When using recovery or recycling equipment manufactured after November 15th, 1993, to make a major repair, you must evacuate a system containing more than 200 lbs of CFC-12 to what vacuum?

• A. 10 inches of Hg vacuum
• B. 15 inches of Hg vacuum
• C. 20 inches of Hg vacuum
• D. 25 inches of Hg vacuum

Answer: (B)

When performing a major repair on a system containing more than 200 lbs of CFC-12 (a refrigerant), it is essential to achieve a proper vacuum level to ensure safe and effective recovery of refrigerants and to prevent environmental contamination. The requirement to evacuate the system to at least 15 inches of mercury (Hg) vacuum is based on industry standards intended to minimize residual refrigerant in the system, thus reducing the likelihood of releasing it into the atmosphere.

Achieving a vacuum level of 15 inches of Hg ensures that most of the CFC-12 has been removed and that there is minimal refrigerant left in the system before opening it up. This practice is vital for compliance with environmental regulations outlined by the EPA, as refrigerants can be harmful to the ozone layer and contribute to global warming.

Other vacuum levels like 10 inches, 20 inches, or 25 inches of Hg would either be insufficient for completely evacuating the system (in the case of 10 inches) or not standard practice for this specific scenario (in the case of 20 and 25 inches). Therefore, achieving a vacuum of 15 inches of Hg is the recognized and required standard for systems with CFC-12 in this context, ensuring compliance with