Practice Test Geeks(313D) Residential Air Conditioning Systems Mechanic Certification Practice Test
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Fundamentals of Air Conditioning Systems Flashcards

7 cards from real 313D practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Fundamentals of Air Conditioning Systems flashcards as text

  1. When charging an R-410A system, the refrigerant cylinder must be kept upright or inverted so that:

    Answer: Liquid is drawn from the cylinder because R-410A is a near-azeotrope blend

    R-410A is a near-azeotropic blend that must be charged as a liquid to maintain the correct refrigerant composition ratio.

  2. What is the typical temperature differential (TD) across a properly functioning residential evaporator coil?

    Answer: 16–22°F

    A properly charged residential system typically produces a 16–22°F temperature drop across the evaporator coil from return to supply air.

  3. Which component prevents liquid refrigerant from entering the compressor during startup?

    Answer: Accumulator

    An accumulator is installed on the suction line to trap and hold any liquid refrigerant before it reaches the compressor, preventing liquid slugging.

  4. A technician finds that both high and low side pressures are lower than normal but the system is cooling adequately. This most likely indicates:

    Answer: Low outdoor ambient temperature reducing load

    Lower ambient temperatures reduce the heat load, causing both suction and discharge pressures to drop while the system continues to operate normally.

  5. What is the purpose of the crankcase heater on a compressor?

    Answer: To prevent refrigerant migration and oil dilution in the crankcase during off cycles

    The crankcase heater keeps the oil warm so refrigerant does not migrate into and dilute the compressor oil during the off cycle, protecting bearings on startup.

  6. According to EPA Section 608 regulations, technicians who service systems containing more than 50 lbs of refrigerant must use recovery equipment that meets which standard?

    Answer: ARI 740 performance standard

    EPA regulations require that recovery equipment for systems over 50 lbs meet ARI 740 performance efficiency standards.

  7. What is the result of non-condensable gases (such as air) in a refrigerant system?

    Answer: Higher-than-normal head pressure, elevated condenser temperature, and reduced efficiency

    Non-condensable gases occupy condenser volume and cannot condense, raising head pressure and reducing system efficiency and capacity.