Job Hazard Analysis: Refrigerant recovery and charging

A general example for this task. Your JHA should reflect your crew, equipment and site — review it with a competent person before work starts.

Steps, hazards and controls

1. 1. Set up: access the unit, shut off power, and lock out the disconnect.

   • Electric shock from an energized 240V disconnect, contactor, or capacitorHigh
     • Turn off the outdoor disconnect and the indoor breaker, then put your own lock and tag on each.
     • Test for zero voltage with a meter you checked on a known live source first.
     • Discharge the run capacitor with an insulated discharge tool before touching terminals.
     • Wear safety glasses and keep hands dry; do not work on wet ground near the disconnect.
   • Falls from an extension ladder or roof edge when reaching a rooftop unitHigh
     • Use the building's fixed roof access or hatch when one exists.
     • Set the extension ladder at a 4-to-1 angle, extend it 3 ft above the roof edge, and tie it off at the top.
     • Haul the recovery machine and cylinders up with a rope; keep 3 points of contact on the ladder.
     • If the unit is within 6 ft of an unprotected roof edge, use guardrails or a harness tied to an approved anchor.
   • Heat stress in attics and on rooftopsMedium
     • Schedule attic and roof work early in the day when possible.
     • Drink water every 15–20 minutes and take shade breaks.
     • Watch your partner for dizziness, confusion, or stopping sweating.

2. 2. Connect the manifold gauges, hoses, recovery machine, and recovery cylinder.

   • Liquid refrigerant spray causing frostbite to eyes and skin when hoses are connectedHigh
     • Use hoses with low-loss fittings and close the valves before connecting.
     • Point service ports and hose ends away from your face and body.
     • Wear sealed safety goggles and refrigerant-rated insulated gloves.
   • Overfilled or wrong recovery cylinder rupturingHigh
     • Use only a gray-and-yellow DOT recovery cylinder within its hydrostatic test date.
     • Put the cylinder on a scale and figure the 80% fill weight before you start.
     • Set up the overfill float switch if the cylinder has one.
     • Never mix different refrigerants in one recovery cylinder.
   • Tripping over hoses and extension cordsLow
     • Route hoses and cords along walls and out of walkways.
     • Use a GFCI-protected outdoor-rated cord for the recovery machine.

3. 3. Recover the refrigerant into the recovery cylinder.

   • Refrigerant leak displacing oxygen in a basement, closet, or atticHigh
     • Open doors and run a fan to move fresh air through small rooms before and during recovery.
     • Check all hose connections with a leak detector once the machine starts.
     • If you smell refrigerant, feel dizzy, or hear a hiss, stop the machine and get to fresh air.
   • Fire from A2L refrigerant near a spark or flameMedium
     • Use a recovery machine and leak detector rated for A2L refrigerants.
     • Shut off gas furnaces, water heater pilots, and other flames in the room.
     • No smoking and no torches within 10 ft while refrigerant is in the hoses.
     • Keep a charged ABC fire extinguisher at the unit.
   • Toxic gas when refrigerant touches a flame or hot surfaceMedium
     • Finish recovery fully before any brazing on the lines.
     • Ventilate the area and leave right away if you smell a sharp, acid odor.

4. 4. Pressure test with nitrogen and pull a vacuum.

   • Overpressure from a nitrogen cylinder without a regulatorHigh
     • Always use a nitrogen regulator with a relief valve; never connect the cylinder straight to the system.
     • Set pressure no higher than the unit's nameplate low-side test pressure.
     • Never use oxygen or compressed air to pressure test.
   • Unsecured high-pressure cylinder tipping and breaking its valveMedium
     • Strap the nitrogen cylinder upright to a cart or fixed object.
     • Keep the valve cap on whenever the cylinder is not in use.
   • Vacuum pump oil burns and spillsLow
     • Let the pump cool before changing oil; catch oil in a container.

5. 5. Charge the system with new refrigerant.

   • Liquid refrigerant contact causing frostbiteMedium
     • Charge liquid slowly through the low side with a metering device, and keep the cylinder on a scale.
     • Wear goggles and insulated gloves the whole time you handle hoses.
   • Wrong refrigerant or overcharging the systemMedium
     • Match the refrigerant type on the cylinder to the unit nameplate before connecting.
     • Weigh in the charge listed on the nameplate and confirm with subcooling or superheat.
   • Contact with spinning fan and live parts when the unit runs to finish the chargeHigh
     • Put all panels and the fan guard back before restoring power.
     • Only the person who placed each lock removes it, after telling the crew.
     • Read pressures from the gauges; keep hands out of the unit while it runs.

6. 6. Disconnect hoses, cap the ports, and check for leaks.

   • Refrigerant spray from hose ends and Schrader valvesMedium
     • Close the hose valves and bleed hoses back to the low side before removing them.
     • Keep your face away from the port and wear goggles.
     • Install the port caps with O-rings and check with the leak detector.

7. 7. Clean up, label, secure, and transport cylinders.

   • Back strain lifting a recovery machine or a full 50-lb cylinderMedium
     • Use a hand truck for cylinders and machines; get help on stairs and ladders.
     • Lift with your legs and keep the load close to your body.
   • Cylinders shifting or overheating in the work truckMedium
     • Strap cylinders upright with valve caps on in a ventilated rack.
     • Do not leave cylinders in a closed cab or in direct sun.
     • Label each recovery cylinder with the refrigerant type and weight.