Questions and Answers
If lubricant is removed by recovery equipment during system refrigerant removal, what must be done with the lubricant?
Re-install lubricant removed by the recovery equipment
Before reuse, what must be done with HFC-134a that has been recovered from a mobile A/C system using recovery-only equipment?
When can HFC-134a become combustible in a mobile air conditioning system?
If shop air is used in the system in an attempt to check for leaks and HFC-134a is present
Which type of mobile A/C system will usually require additional time/precautions to extract all the refrigerant?
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Electronic leak detectors certified to SAE J2791 have the capacity of identifying leakage rates as low as:
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When recovery/recycling equipment is used to remove refrigerant from a mobile A/C system, how much lubricant will be removed during the operation?
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Why is it necessary to ensure that service port caps containing good seals are installed?
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Which of the following statements is correct about flushing A/C systems?
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When using an HFC-134a refrigerant recovery machine, after completing the first recovery process, how long must you wait, then check the machine's gauges for a rise in pressure above vacuum?
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Which type of tank must be used during the transfer of refrigerant?
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When it has been determined that an A/C system has a low refrigerant charge, what should be done?
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One effect of some refrigerant gases in the atmosphere is that they:
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Mixing CFC-12 and HFC-134a in the same system will:
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How much moisture is removed from a mobile A/C system during a typical evacuation?
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Paid technicians who service or repair mobile A/C systems using HFC-22 as refrigerant, or service cargo refrigeration equipment:
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HFO-1234yf is classified as 'A2L-mildly flammable.' This means:
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Section 609 of the Clean Air Act requires that recovery/recycling equipment:
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What is the advantage of using refrigerant identification equipment?
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When performing engine pre-heat for refrigerant removal, the technician should do ALL of the following EXCEPT:
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If a large amount of lubricant is removed from a system during refrigerant recovery:
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PAG lubricant:
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Specific safety information for managing incidents involving refrigerants and other chemicals (inhalation, spills, fires, etc) is found in the:
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What is not identified in the manual as a concern with field-coupled hoses?
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Which of the following is NOT a factor in how much refrigerant can be recovered from an A/C system?
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HFO-1234yf can be used in:
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Study Notes
Refrigerant Recovery and Management
- Reinstall lubricant removed by recovery equipment during refrigerant removal.
- HFC-134a must be recycled before reuse using certified equipment.
- HFC-134a can become combustible if shop air is introduced while checking for leaks.
- Accumulator type mobile A/C systems require more time and precautions to extract refrigerant.
Leak Detection and Equipment
- Electronic leak detectors certified to SAE J2791 can identify leakage rates as low as 0.15 ounces per year.
- Recovery/recycling equipment generally removes very little to no lubricant from A/C systems.
- Service port caps with good seals are essential to minimize refrigerant loss.
A/C System Maintenance
- Flushing A/C systems can leave solvents behind, potentially causing problems.
- After the first recovery process with HFC-134a recovery machine, wait 5 minutes to check for pressure rise indicating remaining refrigerant.
- Tanks marked DOT 4BA must be used for refrigerant transfer.
Refrigerant Charge and Environmental Impact
- Perform leak detection if an A/C system has a low refrigerant charge.
- Certain refrigerant gases in the atmosphere contribute to heat trapping.
- Mixing CFC-12 and HFC-134a results in refrigerant cross contamination.
Moisture and Technician Certification
- A typical evacuation of a mobile A/C system may remove no moisture.
- Technicians servicing mobile A/C systems using HFC-22 must be Section 608 Type II certified.
Safety and Regulations
- HFO-1234yf is mildly flammable (A2L) and can ignite under certain conditions.
- Recovery/recycling equipment must be registered with the EPA under Section 609 of the Clean Air Act.
- Refrigerant identification equipment helps determine the type of refrigerant in the system.
Best Practices in Refrigerant Handling
- During engine pre-heat for refrigerant removal, do not ensure that the compressor is operating.
- A large amount of lubricant removal indicates the system likely had excessive lubricant.
- PAG lubricant is hygroscopic, meaning it absorbs moisture.
Chemical Safety and Equipment Concerns
- Specific safety information for refrigerants and chemicals is found in the Material Safety Data Sheet (MSDS).
- The length of field-coupled hoses is not identified as a concern in management manuals.
- The age of the vehicle is not a factor in how much refrigerant can be recovered from an A/C system.
Applications of HFO-1234yf
- HFO-1234yf can be used in any light vehicle with an A/C system specifically designed for it.
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Description
Test your knowledge on refrigerant recovery and lubricant management with these flashcards for MACS 609 certification. Each card covers essential practices for handling HFC-134a and lubricants in A/C systems. Perfect for those preparing for MACS certification exams.