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Refrigeration Fundamentals Flashcards

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

Read the first 6 Refrigeration Fundamentals flashcards as text

  1. What is the coefficient of performance (COP) used to measure in HVAC?

    Answer: The efficiency of a heating or cooling system

    COP is the ratio of useful heating or cooling output to the energy input, with a higher COP indicating a more efficient system.

  2. What refrigerant replaced R-22 (Freon) in most residential air conditioning systems in the US?

    Answer: R-410A

    R-410A became the standard replacement for R-22 in residential AC systems due to R-22's phase-out under the Clean Air Act.

  3. What is an Thermostatic Expansion Valve (TXV) designed to maintain?

    Answer: Constant superheat at the evaporator outlet

    A TXV senses suction line temperature and pressure to modulate refrigerant flow and maintain a constant superheat at the evaporator outlet.

  4. What does a low suction pressure reading typically indicate?

    Answer: Restricted airflow over the evaporator or low refrigerant charge

    Low suction pressure commonly indicates a low refrigerant charge, restricted metering device, or insufficient airflow across the evaporator coil.

  5. Which type of compressor uses a rotating scroll to compress refrigerant?

    Answer: Scroll compressor

    A scroll compressor uses two interlocking spiral-shaped scrolls—one fixed and one orbiting—to compress refrigerant vapor.

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

    Answer: To keep refrigerant from migrating into the compressor oil during the off cycle

    A crankcase heater keeps the compressor oil warm during the off cycle to prevent liquid refrigerant from migrating and diluting the oil.