Which statement describes the correct measurement unit for vacuum in a vacuum service test?

Which statement describes the correct measurement unit for vacuum in a vacuum service test?

• A. 18 Inches
• B. 20 Inches
• C. 22 Inches
• D. 24 Inches

Answer: (C)

Vacuum is read in inches of mercury (inHg), which tells you how much pressure has been removed from the system. For a vacuum service test, there’s a minimum vacuum you must achieve to pass. A common passing target is 22 inches of mercury, meaning the gauge should read a vacuum of 22 inHg. Readings lower than that (18 or 20) don’t meet the requirement, while a higher reading (like 24) exceeds the minimum but the standard value used for the test is 22 inches. So, the statement describing the correct measurement is 22 Inches.

Vacuum is read in inches of mercury (inHg), which tells you how much pressure has been removed from the system. For a vacuum service test, there’s a minimum vacuum you must achieve to pass. A common passing target is 22 inches of mercury, meaning the gauge should read a vacuum of 22 inHg. Readings lower than that (18 or 20) don’t meet the requirement, while a higher reading (like 24) exceeds the minimum but the standard value used for the test is 22 inches. So, the statement describing the correct measurement is 22 Inches.