ASE Refrigerant Recovery, Recycling, and Handling 2 — Questions and Answers
Question 1: Recovery cylinders used to store used (contaminated) refrigerant must be labeled:
- With the vehicle VIN from which it was recovered
- 'Mixed Refrigerant — Do Not Recycle'
- 'Used Refrigerant — Do Not Mix with New Refrigerant' (Correct answer)
- With the technician's certification number
Correct answer: 'Used Refrigerant — Do Not Mix with New Refrigerant'
DOT regulations require recovered (used) refrigerant cylinders to be clearly labeled to prevent the used refrigerant from being mistakenly introduced into a new vehicle system.
Question 2: What minimum vacuum level should an A/C system reach and hold during a proper evacuation?
- 10 inches Hg
- 20 inches Hg
- 29 inches Hg (500 microns or below) (Correct answer)
- 15 inches Hg
Correct answer: 29 inches Hg (500 microns or below)
A proper evacuation should pull the system to 500 microns (approximately 29.9 in Hg) or below to ensure all moisture and air are removed before recharging.
Question 3: Mixing different types of refrigerants (e.g., R-134a and R-1234yf) in the same cylinder or system is:
- Acceptable if the mix is less than 10% by weight
- Prohibited and creates a contaminated blend that cannot be recycled on-site (Correct answer)
- Allowed only when approved by the vehicle manufacturer
- Permitted for older vehicles over 10 years old
Correct answer: Prohibited and creates a contaminated blend that cannot be recycled on-site
Mixing refrigerants creates a contaminated blend that cannot be recycled on standard equipment and must be sent to a reclaimer, making it both costly and non-compliant.
Question 4: Which of the following is TRUE regarding the purchase of R-134a in containers larger than 2 lbs?
- Anyone can purchase it at an auto parts store without restriction
- Only EPA Section 609-certified technicians may purchase it (Correct answer)
- A state license is required in addition to federal certification
- It is no longer available for purchase in the United States
Correct answer: Only EPA Section 609-certified technicians may purchase it
Since January 2018, EPA Section 609 certification is required to purchase R-134a in containers larger than 2 lbs to ensure proper handling by trained personnel.
Question 5: An electronic refrigerant leak detector is being used after an A/C repair. Where should the technician START the inspection?
- At the highest point of the system since refrigerant rises
- At the compressor front seal only
- At the lowest points and A/C fittings since refrigerant vapors are heavier than air (Correct answer)
- At the cabin air filter to detect interior leaks first
Correct answer: At the lowest points and A/C fittings since refrigerant vapors are heavier than air
Refrigerant vapors from R-134a and R-1234yf are heavier than air and settle at the lowest points, so checking fittings, hose connections, and low areas first improves detection accuracy.
Question 6: What does a HIGH discharge (high-side) pressure reading combined with a NORMAL low-side pressure indicate during A/C diagnosis?
- Refrigerant undercharge
- Restricted condenser airflow or condenser malfunction (Correct answer)
- Compressor internal leak
- Expansion valve stuck open
Correct answer: Restricted condenser airflow or condenser malfunction
A high discharge pressure with normal suction pressure typically indicates the condenser cannot reject heat efficiently, usually due to blocked airflow, fins, or fan failure.
Question 7: Recovery cylinders for refrigerant must be hydrostatically tested and replaced or retested every:
- 2 years
- 5 years (Correct answer)
- 10 years
- 15 years
Correct answer: 5 years
DOT regulations require refrigerant recovery cylinders to be re-tested every 5 years (or 12 years for some cylinder types) to ensure structural integrity under pressure.
ASE Refrigerant Recovery, Recycling, and Handling 2
Recovery cylinders used to store used (contaminated) refrigerant must be labeled: