Practice Test Geeks(A2L) A2L Low GWP Flammable Refrigerant Safety Certification Practice Test
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Specific Service Procedures Flashcards

6 cards from real A2L practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Specific Service Procedures flashcards as text

  1. When performing a standing pressure test on an A2L system, what gas must be used?

    Answer: Dry nitrogen — never pressurize with oxygen, air, or refrigerant for testing

    Nitrogen is inert (non-flammable, non-reactive) and safe for pressure testing. Compressed air contains moisture and oxygen; oxygen with A2L refrigerant residue could create a dangerous mixture.

  2. What is the minimum evacuation (vacuum) level required before charging an A2L system?

    Answer: Typically 500 microns (0.5 mm Hg) or below, held for a specified time, per manufacturer requirements

    A deep vacuum (500 microns or lower) removes moisture and non-condensables from the system. Moisture is particularly problematic in A2L systems as it can create acids that degrade components.

  3. After brazing a repair on an A2L system, what tests must be performed before recharging?

    Answer: Pressure test with nitrogen to verify the repair is leak-free, then evacuate to 500 microns to remove moisture, then leak test all connections before charging

    Post-repair testing follows a sequence: verify the repair integrity (pressure test), prepare the system (evacuation), then verify all connections (leak test) before introducing flammable refrigerant.

  4. How should a technician handle an A2L system that has been contaminated with moisture?

    Answer: Recover all refrigerant, replace the filter-drier, perform a triple evacuation with nitrogen breaks, and recharge with fresh refrigerant

    Moisture contamination requires aggressive remediation: complete refrigerant recovery and disposal, new filter-drier, thorough evacuation (triple evacuation for severe contamination), and fresh charge.

  5. What is the correct method for checking an A2L system's superheat?

    Answer: Same method as R-410A, but for A2L BLENDS, use the dew point (not boiling point) for the saturation temperature at suction pressure

    Superheat measurement is the same concept, but for zeotropic A2L blends (like R-454B with temperature glide), the dew point temperature at suction pressure must be used, not the bubble point.

  6. A system has both R-410A and R-454B versions available. The existing linesets are copper. Can R-454B be used with the existing copper tubing?

    Answer: Yes — R-454B is compatible with standard copper tubing, though line sizes may need to match the new system's specifications

    A2L refrigerants like R-454B are compatible with standard ACR copper tubing. Line sizes should match the new system's requirements, which may differ from R-410A sizing.