Refrigerant Recovery and Cylinder Management

Purpose

This standing instruction governs the part of the job that carries both a rupture hazard and a paper trail, and that gets done last, in the dark, by whoever is still on site.

A recovery cylinder is a regulated pressure vessel, not a bucket. Overfill it and it has no vapor space left to absorb thermal expansion, so a hot truck bed turns a full cylinder into a hydrostatic rupture with no warning noise before it happens. Put two refrigerants in it and the contents stop being reclaimable, so what was a routine return becomes mixed waste the shop pays to dispose of. Skip the log and the shop cannot show where a single pound went. The machine is the easy part of recovery. The cylinder is where the exposure lives.

Safety actions that gate the work

• Fill on a scale, every time, and never past the fill limit for that cylinder and that refrigerant. A cylinder filled liquid-full has nowhere for the liquid to go as it warms, and the pressure rise from there is steep and fast. The scale is not a convenience, it is the control.
• Never recover into a disposable cylinder. DOT-39 non-refillable cylinders are built to be filled once at a factory and are not rated for refilling; recovery goes into a refillable recovery cylinder such as a DOT 4BA or 4BW.
• Liquid refrigerant freezes skin on contact. Gauntlet gloves and sealed eye protection whenever a liquid-side hose is connected or disconnected, and stand out of line with every fitting you crack.
• Refrigerant vapor is heavier than air and displaces oxygen at floor level. Recover in ventilated space; do not run a recovery in a closed mechanical room, a basement or a van with the doors shut, and treat any confined space with a released charge as an entry hazard rather than a smell.
• A2L refrigerants (R-454B, R-32) require recovery equipment rated for flammable refrigerants, and no ignition source in the area during recovery. A machine listed only for A1 refrigerants is not made safe by working carefully.

Scope

Covers recovery from residential and light-commercial appliances, cylinder selection, filling, labeling, storage, transport handoff and the records that follow, on any job where refrigerant leaves a system.

Does not cover the leak decision that sends you here, owned by the refrigerant leak response and repair authorization SOP. Does not cover reclamation processing, which is done by a certified reclaimer and not by a service shop. Does not cover technician certification itself, which is a hiring and licensing matter rather than a job procedure.

Roles and handoffs

Procedure

1. Select the cylinder before you connect anything, and check it against four things. It is a refillable recovery cylinder, its hydrostatic retest date is current (DOT 4BA and 4BW cylinders carry a five-year retest interval), its tag says it is dedicated to the refrigerant you are about to recover, and its water capacity and tare weight stamps are legible. Acceptance: all four confirmed. Stop rule: any failure means the cylinder is tagged out of service and returned to the shop, and you use another one; do not use it "just for this job."

2. Read the fill limit off the cylinder tag rather than computing it in a parking lot. The limit exists because a recovery cylinder must not be filled past 80 percent of its capacity by volume at 130 F, which the shop converts once into a maximum net refrigerant weight per refrigerant and writes on the tag when the cylinder enters service. Acceptance: a numeric maximum net weight on the tag for the refrigerant in hand. Wrong looks like filling to a pressure or to a feel, which on a cool morning will happily take a cylinder past the limit.

3. Establish the starting net weight on the scale before recovery begins. Gross weight on the scale minus the stamped tare weight equals what is already in the cylinder. Acceptance: a recorded starting net weight and the headroom remaining against the tag limit. Wrong looks like starting with a partial cylinder and no idea how partial, which is the single most common route to an overfill because the tech watches the amount added rather than the total contained.

4. Confirm the machine, hoses and appliance class before the first valve opens. Recovery machine rated for this refrigerant, hoses rated for its working pressure with functional shutoffs, filter drier fitted per the machine manufacturer's schedule, and the appliance identified as a small appliance or not. A small appliance is factory-charged, hermetically sealed and holds 5 pounds or less, and it takes a different requirement from a split system. Acceptance: class named, machine and hoses matched. Wrong looks like a machine listed for A1 refrigerants on an A2L system.

5. Recover with the scale in view, and stop on the number rather than on the sound. Take liquid first where the charge is large enough to justify it, then vapor, watching the running net weight against the tag limit. Acceptance: cylinder net weight below the tag limit at all times. Stop rule: if the running weight approaches the limit, close the cylinder valve and change to a second cylinder before continuing, never after. An automatic shutoff float, where fitted, is a backup to the scale and not a substitute for watching it.

6. Pull to the evacuation level the rule requires for this appliance class, and record what you reached. For small appliances, 40 CFR 82.156 requires recovering 90 percent of the charge with the compressor operating, or 80 percent with it not operating, or evacuating to 4 inches of mercury vacuum. For everything larger, the required level depends on the appliance type, its charge size and whether the recovery equipment was manufactured before or after November 15, 1993, so read the row for the machine and appliance in front of you rather than carrying one number across every job. Acceptance: the level reached, written on the ticket.

