How to Recover Refrigerant: What EPA Section 608 Actually Requires

Before you open or dispose of an appliance, 40 CFR 82.156 requires you to remove the refrigerant — including all the liquid — to a set vacuum level, using a recovery machine certified under 82.158. The level depends on the appliance's pressure class, its charge size, and when your recovery machine was built — not when the appliance was built.

That last point is where most of the internet gets it wrong. Search this topic and you will find nine-step procedures from tool manufacturers, forum threads about the fastest method, and training pages that explain how to hook up a machine. Very few of them state the number you are legally required to hit, and several attach the November 15, 1993 cut-off to the wrong piece of equipment. Technique matters, but technique is not what an inspector checks.

What does the law actually require?

The venting prohibition is the starting point. Under Clean Air Act section 608(c) and 40 CFR 82.154(a), no person maintaining, servicing, repairing or disposing of an appliance may knowingly vent or otherwise knowingly release refrigerant into the environment. Recovery is not a courtesy to the atmosphere. It is the thing that keeps you on the right side of a federal prohibition.

Only de minimis releases are permitted — small quantities lost while making a good faith attempt to recapture the refrigerant, such as the puff when you connect or disconnect a hose. EPA treats releases as meeting that test when you follow the recovery requirements in the rule. Follow the procedure and the incidental losses are covered. Skip it and they are not.

How deep a vacuum do you have to pull?

This is Table 1 of 82.156, and it is the most cited table in the whole program. Values are inches of mercury vacuum relative to standard atmospheric pressure of 29.9 inches Hg, except where marked. It does not cover small appliances, MVACs or MVAC-like appliances.

Type of appliance	Recovery equipment made before Nov 15, 1993	Recovery equipment made on or after Nov 15, 1993
Very high-pressure appliance	0	0
High-pressure appliance, or isolated component, charge under 200 lb	0	0
High-pressure appliance, or isolated component, charge 200 lb or more	4	10
Medium-pressure appliance, or isolated component, charge under 200 lb	4	10
Medium-pressure appliance, or isolated component, charge 200 lb or more	4	15
Low-pressure appliance	25 mm Hg absolute	25 mm Hg absolute

Two things drive the numbers. Larger charges leave more refrigerant behind at a given vacuum, so bigger systems get a deeper target. And machines built on or after the cut-off had to meet a tougher certification standard, so the technician using one is held to the tougher figure.

Note that a high-pressure system under 200 pounds — most residential and light commercial work — requires 0 inches. Atmospheric pressure is the target. R-410A and R-22 boil so readily that pulling further down recovers very little extra.

Does the November 15, 1993 date refer to the appliance?

No, and this is the single most common error in circulation. The column headings in Table 1 read "using recovery and/or recycling equipment manufactured or imported before" and "on or after November 15, 1993." The date describes your recovery machine. The age of the system you are servicing is irrelevant to which column you read.

Carrying an older machine is not a violation — pre-1993 equipment is grandfathered. It simply means the figures you must hit are the left-hand column, not the right. The type sections of the exam test this distinction directly, usually by giving you an appliance, a charge size and a machine vintage and asking for a number.

Is 500 microns the requirement?

No. This is the distinction that separates a technician who knows the trade from one who knows the rule, and the two operations are genuinely different.

Recovery evacuation removes refrigerant to a level EPA specifies, measured in inches of mercury vacuum, verified before you open the system. That is Table 1.

Service evacuation removes air and moisture from an already-empty system before you charge it. It is measured in microns, commonly down to 500 or lower, and it needs a micron gauge because a compound gauge cannot resolve anything useful below about 28 inches Hg.

Pulling to 500 microns before charging is good practice, and many manufacturers require it as a condition of warranty. It is not a Section 608 recovery requirement, and no part of 82.156 mentions it. Anyone who tells you the EPA requires 500 microns has merged two separate jobs.

What are the steps?

The rule sets out the sequence more than most people realize.

1. Identify the pressure class and charge size, and check when your recovery machine was built. That determines your target.
2. Recover liquid first where the machine supports it. Liquid recovery is far faster than vapor recovery, and 82.156(a) requires removal of all the liquid refrigerant.
3. Evacuate the whole appliance, or just the part being serviced if the refrigerant in that part can be isolated to a system receiver.
4. Verify the level has been reached before anything is opened. The rule requires verification, not estimation.
5. Close the valves and wait. If pressure creeps back up, refrigerant is still coming out of the oil or air is leaking in. This step is standard practice rather than codified, but it is how you know you are finished.

