MACS 609 CERTIFICATION EXAM PRACTICE QUESTIONS COMPLETE WITH 100% CORRECT ANSWERS

MACS 609 CERTIFICATION EXAM PRACTICE QUESTIONS COMPLETE WITH 100% CORRECT ANSWERS 1. If lubricant is removed by recovery equipment during system refrigerant removal, what must be done with the lubricant? A) Discard the lubricant and replace with new lubricant B) Re-install lubricant removed by the recovery equipment C) Send the lubricant to a recycling facility D) Store the lubricant for future use in other systems Correct Answer: B) Re-install lubricant removed by the recovery equipment Rationale: The lubricant removed during refrigerant recovery must be reinstalled into the system to ensure proper lubrication of the compressor and other components. Failing to reinstall the lubricant can lead to compressor failure. ________________________________________ 2. Before reuse, what must be done with HFC-134a that has been recovered from a mobile A/C system using recovery-only equipment? A) It can be reused immediately without any treatment B) Recycle the HFC-134a before reuse using certified equipment C) Dispose of the recovered refrigerant as hazardous waste D) Filter the refrigerant using a coffee filter Correct Answer: B) Recycle the HFC-134a before reuse using certified equipment Rationale: Recovery-only equipment simply removes the refrigerant. Before the refrigerant can be reused, it must be recycled using certified equipment to remove contaminants, moisture, and acid that may have accumulated in the system. ________________________________________ 3. When can HFC-134a become combustible in a mobile air conditioning system? A) When exposed to direct sunlight B) If shop air is used in the system in an attempt to check for leaks and HFC-134a is present C) When mixed with nitrogen D) When the system pressure exceeds 200 psi Correct Answer: B) If shop air is used in the system in an attempt to check for leaks and HFC-134a is present Rationale: HFC-134a can become combustible when mixed with shop air under pressure. Shop air contains oxygen, and the combination with refrigerant under high pressure can create a flammable mixture. Never use compressed air to leak test an A/C system. ________________________________________ 4. Which type of mobile A/C system will usually require additional time/precautions to extract all the refrigerant? A) Orifice tube system B) Accumulator type C) Expansion valve system D) Thermostatic expansion valve system Correct Answer: B) Accumulator type Rationale: Accumulator-type systems typically require more time and precautions during refrigerant extraction because the accumulator can trap refrigerant oil and refrigerant, making complete removal more challenging. ________________________________________ 5. Electronic leak detectors certified to SAE J2791 have the capacity of identifying leakage rates as low as: A) 0.50 ounces per year B) 1.00 ounces per year C) 0.15 ounces per year D) 0.05 ounces per year Correct Answer: C) 0.15 ounces per year Rationale: SAE J2791 certified electronic leak detectors are sensitive enough to detect leakage rates as low as 0.15 ounces per year, which is approximately 4 grams per year, making them effective for identifying small refrigerant leaks. ________________________________________ 6. When recovery/recycling equipment is used to remove refrigerant from a mobile A/C system, how much lubricant will be removed during the operation? A) Most of the lubricant will be removed B) Generally, very little, if any C) Approximately 50% of the lubricant D) All lubricant must be removed Correct Answer: B) Generally, very little, if any Rationale: During normal refrigerant recovery, very little lubricant is removed because refrigerant and lubricant have different boiling points and physical properties. The recovery process primarily removes refrigerant vapor, leaving most lubricant in the system. ________________________________________ 7. Why is it necessary to ensure that service port caps containing good seals are installed? A) To prevent dirt from entering the system B) To minimize refrigerant loss C) To maintain system pressure D) To prevent unauthorized access Correct Answer: B) To minimize refrigerant loss Rationale: Service port caps with good seals help prevent refrigerant from slowly leaking out through the service ports. Even though small, these leaks contribute to refrigerant loss over time and can lead to system inefficiency. ________________________________________ 8. Which of the following statements is correct about flushing A/C systems? A) Flushing is always required after any repair B) Flushing solvents may remain in A/C systems, causing problems