Maintenance & Reliability · SOP

HVAC Refrigerant Recovery And Evacuation Procedure

This procedure defines the mandatory steps for safely recovering refrigerant from HVAC systems and performing a deep evacuation of the refrigerant circuit. Proper recovery prevents environmental release, ensures compliance with CSA B52 and ASHRAE 15, and removes non-condensables and moisture to prevent compressor failure and maintain system efficiency.

Estimated Time

45 min

Difficulty

Advanced

Regulation

CSA B52 / ASHRAE 15

Version

1.0

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Purpose

This procedure establishes the mandatory steps for safely recovering refrigerant from HVAC systems and performing a deep evacuation of the refrigerant circuit. Proper recovery prevents environmental release of refrigerants (compliance with CSA B52, ASHRAE 15, and provincial OHS regulations) and ensures that non-condensables and moisture are removed before system recharge, preventing compressor failure and maintaining system efficiency. Adherence to this SOP reduces liability, extends equipment life, and supports sustainability targets.

Scope

This SOP applies to all HVAC technicians performing refrigerant recovery and evacuation on residential, commercial, and industrial air conditioning and refrigeration systems. It covers systems using HFC, HCFC, and HFO refrigerants. This procedure is to be followed prior to any major component replacement, system opening for repair, or permanent decommissioning. It does not cover automotive HVAC systems, ammonia-based industrial refrigeration, or systems containing flammable refrigerants (A3 classification) — those require dedicated procedures.

Safety Precautions

LOTOLockout/tagout the main electrical disconnect to the condensing unit and evaporator fan circuit. Verify zero energy with a rated voltmeter before proceeding.
PPEWear CSA-certified safety glasses, cut-resistant gloves (EN 388 level 4), and steel-toed boots. Use a refrigerant-grade respirator if working in a confined space or if refrigerant concentration exceeds 1,000 ppm.
GASEnsure the work area is ventilated to below 1,000 ppm refrigerant concentration. Use a portable gas monitor rated for low-lying refrigerants (R-410A, R-134a, R-32). Position the monitor at floor level for heavier-than-air gases.
CYLNever fill a recovery cylinder beyond 80% of its rated capacity. Use an electronic scale with overfill alarm. Store cylinders upright, secured, and away from heat sources and direct sunlight.
BURNAllow components to cool to ambient temperature before handling. Refrigerant lines and compressors can cause severe burns. Use insulated gloves when touching hot surfaces.

Required Tools & Materials

Refrigerant recovery machine (e.g., Appion G5TWIN or equivalent)
Recovery cylinder with dip tube (for liquid recovery) or without (for vapor recovery)
Electronic scale with 0.1 lb resolution and overfill alarm
Vacuum pump — 8 CFM or greater, two-stage, with isolation valve
Digital micron gauge (range 0–20,000 microns)
Manifold gauge set with colour-coded hoses rated for the refrigerant type and pressure class
Valve core removal tool (for unrestricted flow during recovery and evacuation)
Nitrogen cylinder with pressure regulator and purge hose (for leak testing and system dry-out)
Electronic leak detector (heated diode type, sensitivity ≤ 0.1 oz/yr)
Lockout/tagout kit (padlock, hasp, danger tag, group LOTO if multiple energy sources)
Portable gas monitor (refrigerant-specific sensor, O₂ sensor)
CSA-certified safety glasses, cut-resistant gloves (EN 388 level 4), steel-toed boots
Refrigerant-grade respirator (for confined space or high-concentration scenarios)

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Procedure: Step-by-Step

1 Perform lockout/tagout. Lock and tag the main electrical disconnect to the condensing unit and evaporator fan circuit. Use a rated voltmeter to verify zero energy at all phases. Apply group LOTO if multiple trades are on site.

2 Connect manifold gauge set. Install the valve core removal tool on the low-side and high-side service ports. Connect the manifold gauge set hoses. Purge the hose of air by briefly cracking the refrigerant at the manifold before full connection.

3 Set up recovery machine. Connect the recovery machine inlet to the manifold's common (centre) port and the outlet to the recovery cylinder. Configure for liquid recovery (dip tube cylinder, liquid from liquid line) or vapor recovery based on system charge volume and ambient temperature. Zero the electronic scale.

4 Recover refrigerant. Open the recovery cylinder valve. Start the recovery machine and monitor the scale and manifold pressures. Recover until the system reaches 10 inHg vacuum (15 inHg for deep recovery on large commercial systems). Do not exceed 80% fill on the recovery cylinder.

5 Perform decay check. Close the recovery cylinder valve and shut down the recovery machine. Isolate the system and wait 5 minutes. If the pressure rises above 0 psig, repeat recovery steps until the pressure holds steady.

6 Connect vacuum pump and micron gauge. Disconnect the recovery machine. Connect the vacuum pump to the manifold's common port. Connect the digital micron gauge directly to the system via a dedicated service port — never through the manifold, as manifold seals can leak and give false readings.

7 Pull deep vacuum. Start the vacuum pump. Pull the system down to 500 microns or lower. Continue pulling for a minimum of 30 minutes after reaching 500 microns to ensure all moisture is boiled off and evacuated. Monitor the micron gauge continuously.

8 Perform vacuum rise test. Isolate the vacuum pump by closing the manifold valves and the pump isolation valve. Hold for 10 minutes. If the micron reading rises above 1,000 microns, check for leaks using an electronic leak detector and nitrogen pressure test. Locate and repair any leaks, then repeat evacuation from step 7.

9 Record and finalize. Record the final micron reading, stabilized ambient temperature, evacuation duration, and any leak repair actions in the maintenance log. Disconnect all equipment, cap all service ports with brass caps, remove lockout/tagout, and restore power. Complete the PM log entry with technician name, date, and equipment ID.

HVAC Refrigerant Recovery And Evacuation Procedure

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