HVAC Refrigerant Recovery and Handling 5 — Questions and Answers
Question 1: What action is required if a technician discovers that recovered refrigerant in a cylinder tests positive for high moisture content?
- Add a filter-drier to the cylinder to remove moisture
- Return it to the original system only after verifying the system is dry
- Send it to a certified reclaimer—do not reuse it on any system (Correct answer)
- Vent the cylinder outdoors in a well-ventilated area and reuse the cylinder
Correct answer: Send it to a certified reclaimer—do not reuse it on any system
Contaminated refrigerant with high moisture must be sent to a certified reclaimer; reusing moisture-laden refrigerant can cause acid formation and system damage.
Question 2: Under EPA Section 608, which entity is solely authorized to reclaim refrigerant back to ARI 700 purity standards for resale?
- Any EPA 608-certified HVAC technician
- The original equipment manufacturer (OEM)
- A facility certified by the EPA as a refrigerant reclaimer (Correct answer)
- A state-licensed HVAC contractor with a reclamation endorsement
Correct answer: A facility certified by the EPA as a refrigerant reclaimer
Only facilities that have registered with the EPA as certified refrigerant reclaimers may reclaim refrigerant to ARI 700 standards for resale.
Question 3: What is the purpose of the Schrader valve depressor tool used during refrigerant recovery?
- It prevents the recovery hose from crimping during liquid recovery
- It depresses the Schrader core to allow refrigerant flow without removing the core (Correct answer)
- It seals the valve port after recovery to prevent refrigerant loss
- It regulates flow rate to prevent flash evaporation in the hose
Correct answer: It depresses the Schrader core to allow refrigerant flow without removing the core
A Schrader valve depressor on recovery hose fittings keeps the valve core pressed open continuously, allowing full refrigerant flow during recovery.
Question 4: A technician recovers R-134a from an automotive system into a recovery cylinder and wants to reuse this refrigerant in an HVAC system. What is the problem with this plan?
- R-134a recovered from automotive systems contains PAG oil incompatible with HVAC systems using POE oil (Correct answer)
- R-134a is not approved for use in stationary HVAC equipment by EPA
- Automotive R-134a is a different grade than HVAC-grade R-134a
- Recovery cylinders used for automotive refrigerant cannot be used for HVAC refrigerant
Correct answer: R-134a recovered from automotive systems contains PAG oil incompatible with HVAC systems using POE oil
Automotive systems use PAG oil which is immiscible with the POE oil used in most stationary HVAC systems, making cross-use problematic without reclamation.
Question 5: What does it mean when a recovery machine's low-pressure switch trips and shuts the machine down during recovery?
- The system has been fully evacuated and recovery is complete
- The recovery cylinder is too warm and needs cooling
- The recovery machine's compressor is overloaded from liquid refrigerant slugging
- The suction pressure has dropped below the switch setpoint, indicating the system is nearly empty (Correct answer)
Correct answer: The suction pressure has dropped below the switch setpoint, indicating the system is nearly empty
The low-pressure switch protects the recovery machine by shutting off when suction pressure drops too low, typically indicating the system refrigerant charge is nearly depleted.
Question 6: Which safety precaution is most critical when recovering refrigerant from a system suspected of having a burnout?
- Recover at maximum machine speed to minimize exposure time
- Use an acid test kit after recovery and replace the recovery machine's filter before next use (Correct answer)
- Recover only vapor—never liquid—from a burnt-out system
- Wear only standard work gloves since HFC refrigerants are non-toxic
Correct answer: Use an acid test kit after recovery and replace the recovery machine's filter before next use
Burned-out systems produce acid and carbonized oil contaminants that can damage recovery equipment, so testing for acid and replacing the machine's internal filter after recovery is essential.
Question 7: What is the correct way to determine if a recovery cylinder is safe to continue filling during active recovery?
- Tap the cylinder with a wrench to hear if it sounds hollow or full
- Monitor the cylinder's pressure gauge and weight simultaneously against the refrigerant's maximum fill capacity (Correct answer)
- Continue filling until the relief valve opens, then stop
- Use the cylinder until the recovery machine's discharge pressure exceeds 200 psig
Correct answer: Monitor the cylinder's pressure gauge and weight simultaneously against the refrigerant's maximum fill capacity
Safe fill level is determined by monitoring both pressure and weight—cylinders must not exceed 80% liquid fill by volume, verified by weight at the given temperature.
HVAC Refrigerant Recovery and Handling 5
What action is required if a technician discovers that recovered refrigerant in a cylinder tests positive for high moisture content?