3 Refrigerant Recovery Procedures

Purpose and requirements

Refrigerant recovery removes refrigerant from an appliance and stores it in an external container. The process does not necessarily clean or test the refrigerant. Recovery helps prevent releases and is required before opening many stationary refrigeration and air-conditioning systems.

Use equipment compatible with the refrigerant and follow the equipment manufacturer’s instructions. In the United States, technicians working on stationary equipment generally need EPA Section 608 certification.

Prepare the system and equipment

Identify the refrigerant and prepare equipment

Check the appliance label and service information to identify the refrigerant. If it is unknown or may be contaminated, do not mix it with known refrigerant; use a suitable dedicated recovery arrangement or consult a qualified service provider.

Select recovery equipment appropriate for both the refrigerant and the appliance. Most stationary recovery equipment must meet EPA equipment standards. Check hoses, fittings, valves, and the recovery unit for damage, and set up the equipment as its manufacturer specifies.

Prepare the cylinder and work area

Choose an approved cylinder rated for the refrigerant’s pressure. Inspect the cylinder and its valves, and do not use a damaged or out-of-date cylinder. Confirm its tare weight and allowable fill weight, place it on a scale, and label it with the refrigerant type. Never mix different refrigerants in one cylinder or overfill it; follow the cylinder’s marked limits and applicable transport rules.

Work in a ventilated area. Keep ignition sources away where refrigerants may be flammable, and use the personal protective equipment and safety procedures specified for the refrigerant. Do not use oxygen or compressed air to pressurize or test a refrigerant system.

Choose a recovery method

The appropriate method depends on the system, refrigerant, recovery unit, and service objective. Do not improvise valve positions or bypass equipment safeguards.

• Vapor recovery: Removes refrigerant as vapor. It is a common method for completing recovery and works with most recovery units.

• Liquid recovery: Removes liquid refrigerant and can recover a large charge more quickly when the equipment and setup allow it. Follow the recovery-unit instructions to prevent liquid from entering a compressor that is not designed to handle it.

• Push-pull recovery: Uses vapor pressure to move bulk liquid from the appliance to the recovery cylinder. It can speed recovery of large liquid charges, but it does not remove all remaining refrigerant. Finish with the appropriate vapor-recovery procedure.

Monitor recovery and meet endpoints

Connect the recovery equipment and cylinder using the specified hose arrangement. Open the necessary valves and operate the unit according to its manual. Monitor both system pressure and cylinder weight throughout recovery. A falling system pressure does not show how much refrigerant has entered the cylinder, so use a scale to track the charge and stop before the cylinder’s allowable fill weight is reached.

Watch for abnormal pressure, temperature, noise, leaks, or equipment alarms. Stop and investigate if anything is unsafe or outside the manufacturer’s operating limits.

Stationary appliance evacuation endpoints

For stationary appliances containing more than five pounds of refrigerant, the required evacuation level before opening the appliance depends on its pressure class, full charge, and the relevant recovery-equipment date. The vacuum values below are inches of mercury below standard atmospheric pressure, except where marked absolute. These are regulatory recovery endpoints for the listed appliances, not deep-vacuum targets used when evacuating a system for charging. Follow current requirements applicable to the job and the recovery-equipment manufacturer’s directions.

• Very-high-pressure appliance: The endpoint is $0\ \text{in. Hg vacuum}$ for equipment manufactured before or after November 15, 1993.

• High-pressure appliance with a charge under $200\ \text{lb}$: The endpoint is $0\ \text{in. Hg vacuum}$ for equipment manufactured before or after November 15, 1993.

• High-pressure appliance with a charge of $200\ \text{lb}$ or more: The endpoint is $4\ \text{in. Hg vacuum}$ for equipment manufactured before November 15, 1993, and $10\ \text{in. Hg vacuum}$ for equipment manufactured after that date.

• Medium-pressure appliance with a charge under $200\ \text{lb}$: The endpoint is $4\ \text{in. Hg vacuum}$ for equipment manufactured before November 15, 1993, and $10\ \text{in. Hg vacuum}$ for equipment manufactured after that date.

• Medium-pressure appliance with a charge of $200\ \text{lb}$ or more: The endpoint is $4\ \text{in. Hg vacuum}$ for equipment manufactured before November 15, 1993, and $15\ \text{in. Hg vacuum}$ for equipment manufactured after that date.

• Low-pressure appliance: The endpoint is $25\ \text{mm Hg absolute}$ for equipment manufactured before or after November 15, 1993.

Small appliances have separate requirements. Generally, recover $90\%$ when the compressor works and post-November 15, 1993 equipment is used, or $80\%$ when the compressor does not work or qualifying older equipment is used. Evacuation to $4\ \text{in. Hg vacuum}$ is another permitted option.

Shut down and verify

When the applicable recovery endpoint is reached, isolate the appliance and cylinder and shut down the recovery unit in the order specified by its manufacturer. Close the cylinder valves, then disconnect and cap or secure connections as directed to limit refrigerant loss.

Allow system pressure to stabilize and check it again. If pressure rises above the required endpoint, refrigerant may have boiled off or migrated from oil or cooler parts; continue recovery as appropriate and recheck. Before opening the system, verify the endpoint with suitable gauges and confirm that the equipment is isolated and safe to service.

Handle recovered refrigerant

Keep recovered refrigerant in a properly rated, closed, clearly identified cylinder. Keep different refrigerants, as well as unknown or contaminated refrigerant, separate. Record refrigerant identity and quantity as required by workplace procedures and applicable regulations.

Recovered refrigerant has simply been removed and stored. Recycled refrigerant has been cleaned for reuse under applicable conditions. Reclaimed refrigerant has been reprocessed and verified to required purity specifications. Do not assume recovered refrigerant is ready to charge into equipment. Send it to an appropriate reclaimer or supplier when needed; EPA requires reclamation to applicable purity standards before used refrigerant is sold to another appliance owner.