What are the symptoms of a failing expansion valve?

The symptoms of a failing expansion valve commonly include fluctuating cooling performance and possible icing on the evaporator coil. The expansion valve's primary role is to regulate the flow of refrigerant into the evaporator coil to ensure proper cooling. When it begins to fail, it can either allow too much or too little refrigerant to pass through. This inconsistency leads to fluctuations in temperature, causing the cooling performance to vary significantly.

Moreover, when there is too much refrigerant due to a failure in the valve's ability to modulate flow, the evaporator coil can become too cold, resulting in a buildup of ice. Icing occurs because the excess refrigerant cools the coil beyond its intended operating temperature, causing moisture in the air to freeze on the surface. This phenomenon disrupts the heat exchange process, exacerbating the cooling performance issues.

In contrast, while constant noise can indicate various issues within the unit, and increased energy bills could stem from many factors unrelated to just the expansion valve, and a refrigerant leak is a separate concern that would manifest in distinct symptoms. Thus, understanding how the expansion valve functions and the effects of its failure is crucial for diagnosing related issues in an air conditioning system.