A sudden stop in the operation of the compressor or, conversely, its endless cycle - these are the first signals of a malfunction in the temperature control system. In refrigerators Stinol, as in other equipment, a thermostat, which is often called a thermostat, is responsible for this process. It is this small unit that makes the decision to turn the motor on or off, based on the readings of the temperature sensor inside the chamber.
If you notice that food has begun to deteriorate or, on the contrary, freeze in a compartment not intended for this purpose, you cannot ignore the symptoms. Timely thermal relay diagnostics avoids costly repairs of the compressor, which may fail due to incorrect operating conditions. In this article we will look at how to determine a malfunction without calling a technician.
The verification process does not require complex professional equipment, but does imply compliance with safety precautions. You will need a basic set of tools and an understanding of how an electrical circuit works. Before proceeding with disassembly, make sure that the device is completely disconnected from the power supply.
The principle of operation of the thermostat in Stinol refrigerators
The thermostat is a mechanical or electronic device that closes and opens an electrical circuit. Inside the housing is a sealed tube filled with a temperature-sensitive agent (freon) that reacts to changes in heat in the chamber. When the temperature rises above the set temperature, the gas expands and closes the contacts, starting the compressor.
Models Stinol-101, Stinol-103 and other series use predominantly mechanical regulators. Their reliability is high, but over time the contacts may burn out and the bellows tube may lose its seal. Understanding this mechanism is important for correct interpretation of test results.
Electronic analogs found in more modern modifications work differently, using thermistors with variable resistance. However, the classic checking the thermal relay multimeter is relevant specifically for mechanical systems where there is either physical contact or there is not.
⚠️ Attention: Before starting any diagnostic work, be sure to remove the refrigerator plug from the socket. Working with live electrical components is deadly and can result in a short circuit.
Incorrect adjustment or failure of this unit results in the compressor either not starting at all or running non-stop, trying to reach an unattainable temperature. This creates an excessive load on the entire cooling system.
External signs of a thermostat malfunction
The breakdown can be determined not only by instrumental methods, but also by indirect signs that appear in the behavior of the refrigerator. If you observe one of the following symptoms, the probability of the thermostat failure is extremely high.
- 🔌 The compressor hums, but does not start, or starts for a few seconds and immediately stalls.
- ❄️ The temperature in the refrigerator compartment is higher than normal, food spoils, although the freezer is working normally.
- 🌡️ The refrigerator operates continuously, without turning off, and a thick ice crust forms on the walls of the chamber.
- 🔇 Complete absence of sound from the motor when plugged in (if the socket and cord are working properly).
A particularly alarming symptom is the situation when, when turning the control knob to position "Maximum" or when you tap on the thermostat body, a characteristic click is heard, but the compressor is silent. This may indicate an open circuit or sticking contacts inside the relay itself.
Sometimes the problem lies not in the relay itself, but in a freon leak from the thermostat bellows tube. In this case, the device “thinks” that the chamber is always warm and does not give a command to start, or vice versa - it thinks that there is enough cold and does not turn on the motor.
Preparation for diagnostics: tools and access
To conduct a quality test, you will need a minimum set of tools. The main device will be a multimeter (tester) configured to measure resistance (Ohm) or continuity testing. Without it, accurate diagnosis is impossible, since it is impossible to visually determine the integrity of the contacts inside the sealed case.
You will also need screwdrivers (Phillips and flathead) to remove protective panels and casings. Some models Stinol may require a ratchet wrench to remove additional fasteners. Prepare a container for water in advance if defrosting is required before accessing the units.
☑️ Diagnostic tools
Access to the thermostat in refrigerators Stinol is usually located inside the refrigerator compartment. Depending on the model, it may be hidden behind a plastic panel on the ceiling of the chamber or located next to the lampshade. Carefully remove the decorative trims to gain access to the thermostat housing.
If you move it carelessly, it can easily be damaged, which will lead to the need to replace the entire assembly.
Testing algorithm with a multimeter
The most reliable way to check the functionality is to measure the resistance between the contacts. First, remove the wires from the thermal relay terminals, having previously photographed their location so as not to confuse the polarity during assembly. Usually there are three of them: general, for the compressor and for the lamp (or fan).
Set the multimeter to resistance measurement mode (200 Ohm limit or continuity mode). Touch the probes to a pair of contacts. In normal condition at room temperature, the circuit should ring (resistance close to zero) between the common contact and the compressor contact.
If the device shows one (infinity), then the contacts are open. Try turning the control knob all the way clockwise. If there is no click or change in readings, the thermostat is faulty. You can also immerse the sensitive tube in cold water with ice to simulate a low temperature - the circuit should break.
⚠️ Attention: Do not use the current (Amperes) measurement mode to test resistance! This will cause the multimeter fuse to burn out or the device to fail.
Checking the insulation is also important. Measure the resistance between any contact and the metal housing of the thermostat. The device should show infinity. If there is at least some value, then the insulation is broken, and it is dangerous to operate such a device.
What to do if you don’t have a multimeter at hand?
In emergency cases, you can assemble a simple “control” from a battery and a light bulb, but this method is less accurate and does not provide digital resistance values, allowing only the presence of a contact.
Table typical values and states of contacts
For diagnostic convenience, below is a table describing the expected states of the circuit under various conditions. This data is relevant for most mechanical thermostats installed in equipment. data-i="98">Sound signal Stinol, Indesit And Ariston.
| State | Handle position | Temperature | Resistance (Ohm) | Beep |
|---|---|---|---|---|
| Normal (On) | Average/Max | Room (+20°C) | 0 - 5 Ohm | Yes (beeps) |
| Normal (Off) | Any | Low (-10°C and below) | Infinity (1) | No |
| Fault (Open) | Any | Room | Infinity (1) | No |
| Fault (short circuit) | Off | Any | 0 Ohm | Constantly present |
Please note that resistance values may vary slightly depending on on the length of the probe wires and the quality of the contact. The main thing is the absence of resistance in the closed state and its presence (break) during cooling.
If your measurements match the “Fault” line, then the part requires replacement. Repairing sealed thermostats is not economically feasible and technically difficult at home.
Replacing and setting up a new thermostat
If Diagnostics confirmed the breakdown, you need to purchase an analogue. For refrigerators Stinol universal models or original spare parts marked TAM-133, K-59 or Rancoare often suitable. It is important that the length of the capillary tube of the new sensor matches the old one or is longer (the excess can be carefully rolled up).
When installing a new thermostat, make sure that the sensitive tube fits snugly to the evaporator in a special clamp. Poor contact will lead to incorrect temperature reading and frequent on-off cycles.
After installing and connecting the wires according to the diagram (which you photographed earlier), turn on the refrigerator. Initial setup usually requires the knob to be set to the middle position. Complete cooling of the chambers and reaching the operating mode may take up to 24 hours.
During the initial startup, carefully monitor the operation of the compressor. It should turn on, work for a certain time and turn off when the set temperature is reached. If the cycle is repeated correctly, the repair can be considered successful.