A technician is using an ultraviolet (UV) dye leak detection method on an R-134a commercial refrigerator. After adding the dye and allowing for circulation, what is the critical step to accurately identify leaks?

Question: A technician is using an ultraviolet (UV) dye leak detection method on an R-134a commercial refrigerator. After adding the dye and allowing for circulation, what is the critical step to accurately identify leaks?

Answer options:

• Immediately evacuating the system to see if the dye appears in the recovery cylinder.
• Cleaning the entire system exterior with a solvent to remove any existing oil residue. ✅ Using a UV lamp and yellow glasses to scan all potential leak points for fluorescence.
• Pressurizing the system with nitrogen and listening for a whistling sound.

Correct answer: Using a UV lamp and yellow glasses to scan all potential leak points for fluorescence.

Explanation: After adding UV dye and allowing it to circulate with the refrigerant and oil, the technician must use a UV lamp in a darkened area and wear yellow (or amber) glasses to enhance the visibility of the dye's fluorescence at leak points, making the otherwise invisible leak apparent.