How does UV dye leak detection work and what color indicates a leak under UV light?

How does UV dye leak detection work and what color indicates a leak under UV light?

• A. Dye is added to the refrigerant; under UV light, the dye fluoresces at leak sites, typically showing a bright yellow-green glow to indicate a leak.
• B. Dye absorbs heat and changes color to blue.
• C. Dye is added; leaks turn red under UV.
• D. UV light evaporates dye; no color change.

Answer: (A)

The main idea is using a fluorescent tracer dye that makes leaks visible under UV light. A UV-reactive dye is added to the refrigerant so it travels with the refrigerant through the system. If there’s a leak, the dye exits at the leak site and, when you shine UV light, it fluoresces and produces a bright glow. The common result is a bright yellow-green glow at the leak, providing high-contrast visibility that helps locate even small leaks. This works because the dye is designed to fluoresce under UV (blacklight) illumination, not because the dye changes color with heat or because UV light evaporates it. Other color changes or red outcomes described don’t reflect how UV leak detection is intended to work, where the visible sign is the fluorescence at the leak site.

The main idea is using a fluorescent tracer dye that makes leaks visible under UV light. A UV-reactive dye is added to the refrigerant so it travels with the refrigerant through the system. If there’s a leak, the dye exits at the leak site and, when you shine UV light, it fluoresces and produces a bright glow. The common result is a bright yellow-green glow at the leak, providing high-contrast visibility that helps locate even small leaks.

This works because the dye is designed to fluoresce under UV (blacklight) illumination, not because the dye changes color with heat or because UV light evaporates it. Other color changes or red outcomes described don’t reflect how UV leak detection is intended to work, where the visible sign is the fluorescence at the leak site.