R-Pro › Field cases › Refrigerators & showcases
Refrigerant Recovery and Recharge Procedure — Standard Workflow
Likely causes
Step 1 Recovery — recovery machine standard procedure
Check: Weigh recovery cylinder (DOT certified, fill ≤80% of rated). Connect recovery machine, cylinder, system with thick hoses (3/8" recommended). Select liquid/vapor recovery mode. End recovery when reaching recovery vacuum (≤0.05 MPa(g)).
What to do: 1) Allow recovery cylinder to stabilize 30+ min, re-weigh — confirm actual recovery quantity. 2) If ~0.1 MPa pressure remains in system after recovery, suspect NCG — pull additional. 3) Service recovery machine oil monthly or every 100 hrs. 4) Shake recovery cylinder while filling to assess content level.
Step 2 Evacuation — precise measurement with micron gauge
Check: Evacuate with vacuum pump (2-stage, ≥6 CFM recommended) to ≤500 microns. Measure with micron gauge (not analog vacuum gauge). After reaching vacuum, hold 30 min — rise within 50 microns = pass. 50–500 = leak or residual moisture; over 500 = significant leak.
What to do: 1) If can't reach 500 microns, change vacuum pump oil and retry. 2) Still unable → leak check (pressurize and use soap). 3) Residual moisture → longer evacuation (2–6 hours). 4) Recommend changing vacuum pump oil after every recovery — prevents pump damage from acidic residuals.
Step 3 Charging — weight method vs subcool/superheat method
Check: Weight method = use when nameplate specifies charge amount (e.g., '900g R-410A'). Charge to ±10g with digital scale. If nameplate unknown, measure subcool/superheat and charge until normal range — has subjective judgment.
What to do: 1) Use weight method first when possible — objective and fast. 2) Charge as liquid into liquid line service port — system OFF or low-speed operation. 3) Glide refrigerants (R-407C etc.) require liquid charging. 4) After charging, stabilize 30 min → verify with operating pressures (subcool 5–10°C, superheat 8–12°C).
Recovery → evacuation → charging is a ~1.5–3 hour job. Shortcuts (5-min evacuation, gas-phase charging) cut system life in half. Doing it right gives 5+ years trouble-free.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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