HVAC 403A Practice Exam 2026 – All-in-One Guide to Master Your Certification!

Infrared-based leak detection relies on spotting temperature differences on equipment surfaces. When refrigerant escapes, the released gas often cools the surrounding area due to rapid evaporation and expansion, creating a distinct cold spot. An infrared camera then converts these temperature variations into a visual thermal image, allowing you to see and pinpoint the leak quickly from a distance. This non-contact method is popular because it can scan large areas fast and doesn’t require disassembling equipment, making it practical for spotting leaks across coils, pipes, and fittings. Dye tests and pressure testing don’t use infrared signals—dye tests rely on colored markers visible under UV light, and pressure tests identify leaks by changes in pressure rather than thermal signatures. Electronic leak detectors are specialized sensors for certain refrigerants but don’t provide the broad thermal imaging that infrared cameras offer.