Practice Test Geeks(313D) Residential Air Conditioning Systems Mechanic Certification Practice Test
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Troubleshooting and System Diagnosis 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 Troubleshooting and System Diagnosis flashcards as text

  1. A technician finds the outdoor unit operating but no air movement from supply registers. The indoor unit is energized. What is the most logical first check?

    Answer: Indoor blower motor and capacitor

    If the indoor unit is powered but there is no airflow, the blower motor or its run capacitor has likely failed.

  2. What does it mean when the evaporator coil is completely encased in ice?

    Answer: Airflow is severely restricted or the refrigerant charge is very low

    Complete icing of the evaporator coil results from either severely restricted airflow or a very low refrigerant charge, both of which drop coil temperature below freezing.

  3. During system commissioning, measured suction pressure is within range, but subcooling is 3°F when the spec calls for 10–15°F. What does this indicate?

    Answer: Refrigerant undercharge

    Low subcooling indicates insufficient liquid refrigerant in the condenser, which is a sign of refrigerant undercharge.

  4. A homeowner reports water dripping from the indoor air handler. The evaporator coil is clear and not frosted. What is the most likely cause?

    Answer: Clogged condensate drain line

    A blocked condensate drain prevents condensate from flowing away from the unit, causing it to overflow and drip from the air handler.

  5. A technician uses a clamp meter to measure compressor amperage. The reading is 20% below the rated load amps (RLA). What does this suggest?

    Answer: The compressor has internal valve leakage reducing workload

    A compressor drawing significantly less than its RLA may indicate worn or leaking internal valves that reduce compression efficiency.

  6. A residential system is equipped with a TXV (thermostatic expansion valve). The technician finds high superheat and low suction pressure. What should be inspected?

    Answer: TXV bulb mounting and charge, and refrigerant charge level

    A TXV that is underfeeding the evaporator (due to a faulty bulb, lost bulb charge, or low system charge) causes high superheat and low suction pressure.

  7. After a thunderstorm, a residential system has no cooling. The indoor fan operates, but the outdoor unit does not run. What is the most likely first item to check?

    Answer: Outdoor unit disconnect and fuses or circuit breaker

    Power surges from storms frequently blow fuses or trip breakers to the outdoor unit, making electrical supply the first item to verify.