A compressor breakdown is one of the most critical situations that a refrigeration equipment owner may encounter. It is this unit that is the heart of the system, ensuring the circulation of refrigerant and maintaining a low temperature in the chambers. If you notice that the unit has stopped freezing, but there is light inside and the fan (if there is one) is working, most likely the problem lies in the electrical circuit of the engine.
Before proceeding with dismantling and checking, you must clearly understand the structure of the unit. Atlant refrigerators equipped with reliable piston compressors, which, despite their long service life, are subject to wear and tear Often it is not the motor itself that fails, but the start-protection relay or thermostat. Correct diagnostics will allow you to avoid purchasing an expensive new unit if the old one can still be revived.
In this article we will look in detail at exactly how the compressor is connected, which wires are responsible for what, and how to safely check the functionality of the system. It is important to observe safety precautions, since work is carried out with electric current and refrigerant under pressure.
Design and principle of operation of the compressor unit
The compressor in refrigerators of the brand Atlant is a sealed block, inside of which there is an electric motor and a piston group. The electrical part is located at the bottom of the unit and is covered with a plastic casing. This is where the connection point to the 220 Volt network is located.
The main elements of the electrical circuit are the working and starting stator windings, as well as the starting system. Modern models often use starting relay an induction type or a posistor, which supplies a pulse to the starting winding only at the moment of start. After the rotor accelerates, the circuit opens and the engine operates only on the working winding.
What is the difference between an inverter compressor and a conventional one?
Inverter models do not operate in cycles (on-off), but constantly regulate power. Their connection diagram is more complicated and requires a special control module that converts alternating current into direct current.
In addition, a thermal protection relay is necessarily included in the circuit. It opens the contacts when the windings overheat or excessive current consumption, preventing the motor from burning out. Understanding the interaction of these components is necessary for correct connecting wires.
Necessary tools and safety measures
Working with electrical equipment requires strict adherence to the rules. Before you remove the casing and begin manipulating the wires, you must completely turn off the power to the refrigerator. Unplug the plug from the socket and make sure there is no voltage.
⚠️ Attention: Never touch live parts with wet hands. When checking the operation of the compressor under voltage, use dielectric gloves and tools with insulated handles.
To carry out the work, you will need a standard home handyman's kit. It includes screwdrivers (Phillips and flathead), side cutters or a knife for stripping insulation, a multimeter for continuity testing of circuits and, possibly, electrical tape or heat shrink to restore contacts.
☑️ Checking readiness for repair
It is also worth preparing a container for draining the oil if you plan to open the system, although this is not required when simply replacing the relay or checking the contacts. The main thing is to provide free access to the bottom of the unit, where the motor is located.
Connection diagram and color coding of wires
The most important stage is the correct identification of contacts. On the refrigerator compressor housing Atlant there are usually three terminals covered with a dielectric block. They can be arranged in a triangle or in a row. On some models, the marking is applied directly on the metal case next to the terminals.
The standard marking is as follows:
- 🔴 R (Run) — working terminal, connected to the working winding.
- ⚪ S (Start) — starting terminal, goes to the starting winding through relay.
- ⚫ C (Common) - common output to which phase or zero is supplied (depending on the circuit).
However, you should not rely only on letters, since over time the paint may wear off. In Atlant refrigerators, color coding of the wires running from the relay to the compressor is often found. The red wire usually goes to the starting winding, white or black to the working winding, and the yellow-green wire is the case ground.
Incorrect connection of the terminals can lead to humming of the motor without starting, overheating and eventual combustion of the windings. Therefore, rechecking the circuit before applying voltage is a mandatory procedure.
Diagnostics and continuity testing of windings with a multimeter
Before thinking about how to connect a new compressor, you need to check the condition of the old one. Often the problem lies in a broken internal circuit. To diagnose, remove the plastic cover from the back of the motor to gain access to the contacts.
Set the multimeter to measure resistance (Ohms). Touch the probes to the contacts in pairs. Normal readings for compressors Atlant vary within the following limits:
- 🔍 Between common and working contacts: from 10 to 30 Ohms.
- 🔍 Between common and starting contacts: from 30 to 50 Ohms.
- 🔍 Between working and starting: the sum of the two previous values.
