Recovery machine and cylinder compatibility for A2L refrigerants

What the EPA requires of a recovery machine

Under 40 CFR 82.158, nobody may make or import recovery equipment for appliance service unless it is certified by an approved testing organization. Since January 1, 2017 the rule covers equipment used with any class I or class II refrigerant or any non-exempt substitute, which includes the HFC and HFO A2Ls.

Machines made or imported on or after January 1, 2017 are certified under one of two appendices:

• Appendix B3: non-flammable refrigerants, based on AHRI Standard 740-2016.
• Appendix B4: flammable refrigerants, based on both AHRI 740-2016 and UL 1963 Supplement SB, Requirements for Refrigerant Recovery/Recycling Equipment Intended for Use with a Flammable Refrigerant.

For a flammable refrigerant, the certification route is Appendix B4. Machines made earlier were certified under Appendix B1 (ARI 740-1993, for equipment made from November 15, 1993 to September 21, 2003) or B2 (ARI 740-1995, to the end of 2016); the rule ties Supplement SB only to Appendix B4.

UL 1963 itself has been revised. Intertek’s standards update notice for the March 25, 2021 revision (effective March 25, 2024) adds requirements for equipment intended for refrigerants with a flammability class above 1, and hose assembly requirements under Supplement SB for refrigerants in classes 2L, 2 and 3.

What OEMs and tool makers say

• Carrier, 50FE R-454B instructions: “All service equipment or components must be A2L refrigerant rated. Do not use non-A2L rated equipment or components on R-454B refrigerant equipment.”
• Rheem/Ruud, RP17AY R-454B instructions: recovery and recycle equipment, pumps and hoses must have pressure ratings suitable for R-454B. The recovery equipment must be “suitable for the recovery of the A2L refrigerant,” and the manufacturer should be consulted if in doubt.
• Appion, A2L technical bulletin: the G5Twin and G1Single “are compatible to use with A2L refrigerants,” with training and precautions required.
• Fieldpiece, MR45 manual: designed to recover “most CFC, HFC, HCFC, and some HFO refrigerants that have an A1 or A2L flammability rating only,” and warns “Do not use with hydrocarbons (HC).”

The last point catches people out. An A2L rating does not make a machine suitable for R-290 or R-600a. Check the manual for the refrigerant list before connecting to any flammable system.

Recovery cylinders

Rating and type

Rheem specifies recovery cylinders with a 400 psig service pressure rating, DOT 4BA400 or DOT 4BW400, for R-454B. Worthington’s recovery cylinder spec sheet lists its 30 and 50 lb cylinders as DOT-4BA at 400 psig service pressure (800 psig test), and its larger cylinders as DOT-4BW.

How much to put in

Worthington gives the limit as: maximum allowable gross fill weight = 0.8 × water capacity × specific gravity of the recovered refrigerant at 77°F (25°C) + cylinder tare weight. The water capacity and tare are stamped on the cylinder. The specific gravity changes with the refrigerant, so a cylinder’s capacity in pounds of R-454B is not the same as its capacity in R-22.

Fieldpiece tells users to make sure the cylinder will not go past 80% full during the job, or to have a second cylinder ready, and to avoid overfilling “by following refrigerant manufacturer’s filling instructions and using a weight scale.” Put the cylinder on a scale for every recovery.

Labeling and marking

Worthington’s A2L recovery cylinders have left-hand threads and a red stripe to mark the A2L designation. Its standard recovery cylinders follow AHRI Guideline K: gray with a yellow collar. See refrigerant cylinder colors.

Rheem requires cylinders designated and labeled for the recovered refrigerant, with a pressure relief valve and shutoff valves in good working order. Empty recovery cylinders should be evacuated, and cooled if possible, before recovery. Fieldpiece says to evacuate empty recovery cylinders to 29.6 in Hg before use.

One refrigerant per cylinder

Rheem: “Do not mix refrigerants in recovery units and especially not in cylinders.” Fieldpiece says to match the cylinder to the system’s refrigerant and to avoid cross-contamination.

Required evacuation levels

The refrigerant’s flammability does not change the target. 40 CFR 82.156 Table 1 sets the level by pressure class and charge size. R-32 and R-454B systems are high-pressure appliances. The levels below are for recovery equipment made or imported on or after November 15, 1993.

Inches of Hg vacuum are relative to a standard atmosphere of 29.9 in Hg. The technician must verify the level has been reached before opening the system. These are recovery levels, not the triple-evacuation or micron targets used before charging; see evacuation microns.

Precautions during A2L recovery

Appion and Fieldpiece list similar precautions. Together:

1. Set up a temporary flammable zone with a 3-meter perimeter. Fieldpiece also says to identify and disable all ignition sources in it and to provide at least 5 air changes per hour.
2. Post “No Smoking” and “Do Not Enter” signs (Appion) and keep a CO2 or dry powder extinguisher in the work area.
3. Monitor the air with a flammable refrigerant leak detector.
4. Plug in the recovery machine and other equipment outside the flammable zone.
5. Ground or bond the machine, tank, hoses and system to prevent static. Fieldpiece specifies a grounding strap from the machine outlet to the tank’s unpainted fitting.
6. Do not reset the machine’s circuit breaker unless power has been removed or the area is free of ignitable concentrations (Appion).
7. Disable and lock off power to the system being serviced (Appion).
8. Do not mix A2L refrigerant with air. Use an evacuated DOT recovery tank, and if the system has a suspected leak, stop recovery at 0 psig so air does not enter the tank (Fieldpiece).
9. After recovery, purge the system with oxygen-free dry nitrogen before opening it. Never use compressed air or oxygen.
10. Stay with the machine while it runs (Fieldpiece).

Rheem’s service sequence for A2L systems is: recover, purge the circuit with inert gas (optional for A2L), evacuate (optional for A2L), flush or purge continuously with inert gas when using a flame to open the circuit, then open the circuit.

Quick check before you connect

• Machine certified and labeled for A2L (and for the specific refrigerant, per its manual).
• Hoses rated for the system pressure: Rheem calls for 800 psig service-rated hoses on R-454B.
• Cylinder DOT 4BA400 or 4BW400, marked for the refrigerant, evacuated, on a scale, with room under the 80% limit.
• Leak detector suitable for A2L running, ignition sources cleared, extinguisher at hand.