Household appliances make life much easier for every busy person, but, unfortunately, they sometimes break down. And refrigerators are no exception. At one very unfortunate moment, a tried-and-true refrigerator suddenly breaks down.
It is well, if it has already served its time. But if the term of operation is still far from over, the best way out is to turn to certified masters of refrigerator repair with experience. However, in some cases, you can do it yourself.
Classification by the principle of action
To the unsophisticated user, it might seem that all refrigeration units are built approximately the same. However, this is far from being the case. There are three types of domestic refrigerators according to the principle of operation.
Before you start repairing your equipment, you need to know exactly how the refrigerator works. Therefore, let’s consider each of these types in detail.
The principle of compression refrigerators
To cool the chambers of the refrigerator in this case, a special liquid is used which is capable, under certain conditions, of changing from liquid to gaseous form and back at room temperature.
This is the so-called refrigerant. It is pumped into a closed circuit, moving through which it performs the cooling process. This happens in the following way. First, the refrigerant in liquid form is injected under pressure into the evaporator.
It is shaped like a coil to make the cooling process as efficient as possible. The part through which the refrigerant flows is called the nozzle.
In domestic equipment, it is a small piece of unprofiled capillary tube. In industrial models, where large capacities are required, profiled nozzles are used.
After the refrigerant enters the evaporator, it begins to expand rapidly, turning into a gas. It takes a certain amount of heat from the air, which corresponds to its heat of vaporization. Thus, the temperature in a well-insulated refrigerating or freezing chamber is lowered and everything inside is cooled.
The normal evaporation process will only continue until the pressure inside the evaporator rises. For this reason, the compressor continuously pumps out refrigerant vapor and delivers it to the radiator.
This is another coil inside which the gaseous refrigerant converts to liquid. As it does so, it releases heat into the air. Then the liquid is fed into the die and the cycle repeats. What are the advantages of this design? First of all, the efficiency is approaching 100%.
In addition, compression equipment is economical, efficient and easy to adjust. Absolutely safe and chemically neutral compositions are used as a refrigerant in such units. The main disadvantage is the presence of detachable joints, moving and rubbing parts.
In addition, the refrigeration circuit has mechanical connections with the external environment, which requires quality seals. There is another significant disadvantage.
The nuances of the absorption units
Absorption-type units are designed in a way similar to compression-type units. However, its main difference is the absence of rubbing or moving parts.
Let’s consider the principle of operation of such units. As a refrigerant, a light-boiling composition is used, which is well dissolved in a high-boiling liquid. The latter is called an absorber.
Similarly named is the container that contains a certain amount of concentrated refrigerant. From here it enters the thermopump, which is a vertically mounted tube of copper heated by an electric spiral.
Then the refrigerant moves to the steam generator, which is heated by an electric current. Here the refrigerant evaporates and mixes with the absorber vapor.
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The resulting mixture advances to the dephlegmator. This is a special design radiator, in which the absorber and refrigerant are separated. The former is condensed and goes to the steam generator, and the refrigerant gas goes first to the condenser and then by gravity to the evaporator.
Here, a cooling process similar to that of the compression units takes place. After that, the absorbed heat is sucked in by the absorber and the process repeats.
Thus, the main advantage of absorption models is practically unlimited life due to the absence of moving elements. However, they are not economical enough, because they consume about 1.5 times more energy than compression models.
In addition, such refrigerators freeze rather poorly and slowly. Another significant disadvantage is safety.
Here water is used as an absorber, and ammonia as a refrigerant. As a result, there is highly concentrated ammonia alcohol in the circuit. In the event of a possible leakage, this is dangerous. Models are available that run on isobutane or propane, but this is even more dangerous.
Considering that absorption units can be kept turned off as long as you want, they are willingly purchased for use in homes with seasonal occupancy.
Cold from semiconductor-type appliances
These are not widely used devices, the principle of operation of which is based on the Peltier effect.
It consists in the fact that the junction of dissimilar conductors when an electric current is passed through it in one direction heats up, and in the other – freezes, compensating the heating of the other side. In this way it is possible to get temperatures down to -104ºF and even lower.
