Practice Test Geeks(CFC) Chlorofluorocarbon Certification Practice Test
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System Charging & Evacuation Flashcards

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

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  1. What is the primary reason for using a two-stage evacuation process on large refrigeration systems?

    Answer: It removes moisture and non-condensables more effectively than a single-stage pull-down

    Two-stage evacuation breaks the process into intervals, allowing trapped moisture to vaporize and be removed more thoroughly than a single continuous pull-down.

  2. When charging a refrigeration system with a blended refrigerant such as R-410A, the refrigerant must be:

    Answer: Charged as a liquid to maintain proper blend composition

    Blended refrigerants like R-410A must be charged as liquid because vapor-phase charging causes fractionation, altering the blend ratio.

  3. A vacuum gauge reads 29.5 in Hg during evacuation. What does this approximately equal in microns?

    Answer: 1,270 microns

    29.5 in Hg corresponds to approximately 1,270 microns of mercury (µmHg) on the absolute pressure scale.

  4. Which condition indicates that a system is not holding a vacuum after the pump is isolated?

    Answer: The micron gauge reading rises steadily and does not level off

    A continuously rising micron gauge after pump isolation indicates a leak, because moisture or non-condensables alone would cause the reading to stabilize at a higher level.

  5. What is the recommended recovery cylinder fill limit by weight to prevent hydrostatic overpressure?

    Answer: 80% of the cylinder's rated capacity

    Recovery cylinders should never be filled beyond 80% of their rated capacity by weight to allow for refrigerant expansion and prevent hydrostatic rupture.

  6. After completing a nitrogen pressure test on a new installation, the technician must do what before beginning evacuation?

    Answer: Install the service valve cores and connect the vacuum pump

    Nitrogen is not a regulated substance and can be vented, but service valve cores must be installed before evacuation so the vacuum pump can draw the system to the required vacuum level.

  7. A technician is top-charging a system with R-22. Which method is acceptable under EPA Section 608 rules?

    Answer: Adding refrigerant vapor through the low-side port with the compressor running

    Adding refrigerant vapor through the low-side service port with the compressor running is standard practice and does not introduce liquid to the compressor suction.