7. Label and log the cylinder at the truck, before you drive away. Refrigerant type, date, tech, job or equipment identifier, and the new net weight. Acceptance: the physical cylinder tag updated and the shop log entry made the same day. Stop rule: refrigerant of unknown or mixed identity never goes into a dedicated cylinder; it goes into a cylinder marked for mixed contents and the manager is told, because one careless transfer converts a full cylinder of reclaimable refrigerant into waste.

8. Hand off to the reclaimer or supplier with a document, and keep it. Acceptance: a manifest or receipt naming the cylinder, refrigerant and weight, filed against the shop's records, which are retained for at least the three years required by the Section 608 recordkeeping provisions at 40 CFR 82.166 and longer where a state licensing board says so. Wrong looks like a cylinder that leaves on a supplier's truck with a verbal handoff, which leaves the shop unable to answer the only question an inspection asks.

The record this produces

Two records that must reconcile with each other, which is the point:

• The cylinder log, one running entry per cylinder: cylinder serial, refrigerant dedication, retest date, and every fill and every return with date, tech, job and net weight before and after.
• The job record, one entry per appliance: amount recovered, cylinder serial it went into, evacuation level reached, and the appliance class it was judged against.

Add the two together and they have to agree. A cylinder that gained 9 pounds on a day when the job records show 6 recovered means either a weight was written from memory or refrigerant from a second job went in unlogged, and both are worth finding while the week is still fresh. The office reads the manifests against the log to close the loop. The manager reads recovered-versus-nameplate across jobs, because a system that gives up materially more than its nameplate has been topped off by somebody, and that is a lead worth following.

Worked pass: two condensers recovered on one changeout day, R-410A

Step 1 FAILS on the first cylinder. It is the right type and dedicated to R-410A, but the stamped hydrostatic retest date is five years and four months old, past the five-year interval. Stop rule taken: tagged out of service, strapped back in the van, no recovery into it. Second cylinder pulled from truck stock, retest current, dedicated to R-410A, stamps legible.

Step 2: say the tag on the second cylinder reads a maximum net weight of 47 lb for R-410A, written there by the cylinder custodian when it entered service.

Step 3: scale gross reading minus the stamped tare gives a starting net of 12 lb 6 oz, which is 12.375 lb, or 26 percent of the 47 lb limit. Headroom is 34.6 lb.

Pre-job estimate: the two systems carry nameplate charges of 9 lb 12 oz and 12 lb 12 oz, so 9.75 + 12.75 = 22.5 lb expected. Added to the 12.375 already in the cylinder that predicts a finish at 34.9 lb, or 74 percent of the limit. One cylinder should do the day.

Step 5, system one: recovered net 9 lb 13 oz, which is 9.8125 lb. Cylinder net now 12.375 + 9.8125 = 22.1875 lb, printed as 22 lb 3 oz on the scale, 47 percent of the limit.

Step 5, system two: recovered net 13 lb 4 oz, which is 13.25 lb, half a pound more than that system's nameplate. Cylinder net now 22.1875 + 13.25 = 35.4375 lb, printed as 35 lb 7 oz, 75 percent of the limit. Under it, and the scale was watched the whole way rather than the estimate being trusted.

Note the estimate against the outcome. The prediction was 34.9 lb and the finish was 35 lb 7 oz, because system two held more than its nameplate. That extra half pound is not a rounding artifact, it is a fact about that system, and it goes on the changeout record as evidence that somebody had been adding to it.

Step 6: neither of these is a small appliance, since both are field-charged split systems well over the 5 pound hermetically-sealed factory-charge definition, so the small appliance percentages do not apply and the required level was read off the row for this appliance type and this machine's manufacture date. The vacuum reached is written on each ticket.

Step 7 and 8: cylinder tag updated to 35 lb 7 oz of R-410A with the date and both job numbers, shop log entered the same evening, cylinder returned to the supplier the following week against a receipt naming the serial, the refrigerant and the weight.

Checking the pass against the sections above: every weight here is net refrigerant weight taken as gross minus the stamped tare, in the same pounds-and-ounces unit, and every percentage is stated against the same 47 lb tag limit named in step 2. The failing cylinder was removed under step 1's stop rule before any refrigerant touched it, which is why no partial recovery had to be transferred, and a transfer is the operation step 7 warns turns good refrigerant into mixed waste.

References

• 40 CFR 82.156 for required evacuation levels by appliance type and recovery equipment vintage, and for the small appliance recovery percentages
• 40 CFR 82.166 for the Section 608 recordkeeping and retention requirements
• 49 CFR Part 180 Subpart C for periodic requalification of DOT specification cylinders, including the retest interval marked on the cylinder
• AHRI Standard 740 for recovery and recycling equipment performance, and the machine manufacturer's instructions for filter drier service intervals
• See related: the refrigerant leak response and repair authorization SOP, and the system changeout day-of-install standard