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 measures a compressor drawing high amperage with low suction and high discharge pressure. What is the most likely diagnosis?

    Answer: Refrigerant overcharge

    Refrigerant overcharge increases system pressures and compressor workload, resulting in elevated amperage draw.

  2. A homeowner complains of short cycling. The technician measures that the compressor runs for less than 2 minutes per cycle. Which component should be tested first?

    Answer: High and low pressure safety switches

    Short cycling is frequently caused by pressure switches that trip due to abnormal operating pressures, making them the first item to test.

  3. A technician notices the system cools adequately in the morning but loses capacity significantly in the afternoon heat. Which diagnosis is most consistent with this behavior?

    Answer: Dirty or blocked condenser coil

    A partially blocked condenser coil can handle lighter loads in cooler morning temperatures but cannot reject adequate heat when ambient temperatures peak in the afternoon.

  4. While troubleshooting a residential system, a technician finds oil stains near the compressor service valves. What does this indicate?

    Answer: A refrigerant and oil leak at that location

    Oil stains near refrigerant connections indicate a refrigerant leak, since oil travels with refrigerant and deposits at leak points.

  5. What is the purpose of measuring the temperature difference across a filter-drier (liquid line drier) during operation?

    Answer: To detect a restriction inside the drier

    A notable temperature drop across a filter-drier (more than 1–2°F) indicates the drier is restricted and should be replaced.

  6. A technician is troubleshooting a system with intermittent cooling. The contactor closes normally but the compressor hums and does not start. What is the most likely cause?

    Answer: Failed run capacitor

    A failed or weak run capacitor prevents the compressor from developing enough starting torque, causing it to hum without starting.

  7. When a residential air conditioner produces adequate cooling but the homeowner reports unusually high humidity indoors, what should the technician evaluate?

    Answer: Evaporator coil temperature and airflow rate

    Excessive airflow or elevated evaporator coil temperature reduces the system's ability to condense and drain moisture from the air.