To what level must an appliance containing more than 200 pounds of R-410A be evacuated before repair?

The correct evacuation level for an appliance containing more than 200 pounds of R-410A before repair is to achieve a vacuum of 10 inches of Hg. This level of evacuation is important for ensuring that all refrigerant is removed from the appliance, which prevents potential environmental harm and allows for safe maintenance or repair work.

Achieving 10 inches of mercury vacuum helps remove moisture and non-condensable gases from the system. Moisture can mix with refrigerants and create acids, which can corrode the system and lead to further failures. Therefore, reaching this specific vacuum level ensures the system is adequately prepared for service, promoting both safety and efficiency in repair operations. In contrast, higher vacuum levels, such as 30 inches of Hg, are not typically necessary or practical for standard industry practices regarding R-410A evacuation procedures.