The sudden stop of the refrigerator often confuses the owner, forcing him to guess about the causes of the breakdown and the cost of future repairs. The most common and expensive component, the failure of which paralyzes the entire system, is compressor. It is he who is responsible for the circulation of the refrigerant, creating the necessary pressure in the cooling circuit.
Before calling a technician or looking for a replacement unit, it is worth carrying out the initial diagnostics yourself. This will filter out simple faults, such as problems with the start relay or thermostat, from actual engine failure. The answer to the question of how to ring a compressor on a refrigerator lies in using a conventional multimeter and understanding the principles of operation of an electric motor.
The testing procedure does not require deep knowledge of electrical engineering, but requires strict adherence to safety rules. Incorrect actions can lead to electric shock or permanent failure of the equipment. In this article we will analyze in detail the algorithm of actions, resistance standards and signs indicating the need to replace the unit.
Preparation for diagnostics and safety measures
The first and most important step before starting any work is to completely disconnect the refrigerator from the electrical network. Unplug the cord as you will be dealing with exposed terminals and high voltage internal components. Even if the compressor is not working, a dangerous potential may remain on its contacts.
To carry out diagnostics, you will need a minimum set of tools: a multimeter (tester), a screwdriver and pliers. It is also recommended to prepare a clean rag to remove dust from the contacts. If you do not have a multimeter, you can purchase it at any electrical goods store or ask your friends, as this is a universal device for the home handyman.
⚠️ Attention: Before starting work, make sure that the room is dry and your hands are not wet. Working with electrical appliances in damp conditions is strictly prohibited and can be fatal.
Next you need to gain access to the technical area. In most modern models, such as Indesit or Atlant, the compressor is located in the lower rear part of the housing. Remove the protective cover by unscrewing the fixing screws and inspect the unit for external damage, melting or traces of burning.
Removing the starting relay and accessing the contacts
To ring the motor windings, it is necessary to release the contact group. At the end of the compressor there is a plastic box - a starting relay, to which the power cable fits. Carefully remove it, having previously photographed the position of the wires, so as not to confuse anything during assembly.
Under the relay you will see three contacts forming a triangle. These are the winding terminals: two working and one starting. In some models, for example Liebherr, the contacts may be hidden under additional insulation, which must be carefully pushed aside. Do not use excessive force to avoid breaking the fragile terminals.
After removing the relay, inspect the box itself. Inside there is a starting capacitor and a thermal release. It often happens that the motor itself is working properly, but the problem lies precisely in the sticking of the relay contacts. If you see blackening inside the relay or smell a burning smell, perhaps replacing this part will solve the problem without replacing the compressor.
Setting up a multimeter and checking the circuit
To check the integrity of the windings, you need to translate multimeter in resistance measurement mode. On the device, this mode is indicated by the Ohm symbol (Ω) or a sound signal (continuity). Select the measurement limit of 200 Ohms or 2 kOhms, since the winding resistance is usually in the range from 10 to 100 Ohms.
Before touching the compressor contacts, check the serviceability of the tester probes. Connect them together: the device should show zero or emit a beep. If the readings fluctuate or the device is silent, replace the battery or check the probe wires, otherwise the diagnosis will be incorrect.
Now you can start measuring. Attach the probes to the paired contacts on the compressor block. You need to get three resistance values between different pairs of contacts. Write down the numbers obtained, since it is their ratio that will indicate the condition of the engine.
Analysis of readings: normal, open and shorted
The obtained resistance values must be analyzed. For a serviceable single-phase motor, the sum of the resistances of the starting and operating windings should give a resistance between the extreme contacts. Typically, the resistance of the starting winding is 1.5-2 times higher than the working winding.
If the device shows one (infinity) in any of the sections, this indicates the break winding. It is impossible to restore such an engine at home; the compressor must be replaced. A break often occurs due to overheating or a manufacturing defect.
