Refrigerant recovery is one of the most fundamental and most regulated procedures in HVAC service work. Since the Clean Air Act established the Section 608 venting prohibition, every technician has been required to recover refrigerant before opening a system. The AIM Act’s Subpart C extends similar requirements to HFC refrigerants. Getting recovery right means doing it safely, completely, and with proper documentation.
Before You Start: Pre-Recovery Assessment
Identify the Refrigerant
Never assume you know what refrigerant is in a system. Verify the type using the equipment nameplate, service records, or a refrigerant identifier. Mixed or unknown refrigerants must go into dedicated contaminated refrigerant cylinders. Common identification methods include:
- Equipment nameplate: Lists the design refrigerant type and charge weight
- Previous service records: May indicate if the system was retrofitted
- Refrigerant identifier: A handheld instrument that samples and identifies the composition, essential for older systems
Assess System Condition
Evaluate conditions that could complicate recovery:
- Known leaks: Estimate remaining charge based on operating pressures versus expected saturation pressure at ambient temperature.
- Compressor burnout: Acid-contaminated refrigerant needs a separate recovery cylinder and will require reclamation or destruction.
- Oil logging: Systems off for extended periods may have significant refrigerant dissolved in oil, extending recovery time.
Select the Right Recovery Cylinder
Recovery cylinders must be DOT-rated for the pressures involved, properly labeled with refrigerant type and “RECOVERY” markings, within hydrostatic test date (retest every 5 years), and not overfilled from previous operations. Never exceed 80% of the cylinder’s water capacity by weight.
Required Vacuum Levels
EPA Section 608 mandates specific vacuum levels before a system can be opened:
| Charge Size | Required Vacuum (Modern Equipment) |
|---|---|
| Less than 5 lbs | 90% recovery or 4 inches Hg vacuum |
| 5-200 lbs | 10 inches Hg vacuum |
| More than 200 lbs | 0 inches Hg (full vacuum) |
In practice, most field operations on residential and commercial equipment target 10 inches Hg vacuum.
Step-by-Step Recovery Process
Step 1: Connect and Verify
Connect your recovery machine to the system’s service ports with clean, undamaged hoses. Purge your hoses before connecting to prevent introducing air or moisture. Verify all connections are secure before starting.
Step 2: Liquid Recovery Phase
Begin by recovering liquid refrigerant first for maximum efficiency. Connect to the liquid service valve or high side. Monitor cylinder weight continuously and never leave recovery unattended. If the cylinder approaches 80% capacity, switch to a fresh cylinder. When the sight glass shows vapor instead of liquid, the liquid phase is complete.
Step 3: Vapor Recovery Phase
Switch to vapor recovery from the low side. This phase takes longer per pound recovered. To accelerate, apply gentle heat to the evaporator using a heat gun or warm water to drive dissolved refrigerant out of the oil. Never use an open flame.
Step 4: Reach Required Vacuum
Continue until the system reaches the required vacuum level. Close recovery machine valves and let the system sit for several minutes. If pressure rises significantly, refrigerant is still coming out of solution. Resume recovery until vacuum holds stable.
Step 5: Disconnect and Secure
After vacuum holds, disconnect recovery equipment, cap all service ports, weigh the recovery cylinder, and record the total amount recovered.
Preventing Cross-Contamination
Mixing refrigerant types renders cylinder contents unsuitable for reuse. Prevention measures:
- Dedicate recovery cylinders by refrigerant type with clear, prominent labels
- Flush your recovery machine and hoses when switching refrigerant types
- Use a refrigerant identifier when there is any doubt about system contents
- Verify cylinder contents before each recovery by checking both label and pressure
Documentation Requirements
For each recovery event, document:
- Date of recovery
- Type of refrigerant recovered
- Quantity recovered (by weight)
- System identification (equipment type, location, owner)
- Disposition of recovered refrigerant (stored, sent for reclamation, sent for destruction)
Under Subpart C, which covers HFC systems with 15+ pounds of charge and GWP above 53, documentation requirements include chain-of-custody tracking.
FieldPad’s compliance log captures all required recovery documentation as part of the service record. The cylinder management feature tracks individual cylinders by serial number and weight, automatically calculating capacity and flagging cylinders approaching the 80% limit.
Subpart C Considerations for HFC Recovery
For HFC refrigerants under Subpart C, the key threshold is 15 pounds of charge in systems using refrigerants with GWP above 53. This captures most commercial and many residential systems using R-410A, R-134a, and R-404A. Recovery procedures match Section 608, but recordkeeping is more detailed. FieldPad automatically applies the correct regulatory framework based on refrigerant type and charge size.
Key Takeaways
- Always identify the refrigerant before beginning recovery. Assumptions lead to cross-contamination.
- Use dedicated, properly labeled recovery cylinders and never exceed 80% capacity.
- Recover liquid first, then vapor for maximum efficiency.
- Reach the required EPA vacuum level and verify it holds before opening the system.
- Prevent cross-contamination by dedicating cylinders, flushing equipment, and verifying contents before each use.
- Document every recovery with date, type, quantity, and disposition. FieldPad automates this recordkeeping.
- Subpart C extends HFC recovery documentation. Know whether the system falls under Section 608, Subpart C, or both.
Sources & Regulatory References
- EPA Section 608 — EPA regulations including refrigerant recovery requirements and evacuation levels
- 40 CFR Part 82, Subpart F — Section 608 required practices including recovery vacuum levels
- 40 CFR Part 84 — AIM Act Subpart C recovery and documentation requirements for HFC systems
