A sudden stop in the operation of the refrigerator compartment or the appearance of a loud hum followed by a clicking sound often indicates a breakdown of the starting mechanism. Start relay is a small but critical component that supplies current to the compressor motor windings at the time of startup. If this element fails, the motor hums, but cannot start, and the food begins to deteriorate. Understanding how to properly dismantle this component is the first step to restoring the functionality of household appliances.
The process of removing the part requires care and compliance with safety regulations, since the work is carried out with electrical components and fragile elements of the cooling system. In this article, we will analyze an algorithm of actions that will allow you to safely remove the relay, check its condition and, if necessary, replace it with a new one. Important understand that even a simple replacement requires attention to the details of the design of your unit.
Before starting disassembly, you need to prepare the workplace and tools. You will need a flathead and Phillips screwdrivers, pliers, a diagnostic multimeter and possibly a contact stripper. Be sure to unplug the refrigerator 15-20 minutes before starting work so that the capacitors have time to discharge and the refrigerant in the system has stabilized. Ignoring this rule may result in electric shock or damage to the electronics.
Diagnostics of a faulty starting device
Before disassembling the equipment, you should make sure that the problem lies in the relay, and not in the compressor or thermostat itself. A characteristic sign of a faulty starter is a cyclic repetition of the process: the refrigerator turns on, there is a loud hum, then a click, and the unit goes silent again. This indicates that the engine is trying to start, but the starting winding does not receive the required impulse or the current exceeds the permissible limits, and the protection opens the circuit.
Visual inspection can also provide a lot of information. If you have already removed the casing and see blackening, melted plastic, or feel a burning smell coming from the black box on the compressor, then the diagnosis is complete - the element has burned out. However, sometimes there are no external signs, and then a deeper check using measuring instruments is required. Diagnostics helps to avoid purchasing unnecessary spare parts if the problem, for example, is a jammed compressor piston.
⚠️ Attention: If after removing the relay and checking the contacts you find that the motor shaft the compressor turns with great difficulty or does not turn at all when trying to start (check only for experienced technicians), replacing the relay will not help. In this case, complex repairs or replacement of the compressor itself will be required.
A frequent cause of failure is a voltage surge in the network or natural wear of the contact group. Over time, the contacts burn out, the resistance increases, which leads to overheating and destruction of the case. If your refrigerator is old, the probability of failure of this particular unit is more than 60% of all cases of motor failure.
Preparation for dismantling and access to the compressor
To begin work, it is necessary to ensure free access to the rear of the unit. Move the refrigerator away from the wall to a distance that allows you to freely approach the compressor compartment. In modern models, access may be blocked by a decorative panel, which must be carefully removed by unscrewing the fixing screws or releasing the latches. In older models, the compressor is often open, but covered by a metal casing.
Removing the metal casing is usually not difficult. It is secured with screws or special clamps. Use a screwdriver of the appropriate size to avoid stripping the threads. After removing the cover, you will have a view of the black cylindrical or pear-shaped compressor housing, copper condenser tubes and the very black box that we need to remove. Safety precautions requires that the work area be dry and light.
Pay attention to the location of the tubes. Copper lines are fragile, and their accidental bending or damage will lead to freon leakage, which will make further repairs economically impractical. Be careful not to lean on or pull on the tubes when removing the casing. If the casing fits tightly, do not use force, but check that all the screws are unscrewed.
☑️ Preparing the workplace
Algorithm for removing the relay from the compressor
The process of removing the start relay itself is as follows. On the side of the compressor you will see a protruding rod with three contacts, on which a plastic or black box is attached. This is our desired device. It can be attached simply due to the tight fit on the contacts or additionally fixed with a metal clamp-bracket.
If there is a fixing bracket, it must be carefully bent or removed. Do this with pliers or a thin screwdriver, being careful not to damage adjacent elements. After removing the retainer, the relay is held only by the contacts. Take the relay body confidently, but without excessive force, and swing it from side to side, pull it down. Contact group should come out of the compressor socket.
It is important not to pull on the wires going to the relay, as they may be soldered or have internal twisting, which can be easily damaged by jerking. You need to pull exactly on the body of the plastic block. If the relay sits very tightly, you can slightly pry it with a flat screwdriver between the compressor housing and the relay housing, using it as a lever, but with great care.
Disassembling and checking the removed element
After removing the device from its seat, it must be inspected. Often the relay is a composite structure: a housing, a starting coil, a thermal relay and a contact group. The case can be soldered or assembled with latches. If it is sealed, for internal diagnostics you will have to carefully open it with a knife or saw it, remembering that it will no longer be possible to assemble it back hermetically.
Inside you will see a copper coil, a movable core and contacts. The main sign of a malfunction is carbon deposits on the contacts or a break in the coil winding. Also check the thermal relay (bimetallic strip), which is often built into the overall design. It should close the circuit when cold and open when heated. Multimeter in the continuity mode it will help determine the integrity of the circuits.
