Air Conditioning Repair Certification (ETI) Practice Exam 2025 – Your All-in-One Guide to Success!

The thermostatic expansion valve (TXV) plays a crucial role in air conditioning systems by regulating the flow of refrigerant into the evaporator. It does this by adjusting the flow based on the temperature of the refrigerant within the evaporator. The primary function of the TXV is to ensure that the evaporator operates at the optimal temperature for efficient heat absorption. When the evaporator temperature rises, indicating that more cooling is needed, the TXV opens up to allow more refrigerant to flow through. Conversely, if the temperature drops, the valve restricts flow to prevent flooding the evaporator with too much refrigerant.

This temperature-sensing mechanism helps maintain a consistent cooling performance and prevents issues such as refrigerant starvation or flooding of the evaporator. Although other factors like condenser temperature, ambient pressure, and refrigerant type have their importance in an air conditioning system, they do not dictate the flow adjustment of the TXV directly. Instead, the evaporator temperature is the key variable that the TXV relies upon for its operation.