If the device shows infinity (break) or zero (short circuit), the compressor is faulty and requires replacement. It is also important to check that there is no breakdown in the housing. Press one probe against the cleaned area on the body (scratches), and touch each of the three contacts with the other. The multimeter should show infinity.
The table below shows typical resistance values for popular models of compressors installed in Atlant refrigerators:
| Compressor model | Resistance R (Operating) | Resistance S (Startup) | Status |
|---|---|---|---|
| CKK60NL2.10G | 18.5 Ohm | 42.0 Ohm | Normal |
| FK8.12GZ | 14.2 Ohm | 35.6 Ohm | Normal |
| NL10FT | 22.0 Ohm | 48.5 Ohm | Normal |
| Faulty | ∞ (Infinity) | ∞ (Infinity) | Break |
The obtained data allows you to accurately determine the integrity of the electrical part of the engine. If everything is in order with the windings, but the motor does not start, the problem may be a mechanical jam or a malfunction of the starting relay.
Replacing the starting relay and connecting a new compressor
If the diagnostics showed that the motor itself is working, but does not start, most often the start protection relay is to blame. This device fits directly onto the compressor terminals. To replace it, you do not need to unsolder the tubes and release freon, which makes the procedure accessible to beginners.
Remove the old relay by disconnecting the wires. Pay attention to the orientation: there is a marking UP or an arrow pointing up on the relay body and on the compressor terminals. Installing the relay upside down will result in failure to start or burnt out contacts.
⚠️ Attention: When installing a new relay, make sure it fits snugly on the compressor contacts. Poor contact will cause sparking, heating and repeated failure.
If a complete replacement of the compressor is required, the process becomes more complicated. It is necessary:
- ❄️ Pump out the remaining refrigerant (only by a licensed specialist).
- 🔥 Unsolder the copper tubes of the condenser and evaporator from the old motor.
- 🔧 Install a new compressor, observing the angles of inclination (usually not more than 40 degrees).
- 💨 Evacuate the system and charge it with freon.
Independent soldering and refilling require special equipment and skills. An error in the amount of refrigerant or the presence of moisture in the system will lead to the former breakdown of a new expensive unit.
Typical mistakes during self-repair
When trying to restore the operation of the refrigerator with their own hands, enthusiasts often make mistakes that can be fatal for the equipment. One of the most common is ignoring the state of the capacitor (if it is in the circuit) or using a relay from a different model.
Relays from refrigerators of other brands may have a different cutoff current. If the response threshold is too high, the relay will not turn off the starting winding, and it will burn out in a few seconds. If it’s too low, the motor will constantly click without starting.
Grounding is also often forgotten. The compressor housing must be grounded. In old apartment wiring there may be no grounding, but inside the refrigerator the yellow-green wire must be securely screwed to a metal frame or a special screw on the motor housing.
Is it possible to start the compressor directly without a relay?
Technically, it is possible by applying 220V to the working winding and briefly to the starting winding. But this is dangerous and ineffective. Without thermal protection, the motor will burn out when jammed, and without proper timing of the starting pulse, it can simply hum.
Another mistake is incorrect connection of the wires. Twists in household electrical appliances, especially when the refrigerator vibrates, oxidize and heat up over time. Use terminal blocks or high-quality soldering with insulation.
Frequently asked questions (FAQ)
How many wires should go to the Atlant compressor?
Usually three main wires (phase, neutral, ground) plus wires from thermostat. Inside the relay, the circuit may be more complex, but at the input to the motor there are three of them: for the starting winding, for the working winding and the common one.
Why does the compressor hum but does not start?
This is a classic sign of a faulty starting relay or a jammed piston group. It is also possible that there is a voltage drop in the network or a break in the starting winding.
Is it possible to change the compressor to an analogue from another company?
Yes, it is possible if the overall dimensions, power (or cooling capacity) and type of refrigerant are the same. However, it is better to look for original spare parts or certified analogues for Atlant.
Is it necessary to vacuum the system when replacing the relay?
No, when replacing only the start relay, you do not need to open the freon circuit. Evacuation is required only when the system is depressurized (replacing the compressor, filter drier or repairing leaks).
What tool is needed to unscrew the nuts on the tubes?
To unscrew the nuts on copper tubes, special adjustable wrenches or open-end wrenches of the appropriate size are required (usually 10, 12, 14 mm). It is important not to tear off the edges of the soft nuts.