Refrigerant Recovery, Recycling, and Handling
Core concepts
Recovery removes refrigerant from a system; recycling cleans it for reuse in the same equipment; reclamation restores it to specification for resale. Know which machine does what, and that recovery cylinders must be DOT-approved, labeled, and never filled above 80% by weight. Understand recovery rates, the need to recover from both high and low sides, and why non-condensable gases (air) must be purged from the recovery cylinder.
Handling and contamination
Candidates must recognize moisture and acid as the two great enemies. Moisture forms ice at the expansion device and combines with refrigerant/oil to create acids that attack the system; filter-driers and proper evacuation address this. Deep vacuum (evacuation to a specified micron level) removes moisture and non-condensables before charging. Know how to identify refrigerant by identifier or manifold gauge behavior, and never mix refrigerants - mixed refrigerant becomes hazardous waste. Recognize that R-1234yf systems require dedicated, often sealed, service equipment to avoid cross-contamination.
Traps and a worked rule
Common traps: confusing recovery with reclamation; assuming a full cylinder is safe; forgetting to recover before opening a circuit; and ignoring that a system under vacuum can draw in air and moisture if left open. Rule of thumb: a recovery cylinder should never exceed 80% of its water capacity by weight, so weigh the cylinder before and during recovery rather than trusting the gauge alone.
Worked example
A 30-lb water-capacity cylinder weighs 20 lb empty. Maximum refrigerant = 0.80 × 30 = 24 lb, so stop when total weight reaches 44 lb (20 lb tare + 24 lb refrigerant). Exceeding this risks hydrostatic rupture.