Low-Pressure Refrigerant Recovery, Recycling, and Reclamation
Type III questions in this domain test whether you can choose the right recovery endpoint and distinguish recovery, recycling, and reclamation for low-pressure appliances-mainly chillers using R-11, R-123, R-113, or R-114. A low-pressure appliance is defined by the refrigerant’s boiling point being above 0°C at atmospheric pressure, not by the size of the equipment.
Core rules
- Recovery removes refrigerant from the appliance and stores it. Recycling reduces moisture, acid, and particulates so refrigerant can be reused; it does not restore full purity. Reclamation reprocesses refrigerant to AHRI 700 purity and must be done by an EPA-certified reclaimer.
- Before opening, servicing, or disposing of a low-pressure appliance, recover to 25 mm Hg absolute. That is about 1 inch Hg absolute, or roughly 25,000 microns-not 25 inches of vacuum and not 0 psig.
- Low-pressure refrigerant has little vapor pressure, so liquid recovery first, then vapor recovery, is usually fastest. Use recovery equipment and hoses rated for low-pressure refrigerants.
- Recovery cylinders must be DOT-approved, labeled for the refrigerant, and filled to no more than 80% by weight. Never rely on system pressure alone to move refrigerant; use a recovery machine.
- Mixed refrigerant cannot be recycled for reuse as a specified refrigerant; it must be reclaimed or destroyed. Reclaimed refrigerant must meet AHRI 700.
Worked example
A 600-lb R-123 chiller must be opened for an evaporator repair. The technician pulls vapor until the manifold reads 0 psig, then stops and opens the system. Is this acceptable? No. 0 psig is essentially atmospheric pressure; it is not the Type III endpoint. The technician must continue recovery with low-pressure-rated equipment until the appliance reaches 25 mm Hg absolute, then document the evacuation. Stopping at 0 psig leaves refrigerant in the shell and can cause a prohibited release when the system is opened.
Traps that cost marks
- Reading the rule as 25 inches Hg vacuum instead of 25 mm Hg absolute.
- Using a high-pressure recovery cylinder or machine without checking low-pressure compatibility.
- Calling on-site filtering “reclamation”; reclamation requires a certified reclaimer and lab-grade purity.
- Assuming recycled refrigerant is automatically acceptable for another owner’s equipment.
- Forgetting the 80% cylinder fill limit because the refrigerant is low-pressure.