How to recover refrigerant

Before you connect

Yellow Jacket’s YJ-LTE guide: “Know the type and quantity of refrigerant present before servicing any system.” Fieldpiece’s MR45 manual adds: match the recovery cylinder to it. If in doubt, identify the refrigerant first. Then check:

1. The machine is certified and suits the refrigerant. Machines made on or after January 1, 2017 are certified under Appendix B3 (non-flammable) or B4 (flammable) of 40 CFR 82.158. Each carries a permanent certification label. Check the manual’s refrigerant list too: the YJ-LTE guide says “Do not recover flammable refrigerants such as R-290, R-600 or R1234yf,” and the MR45 is rated for A1 and A2L refrigerants only. See recovery machine compatibility.
2. The method is allowed. System-dependent (passive) recovery may not be used on appliances with a full charge over 15 lb unless it is a permanently attached pump-out unit (82.156(e)).
3. You have enough cylinder capacity for the whole charge (below).

Required recovery levels

Before opening an appliance (other than small appliances, MVACs and MVAC-like appliances) or disposing of it, recover the refrigerant, liquid included, to the levels in 82.156 Table 1:

Inches of Hg vacuum are measured from a standard atmosphere of 29.9 in Hg. Pressure classes are defined in the 608 certification guide; residential R-22, R-410A and R-454B systems are high-pressure. You may recover only the part being serviced if its refrigerant can be isolated in a system receiver. Either way, the technician must verify the level has been reached before opening.

Exceptions in 82.156(a):

• Non-major repair, system not being evacuated to atmosphere afterward: medium-, high- and very-high-pressure appliances only need to be at 0 psig or lower before opening. For oil changes the limit is 5 psig.
• Leaks make the level unreachable: isolate leaking from non-leaking parts where possible and take the non-leaking parts to Table 1. Take leaking parts as low as you can without substantially contaminating the refrigerant, and never above 0 psig.
• Small appliances (82.156(b)): with a machine made on or after November 15, 1993, recover 90% of the charge if the compressor runs or 80% if it does not, or pull to 4 in Hg vacuum.

EPA’s 608 test topics add: after reaching the vacuum, wait a few minutes. A pressure rise means liquid is still in the system or the oil, so keep recovering. These levels are not the micron targets used before charging; see evacuation microns.

Prepare the recovery cylinder

• Right cylinder, labeled: a recovery cylinder (gray with a yellow top under AHRI Guideline K) rated for the refrigerant’s pressure and marked for that refrigerant. A2L cylinders: see cylinder colors.
• Evacuated: Fieldpiece says to evacuate empty recovery cylinders to 29.6 in Hg before use.
• On a scale, under 80%: Worthington’s recovery cylinder spec sheet gives the limit as maximum gross weight = 0.8 × water capacity × specific gravity of the recovered refrigerant at 77°F + tare weight. Water capacity (WC) and tare (TW) are stamped on the cylinder collar. Specific gravity differs by refrigerant, so capacity in pounds does too. Fieldpiece says to make sure the job will not take the cylinder past 80%, or to have a second cylinder ready.
• Cool: recovery is faster into a cooler cylinder. Fieldpiece suggests an ice bath if the cylinder gets hot.
• One refrigerant per cylinder. EPA lists the “need to avoid mixing refrigerants” as a core recovery topic. If a cylinder is already mixed, see unknown or mixed refrigerant.

Direct liquid/vapor recovery

Fieldpiece calls it “the typical recovery method.” The MR45 sequence, condensed:

1. Close the valves on the cylinder, machine and manifold. Connect the manifold to the liquid and vapor service ports, the manifold to the machine’s inlet, and the machine’s outlet to the cylinder’s vapor valve.
2. Use short hoses (Fieldpiece: 3/8 in hose, 1/4 in fittings, core depressors removed, ball valves) and pull the Schrader cores with core tools if you have them.
3. Set the machine to RECOVER and open the high side of the manifold first, for liquid.
4. Purge air from the hoses. Fieldpiece does this by briefly unseating the hose fitting at the cylinder until vapor shows, then at the low side of the manifold.
5. Open the cylinder vapor valve fully and start the machine. If it knocks (liquid slugging), throttle the inlet.
6. When the liquid is out, open the low side for vapor.
7. Run to the required level. The MR45 auto-stops at 0 psig by default, and can continue to 10 in Hg or 20 in Hg.
8. Self-purge the machine into the cylinder to clear the refrigerant left in its condenser. Then close the cylinder and manifold valves.

