop working.
There are also electronic analogues, but in classic Stinol models mechanics dominate. Its advantage is independence from power surges and ease of replacement. However, over time, mechanical contacts can burn out, sticking in a closed state, which leads to continuous operation of the motor.
Principle of operation and temperature conditions
The operation of the system is based on a cyclical process. When you set the adjuster knob to a specific position, you are setting the spring force that the bellows must overcome. As soon as the temperature in the chamber reaches a predetermined threshold, a click occurs and the circuit breaks. The compressor stops and the “rest” phase begins.
Gradually, the temperature inside the refrigerator compartment increases due to heat inflows through the walls and when the door is opened. The working fluid in the thermostat expands again, the pressure increases, and at a certain moment the contacts close. It starts compressor, the refrigerant begins to circulate, taking away heat. This cycle is repeated endlessly as long as the refrigerator is connected to the network.
Below is a table of typical operating temperature ranges for common models of thermostats installed in Stinol equipment:
| Thermostat model | Switching temperature (°C) | Switch-off temperature (°C) | Capillary length |
|---|---|---|---|
| TAM-133 | -12...-14 | +3...+5 | 0.73 m |
| TAM-145 | -24...-26 | -18...-20 | 0.73 m |
| TAM-118 | -12...-14 | +3...+5 | 1.3 m |
| K-59 | -10...-12 | +3...+5 | 0.73 m |
The difference between the on and off temperatures is called the differential. For normal food storage, this parameter is critically important, since turning on the motor too frequently wears out the motor, and turning on too rarely leads to food spoilage.
Typical symptoms of a thermal sensor malfunction
Diagnostics begins with observing the behavior of the unit. If you notice that the refrigerator does not turn off and works around the clock, making only rare stopping sounds, this is the first sign that the thermostat contacts are “stuck” in the closed position. In this case, the compressor works hard, trying to reach a temperature that the sensor “does not sense.”
The opposite situation - the motor does not start at all, although there is voltage in the network and the light inside is on. This may mean that the contacts have oxidized or the circuit inside the thermostat itself has broken. It is also worth paying attention to the formation of a “snow coat” or, conversely, the complete absence of cold when the engine is running.
- 🧊 Continuous operation: The compressor hums without interruption, the back wall of the refrigerator compartment is covered with ice, the products in the upper part can freeze.
- 🔇 Silence: The unit is silent, indicators they are burning, but there is no cold. Often accompanied by relay clicks, but the engine does not start.
- ❄️ Short cycle: The motor turns on for 1-2 minutes, turns off and turns on again after the same period. This indicates a loss of sensitivity of the bellows.
Sometimes the problem may not be in the thermostat itself, but in a freon leak. In this case, the thermostat regularly waits for the temperature to drop, but there is not enough refrigerant in the system to achieve it. Therefore, before replacing the sensor, it is important to ensure the integrity of the circuit.
How to distinguish a freon leak from a thermostat failure?
If the refrigerator runs constantly, but there is no cold, and the condenser (grid at the back) is barely warm or cold, there is most likely a leak. If the grille is hot and the thermostat does not click, the problem is in the sensor or relay.
Dismantling and preparation for testing
Before starting repairs, you must de-energize the refrigeratorunplug the plug from the socket. This is a basic safety rule and, if ignored, may result in electric shock or short circuit. Access to the thermostat in Stinol models is usually located inside the refrigerator compartment.
Depending on the model, the thermostat may be hidden under a plastic cover on the ceiling of the chamber or located next to the temperature control knob. For dismantling, you will need a flat-head screwdriver to carefully remove the decorative plugs, and a Phillips screwdriver for the fastening screws.
⚠️ Attention: Do not use sharp objects (knives, awls) to pry up the plastic panels. The plastic in old refrigerators becomes brittle and breaks easily, which will require replacing the entire cladding assembly.
After removing the casing, you will see the thermostat itself with suitable wires and a capillary tube coming out of it. The tube is secured with special clips to the evaporator. It must be carefully released, remembering or photographing the installation path. Then the electrical wires are disconnected. It is recommended to mark them in advance with a marker so that during assembly you do not confuse phase and zero.
☑️ Preparation for diagnostics
Methods for diagnosing a thermostat
The most reliable way to check is to use multimeter in the mode calls. To do this, you need to remove the thermostat from the refrigerator. If you want to check it without dismantling, this can be done by reaching the contact group, but the accuracy of such a check is lower.
Immerse the sensitive part (capillary tube) in a container with water having a temperature of about +5...+10°C (ice melting temperature). In this state, the contacts should be closed and the multimeter should read zero or beep. If there is no signal, the contacts inside are damaged or oxidized.
Then lower the tube into hot water (about +50°C). When heated, the pressure inside the bellows should increase and break the chain. The multimeter should stop ringing. If the chain does not break even when the water boils, it means that the tightness of the bellows is broken or the elasticity of the spring is lost.
There is also a “folk” method of checking if you don’t have a multimeter at hand. You can carefully short-circuit the wires going from the network to the compressor, bypassing the thermostat. If, after connecting to the network, the refrigerator started working and began to freeze, then the problem is in the regulator. However, this method requires extreme caution and knowledge of electrical engineering.
Replacing and setting up a new device
The process of installing a new thermostat is performed in reverse order. Pay special attention to securing the capillary tube. It should fit snugly against the evaporator in the area where the old sensor was removed. Often a special clamping bar or bracket is used for this.
The ends of the tube should not touch moving parts or sharp metal edges that could damage it during vibration. After connecting the wires and assembling the plastic panels, you can plug the refrigerator into the network. The initial setting is made experimentally.
Set the regulator knob to the middle position. Let the refrigerator run one full cycle (turn on, operate, turn off). If the operating time is 10-15 minutes, and the pause is 30-40 minutes, then the setting is correct. If the cycle is too short, reduce the power; if it is too long, add more.
In modern conditions, the range of spare parts may change. Thermostat models may have different analogues, so before purchasing, check the markings and length of the capillary tube with the original, and also check compatibility with spare parts suppliers.
Questions and answers (FAQ)
Is it possible to repair an old thermostat rather than changing it?
Theoretically, you can replace the contact group or bend the spring, but in practice this is a temporary measure. The tightness of the bellows is compromised due to corrosion or microcracks, and it is impossible to restore the factory gas filling parameters at home. It is more reliable and safer to buy a new sensor.
Why does the new thermostat click, but the refrigerator does not turn on?
The click means that the mechanics are working, but the electrical circuit may not be assembled correctly. Check that the wires in the terminal block are securely connected. Also, the problem may be in the compressor start relay or in the electric motor itself, which could burn out.
Which thermostat is better: with or without a defrost button?
For Stinol refrigerators with a drip defrost system (crying evaporator), thermostats are often equipped with a forced defrost button. If your model did not have such a button initially, it makes no sense to install a thermostat with a button, since there is nothing to control it. Use a direct analogue.
How to understand that the thermostat is “lying” based on temperature?
To do this, you will need an external thermometer placed in a glass of water on the middle shelf. If, according to the readings of the thermometer in the chamber, it is +8°C, and the compressor does not turn on (although it should be at +5°C), then the thermostat response range is shifted and requires adjustment with a screw on the housing or replacement.