Oklahoma Service Technician Practice Exam

A hissing sound or ice buildup on coils is a common and definitive indicator of a refrigerant leak. When refrigerant escapes from the system, it can create an audible hissing noise as it escapes under pressure. This sound is particularly noticeable in areas where the refrigerant lines are exposed, signaling that the system is not maintaining the proper refrigerant level required for efficient operation.

Additionally, refrigerant is essential for absorbing heat from the indoor air and returning to the system to be cooled again. If there is a leak, the system may not have enough refrigerant to function properly, leading to a drop in temperature around the evaporator coils. This drop in temperature can cause moisture in the air to freeze on the coils, resulting in ice buildup. Ice accumulation further reduces the system's efficiency and indicates a malfunction that needs to be addressed, typically related to refrigerant levels.

While increased energy bills, unit overheating, and frequent system shutdowns can also indicate problems within an HVAC system, these issues do not specifically point to a refrigerant leak as clearly as the hissing sound and ice buildup do. Those symptoms could be reflective of a range of issues not directly related to refrigerant levels.