The refrigerator has stopped freezing, and you hear strange clicks or, conversely, deathly silence instead of the usual hum? Most often, the cause of a breakdown is the motor, which is the heart of the entire cooling system. You can understand how to determine whether a refrigerator compressor is working or noton your own if you know the sequence of actions and safety measures. Don’t rush to call a technician or buy new equipment - often the problem lies in small things that can be easily fixed.
Primary diagnostics begins long before you pick up the tools. Careful observation of the behavior of the unit can provide up to 70% of information about the condition of the unit. If you notice that the starting relay clicks frequently, but the motor does not start, this is a sure sign that the system is trying to start, but is encountering an obstacle. In other cases, the unit may hum, but not create cold, which indicates an interturn short circuit or a wedge of the piston group.
Before proceeding with a detailed check, make sure that the refrigerator is disconnected from the power supply. Working with electricity requires extreme caution and compliance with all safety standards. Any manipulations with wiring or internal components should be carried out only after the device has been completely de-energized.
⚠️ Attention: If you smell burning or see sparking in the motor area, immediately stop any attempts at self-repair and call a specialist.
Visual inspection and initial diagnosis
The first stage of verification does not require complex equipment and is accessible to every user. Carefully inspect the back wall of the refrigerator where the compressor unit is located. Pay attention to the condition of the wiring, the absence of melted areas and the integrity of the insulation. Often compressor malfunction accompanied by visible signs of overheating or mechanical damage.
Evaluate the temperature of the motor housing. If the refrigerator has been left turned off for several hours and the motor housing remains hot, this may indicate a recent malfunction or short circuit. Normal refrigeration unit when idle it should be at room temperature. Also check for traces of oil on the tubes - freon leakage often goes hand in hand with motor problems.
Plug in the device and listen. If you hear a humming noise that ends abruptly with a click, and this repeats several times, it means the starting system is not coping. This is a classic symptom when motor windings is intact, but the trigger mechanism or the motor itself cannot overcome the resistance. In rare cases, the motor can operate absolutely silently, which indicates a break in the power circuit.
Checking the starting relay and contacts
Before sinning on the motor itself, it is necessary to rule out a malfunction of the starting relay. This small block is responsible for supplying voltage to the windings at the time of start. If the relay is stuck or fails, the compressor will not start, even if it is fully operational. Remove the protective casing and carefully remove the relay from the motor contacts.
Visually inspect the insides of the relay for carbon deposits, melted plastic or oxidation of the contacts. Shake the relay next to your ear - if you hear a knock inside, it means the mechanism is destroyed. For a more accurate check, you can use a multimeter in dial mode. The resistance must correspond to the standard indicated on the case or in the technical documentation for your model Indesit or Bosch.
Also check the contacts on the compressor itself. The three pins coming out of the housing must be clean, free of oxides and signs of corrosion. If the contacts are oxidized, they can be carefully cleaned with fine sandpaper, but you must act extremely carefully so as not to damage the insulation.
☑️ Diagnostics of the start relay
Testing the windings with a multimeter
The most reliable way, how to determine whether a refrigerator compressor is working or not - this is checking the resistance of the windings using a multimeter. To do this, remove the start relay and protective cover to gain access to the three motor contacts. Switch the tester to the resistance measurement mode (Ohms) to a limit of 200 Ohms.
You need to ring the contacts in pairs. Typically, the terminals are marked on the diagram or case: common (C), starting (S) and working (R). The resistance between the common and working contacts should be minimal, between the common and starting contacts - slightly higher, and between the working and starting contacts - total. If the device shows infinity (break) or zero (short circuit), compressor winding the compressor winding has burned out.
Pay special attention to checking for breakdown of the housing. Press one multimeter probe to any contact, and the second to the copper tube or metal motor housing. The device should show infinity. If you see any resistance value, it means that there is a current leak to the housing, which is life-threatening and requires replacing the unit.
| Pair of contacts | Normal resistance (Ohm) | What does deviation mean |
|---|---|---|
| Common - Working | 10–25 Ohm | Open or short circuit |
| Common - Start | 20–40 Ohm | Starting winding malfunction |
| Worker - Starter | The sum of the two is higher | Violation of circuit integrity |
| Contact - Housing | Infinity (∞) | Insulation breakdown (dangerous!) |
⚠️ Attention: When testing, touch the probes only with plastic handles. The metal part of the probes should not touch your fingers, so as not to distort the readings of the device.
Measuring current consumption at start-up
If the continuity of the windings shows the norm, but the motor still does not start, it is necessary to measure the current strength. To do this you will need current clamps. This method allows you to understand whether electric motor the current is consumed and whether it is mechanically jammed. The normal operating current depends on the power of the motor and usually ranges from 0.3 to 1.5 Amperes.
Connect the refrigerator to the network through a current clamp, covering one of the power wires. At the moment of startup, the current may jump briefly, but then it should stabilize. If the clamps show a current significantly higher than the rated current (for example, 3-5 Amps and above), and the machine immediately knocks out or the protection is triggered, it means that an interturn short circuit has occurred in the windings.
In the case when the current consumption is zero, but there is voltage at the input to the compressor, this indicates an internal open circuit, which may not have been detected during the initial test due to thermal contact. If the current is normal, the motor hums, but does not turn, a mechanical wedge of the piston group is likely.
What is an interturn short circuit?
An interturn short circuit is a violation of the insulation between the turns of the electric motor winding. This leads to a sharp increase in current consumption, overheating and rapid failure of the unit. It is impossible to rewind the compressor at home.
Signs of a mechanical wedge and wear
A mechanical wedge is a situation when the piston group gets stuck and cannot perform reciprocating movements. This can be determined by the characteristic sound: the engine tries to start, hums for a few seconds, then there is a click of protection and silence. The cycle is repeated regularly.
Sometimes it is possible to force the motor to “unwedge” by applying voltage directly to the working winding, bypassing the starting relay. However, this method is risky and requires experience. If after a short-term voltage supply the motor does not jerk, it means the jam is serious. In modern models with inverter motors, such diagnostics are impossible without a special tester. Also, increased noise and vibration during operation can be a sign of mechanical wear. If the compressor is running but making clunking or knocking noises, the bearings may be broken or the springs inside the casing may be loose. In such cases LG or Samsung With inverter motors, such diagnostics are impossible without a special tester.
Increased noise and vibration during operation can also be a sign of mechanical wear. If the compressor is running but making clunking or knocking noises, the bearings may be broken or the springs inside the casing may be loose. In such cases compressor repair it is not economically feasible, a complete replacement is required.
Specifics of diagnostics of inverter models
Modern refrigerators are increasingly equipped with inverter compressors, which operate on the principle of frequency conversion. Check such a motor with a conventional multimeter or by supplying 220V directly absolutely not. This will lead to instant burning of the expensive control board or the motor itself.
Diagnostics of inverter systems requires a special tester that simulates the operation of the control board. Without such equipment, you can only check the integrity of the windings for breaks or breakdowns to the housing, but you will not be able to assess the performance of the electronics. Often in inverter models it is the board that breaks, but the motor itself remains intact.
If your refrigerator marked Inverter does not turn on, first check the voltage at the input to the control board. No power may be caused by wiring problems or power surges. Self-repair of inverter units is only possible for qualified engineers with an oscilloscope.
⚠️ Attention: Inverter compressors are sensitive to voltage surges. Use a stabilizer to extend the life of the complex electronics of the refrigerator.