CFC Recovery Equipment & Techniques 2 — Questions and Answers
Question 1: What is the minimum required recovery efficiency for systems containing more than 200 pounds of refrigerant when using system-dependent (passive) recovery equipment?
- 70%
- 80%
- 90% (Correct answer)
- 95%
Correct answer: 90%
EPA regulations require 90% recovery efficiency for systems with more than 200 pounds of refrigerant using system-dependent equipment.
Question 2: Which type of recovery cylinder is specifically prohibited for use when recovering refrigerants?
- DOT-approved recovery cylinders
- Previously used refrigerant cylinders with intact valves
- Disposable cylinders originally used for refrigerant (Correct answer)
- Gray-bodied cylinders with yellow tops
Correct answer: Disposable cylinders originally used for refrigerant
Disposable (non-refillable) cylinders must never be reused for refrigerant recovery as they are not designed to withstand refilling pressures.
Question 3: When recovering refrigerant from a system with a severely contaminated compressor, the BEST practice is to:
- Use the system compressor to push refrigerant into the recovery cylinder
- Recover through the high-side port only to avoid drawing oil
- Use a dedicated recovery machine with an oil separator (Correct answer)
- Vent the refrigerant and replace with fresh refrigerant
Correct answer: Use a dedicated recovery machine with an oil separator
A recovery machine with an oil separator prevents contaminated oil and debris from damaging the recovery equipment and keeps the recovered refrigerant cleaner.
Question 4: What does a 'push-pull' recovery method accomplish that single-port recovery does not?
- It allows recovery without a recovery machine
- It speeds recovery by simultaneously pushing vapor from the high side and pulling from the low side (Correct answer)
- It eliminates the need for an oil separator
- It allows liquid recovery without risk of slugging
Correct answer: It speeds recovery by simultaneously pushing vapor from the high side and pulling from the low side
Push-pull recovery uses both high and low side ports simultaneously to accelerate refrigerant removal from the system.
Question 5: A technician notices the recovery machine is running but refrigerant flow has stopped and suction pressure has risen. The MOST likely cause is:
- The recovery cylinder is empty
- The recovery machine's internal check valve has failed open
- The recovery cylinder is full or the recovery machine is overheating (Correct answer)
- The system refrigerant has all been recovered
Correct answer: The recovery cylinder is full or the recovery machine is overheating
Rising suction pressure with no flow typically indicates the recovery cylinder is at capacity or the machine has shut down due to high discharge temperature.
Question 6: Before connecting recovery equipment to a system, a technician should FIRST:
- Open all system service valves fully
- Purge the recovery hoses with nitrogen
- Identify the refrigerant type using an identifier (Correct answer)
- Set the recovery machine to maximum speed
Correct answer: Identify the refrigerant type using an identifier
Identifying the refrigerant type before recovery prevents cross-contamination and ensures the correct recovery cylinder is used.
Question 7: What happens to recovery efficiency when ambient temperature is very low during the recovery process?
- Efficiency increases because refrigerant condenses faster
- Efficiency decreases because low temperature reduces refrigerant vapor pressure (Correct answer)
- Efficiency is unaffected because recovery machines compensate automatically
- Efficiency increases because the recovery cylinder absorbs refrigerant faster
Correct answer: Efficiency decreases because low temperature reduces refrigerant vapor pressure
Low ambient temperatures reduce refrigerant vapor pressure, making it harder to pull vapor into the recovery machine and reducing overall efficiency.
CFC Recovery Equipment & Techniques 2
What is the minimum required recovery efficiency for systems containing more than 200 pounds of refrigerant when using system-dependent (passive) recovery equipment?