When the multimeter shows zero or a value close to zero, it can be diagnosed turn-to-turn short circuit. This is a more dangerous malfunction, which can lead to knocking out plugs in the apartment when trying to start. It is also critically important to check for breakdown on the housing.
Why is it important to check for breakdown?
If the insulation of the windings is broken, voltage can get to the metal body of the refrigerator. Touching such a unit is deadly, even if it seems to be turned off.
Checking for insulation breakdown (short circuit to the housing)
One of the most dangerous malfunctions is a short circuit of the winding to the metal housing of the compressor. To check this parameter, clean a small area on the unit body from paint to metal to ensure reliable contact.
Press one multimeter probe to the cleaned area on the body, and the second one in turn to each of the three contacts of the block. In good condition, the device should show infinity (one in the most significant digit). Any other values indicate an insulation failure.
If a breakdown is detected in the housing, operation of the refrigerator is prohibited. Even if by some miracle it starts, the risk of electric shock from touching the door or metal parts is too great. The table below shows approximate values for different conditions.
| Circuit condition | Multimeter readings | Actions | Probability of repair |
|---|---|---|---|
| Normal | 10-50 Ohm (working), 20-100 Ohm (starting) | Look for a problem in the relay or thermostat | High |
| Break | Unit (∞) for all within | Replacement of the compressor | Zero |
| Short circuit | Close to 0 Ohm | Replacement of the compressor | Zero |
| Breakage to the body | Any numerical value | Urgent replacement, life-threatening | Zero |
⚠️ Attention: Resistance values may vary depending on the model and manufacturer, for example, Bosch and Samsung they may differ. The main rule is the absence of zero and infinity in working pairs.
Additional diagnostics: thermal relay and current
If the electrical part of the engine is in order, but the refrigerator does not start, it is worth checking the thermal protection relay. It can open the circuit if it overheats. Call his contacts: they should be short calls. If the circuit is open, allow the relay to cool or replace it.
A more accurate diagnosis can be made using current clamps, if you have the ability to start the engine. The starting current should not exceed the rated value indicated on the compressor tag. Excess current indicates mechanical jamming of the piston group.
Sometimes the compressor hums, but does not start. This may be a sign of jamming. In some cases, short-term supply of increased voltage through a special device helps, but this method is risky and requires professional skills.
☑️ Diagnostic checklist
Replacement of the faulty compressor
If the diagnostics showed a break, short circuit or breakdown on the housing, the only solution remains replacement of the unit. This is a complex process that requires a vacuum pump, a pressure gauge station and skills in soldering copper tubes.
Independent replacement without special equipment is impossible, since the system must be absolutely sealed and free of moisture. An attempt to simply resolder the tubes without evacuation will lead to rapid failure of the new compressor due to the presence of air and moisture in the freon.
When choosing a new compressor, pay attention to the markings of the old one. The power, refrigerant type (R134a, R600a) and overall dimensions must match. An incorrectly selected unit will work ineffectively or will quickly break down.
Frequently asked questions (FAQ)
Is it possible to check the compressor without multimeter?
It is impossible to qualitatively check the windings without instruments. You can only visually assess the state of the relay and try to start the engine directly, but this is dangerous and does not provide accurate information about the state of the insulation of the windings.
Why is the compressor warm, but the refrigerator does not freeze?
This may indicate a freon leak or a clogged capillary tube. The engine idles, trying to build up pressure, but no coolant is circulating. It is also possible that the compressor itself is malfunctioning and does not create compression.
Which brand of compressors are considered the most reliable?
Units from the brands Secop (formerly Danfoss), Embraco and LG. However, reliability often depends on operating conditions and the stability of the network voltage.
How much does it cost to replace a compressor during a service?
The cost consists of the price of a new unit, the cost of soldering, vacuuming and refilling with freon. Depending on the region and model of the refrigerator, the price can vary significantly.
Is it dangerous to change the compressor yourself?
Yes, it is dangerous. You work with 220V electricity, hot solder and pressurized gas. An error may result in fire, explosion, or injury. Without experience and tools, it is better to entrust this to professionals.