To ensure an evacuation is complete, what vacuum level should the system be evacuated to?

Evacuating a refrigeration or HVAC system to a specific vacuum level is critical for removing moisture and non-condensable gases, which can significantly affect the performance and longevity of the system. The correct vacuum level to achieve is 500 microns.

At this level, it is generally accepted that the majority of moisture and any contaminants have been successfully removed from the system. Lower levels, such as 200 microns, are often used in more specialized applications where absolute dryness is necessary, but for standard residential and light commercial systems, reaching 500 microns is usually sufficient to ensure that the system is ready for charging with refrigerant.

If the system is evacuated to a higher micron level, such as 1000 or 1500 microns, this indicates that moisture may still be present, which could lead to system problems such as acid formation, freeze-ups, or decreased efficiency. Therefore, evacuating to a vacuum level of 500 microns strikes the right balance between thoroughness and practicality for most HVAC applications.