As a service technician, one of the jobs you will be doing nearly every week is recovering refrigerant. It is against Federal law to release refrigerants into the atmosphere so a recovery machine is required remove the refrigerant from an inoperative or condemned air conditioning system

There are two methods of removing refrigerant from a system. The first is to pump all available liquid into an approved refrigerant cylinder using the refrigeration system containing the refrigerant.

The second is to use refrigerant recovery equipment commercially manufactured for refrigerant recovery. In this post we will discuss the the second method.

The following information is for educational purposes only and should not be performed unless you have completed HVAC training and hold your EPA 608 Refrigerant Handling Certification.

SAFETY PRECAUTIONS: DO NOT OVERFILL ANY REFRIGERANT CYLINDER; USE ONLY APPROVED CYLINDERS. Do not exceed the net weight of the cylinder. Wear gloves and safety glasses while transferring refrigerants.

Pumping the Liquid from the System Using Passive Recovery

You must have an approved recovery cylinder to perform refrigerant recover.

  1. Note the capacity of the recovery cylinder.
  1. Calculate 80% of the cylinder’s capacity. Example 30 lbs. X .80 = 24 lbs. CAUTION – DO NOT FILL A REFRIGERANT RECOVER CYCLINDER ABOVE 80% OF ITS CAPACITY
  2. Fasten the low-side gauge line from you refrigerant gauge manifold to the suction connection of the AC system being recovered.
  3. Fasten the high-side gauge line to the king valve or a liquid-line connection of the AC system being recovered.
  4. Loosely connect the centerline of the gauge manifold to the refrigerant cylinder. 
refrigerant cylinder

Note: More refrigerant can be transferred from the system to the recovery tank if the tank is empty and in a vacuum.

  1. Bleed a small amount of refrigerant from each line through the center line and allow it to seep out at the cylinder connection. This purges any contaminants from the gauge manifold and the refrigeration hoses.
  2. Set the recovery cylinder on the scale.  
  3. Zero the display on the refrigerant scale.
  4. Start the system and open the valve arrangement between the liquid line and the cylinder. Liquid refrigerant starts to be pumped into the cylinder cylinder compressor the AC system.
  5. Watch the high-pressure gauge and do not allow the system pressure to rise above the working pressure of the refrigerant cylinder.


  1. Watch the suction pressure on you gauge manifold and do not allow it to fall below 0 psig. When it reaches 0 psig, you have removed all the refrigerant from the system that you can, using this method.
  2. Remove the refrigerant cylinder. You may need to recover the remaining refrigerant using recovery equipment.
  3. Recovery can be sped up by setting the recovery cylinder in a bucket of ice, thus reducing the pressure in the cylinder.

There you have it! Most HVAC Service Technicians have not had the proper training on using this method of refrigerant recovery.

You can learn this and more with our online HVAC Training platform. Our HVAC training is video intensive and comprehensive way to learn HVAC online.

Across the US, air conditioning technicians are in short supply and high demand. This is a high paying career ($75K-$100K) for top technicians and cannot be outsourced and one of the few trades that survived and flourished during the 2020 Covid-19 pandemic.

Ron Walker
Ron Walker

After retiring from the U.S. Marines and achieving his B.S. degree, Ron Walker entered the HVAC field. He has been an HVAC technician, service manager, and business owner. Working as a service manager, he spent many years training HVAC technicians to be more technically competent and really understand their trade. His passion for teaching and helping others resulted in the creation of HVAC Training Solutions, LLC.