Why R-410A recovery has its own quirks

R-410A is a near-azeotropic blend of R-32 and R-125 in a 50/50 mass ratio. Unlike R-22 (an azeotrope), R-410A exhibits a measurable temperature glide of about 0.3 °F as it evaporates and condenses across its saturation curve. That glide changes how a technician must perform liquid recovery, how the cylinder should be filled, and how the recovered refrigerant is sampled for reuse.

R-410A also runs at much higher discharge pressures than R-22 — typically 400 to 550 psig in operating equipment versus 200 to 275 psig for R-22. That means you need equipment rated for the higher pressures and cylinders rated for the higher pressures (PSIG of 400 minimum for the working pressure side, with a 50 percent overfill margin).

The required evacuation levels

Under §82.156(a) for Type II appliances (high-pressure, which includes R-410A), recovery requires:

• Liquid recovery to a pressure of 10 psig before switching to vapor.
• Vapor recovery down to 0 psig gauge, then a standing vacuum of 10 inches Hg (or -14.7 psig).

Or, if your recovery machine is rated to evacuate to the required level, you can pull the appliance into the recovery cylinder to 0 psig and stop there if the appliance contains less than 200 pounds of refrigerant. For appliances with 200 pounds or more, the rule is stricter: 15 inches Hg vacuum, with a 5-minute standing test to confirm no refrigerant remains.

The exam question you'll see most often is the order of operations: always pull liquid first when possible, then vapor, then confirm with a vacuum. Reversing the order wastes time and risks pushing liquid into a compressor not designed to handle it.

Step-by-step recovery procedure

1. Verify cylinder condition. Check the cylinder hydrostatic test date, ensure it is DOT-rated for R-410A pressures, and confirm it is within its tare-weight allowance. R-410A cylinders are typically colored pink or rose for clarity, but color alone is not a regulatory indicator — the label is.

2. Connect with proper hoses. Use hoses rated for R-410A working pressure. Attach the recovery machine's liquid line to the appliance's liquid service port and the vapor line to the vapor service port.

3. Open the cylinder valve and purge hoses. Run the recovery machine briefly with the appliance valves closed to evacuate air from the hoses. Closing the valve before disconnecting prevents moisture ingress.

4. Recover liquid first. Open the appliance liquid service valve. Run the machine in liquid recovery mode until the appliance pressure drops to 10 psig or the recovery cylinder reaches 80 percent of its net weight.

5. Switch to vapor recovery. Close the liquid service valve, open the vapor service valve, and continue pulling vapor until the appliance gauge reads 0 psig.

6. Pull the required vacuum. Switch the recovery machine to its evacuation mode and pull the system down to 10 inches Hg. Close the cylinder valve, shut off the machine, and watch the gauge — the vacuum must hold.

7. Cap and label. Tag the cylinder with the refrigerant type, the recovery date, the appliance from which it was recovered, and the technician's certification number.

Sampling matters

Because R-410A has glide, the composition in the recovery cylinder can fractionate if it sits for weeks. AHRI 700 sampling requires a liquid sample drawn from a temperature-stabilized cylinder, not a vapor sample. If you intend to reuse the recovered R-410A in another appliance — even after on-site recycling — a failed purity test (typically moisture, acid, or non-condensables) means the cylinder goes to a reclaimer, not back into service.

Common exam traps

• Confusing the evacuation requirement (10 inches Hg for under 200 lb) with the 500-micron standing vacuum test (which is a leak-check tool, not a recovery endpoint).
• Forgetting that liquid recovery requires a liquid port and is faster, but vapor recovery is mandatory at the end to capture the residual refrigerant held in the oil.
• Thinking the cylinder can be filled to 100 percent — under DOT rules the limit is 80 percent by weight for nonflammable refrigerants at 70 °F to allow for thermal expansion.

A closing note

Done correctly, recovery is fast and clean. Done wrong, it contaminates the cylinder, misrepresents your service record, and risks a fine of up to $44,540 per day per violation under the 2024 adjusted civil penalty schedule. Use the right equipment, follow the §82.156 sequence, and document everything.