Evaporator coil icing is a problem that can lead to increased energy bills. This is because the presence of ice on the surface of the air conditioner's evaporator coil will serve as a layer of insulation. It will then reduce the efficiency with which the refrigerant absorbs heat through the copper walls of the evaporator coil. The effect of this is that the air that will be leaving the evaporator coil area won't be as cool as it should be, something that will eventually cause your air conditioner to work harder and longer in order to make your home comfortable.
The thermostatic expansion valve and the cooling process
In order for cooling to occur, the liquid refrigerant has to change into a gas. This process, which takes place in the evaporator coil, is usually accompanied by an absorption-of-heat process that is responsible for the cooling effect necessary for air conditioning.
The fact that the air conditioner's refrigerant is great at easily changing from a liquid to a gas and then back to a liquid usually helps to ensure that the cooling process is flawless. However, to improve the efficiency of the conversion process and the magnitude of the resultant cooling effect, turning the evaporator coil area into a low pressure region is a must. This is where the thermostatic expansion valve comes in handy.
The thermostatic expansion valve does the job of controlling the rate at which the liquid refrigerant enters the evaporator coil area. By doing so, it usually ensures that the pressure at the evaporator coil region is low enough to guarantee that the conversion of the liquid refrigerant into a gas is not only efficient, but also that it has the maximum effect so far as cooling the warm air is concerned.
A malfunctioning thermostatic expansion valve and coil icing problems
The thermostatic expansion valve can get clogged or stuck. It can also be defective in such a way that it just doesn't allow the right amount of refrigerant to get through at a given time. This usually has the effect of causing the pressure in the evaporator coil region to drop to abnormally low levels. As a result, the cooling effect that results from the conversion process is usually so extreme that it not only causes the air moisture to condense, but also causes the resulting moisture to freeze. This is what eventually leads to evaporator coil icing complications.
Coil icing problems that result from a malfunctioning thermostatic expansion valve are usually solved by simply replacing it. In such cases, contacting a qualified air conditioner contractor, like one from Daniel's Heating Air & Plumbing Inc, is recommended.