Practice Test GeeksEPA 609 - EPA Section 609 Refrigerant Certification Practice Test
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Leak Detection & System Diagnosis Flashcards

7 cards from real EPA 609 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. Which type of leak detector offers the highest sensitivity for finding very small refrigerant leaks?

    Answer: Heated diode (infrared) or heated element electronic detector

    Heated diode and infrared electronic detectors are highly sensitive to refrigerant molecules and can detect leaks as small as 0.1 oz/year, far below what other methods can detect.

  2. A vacuum pull-down test is used in MVAC service to:

    Answer: Verify the system holds a vacuum, confirming no leaks remain after repair

    After evacuation, monitoring the vacuum gauge for 15–30 minutes confirms the system is leak-free and moisture-free — if vacuum rises (pressure increases), a leak or residual moisture is still present.

  3. Under EPA Section 609, if a technician discovers a leak during MVAC service, the required action is:

    Answer: Recover the refrigerant and repair the leak before recharging

    EPA 609 regulations require that leaks be repaired before refrigerant is recharged, preventing the intentional venting of refrigerant into the atmosphere.

  4. What does a restriction in the HIGH side of an MVAC system (such as a plugged liquid line drier) typically cause?

    Answer: High pressure upstream of the restriction, low pressure downstream toward the metering device

    A high-side restriction creates abnormally high pressure before the blockage and starves the metering device of liquid refrigerant downstream, reducing cooling performance.

  5. Nitrogen is sometimes used during leak testing of MVAC systems because:

    Answer: Nitrogen is an inert, dry gas that safely pressurizes the system for leak checking without adding moisture

    Dry nitrogen is inert and moisture-free, making it safe for pressurizing recovered or empty MVAC systems to locate leaks without risk of contamination or chemical reaction.

  6. After completing refrigerant charge on an MVAC system, system performance is most accurately verified by:

    Answer: Measuring vent outlet temperature and comparing manifold pressures to specification charts

    Measuring actual vent temperature (typically 35–45°F from center vents) and comparing gauge pressures to ambient-temperature-based specification charts confirms the system is performing within design parameters.

  7. A refrigerant identifier should be used before recovering refrigerant from an MVAC system primarily to:

    Answer: Detect refrigerant contamination or incorrect refrigerant type that could damage recovery equipment

    Contaminated or mixed refrigerants can damage recovery machines and cross-contaminate the recovery cylinder; identifying the refrigerant type first protects equipment and ensures proper handling.