Practice Test Geeks(RSES) Refrigeration Service Engineers Society Certification Practice Test
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Expansion Devices Flashcards

7 cards from real RSES 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. A low-side float valve opens when the liquid level in the evaporator:

    Answer: Falls below the setpoint

    When liquid level drops, the float falls and opens the valve to admit more refrigerant, maintaining the correct flooded level.

  2. Which factor primarily determines the refrigerant flow capacity of a capillary tube?

    Answer: Tube length and inside diameter

    Capillary tube flow capacity is determined by its length and inside diameter, with shorter/larger diameter tubes passing more refrigerant.

  3. An electronic expansion valve (EEV) in a variable refrigerant flow (VRF) system is typically controlled by:

    Answer: A microprocessor receiving inputs from multiple sensors

    EEVs in VRF systems are controlled by microprocessors using inputs such as suction superheat, coil temperature, and load demand for optimal performance.

  4. When replacing a TXV, which specification is most critical to match?

    Answer: Refrigerant type, capacity rating, and evaporator temperature range

    The replacement TXV must be rated for the same refrigerant, system capacity, and operating temperature range to ensure proper performance.

  5. What symptom would a refrigeration technician observe if the TXV sensing bulb loses its refrigerant charge?

    Answer: TXV closes fully, starving the evaporator

    Without bulb pressure as the opening force, the spring pressure keeps the TXV closed, starving the evaporator and causing high superheat.

  6. The short-tube orifice (fixed orifice) expansion device is commonly used in which type of system?

    Answer: Residential heat pumps with scroll compressors

    Short-tube orifices are widely used in residential heat pumps because they allow bidirectional flow needed for heating and cooling mode switching.

  7. Technician A says superheat should be measured at the evaporator outlet. Technician B says superheat should be measured at the compressor inlet. Who is correct?

    Answer: Both technicians, depending on what is being measured

    Evaporator superheat is measured at the evaporator outlet for TXV adjustment, while total (compressor) superheat is measured at the compressor inlet for overall system evaluation.