The situation when the Stinol refrigerator stops cooling, and the motor is silent or makes only noise a quiet click, familiar to many owners of this equipment. Compressor is the heart of the refrigeration unit, and it is from here that troubleshooting begins if the chamber suddenly becomes warm. Often users are frightened by silence or, conversely, buzzing without starting, not suspecting that in some cases the problem can be solved on their own without calling a technician.
Before taking active steps, you need to clearly understand that refrigeration unit is a complex system under pressure. If you hear the engine humming but won't start, or if it is completely de-energized, your actions will be radically different. In this article we will analyze the mechanical and electrical aspects of restoring engine operation, paying special attention to models Stinol 101, 102, 103, 104 and more modern series.
It is important to immediately tune in to working with electricity and tools. You will need a minimum set: screwdrivers, a multimeter (tester) and, possibly, new spare parts if the diagnostics reveal their failure. You should not try to “unfreeze” the system by blowing a hairdryer into the back wall if the problem lies in the electrical circuit start relay. Let's take a step-by-step look at how to safely diagnose and start the motor.
Primary diagnostics and voltage check
The most commonplace, but often ignored reason for lack of starting is the lack of voltage in the network or poor contact. Before disassembling the back panel of the refrigerator, make sure that the outlet is working properly. Connect another electrical appliance to it, such as a hair dryer or lamp. If they work, then the problem is localized inside the refrigerator body or in its power cord.
Carefully inspect the power cord and plug. In older models Stinol the wire could rub against the body or be damaged by pets. If there are no visual defects, we move on to the insides. Remove the rear metal cover covering the motor-compressor. Usually it is secured with 4 bolts or latches. Attention: all manipulations are carried out only with the device completely disconnected from the network!
Find the thermostat. In mechanical models, it looks like a knob with divisions inside the chamber, and the electrical part is located at the back. Test the circuit with a multimeter. If there is no current flowing through the thermostat, the compressor will not be commanded to start, even if it is fully operational. Also check the defrost button, if it is provided by the design of your model.
⚠️ Attention: If you find melted contacts on the plug or at the point where the wire enters the body, do not plug in the refrigerator under any circumstances. This may cause a short circuit or fire. Replace the entire cord before further diagnostics.
The design of the starting relay and its testing
The key element responsible for starting the engine is the starting relay. In Stinol refrigerators, relays of the RTP, RT type or more modern posistor analogues are most often found. It is this small black or white box, placed over the compressor contacts, that supplies the initial impulse to the starting winding.
Remove the relay by carefully disconnecting it from the motor contacts and wires. Visually inspect the body: if traces of burning, soot or melting are visible on the plastic, the part definitely requires replacement. Inside the relay there may be a posistor (ceramic element) or a coil with a core. In any case, the integrity of the contacts inside is a critical parameter.
For accurate diagnostics, use a multimeter in dial mode. Check the circuit between the contacts. If the relay is mechanical (with a coil), it should “ring” in a certain position. PTC relays are tested for resistance: when cold it should be low, and when heated (which is difficult to check without heating) it should go to infinity. It often happens that a posistor is “broken” and does not create the necessary jump in resistance to switch the windings.
How does a posistor work in a relay?
A posistor is a thermistor with a positive temperature coefficient. When the refrigerator is turned on, it is cold and has low resistance, passing current to the starting winding. The current heats up the posistor, its resistance increases sharply, and the current practically stops flowing to the starting winding. The motor continues to run on the main winding. If the posistor is faulty, this cycle does not occur.
If the relay is working properly, but the motor does not start, the problem may be deeper. However, in 60% of cases of “non-start” the relay is to blame. Its cost is low, and replacement takes 5 minutes. When purchasing a new part, pay attention to the markings: they must match the original or be universal analogues with a suitable power range.
☑️ Relay diagnostics
Diagnostics of electric motor windings
If with the relay and voltage are all right, let's move on to checking the motor-compressoritself. There are three contacts on the motor housing, covered with a rubber gasket and a plastic cover. By removing the relay you have access to these pins. Usually they are arranged in a triangle.
You need to determine which pair of contacts corresponds to the starting winding and which to the working winding. In most Stinol models, the circuit is as follows: the two upper contacts are the starting winding (lower resistance), and the lower (or side, depending on the model) with the upper one is the working winding (higher resistance). There should be a total resistance between the other two contacts.
Using a multimeter, measure the resistance between each pair of contacts. Normal values vary within:
- 🔌 Between working and common: 20–40 Ohm
- 🔌 Between starting and common: 10–25 Ohm
- 🔌 Between working and starting: 30–60 Ohm (sum of two previous)
If the multimeter shows infinity (open) or zero (short circuit) on any of the windings, the motor is faulty and requires replacement. Also be sure to check the resistance between any contact and the copper tube of the housing (the copper should be stripped). There should be a “break” (infinity) here. If the device shows any value, it means there is a breakdown in the housing, and the operation of such a refrigerator is deadly.
