It is at the evaporator coil area that the liquid refrigerant changes into a refrigerant gas. This change of state is central to the air conditioning process simply because it is what allows the refrigerant to absorb heat from the air passing over an air conditioner's evaporator coil.
The fact that the evaporator coil plays such an important role in the air conditioning process makes it possible for a homeowner to tell whether there is a problem with various parts of the air conditioning system simply by examining the evaporator coil area. Here are some of the defects that you can detect by simply looking at the evaporator coil area.
Air filter problems
All the air that passes over the evaporator coil has to first pass through the air conditioning system's air filters. When they are in good shape, these filters usually trap dust and mold particles, something that then reduces the rate at which dirt accumulates over the evaporator coil.
When an evaporator coil gets covered with dirt almost immediately after cleaning, chances are that a homeowner is dealing with worn-out air filters. Replacing these filters is therefore necessary if your want to restore your air conditioning system's efficiency.
Refrigerant leak problems
If the copper tubing that makes up the evaporator coil gets punctured, it will leak the refrigerant. If there is a significant enough leak, you will be able to see refrigerant stains around the area of the leak.
The refrigerant that is used in air conditioning systems is usually recycled. Therefore, the most common cause of an air conditioning system refrigerant undercharge is a refrigerant leak. One of the main symptoms of low refrigerant is icing at the evaporator coil region.
Evaporator coil icing usually happens mainly because when the system is low on refrigerant, the pressure at the evaporator coil will drop to extremely low levels. This has the effect of causing extreme temperature drops at the evaporator coil area that not only causes condensation, but also results in the freezing of the formed condensate. Therefore, if you notice that ice has formed on your system's evaporator coil, chances are that you are dealing with a leak in one of the pipes or air conditioner parts that handle the refrigerant.
Thermostatic expansion valve problems
The thermostatic expansion valve usually determines how much of the liquid refrigerant enters an air conditioning system's evaporator coils. If the valve is stuck, dirty or frozen, the amount of refrigerant that it releases into the evaporator coil of your air conditioner will be too little to maintain the normal operation pressure. The resulting drop in pressure will then lead to extreme low temperatures at the cooling coil area than may then cause ice formation at the coils. Therefore, if you on inspection you find that your coils are covered with ice, there is a chance that your system has a defective thermostatic expansion valve that needs to be replaced. In such a case, calling an air conditioning company as soon as possible is advisable.