ESCO Air Conditioning Practice Exam 2025 - Free AC Certification Practice Questions and Study Guide

A rise in evaporator pressure directly influences the function of an automatic expansion valve, which is designed to regulate the flow of refrigerant into the evaporator based on pressure changes. When the evaporator pressure increases, it indicates that there is a higher amount of refrigerant in the evaporator or that the refrigerant is absorbing heat more effectively.

In this scenario, the automatic expansion valve responds to the increase in evaporator pressure by closing or reducing its opening. This action helps to limit the amount of refrigerant entering the evaporator in order to maintain a consistent pressure and prevent flooding, which could lead to inefficient operation and potential damage to the system. By controlling refrigerant flow, the valve helps maintain optimal conditions within the evaporator, enhancing overall system performance and efficiency.

The remaining options do not accurately describe the action of the valve in response to rising evaporator pressure, demonstrating that the valve is specifically designed to close when the pressure increases to prevent excessive refrigerant flow.