For years, HVACR technicians have been used to primarily working with nonflammable (A1) refrigerants, such as R-410A, R-22, and R-404A. Now that HCFCs are being phased out and there is growing concern over the high GWP of some HFCs, new lower-GWP alternatives have been developed to take their place. However, some of these new refrigerants, such as R-32 and R-454B, are mildly flammable (A2L), which means additional safety precautions must be followed when handling them.

That includes using a recovery machine designed specifically for A2L refrigerants. Most standard recovery machines are designed to handle A1 refrigerants, which means they may not have the safety features required for mildly flammable refrigerants.

SAFETY FEATURES

When it comes to recovering any type of refrigerant, technicians should always follow the manufacturer’s guidelines and only use a recovery machine for the refrigerants that it was designed for, said Jon Romenesko, educational manager/communication and training, Appion Inc.

“Standard recovery equipment is not suitable for flammable refrigerants and should never be used,” he said. “Since ignition requires a specific ratio of three elements (fuel, air, and heat) to happen, the easiest way to reduce the risk [when recovering A2L refrigerants] is to lessen or eliminate at least one of the variables. One way this can be achieved is by using a recovery machine that features a high volume of airflow through the machine, which prevents any accumulated refrigerant leaks at or near the machine or its electrical components.”

A machine with a high volume of airflow will prevent any accumulation around the internal components should a leak occur, and since airflow is key to condensing power, it will also improve recovery times, said Romenesko.

“Machines with a refrigerant-isolated crankcase will also allow technicians to easily switch from nonflammable to mildly flammable refrigerants,” he said. “Look for machines that are designed to handle straight liquid refrigerant, since this will allow faster recovery rates than vapor-only machines.”

For A2L recovery machines, contractors and technicians should look for the machine to be labeled as being compatible or certified for use with A2L refrigerants, said Bob Belvick, product manager of service tools and leak detection, INFICON.

“A standard recovery machine can cause sparks, which could cause an explosion in certain conditions, particularly with A3 (flammable) refrigerants,” he said. “A2L refrigerants are generally safer to work with, but it’s best to use a machine that has been certified for use with A2L refrigerants to be safe.”

The GWP for common A3 refrigerants such as R-290 (propane), R-600a (isobutane), and R-441a (a hydrocarbon mixture) is negligible, so recovery is not required for these gases, said Belvick. For that reason, it is rare for a manufacturer to design a recovery machine that can handle A3 refrigerants.

A2L MACHINES

Even though recovering A2L refrigerants may not be something that technicians do every day, the good news is that they may not need a different recovery machine when the occasion arises. Specifically, recovery machines with refrigerant-isolated crankcases can be used with multiple refrigerants, because the machine will only store de minimis amounts of refrigerant, said Romenesko.

Appion’s flagship G5Twin is one of the machines that can be used to recover A2L refrigerants. It utilizes a high-speed gear-driven fan assembly, generating over 600 cfm of cooling airflow through the machine, which prevents any accumulated refrigerant leaks at or near the machine or its electrical components. The machine can be used with multiple refrigerants by simply pulling a vacuum on the outlet side and then running a capful of oil through the machine to scavenge out any residue before moving onto the next refrigerant.

“The G5Twin will have no issue pumping R-32 and R-1234ZE/YF, but again, safety is always the priority with these refrigerants to ensure that they cannot be ignited,” said Romenesko. “Attempting to recover a highly flammable gas such as a hydrocarbon into a closed cylinder can create a very dangerous situation, which is why under NO circumstances should Appion equipment be used for the recovery of flammable refrigerants.”

Also confirmed safe to use with A2L refrigerants is INFICON’s Vortex Dual recovery machine, which has a self-purge system that allows the recovery machine to pump out residual refrigerant, reducing the chance of cross-contamination. The machine also features a 1-hp dual piston compressor for fast recovery rates; a microchannel condenser, which helps maintain recovery rates throughout the entire recovery cycle; simple two-valve operation; and full-size protected gauges for both suction and tank pressure.

The F6-DP refrigerant recovery unit from JB Industries is also safe for use with A2L refrigerants, said Dave Madden, director of manufacturing, JB Industries.

“To prevent cross-contamination, the F6-DP has a self-purging system that will pump out residual refrigerant,” he said. The machine also features a microchannel condenser, a 1-hp motor, an oversized cooling fan, a dual-piston compressor, simple two-valve operation, and a heavy-duty handle with comfortable rubber grip.

As for the actual recovery of A2L refrigerants, the procedure does not differ greatly from what technicians are used to with A1 refrigerants, said Romenesko.

“However, extra care needs to be taken in terms of safety, including ventilation, ensuring equipment is leak-free, and purging hoses to reduce the chances of introducing non-condensables (oxygen) into the recovery cylinder,” he said.

Maintenance is also much more critical when dealing with A2L refrigerants.

“The technician must take every precaution to ensure that there are no leaks in any of the internal components,” said Romenesko. “If the machine has a ‘bench test’ function (to test performance), it’s recommended to perform it before every job to ensure that the machine hasn’t developed a leak since the last time it was used. If a leak is discovered, the technician should repair the machine either with a repair kit or by sending it to an authorized repair facility.”

There are numerous recovery machines available, and they all have various features that will appeal to different technicians and contractors. As with any other purchase, it is always a good idea to read up about the machine online, and if that is not sufficient, ask the distributor or manufacturer for more information.

“It’s challenging to design a machine that will work with all refrigerants,” said Belvick. “Customers typically want the fastest machine, but they also want the smallest, lightest, and cheapest, too. Unfortunately, it’s pretty rare that these things can all come together in a single product.”

Publication date: 6/3/2019

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