Use the equipment according to the manufacturer's directions unless those directions conflict with Subpart F, which 82.156(g) requires.

What if the system is leaking or the repair is minor?

Two provisions let you stop short of the Table 1 vacuum.

If the appliance will not be opened to atmosphere afterward and the work is not major, 82.156(a)(1) allows you to evacuate a medium-, high- or very high-pressure appliance to a pressure no higher than 0 psig. A low-pressure appliance is pressurized to no higher than 0 psig instead — you bring it up to atmospheric rather than down. Major service is defined at 82.152 as work involving removal of the compressor, condenser, evaporator or auxiliary heat exchanger coil. For an oil change specifically, 5 psig is permitted.

If leaks make the Table 1 level unattainable, 82.156(a)(2) requires you to isolate leaking from non-leaking components, evacuate the non-leaking components to the full Table 1 level, and evacuate the leaking components to the lowest level attainable without substantially contaminating the refrigerant — a level that may not exceed 0 psig. A leaking system is not a license to leave it at 30 psig. Atmospheric pressure is the floor, not the ceiling.

What about small appliances?

Small appliances — five pounds or less, factory-sealed and factory-charged — are excluded from Table 1 entirely and governed by 82.156(b).

Recovery equipment	Requirement
Made before Nov 15, 1993	Recover 80% of the charge
Made on or after Nov 15, 1993, compressor working	Recover 90%
Made on or after Nov 15, 1993, compressor not working	Recover 80%
Any equipment, alternative method	Evacuate to 4 inches of mercury vacuum

Same date, same logic, different units. It is a percentage of the charge, not a vacuum level, unless you take the four-inch alternative.

What this means on the job

The practical consequence is that "recovered it properly" is a specific claim with a number attached, and the number changes with the truck you drove that morning. Two technicians on the same rooftop unit, one with a 1991 machine and one with a 2024 machine, can face different legal targets on identical equipment.

The other real-world catch is equipment type. System-dependent recovery equipment — the passive kind with no compressor of its own, which relies on the appliance's own compressor or internal pressure — may not be used on appliances with a full charge of more than 15 pounds, unless it is permanently attached as a pump-out unit. Fifteen pounds, not the five that defines a small appliance. Those two figures sit close together and get swapped constantly.

If you are preparing for the exam rather than the inspection, these tables are worth drilling until they are automatic. Working through timed practice questions surfaces the appliance-class-plus-charge-size combinations far faster than rereading the table does, and the study guide covers how the pressure classes map onto specific refrigerants.

Frequently asked questions

Which is the fastest way to recover refrigerant?

Recover liquid first, then vapor. Liquid recovery moves far more refrigerant per minute than vapor recovery, and 82.156(a) requires removal of all liquid refrigerant anyway. Keeping the recovery cylinder cool and using large-diameter, short hoses also cuts recovery time substantially on larger systems.

How do you recover refrigerant without a recovery machine?

You generally cannot, legally. 82.156 requires a machine certified under 82.158 for appliances and small appliances alike. System-dependent equipment uses the appliance's own compressor rather than its own, but it still must be certified, and it cannot be used on charges over 15 pounds unless permanently attached as a pump-out unit.

Can you put recovered refrigerant back into the system?

Yes. Under 82.156(h), refrigerant may be returned to the appliance it came from, or to another appliance owned by the same person, without being recycled or reclaimed. The exception is MVAC and MVAC-like appliances, which are carved out. Refrigerant sold or transferred to a different owner must be reclaimed first.

Do you need certification to recover refrigerant?

Yes. Section 608 technician certification is required for anyone maintaining, servicing, repairing or disposing of appliances in a way that could release refrigerant. Which type you need depends on the equipment — our guide to what Section 608 certification covers sets out who needs which.

Does a leaking appliance excuse you from the vacuum requirement?

Only partially. You must still isolate leaking from non-leaking components, bring the non-leaking parts to the full Table 1 level, and bring the leaking parts to the lowest level you can reach without contaminating the refrigerant. That level may not exceed 0 psig.

Sources

• 40 CFR 82.156 — Proper evacuation of refrigerant from appliances
• 40 CFR 82.154 — Prohibitions
• 40 CFR 82.158 — Standards for recovery and recycling equipment
• EPA, Stationary Refrigeration Service Practice Requirements
• EPA, Prohibition on Venting Refrigerants