Automotive Service Excellence (ASE) Air Conditioner Certification Practice Exam 2025 – Your All-in-One Guide to Exam Success!

The primary function of a thermal expansion valve (TXV) in an air conditioning system is to regulate the flow of refrigerant into the evaporator. This component plays a critical role in maintaining the efficiency and effectiveness of the A/C system.

The TXV adjusts the amount of refrigerant entering the evaporator based on the cooling demand, which is determined by the temperature of the refrigerant that leaves the evaporator. By doing so, the TXV ensures that the evaporator operates at optimal capacity, enabling proper heat absorption and efficient cooling of the cabin air. This regulation helps prevent issues like flooding the evaporator with too much refrigerant or not allowing enough, both of which can lead to decreased system performance and potential damage.

Understanding this function highlights the importance of the TXV in the A/C system's overall operation. While other components may handle different aspects of the system, the TXV's capacity to intelligently control refrigerant flow directly impacts the system's ability to provide comfort inside the vehicle.