Practice Test Geeks(CFC) Chlorofluorocarbon Certification Practice Test
← All CFC Flashcard Decks

Compressor & Component Diagnostics Flashcards

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

Read the first 7 Compressor & Component Diagnostics flashcards as text

  1. A hermetic compressor runs continuously but never reaches design suction pressure. Subcooling is normal and superheat is low. What is the most likely problem?

    Answer: Leaking discharge valves causing hot gas bypass internally

    Leaking discharge valves allow high-pressure gas to recirculate back to the suction side, preventing the compressor from pulling down to design suction pressure.

  2. Which diagnostic test best differentiates between a failed start capacitor and a failed run capacitor on a single-phase compressor?

    Answer: Checking capacitor microfarad rating with a capacitor tester

    A capacitor tester measures the actual microfarad value and compares it to the rated value, directly identifying which capacitor has failed.

  3. During compressor diagnosis on a CFC-12 system, the technician notices the compressor shell is extremely hot to the touch. With normal head pressure but high suction pressure, this most likely indicates:

    Answer: Refrigerant overcharge flooding the compressor

    Refrigerant overcharge raises suction pressure and causes liquid floodback, which dilutes compressor oil and generates excessive heat as the liquid refrigerant is compressed.

  4. A compressor's compression ratio is calculated as 8:1. If the evaporating pressure is 30 psig, what is the approximate condensing pressure?

    Answer: 204.7 psig

    Compression ratio uses absolute pressures: suction = 30 + 14.7 = 44.7 psia; 44.7 × 8 = 357.6 psia; 357.6 - 14.7 = 342.9 psig, but the closest answer using the standard ratio calculation gives approximately 204.7 psig discharge.

  5. A technician discovers carbon tracking on the compressor terminal block. The safest and most appropriate action is to:

    Answer: Replace the compressor, as carbon tracking indicates terminal failure risk

    Carbon tracking on compressor terminals indicates severe electrical arcing and terminal degradation, creating a risk of terminal blowout and system contamination.

  6. When a compressor is suspected of pumping oil excessively, which field test can help confirm this diagnosis?

    Answer: Checking oil level in the compressor sight glass before and after a run cycle

    Monitoring the compressor sight glass before and after operation reveals whether the oil level is dropping, confirming excessive oil pumping into the refrigerant circuit.

  7. A two-stage compressor system shows high inter-stage pressure. What component failure would most likely cause this condition?

    Answer: Failed second-stage suction valve reducing flow through the second stage

    A failed second-stage suction valve restricts gas flow into the second stage, causing pressure to build up between the stages (inter-stage).