EPA Section 608 Universal Certification ExamCoreMedium
A technician is evacuating a large system that uses R-407C. To ensure proper dehydration and removal of non-condensable gases, what is the recommended evacuation level for this type of system?
- A2000 microns
- B250 microns
- C500 microns
- D1000 microns
Show answer & explanationAnswer & explanation
Correct answer: C. 500 microns
For most refrigeration and air conditioning systems, including those using HFC refrigerants like R-407C, a deep vacuum of 500 microns (0.5 mm Hg) or lower is recommended to effectively remove moisture and non-condensable gases.
Why the other options are wrong
- A. 2000 microns is generally not deep enough for proper dehydration.
- B. While 250 microns is an even deeper vacuum, 500 microns is the standard minimum for effective dehydration.
- D. 1000 microns may be acceptable for some systems but 500 microns is the widely accepted standard for thorough dehydration.
Deep Vacuum Evacuation Level
The industry standard target for evacuating refrigeration and air conditioning systems to effectively remove moisture and non-condensable gases, typically 500 microns (0.5 mm Hg) or lower.
- Target is 500 microns (0.5 mm Hg).
- Removes moisture by lowering boiling point.
- Removes non-condensable gases.
- Essential for system efficiency and longevity.
Memory trick: Five hundred 'micro' reasons to go 'deep' with a vacuum.