The heat exchange process that takes place at the evaporator coil is central to the air conditioning process. To ensure that this process is as efficient as possible, manufacturers usually use copper to make air conditioner coils. This is because it is a good conductor of heat -- something that makes it easier for the refrigerant to absorb heat from the air that passes over the evaporator coils.

The formation of ice on the surface of evaporator coils usually reduces the efficiency of an air conditioner. This is because ice is a poor conductor of heat and hence its presence in the evaporator coil area is bound to reduce the efficiency of the heat exchange process. This may then lead to increasing energy bills. Here are common causes of this air conditioner problem.

Dirty air conditioner filters

The ample supply of air to the evaporator coil area is necessary not only because it helps to ensure that there is enough air to be cooled by the evaporating refrigerant, but also because it helps to keep the area's temperature from dropping below the freezing point. This is because the incoming air is warm. Having enough of it is usually necessary to counteract the cooling effect of the refrigerant.

Air filters work by trapping dirt and dust particles. The continued accumulation of these particles usually ends up clogging the filters, something that then limits the amount of air that they can let into the air conditioning system. This eventually reduces the amount of warm air that is available in the evaporator coil area hence the icing of the coils.

To prevent this airflow-triggered icing problem, simply clean your filters with a damp piece of clothing. Replacing the filters after every 3 months will also help to reduce any chances of air filter problems and is thus advisable.

Faulty thermostatic expansion valve

In order for cooling to take place at the evaporator coil, the refrigerant has to evaporate. Making sure that the pressure in the evaporator coil is low usually helps to make the evaporation process as efficient as it should be. The thermostatic expansion valve usually helps to regulate the rate at which the refrigerant enters the evaporator coil. This usually allows it to guarantee the low pressure that is necessary for an efficient cooling process.

However, if the thermostatic valve is clogged, or faulty, it can cause the pressure in the evaporator coil to drop to abnormally low levels. This will then lead to extreme temperature drops that will then cause air moisture to not only condense, but also freeze and hence causing coil icing problems.

Thermostatic expansion valve icing problems are usually solved by having the valve replaced. For more information, contact Smedley & Associates, Plumbing, Heating, Air Conditioning or a similar company.