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

A partially clogged capillary tube can cause a starved evaporator. This happens because a capillary tube restricts the flow of refrigerant into the evaporator coil. If the tube is partially clogged, it further limits the amount of refrigerant reaching the evaporator coil, leading to insufficient cooling capacity. This condition results in the evaporator not receiving enough refrigerant to absorb heat efficiently, causing a starved evaporator.

High head pressure, increased airflow, and an overcharged evaporator are not directly caused by a partially clogged capillary tube. High head pressure usually occurs due to issues with the condenser side of the system, while increased airflow can be a result of a different problem within the air handling unit. An overcharged evaporator would typically result from adding too much refrigerant to the system rather than a clogged capillary tube.