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Red Seal Refrigeration & AC Mechanic study materials
Red Seal Refrigeration & AC Mechanic study resources

Red Seal Refrigeration & AC Mechanic: Refrigerants, Lubricants, Recovery, Recycling, and Reclamation

Red Seal Refrigeration & AC Mechanic · Work through your exam, one topic at a time.

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Refrigerants, Lubricants, Recovery, Recycling, and Reclamation

Refrigerants, Lubricants, Recovery, Recycling, and Reclamation is the regulated heart of the trade. Items test refrigerant identification, safety classification, glide and fractionation, oil compatibility, and the handling sequence: recover, recycle, reclaim, never vent.

Refrigerant families

  • CFCs (R-12) and HCFCs (R-22) deplete ozone and are no longer produced in Canada. HFCs (R-134a, R-404A, R-410A) have high GWP and are being phased down under the Kigali Amendment. HFOs and HFC/HFO blends (R-1234yf, R-454B, R-513A) have low GWP, and many are A2L.
  • Azeotropes behave like a single substance. Zeotropes have temperature glide and fractionate: leaked vapour changes composition, so charge blends as liquid.
  • Always identify the refrigerant in a system. Mixing refrigerants makes the whole cylinder unreclaimable.

Lubricants

  • Mineral oil for CFC and HCFC systems; POE for HFC and HFO systems. POE is hygroscopic and absorbs moisture in minutes - keep containers sealed and never top up from an open jug.
  • Oil return depends on refrigerant velocity and oil miscibility. Moisture in POE forms acids; acid test kits and filter-drier changes are part of the repair.

Recovery and reclamation

  • Recover into a certified cylinder and never exceed 80% of water capacity by weight. Recovery cylinders are grey with a yellow band in North America.
  • Liquid recovery is faster than vapour recovery; system-dependent (passive) recovery is only permitted for small appliances.
  • Recycling cleans refrigerant on site; reclamation reprocesses it to new-product specification and requires a laboratory analysis.

Worked example

A recovery cylinder has a tare of 15 kg and a water capacity of 50 kg. Maximum refrigerant = 0.80 × 50 = 40 kg, so maximum gross weight = 15 + 40 = 55 kg. Filling stops on the scale at 55 kg regardless of what the gauge says.

Traps

  • Charging a zeotropic blend as vapour.
  • Venting "just a little" to clear a hose.
  • Using a cylinder with no tare weight or an expired test date.
  • Adding mineral oil to an HFC system.