To speed it up (Fieldpiece and EPA test topics): liquid first, both ports at once, a cool cylinder, and a heat gun on the lines to boil off trapped refrigerant.

Push-pull liquid recovery

Push-pull moves large amounts of liquid fast. As Yellow Jacket describes it, the machine “pulls” vapor from the recovery cylinder and sends high-pressure discharge gas that “pushes” liquid out of the system into the cylinder. The system’s liquid port connects to the cylinder’s liquid valve, and the cylinder’s vapor valve feeds the machine. A sight glass in the liquid hose shows when liquid stops flowing.

When to use it:

• Fieldpiece: only on systems with at least 30 lb of liquid refrigerant, and it recommends push-pull for anything over 30 lb.
• Yellow Jacket: do not use it if the system holds less than 10 lb, is a heat pump or has a reversing valve, has an accumulator between the service ports, or cannot form a solid column of liquid.

When the sight glass shows no more liquid, stop. Push-pull leaves vapor behind, so reconnect for vapor recovery and pull the system to the required level. Use a sight glass rated for the refrigerant’s pressure.

A2L systems

Recovery levels are the same for R-454B and R-32; the equipment and work area change. Use a machine rated for the refrigerant (Appendix B4). Set up a flammable zone with ignition sources removed, monitor it with a suitable leak detector, ground the machine and cylinder, keep a dry-powder extinguisher at hand, and never let air into the cylinder.

Fieldpiece also says that if a leak is suspected, stop recovery at 0 psig so air cannot be drawn into the tank. For leaking components, 82.156(a)(2) asks for the lowest level reachable without substantially contaminating the refrigerant, and never above 0 psig. After recovery, purge with nitrogen before opening the circuit; see the nitrogen pressure test guide. Full precautions: A2L recovery machines.

Non-condensables in the cylinder

If a cylinder reads higher than the PT chart for its temperature, it may have air at the top. Fieldpiece’s fix is to let it settle overnight, then bleed vapor into a second evacuated cylinder until it reads 5 psi above the chart pressure. The steps are in how to identify refrigerant.

What happens to recovered refrigerant

• Back into the same owner’s equipment: refrigerant may be returned to the appliance it came from, or to another appliance owned by the same person, without recycling or reclaiming (82.156(h)). MVAC and MVAC-like appliances are the exception.
• Sold to anyone else: under 82.154(d), used refrigerant may be sold for use as a refrigerant only if an EPA-certified reclaimer has reclaimed it to the AHRI 700 specifications in Appendix A. For HFCs, 40 CFR 84.104 says the same and adds that recovered refrigerant may be transferred to a new owner solely for reclamation or destruction.
• Where it goes: EPA’s reclamation page says contractors can return recovered refrigerant to a consolidator (a refrigerant manufacturer, supplier, wholesaler or recovery company), or sometimes directly to a certified reclaimer.
• Flammables: EPA’s SNAP listing for A2L refrigerants in residential and light commercial AC notes that flammable refrigerants recovered from those appliances “are likely to be hazardous waste” under RCRA. That note is guidance in the listing, not a use condition.

Disposing of small appliances

For refrigerators, window units, dehumidifiers and other small appliances being scrapped, 40 CFR 82.155 requires recovery to the small-appliance levels above, using equipment certified for small appliances. The final processor (scrap recycler or landfill) must either recover the refrigerant itself or get a signed statement or contract that it was recovered. It keeps those records for three years.

For appliances with more than 5 and less than 50 lb being disposed of, the technician keeps the recovery records described in the 608 guide for three years.