Checking the starting capacitor
In some models of Stinol refrigerators, especially in two-compressor or more powerful versions, a starting capacitor may be present in the circuit. It helps the engine gain the necessary speed at the moment of start. If the capacitor has “dried up” or lost capacity, the motor will hum, twitch, but will not start.
The capacitor is usually mounted next to the relay or on the frame of the refrigerator. Visually inspect it: a swollen body, electrolyte leaks or deformation indicate the need for replacement. Even if it is externally intact, it is better to check its capacity with a special device or replace it with a known-good one of similar capacity (usually from 10 to 30 µF).
Replacing a capacitor is a simple process, but requires compliance with polarity (if the capacitor is electrolytic, which is rare for starting ones, they are more often non-polar). Cut off the old wires or unsolder them and attach the new element. Make sure that the wires do not touch hot parts of the compressor.
⚠️ Attention: Capacitors can retain a charge even after being unplugged. Before touching the contacts, close them with a screwdriver with an insulated handle to avoid electric shock.
Mechanical wedge of the compressor
There are cases when the electrical part is completely working: the relay is new, the windings ring, there is voltage, but the motor only hums a little seconds and then the protection relay clicks. This is a sure sign that the piston group inside the sealed casing has occurred. mechanical wedge piston group inside a sealed casing.
The causes of the wedge are varied: lack of oil, moisture entering the system, long-term simple or natural wear. Trying to start such a compressor in the usual way is useless and can completely kill it. There is a method of “wedging” by applying increased voltage, but doing this at home without experience and special equipment (like a pressure jack or a powerful transformer) is risky.
If you decide to try the “kick” method (short-term supply of voltage directly to the working and starting windings, bypassing the relay), do it extremely carefully. The feeding time should not exceed 3-5 seconds. If the engine doesn't jerk, it's most likely dead. In modern refrigerators with inverter compressors, such methods do not work at all.
Table of typical faults
For ease of diagnosis, we will summarize the main symptoms and probable causes in a single table. This will help you quickly navigate the situation and make the right decision about repairs.
| Symptom | Probable cause | Action | Difficulty |
|---|---|---|---|
| Silence, no reactions | No voltage, thermostat burnt out | Check socket and thermostat circuit | Low |
| Click, silence | Faulty starter relay | Replace relay | Low |
| Humming 5-10 sec, clicking | Compressor wedge or weak relay | Checking windings, replacement relay | Medium |
| Humming, does not start | Winding breakdown, capacitor | Ring the windings, check the capacitor | High |
| The motor is hot, does not work | Thermal protection has tripped | Let it cool, check the ventilation | Low |
As can be seen from the table, most problems can be solved by replacing inexpensive components. However, if the table indicates a breakdown of the windings or a wedge, repairs become economically feasible only if you have access to a free donor compressor.
Replacement and first start-up process
If the diagnostics reveal a faulty relay or capacitor, we proceed to replacement. Install the new parts into place, ensuring tight contact. The contacts must sit tightly on the compressor terminals, without play, otherwise there will be sparking and heating. Reassemble the structure in the reverse order.
Before plugging it into the network, check again to see if there are any unnecessary parts or tools left inside the case. Plug in the refrigerator. In the first seconds you will hear a characteristic startup sound. If the motor starts running smoothly, without vibrations or extraneous knocks, you can consider the task completed.
After starting, let the refrigerator run empty for about 30-40 minutes. Check the heating of the compressor housing. It should be warm or hot (up to 80-90 degrees), but not hot to the point where you can’t touch it. Also check the condenser grid at the back - it should warm up evenly.
What to do if the new compressor does not start?
If after replacing the relay or even the compressor itself there is no starting compressor, check that the wires are connected to the terminals correctly. An error in connecting the start and run windings can lead to humming and rapid heating. Also check if the new unit is jammed during transportation (rarely, but it happens).
Is it possible to start an old compressor without a relay?
Theoretically, you can apply voltage directly, artificially creating a phase shift, but this is a temporary “die-in” measure. Without the correct relay, the compressor will not work for long and will burn out. Using a circuit with a capacitor for continuous operation is possible, but the efficiency will be low.
Why does the Stinol compressor run for 2 minutes and turn off?
This is a thermal protection relay triggered. Reasons: overheating due to contamination of the condenser at the rear, a malfunction of the relay itself (opens the circuit too early) or a starting wedge of the compressor. Check the cleanliness of the radiator at the back.
Which compressor is better to install instead of the burnt one?
It is best to look for the original Danfoss or Aspera (former Danfoss), which were often installed on Stinol from the factory. What matters is the wattage (W or BTU) and the refrigerant (R134a or R600a). Switching to another type of freon requires a complete flushing of the system.
Is it necessary to vacuum the system when replacing the compressor?
Yes, definitely! If you change the compressor itself, the system will depressurize. Moisture and air getting inside will lead to the formation of acids and ice plugs. A vacuum pump and freon charging by scale are required.