To check the coil, switch the tester to resistance measurement mode. The normal resistance of the starting winding is usually several tens of ohms (depending on the model). If the device shows infinity (open circuit) or zero (short circuit), the part must be replaced. Also check whether the mechanical rod moves freely inside the housing and whether it is jammed by combustion products.
| Fault type | Symptom on the multimeter | Visual sign | Action |
|---|---|---|---|
| Breakage coils | Resistance infinity | Blackening, burning smell | Relay relay |
| Short circuit | Resistance close to 0 | Melted contacts | Replacing the relay |
| Sticking contacts | The circuit is constantly closed | Deposit on the contacts | Cleaning or replacement |
| Thermal malfunction | No circuit in cold state | Plate deformation | Element replacement |
Replacement and installation of a new starter
If the diagnostics confirmed a breakdown, purchase an analogue. The markings are usually applied to the body of the old relay. When installing a new element, ensure that the orientation is correct. There is often an arrow on the case with the inscription UP or TOP, which should look straight up. This is critical for proper operation of the thermal release and gravity starters.
The installation process is in reverse order. Push the new relay onto the compressor contact rod until it stops. Make sure it fits snugly and doesn't wobble. If there was a retaining bracket, return it to its place. Connect the wires to the terminals, following the color coding or diagram photographed before disassembly. Contact must be clean and tight.
It is recommended to conduct a test run before final assembly of the casing. Plug in the refrigerator and listen. The compressor should start with a characteristic sound, without prolonged buzzing or clicking. If the motor runs smoothly, let it run for 10–15 minutes, checking the heating of the relay housing. It may get warm, but should not be hot.
⚠️ Attention: Never leave the refrigerator turned on without the rear protective panel for a long time. This interferes with air circulation to cool the compressor and creates the risk of electric shock if moving or live parts are accidentally touched.
If you are faced with a situation where the new relay clicks, but the compressor does not start, there may be a deeper problem. This may indicate an interturn short circuit in the windings of the motor itself or a wedge in the mechanical part. In such cases, self-repair is often impossible without special equipment for overhauling the compressor.
Common mistakes during self-repair
One of the most common mistakes is ignoring cleaning the contacts. When installing a new relay on old, oxidized mating parts on the compressor, the contact may be unstable. This will lead to sparking and rapid failure of the new part. Always clean the contact pads on the compressor rod with fine sandpaper before installation.
Another mistake is using the wrong analogue. Externally, relays may be similar, but have different current characteristics. Installing a relay that is too powerful may result in it not opening the circuit when overloaded, which will burn out the motor winding. Installing a weak relay will cause constant false shutdowns.
Also, novice repairmen often forget to check the integrity of the wires going to the relay. Frayed insulation or a broken wire at the very entrance to the relay housing can simulate its breakdown. Carefully feel the entire wiring harness along its entire length. Wiring integrity —the basis for any electromechanical system.
Prevention and further operation
To extend the life of the new relay and compressor, Provide the refrigerator with correct operating conditions. The main enemy of technology is overheating. Make sure that the refrigerator is not close to the wall, but with a gap of at least 5-10 cm for free air circulation. Regularly, once every six months, vacuum the condenser (the black grille at the back), removing dust and animal hair.
Power surges in the network are also detrimental to starting equipment. If the lights in your home flicker frequently or there are interruptions, it is recommended to install a voltage stabilizer or at least a surge protector with protection. This will protect not only the relay, but also the electronic control board, if your model has one.
Make sure the door seals are tight. If the door does not close tightly, the compressor runs almost non-stop, trying to maintain the temperature. This mode of wear-and-tear operation quickly leads to overheating and failure of the starting elements. Regular checks seals and adjusting the hinges will help avoid this problem.
How long does the starting relay last on average?
Average period The service life of a high-quality relay is 5–10 years. However, if there are frequent power surges or operation in overheated conditions (clogged capacitor, high room temperature), it may fail within 2–3 years. The resource directly depends on the number of on-off cycles of the compressor.
Is it possible to start a refrigerator without a relay?
Theoretically, you can start the motor by applying voltage directly to the working and starting windings, but this is dangerous and requires qualifications. Without a protective relay, the compressor will be left without protection from overheating and jamming, which will lead to its combustion in a few minutes. Operation without a relay is prohibited.
Why does a new compressor hum after replacing the relay?
The hum can be caused by several reasons: vibration of the tubes (you need to bend them away from the body), incorrect installation of the relay (not fully put on), or a malfunction of the compressor itself (bearings, valves), which is not possible when replacing the relay eliminated. A hum is also possible due to water hammer if oil has entered the system.
Where can I find the relay markings?
The marking is applied to the side or top edge of the plastic relay housing. It shows the model number, voltage, frequency and current characteristics. If the inscription is erased, you will have to look for an analogue by the model of the compressor itself (indicated on the metal tag on the motor housing) and the model of the refrigerator.