To what level must a high-pressure appliance containing 210 lbs of R-407C refrigerant be evacuated?

• A. 15 inches of vacuum
• B. 20 inches of vacuum
• C. 10 inches of vacuum
• D. 5 inches of vacuum

Answer: (C)

For a high-pressure appliance containing 210 lbs of R-407C refrigerant, the evacuation level must reach 10 inches of vacuum. This specific requirement is aligned with EPA regulations designed to minimize the potential for refrigerant contamination and environmental harm. When evacuating a system to this level, technicians ensure that as much of the refrigerant as possible is removed from the system, which helps prevent leaks and preserves the integrity of the refrigerant. The 10 inches of vacuum is typically sufficient to remove non-condensables and moisture, which can affect system performance and efficiency.

Selecting a higher vacuum level, like 5 inches, may not adequately ensure the removal of harmful contaminants, whereas levels like 15 or 20 inches would be excessive and may not provide additional benefits in the context of R-407C. This is why 10 inches of vacuum is the correct evacuation standard for compliance with EPA protocols for high-pressure appliances.