However, the system has significant disadvantages. First of all, it has a high power consumption. It is much higher than that of low-economy absorption devices. In addition, Peltier elements have a limited service life.
At the same time, semiconductor refrigerators are not sensitive to mechanical influences, quickly and effectively freeze products. If necessary, the current direction can be switched, allowing the system to be defrosted quickly.
Self-repair: what you can and can’t do?
In order to repair your refrigerator and not permanently break it, you need to know exactly which parts of the system can be repaired yourself, and which it is better not to touch. There are four circuits in any refrigerator unit:
The refrigeration system. This includes the actual cooling circuit, including the coils. It is the least suitable for the self-repair part of the unit.
Masters strongly advise not to try to make repairs by yourself if you have no knowledge and experience in this area. Self-repair can be very expensive. Unqualified repair most often ends with the need to buy a new unit.
The system of thermoregulation. This is where most breakdowns occur. Repair is most often possible, but it is desirable to have experience in such works.
It should be understood that an independent repair will require spare parts, which are not always readily available. Most likely you will have to order them from a specialized online store and wait some time for delivery. For this reason, it may be a better solution to call a refrigeration repairman.
Mechanical system. Includes seals, shelves, lids, door and compressor hangers, and the like.
The repair itself is usually uncomplicated and can be done even by the most inexperienced home handyman. Usually it consists of adjusting the door, replacing the seal and fixing the shelves. Special knowledge is not required here.
The electrical system. Represents the electrical circuit that ensures the normal operation of the refrigeration unit. Includes wiring, starting relay, motor-compressor, etc.
It is quite repairable. You will need a tester, a soldering iron, and some knowledge of electricity. Almost any breakdown can be repaired with this system.
Common problems of refrigerators
Before diagnosing the problem, you should decide on the type of your refrigeration equipment.
Thermoelectric units rarely break down. The most common breakdown is when the thermocouple battery runs out of power. There is probably no point in replacing it, since its cost is quite comparable with that of the unit itself.
In addition to this, sometimes in such refrigerators the contacts get burnt, which can be repaired even by an inexperienced technician. Much more problems with compression models. If such a refrigerator does not work, there can be many reasons. Let’s talk about the most common ones.
If the device does not work when plugged in, perhaps the power supply circuit is “guilty”. This includes the socket, plug, power cord, split contacts in the compressor compartment. Perhaps the problem is in the protective relay or the thermostat. The latter should be “tested” with a tester to find out the cause. In case of breakage there will be no signal.
If the mains supply is fully operational and the compressor does not start or starts but immediately stops, the problem is most likely in the starting relay.
In almost the same situation with a functioning mains it takes three to five seconds to start the compressor or it does not start from the first attempt to start, you should look for a problem in the starting relay.
The unit freezes badly, but reacts properly to the signals of the thermoregulator. At the same time the compressor heats up, shakes, and overheat protection activates. Relays of thermal protection and start-up are fully functional.
The compressor motor winding should be diagnosed for inter-turn faults. If a fault occurs in the starter winding then the compressor will not start at all. However, the thermal protection and start relays will be intact. In both cases a replacement will be required.
Another malfunction. The unit is freezing very hard, and the compressor runs without interruption, or its operation is interrupted by the thermal protection device. The equipment practically does not respond to the thermostat, only turning the knob to the “0” position stops the compressor.
The latter makes much more noise than usual. At the same time, the meter shows that the electricity consumption is much higher than usual. All this indicates that the starting relay is jammed. This is quite a dangerous condition for the compressor, because it leads to its overheating and burning out.
If the unit freezes poorly, the refrigerator’s thermostat is set correctly. By the moment of disconnection of the compressor, the condenser is normally warmed up so that it is necessary to pull your hand away.
More often the problem is in a defective thermostat. It will have to be replaced. In some cases it is possible to repair it. The thermostat is also broken if the unit turns on, but freezes too weakly or strongly.
It does not respond to the position of the thermostat knob. At the same time the condenser heating and compressor hum is normal.
The unit operates on a short cycle, which is characterized by frequent switching off of the compressor. At that, it freezes badly, and the condenser does not have time to heat up properly at the moment of compressor switching off. The cause of such malfunction is breakage of the thermal protection relay or thermostat.
