When a mini fridge is not cooling, much like a standard size refrigerator, it needs to be diagnosed to see if the problem is big or small.
From fixable problems to the end of the life span for the refrigerator, it is important to diagnose it properly before throwing in the towel.
Some of the many reasons a mini fridge may not be running properly could be due to an issue in the sealed system, a failed compressor, failed evaporator fan motor, condenser fan motor, or a thermostat. Other issues could range from evaporator coils, start relays, the control board, or a restriction in the drier filter.
First Step is Listening to the Compressor
The first step in diagnosing a failing mini fridge is to slide the unit out and carefully listen for the sounds the compressor may or may not be making.
If the Compressor is Running
The job of the compressor is to compress the freon and push that freon into the condenser.
If the first step determines that the compressor is running, then the refrigerator could have a faulty sealed system.
The sealed system consists of the compressor, evaporator, and condenser. The job of the condenser is to cool the gas after flowing through the compressor.
If the compressor is running, then the condenser could be restricted, or a capillary tube attached to the condenser could have a tiny leak.
The evaporator is an important piece of the sealed system that evaporates the freon to produce a cooling effect.
It is connected directly to the condenser by the capillary tube. If the capillary tube is not leaking, then the evaporator could have gone out.
Sometimes, mini fridges, like their bigger counter parts, have evaporator coils. Just like the condenser coils, these coils can also go out.
However, it is important to research whether the refrigerator has these coils.
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Some mini fridges have a freezer box as opposed to evaporator coils, eliminating the potential for faulty evaporator coils.
If the particular model mini fridge does have evaporator coils, they could have frosted over and frozen, leaving them non-functional.
However, if this happens again and again, there is a more serious problem causing this to happen.
Finally, after checking the coils, condenser and evaporator, the problem could lie within the compressor itself.
Some of these compressors just wear out from hours and years of use. A replacement compressor can run upwards of $300, so it may be better to replace the entire machine if the compressor has failed.
If the Compressor is Not Running
Things are generally more complicated in a mini fridge if the compressor is not running.
The sealed system described about can generally be easy to diagnose. If a compressor is not running at all, a completely different approach must be taken.
The start relay is equivalent to the ignition of an automobile. It starts the compressor over and over.
When a person hears a click on a refrigerator, followed by a motor sound, this means that the start relay has just started the compressor.
If there are no audible clicks when the mini fridge is plugged in, then chances are the start relay has failed.
It would need to be replaced in order to start the compressor. Luckily, these can usually be purchases for around $30 or less.
It is important to remember that if the audible clicks are present, the issue is with the compressor or another part of the sealed system (not the start relay).
Sometimes the temperature thermostat can fail, and no power will be sent to start the compressor.
When the temperature gets above a certain point, the temperature thermostat should be able to sense this and start the compressor.
Unfortunately, these can be very pricey and rather difficult to wire in.
Newer models of mini fridges have something called a control board. The control board is like the “brain” of the refrigerator.
It can help to save power, dial in a specific temperature number, and even do a power cool cycle if the door has been open too long.
These control boards are found on newer models with more user programmable settings.
If the control board goes out, the compressor will not start. Usually, these are not worth replacing as it is one of the most expensive parts of the mini fridge. They can run upwards of $150.
The final scenario is that the compressor can be very hot and making no sound. In this case, the compressor has gone out.
As mentioned above, a compressor can easily run upwards of $350 and many not be worth the replacement cost.
If the Compressor is Running but the Unit is Not Cold Enough
If the compressor on the mini fridge is running, the unit can be cool but not where a person would like it. In other words, the refrigerator should be colder inside.
When this happens, a common culprit could be an evaporator fan motor.
It is important to remember that not all mini fridges come with an evaporator fan motor. A person should research this and see if their unit is equipped with one.
Evaporator Fan Motor
The problem with an evaporator fan motor failing is that the air circulation will be limited or none at all. This can cause the problem of having cool air, but not cold air.
Another issue could be the condenser fan motor. Like the evaporator fan motor, not all refrigerators are equipped with a condenser fan motor.
It should be researched to see if this issue could even be present.
Faulty Condenser Fan Motor
When the condenser fan motor (if equipped) fails, then the compressor will be struggling because the heat will not be exchanged properly.
As mentioned earlier, the job of the compressor is to compress the freon and push it in to the condenser.
If the condenser and the compressor are unable to exchange heat properly due to a fault condenser fan motor, then the mini fridge will never be able to get cold like it was designed.
Partially Restricted Drier Filter
Finally, a drier filter could be to blame. A drier filter is located in the sealed system, and its job is to filter freon from compressor oil, as well as water condensation.
A partial restriction in the drier filter could prevent the freon from moving quickly enough to cool the fridge.
While sort of complicated, the main thing to understand about a refrigerator or a mini fridge is the vocabulary. From compressors, to condensers, to evaporators, to coils, there are many different working parts involved. It is important for a person to be able to distinguish the difference in the parts to be able to begin diagnosing the problem.
The compressor is the “backbone” of sorts of any refrigerator. The reason for this is that without gases being compressed, none of the other parts would work or have a purpose. Also, the compressor is the loudest part on a refrigerator.
The reason it is recommended to start the diagnostic procedure by listening for compressor sounds is because whether or not it is running, certain issues could be overruled. It can be challenging and frustration to try and work on a refrigerator without knowing what part is what.
With a little bit of common sense and some understanding of vocabulary, mini fridges can often be successfully repaired. It is recommended that if the machine is still covered under warranty to call the company and see about repair or replacement.
If the mini fridge is no longer under warranty, then things get more difficult. Using the guide from above is a good place to begin troubleshooting.
An important recommendation is to look up the price of the broken parts. Some of these parts can be very expensive, and may not be worth it to replace. The reason for this is because often times a new refrigerator could be more cost effective than replacing the part.
It is also important to take in to consideration how many model years old the fridge is. If it is an older machine, the needed parts may not be produced any longer. In this case, it is usually recommended to properly dispose of the older machine and purchase a new one.
Anytime a mini fridge or any refrigerator is to be looked at and worked on, it is a good idea to take proper safety precautions. The machine should always be unplugged, and sometimes electrically discharged. The process for doing this can usually be found in the owner’s manual.
When troubleshooting a fridge, it is important to remember where each part, nut, bolt, and screw was located; this will save plenty of time and hassle later on.