FieldBench
How To
Recovery14 min · 4 steps

Recover refrigerant

Identify the gas, stay under 80% of the tank, pull the cores, weigh everything. Mixing refrigerants is how you scrap a bottle.

Before you start

  • EPA 608: recover. Venting is illegal. A ‘hiss to atmosphere’ is a violation, not a shortcut.
  • Never mix refrigerants in a tank. Never fill past 80% — hydrostatic pressure will rupture a liquid-full cylinder.
  • Max gross = 0.8 × water capacity × specific gravity + tare weight. Use the worst-case tank temperature, not a cool morning number.
  • A2L: recovery machine and hoses rated for flammable refrigerants. No ignition sources at the unit.

On the truck

  • Recovery machine rated for this refrigerant (A2L-rated on R-32 / R-454B)
  • DOT recovery tank in date, same gas or truly empty
  • Charging scale under the tank
  • Core-removal tools and short large-bore hoses
  • In-line filter-drier on the recovery inlet
  • A2L leak detector if that is the gas

Steps

  1. 1 Identify the refrigerant and the tank

    Read the unit nameplate and the tank stamp. Same gas, or a tank you evacuated below 500 microns and labeled. Check the tank hydro date. Put the tank on the scale and write tare + current weight before you open a valve.

    Expect: Nameplate gas = tank gas. Hydro in date. Room on the scale to the 80% number.

    If it fails: Wrong tank or no scale → stop. Do not ‘just recover a little’ into an unknown bottle.

  2. 2 Pull the cores and purge the hoses into the recovery path

    Schrader cores left in are a pressure drop that turns a 15-minute recover into an hour. Core tools on both ports. Purge air out of the hoses into the machine / tank path — not into the yard. Skip the manifold on a digital recovery machine; wye the hoses.

    Expect: Cores out. Hoses short and large. Air purged. Inlet drier installed.

    If it fails: Hissing at a hose or a warm machine with no weight gain = leak or a closed tank valve.

  3. 3 Liquid first, then vapor. Keep the tank cool

    Standard recover: liquid out of the system into the machine, vapor port on the tank (or invert the tank so liquid enters without fighting a dip tube — HVACR School). When liquid stops, flip the tank upright and finish vapor. Watch the scale. Ice or water on the tank if it is heat-soaking. Push-pull (tank vapor drives liquid out of a large system into the tank, machine on the vapor) is for big charges, not a 3-ton split.

    Expect: Scale climbing. Tank stays under the 80% gross. Machine not in high-pressure cutout.

    If it fails: Tank at 80% → swap tanks. Machine cutting out on high → tank is hot or the inlet is restricted.

  4. 4 Recover to the required vacuum, then isolate

    Finish to the EPA required vacuum for that appliance type (or the OEM number if tighter). Close the tank. Isolate. Weigh the recovered amount and write it on the tank tag and the ticket — job number and pounds. HVACR School treats that tag as required, not optional.

    Expect: Required vacuum held. Recovered weight on the ticket. Tank labeled.

    If it fails: If you cannot pull into vacuum, there is still liquid, a leak to atmosphere, or a core still in.

Field notes

  • A factory nitrogen holding charge is not refrigerant — do not run it through the recovery machine as if it were 410A.
  • Bigger hoses, bigger drier, cooler tank. That is the speed list. A manifold full of 1/4" hose is the slow list.
  • After recovery, a leak-down of the isolated system tells you if it is empty or if a service valve is still shut.

Related

Sources

Practice distilled from public HVACR School and AC Service Tech material. OEM I/O and EPA 608 still win.