The equipment functions on a long cycle, sometimes even continuously. In the freezer, ice appears on the section of the refrigerant pipe. At the same time, there is no ice on the opposite side. The situation is stable and does not change.
The cause of malfunction in this case is refrigerant leakage. Most likely there is a micro-crack somewhere. The circuit should be diagnosed in order to find it and refill the system.
In some cases it is possible to refill the freon. This is not recommended to do it yourself. If the refrigerator does not freeze at all, the reason may be the lack of refrigerant in the circuit. In this case, when you turn it on, you will feel a strong vibration, the compressor will start banging and ringing when working.
The compressor cannot be repaired by itself. In some cases, repair work can cost more than a new unit, which should be taken into account.
The equipment only works on a short cycle and freezes hard. The sound of the compressor running is alarming. It is too loud, as if a crunching or sobbing sound.
The reason most often lies in unskilled maintenance of the unit. Too much refrigerant is being poured into the compressor, causing a more concentrated “fog” of freon rather than vapor.
This is extremely dangerous for the integrity of the tubes and compressor. It is therefore necessary to call a technician urgently. The unit is freezing too much. So much so that you have to set the thermostat to a position no higher than 4.
The compressor heats up quickly and makes a lot of noise, there may be a smell of melting insulation. This is caused by a loose bimetal plate located in the thermal protection relay.
Strong vibration, excessive compressor noise, but otherwise normal. It is necessary to check the compressor suspension and adjust it if necessary. If it did not help, then the reason is in its increased wear.
You will have to think about replacing the compressor. A freezer that freezes too much indicates problems with the tightness of the door or poor quality insulation. In the latter case, repair is extremely difficult or even impossible.
Basic diagnostics and simple repairs
Let’s look at the simplest operations to test your refrigerator. To begin with determining the quality of the mains voltage. It must strictly correspond to 110 V. Smaller values may cause failure in the operation of the unit.
It is necessary to inspect the mains plug with cord as well. There should be no bends, kinks or damage. If the elements are hot or sparking, this is a clear sign of trouble.
Check the compressor terminals, which must be in working order. After that, it is necessary to use a tester to check whether the device receives sufficient voltage from the mains.
After making sure that it is of proper quality, the unit must be unplugged. Now it is necessary to carefully inspect the compressor located at the bottom of the unit. There should be no visible damage here.
To check the winding, the tester is switched to ohmmeter mode. One end of the wire is attached to the tester, and then the leads are checked one by one. A paired diagnosis is also carried out. No movement of the tester arrow will indicate a shorted or damaged winding.
Next, the control circuits are checked. To do this, the wires are disconnected from the relay and shorted, and then check for contact between them and the power plug. The presence of such a contact indicates that the relay, cord and temperature sensor are serviceable.
If you find a problem, you will have to check each unit separately. To test the temperature sensor, remove it and disconnect the wires.
Then each of the wires should be checked, and if there is a short circuit, the detector is defective. It should be replaced. If the control circuit works normally, there are no breaks, the protection and start relays are checked.
To gain access you will have to remove the cover. With older models, it is mounted on latches, with newer models – on rivets. They must be carefully drilled out, and after inspection, fasten the cover with screws.
The most frequent failures of this unit are jamming of the spring or core in the coil, burning of the contacts or breakage of the rod. All of these can quite easily be corrected. To begin, the coil is removed from its latches, and the core and rod with contacts are removed from it.
Then all these elements are thoroughly cleaned. In the simplest cases, a soft cloth with alcohol impregnation will suffice. In more complex cases, it will be necessary to work with sandpaper or even a file to ensure free movement with the core. All contacts are also cleaned.
If it turns out that the rod is broken, which is often the case, since it is a rod of plastic, it can be replaced with a piece of an ordinary nail. After the repair, the assembly is assembled in the reverse order, put in place and connected.
It is not easy to repair your refrigerator yourself. It is a complex unit, the work with which requires special knowledge. An inexperienced technician is unlikely to be able to perform all the necessary repair work correctly and without mistakes.
Unfortunately, even small inaccuracies, not to mention large miscalculations can completely put the refrigerator out of operation. Then you won’t have to think about repairing it. You will need to look for funds to buy a new refrigerator.