EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Easy
A technician is evacuating a low-pressure chiller before charging. The primary purpose of dehydrating the system to a deep vacuum is to remove:
- ARefrigerant oil and sludge
- BExcess refrigerant charge
- CNon-condensable gases and moisture
- DMetal shavings and debris
Show answer & explanationAnswer & explanation
Correct answer: C. Non-condensable gases and moisture
The primary purpose of evacuating a refrigeration system to a deep vacuum is to remove non-condensable gases (like air) and moisture. Both can cause significant operational problems, including increased head pressure, corrosion, and formation of acids.
Why the other options are wrong
- A. Refrigerant oil and sludge are typically removed by flushing or filter-driers, not primarily by vacuum.
- B. Excess refrigerant charge is removed by recovery, not by evacuation to remove contaminants.
- D. Metal shavings and debris are removed by flushing or filters, not by vacuum.
Deep Vacuum Dehydration Purpose
The main objective of evacuating a refrigeration system to a deep vacuum, specifically to eliminate harmful contaminants.
- Removes non-condensable gases (e.g., air).
- Removes moisture (water vapor).
- Prevents high head pressure, corrosion, acid formation.
- Essential for system efficiency and longevity.
Memory trick: Vacuum deep, air and water flee, clean system's what we want to see.