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TECH | Recovery or Evacuation?

 November, 22nd 2017     Comments     Views

By Randy Petit Sr., Esco Group

When a technician removes refrigerant from a system, is he or she evacuating the system, or recovering the refrigerant? 

A couple of the definitions for Evacuate are: to remove the contents of, or to create a vacuum in. 

In the HVACR world, we normally referred to evacuate as the process to remove non-condensable and moisture from a system by pulling a deep vacuum of 500 microns or more. EPA on the other hand uses the term to describe the level of recovering refrigerant from a system.

What does this mean? Persons taking the Section 608 of the Clean Air Act certification exam must carefully read the questions and not misinterpret what is being asked. There are questions that cover knowledge of the recovery process and levels, and those that refer to system evacuation of air and moisture. They may both use the term evacuate.

When developing questions for the new exams we tried to make it clear and concise as to what a question is referring to “Evacuation or Recovery.” The good news is that, as far as I know, all of the questions for EPA Required Level of Evacuation of Appliances refer to recovery equipment manufactured after 1993.

The EPA has redefined appliances into four categories. The types are based on a refrigerants condensing pressure for its liquid phase temperature at 104°F/40°C. There are now four types; Very High, High, Medium, and Low pressure appliances. 

  • Very high-pressure - saturation pressure above 340psig/ 355psia at 104°F.
  • High-pressure - saturation pressure between 155psig/170psia and 340psig/355psia at 104°F.
  • Medium-pressure - saturation pressure between 30psig/45psia and 155psig/170 psia at 104°F.
  • Low-pressure - saturation pressure below 30psig/45psia at 104°F.

Over the next several weeks, I will continue to monitor updates to keep you apprised of the changes. I will share these in posts in the HVACR Educators Group where they can be accessed at your leisure, at Also, visit for more information.