How is a Freon container checked for proper pressure?

• A. By weighing the container to determine charge
• B. A chart must be used to determine the maximum and minimum gauge pressure readings based on the ambient temperature
• C. By a simple gauge reading at room temperature only
• D. By listening for a hiss when opened

Answer: (B)

Freon pressure inside a cylinder depends on temperature, not a fixed value. To tell if the charge is right, you don’t rely on a single reading or a guess from room temperature. Instead you read the cylinder’s pressure with a gauge and compare it to a refrigerant-specific pressure–temperature chart that gives the acceptable minimum and maximum gauge pressures for the current ambient temperature. If the reading falls within that range, the charge is considered proper for that temperature; if not, the system is either undercharged or overcharged. Weighing the container or listening for a hiss doesn’t provide a reliable or Quantitative check of the correct charge, so the chart-based comparison is the correct method.