Refrigerant Recovery: Three tips for better results

By Tony Gonzalez

Tony Gonzalez is technical training manager at Fieldpiece Instruments, Inc., a manufacturer of professional-grade tools for the HVAC/R industry.

Refrigerant recovery is among the most common procedures done by service technicians, but best practices continue to change and evolve over time. This means continued learning and professional education are a must.

Where recovery once revolved around time-consuming methods and heavy, cumbersome equipment, updated techniques and new technology allow for more options, easier-to-use equipment and faster recovery times.

Being in-the-know about emergent tips and tricks within the field helps create greater levels of day-to-day professional efficiency and, since time is money, this translates to cost savings too. Implementing refrigerant recovery best practices allows experienced technicians and industry newcomers alike to optimize processes, prevent harm to themselves and premature equipment failure, finish the job more quickly, and ensure greater accuracy in the process.

 

Emphasize refrigerant recovery safety

With the ever-present concern that refrigerants could discharge at some point during a procedure, service technicians should be aware of pertinent regulations as well as the appropriate personal protective equipment that should be utilized when working with refrigerant, recovery machines and cylinders. Items such as protective gloves and shoes, as well as splash-proof safety goggles or glasses, should always be worn.

Specifically, provincial and federal refrigerant regulations mandate that refrigerant recovery be performed before opening any ACR system, whether for service or repair. This work must be conducted by a provincially- or federally-certified mechanic or technician, educated in the proper handling of refrigerant and adhering to established recovery practices. Whether in liquid or vapour form, refrigerants are considered highly harmful to the environment. As such, it is a violation of provincial and federal regulations to:

  • Fail to keep, or knowingly falsify, refrigerant records.
  • Fail to reach required evacuation rates prior to opening or disposing of appliances.
  • Knowingly release CFCs, HCFCs, or HFCs when repairing appliances.
  • Vent CFCs, HCFCs or HFCs.

When refrigeration or A/C systems are being replaced, undergoing repairs or being serviced, refrigerants have the potential to be released into the surrounding environment and eventually impact the ozone layer. Provincial and federal regulations allow for the safe handling of these harmful synthetic compounds by properly trained and certified professionals – allowing techs and HVAC/R companies to avoid costly government fines for violations while guaranteeing the safety of the environment and local communities they serve.

More provincial and federal regulatory requirements to keep in mind include:

  • Do not vent refrigerants, as most cannot be legally vented.
  • Do not mix refrigerants in the recovery tank or in the system.
  • Recharging is generally okay.
  • Be sure to keep records of charge and recovery.

In addition, using a recovery machine as required with each individual job, for example, ensures that refrigerant recovery is safely conducted, thus keeping refrigerant out of the environment.

 

UNDERSTAND RECOVERY OPTIONS

As trained service technicians know, refrigerant is consistently flowing throughout the line set of the HVAC/R equipment. As such, any time a technician encounters a leak in the system or must cut into the refrigerant circuit to remove or install a new part, they must recover the refrigerant from the system first. Recovery is the process of safely transporting refrigerant from an HVAC/R system to a recovery cylinder. The speed at which this process is effectively and safely completed is of fundamental concern to the service technician.

To completely recover all the refrigerant, there are three different methods most utilized in the field: liquid, vapour, and push-pull.

  • Liquid refrigerant recovery refers to the method where service technicians transfer refrigerant while it is in the liquid state. Refrigerant recovered in liquid form is by far the fastest method, but it has the potential to be problematic as it may cause liquid slugging at the recovery machine if the flow rate isn’t governed by a variable speed motor or a manual throttle. Likewise, depending on the specifications and circumstances of the job, this recovery method is not always possible, such as when outside ambient temperatures of approximately 21ºC or more cause refrigerant to vaporize.
  • Vapour refrigerant recovery refers to the method where refrigerant is removed while in a vapour state. Overall, the most time spent recovering refrigerant is in vapour form. When done effectively and with an advanced recovery machine, more removed vapour is then condensed into a liquid in the recovery cylinder. This option is typically slower than liquid recovery as higher pressures build within the recovery tank, and the tank may require cooling via either submersion in an ice bucket or by running cold water over the cylinder.
  • Push-pull refrigerant recovery refers to the method where the recovery unit effectively pulls vapour from the recovery cylinder, creating pressurized gas that then pushes the liquid from the entire system, ultimately returning it once again to the recovery cylinder. This process is slightly more complicated and should only be used for faster recovery on larger systems with more than 10 kilograms of refrigerant. For service technicians who know that a larger job requires more time, push-pull recovery is the best choice.

 

USE THE CORRECT HOSES AND FILTERS FOR OPTIMAL PERFORMANCE

Knowing the impact that hoses and Schrader valves have on the overall speed of any given recovery method is extremely important to the efficiency of the job. As a rule of thumb, using a hose thick in diameter and short in length results in faster rates of recovery. Utilizing short, larger diameter hoses lessens the restriction within the hose itself and provides a larger pathway for the refrigerant to travel through thereby creating a greater flow of refrigerant recovered in far less time. Similarly, using valve core removal tools to remove the Schrader valves minimize restrictions and allow for even smoother flow of refrigerant.

To simplify overall setup for any job, connecting the recovery machine directly to the system and throttling as necessary at the recovery machine speeds up set-up time, eliminates one more hose connection that would otherwise be required and means one less hose, one less step.

It is recommended that service technicians use a filter dryer before the inlet port to ensure the continued protection of the recovery machine. The state of your filter dryer is telling of how bad the contaminants or physical filtration within the system may be. Through general use, these machines are likely to be exposed to external contaminants that impact the longevity and life of professional equipment. Keeping dirt, metallic slivers and other debris out of the machine, and making it a practice to swap out filter driers and screens regularly aids greatly to ensuring quality and reliable use.

 

 

 

 

 

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