ABYC Air Conditioning & Refrigeration Certification Practice Exam 2026 - Free Practice Questions and Study Guide

Icing on evaporator coils is a common indication of an internal blockage in refrigerant flow. When the refrigerant cannot flow properly through the system, it often results in insufficient heat absorption at the evaporator coils. This leads to a drop in temperature, causing moisture in the air to freeze on the coils. The accumulation of ice further impedes airflow and can exacerbate cooling issues within the system.

The presence of ice on the evaporator coils is a direct symptom of a restricted refrigerant path, which could be caused by issues such as a clogged filter drier, a blocked expansion valve, or other obstructions. Recognizing this sign allows technicians to diagnose and address the root cause of the blockage, ensuring efficient operation of the air conditioning system.