It may not be the Hatfields and the McCoys or even the Democrats and the Republicans, but there are definitely two schools of thought when it comes to using leak-stop agents in refrigeration and air conditioning systems.

Some contractors have used them successfully for years and consider them practical and cost-effective ways to seal small, hard-to-find leaks in systems. Other contractors feel strongly that only two things belong in a system: refrigerant and oil.

Joseph Kokinda, president and CEO of Professional HVACR Services Inc. in Avon Lake, Ohio, said he has seen it all in his 40-plus years in the mechanical trades, and, based on his experiences, he is not a fan of leak-stop agents.

He relayed a story of recently finding a huge pool of leak-stop agent around a missed brazed joint in a large refrigeration system. The customer’s records showed the system had about 90 pounds of R-404A added to it each quarter since 2004. According to Kokinda, an acceptable leak rate for the HVACR industry should be zero, and the way to achieve that is through proper installation upfront and proper service throughout the equipment’s life.

“Most leaks in systems are there because the installer didn’t properly evacuate the system to ensure tightness,” Kokinda said. “The HVAC trades fall woefully short when it comes to properly dehydrating piped systems using micron gauges to fix a leak, especially after an installer has pulled in air, moisture, and non-condensables because of a missed joint during an evacuation procedure.”

Dave Boyd, vice president of sales and education, Appion Inc., noted compressor manufacturers will never bless using foreign materials on an air conditioning or refrigeration system, and he agrees with that stance.

“The only thing that should ever be in a system is pure virgin refrigerant and oil,” he said. He cited Kokinda’s story as a perfect example of why systems must be properly brazed or crimped, pressure tested, and evacuated.

“Unfortunately, that is not always the case,” he said. “If the EPA [U.S. Environmental Protection Agency] got its act together, it would not let systems like this be continuously topped off. The 35 percent leak rate the EPA allows for these types of systems is ridiculous.”

D. Brian Baker, president of Custom Vac Ltd. in Winnipeg, Manitoba, Canada, said it’s unfair to lump all leak-stop products together, as some have much different formulations than others.

“It always comes down to using a trusted product,” he said. “Furthermore, we all should understand these are not permanent repair products and, therefore, have limited use and specific uses. There is never a replacement for clean, dry, and tight.”

Baker agreed with Kokinda that most leaks occur because of improper installation procedures.

“That’s why these products are not the correct answer and why in Manitoba and Winnipeg they are considered temporary and can only be added to a known leak-free system before a leak develops or after a leak has been repaired,” he said. “Other than that, all leaks must be repaired immediately. There is a $50,000 fine for noncompliance, an additional $1,000-a-day fine from the day of the conviction up to prosecution, and/or six months in jail.”

Having said that, Baker stressed that this does not mean the additives don’t have a place, adding they could work well in limited, preventive roles.

“I do think there is something to be said for additives that could seal small leaks, since it is almost impossible to be 100 percent leak-free, even for the best of the best,” he said. “However, these products should not be allowed as permanent repairs.”

He added that doing it right the first time takes less time than repairing a leak after a problem shows itself.

“We need higher test pressures, longer wait times, and advanced installation practices if we are to achieve leak-free systems,” he said. “We can do much better than we are doing. Personally, I think the U.S. should follow Canada and have a policy of zero leak tolerance.”

Kevin Wood, owner of Holly Wood Air in Visalia, California, said he has used leak-stop agents for the past five years and has found that they work great for hard-to-find leaks or those that are in the middle of coils.

“I’ve had it in some systems for five years now, and I’ve not had a call back on a leak,” he said. “If the leak is accessible and easy to repair, I always do it the conventional way, but many times there are leaks that can’t be located or are in inaccessible places, and this stuff becomes a lifesaver.”

Yogesh Patel, owner of A Green Temp Inc. in South Elgin, Illinois, said he’s had great success using leak-stop agents when it comes to very small leaks. “We don’t have callbacks, and it saves our customers a lot of money,” he said. “As a company owner myself, I feel that is a fair deal to them.”

Joe Moravek, training director at Nance HVACR Tech School in Beaumont, Texas, said his results with leak-stop agents have varied.

“Sometimes it solved an unfound leak problem and other times, not so,” he said. “We’re willing to try to find a leak and repair it ourselves, though leak sealers are our last option.”

Moravek said he has not experienced any equipment damage from using a leak-stop agent.

In the Jan. 18, 2016, NEWS article, “Climate Pacts Create Turbulence,” Gordon McKinney, vice president and COO of Icor Intl., said, not only are leak-stop agents effective, they are also underrated contributors to air conditioning and refrigeration systems being tighter and more leak-free than ever before.

“I know stop-leak additives are not endorsed by the OEMs, but they’ve proven themselves as highly effective and efficient,” McKinney said. “They’re not degrading system performance or causing system failures, and, over the past five to 10 years, they’ve helped keep vast amounts of refrigerant inside systems. The industry’s low leak rates are just one more reason we should take a step back and ask if we really want to get rid of a whole generation of highly reliable, effective, proven refrigerants, such as the HFCs.”

Nicholas Griewahn, a refrigeration service technician and refrigeration instructor at Northern Michigan University, said he teaches students that only two substances are to be used in refrigerant-containing systems: refrigerant and the appropriate oil. He considers any other substance in the system a contaminant.

Griewahn said he believes leak-stop additives encourage a quick fix and aren’t necessary based on the capabilities of modern leak detectors.

“I cringe whenever I see a piece of equipment tagged with any additive,” he said. “The traditional way of leak location and repair is the way to go.”

Griewahn said he has two major issues with leak-stop additives. The first is safety: “Many local and state mechanical codes dictate where refrigerant-containing components can be located in buildings because of the fear of refrigerant entering a confined space in high concentrations,” he said. “I can’t speak for everyone, but, if I had a leak in a system like this, I would prefer to have direct control of finding and repairing it instead of leaving it up to a chemical that’s added to the system.”

His second major issue is that compressor manufacturers largely do not approve leak-stop chemicals.

“There’s a reason for that,” he said. “Who invests the most resources testing and analyzing performance? Who knows their equipment and components the best? Who has the most vested interest in the longevity and reliability of the equipment? The manufacturer should be the foremost experts on what works and what doesn’t work in their equipment. Not only that, but I don’t want to be the one to tell a customer the warranty is void due to an unapproved chemical my company added into the system.”

Finally, according to Griewahn, working on systems that have leak-stop agents added can compromise a technician’s tools.

“I have found dyes and leak-stop additives can degrade the performance of manifold gauges, vacuum gauges, vacuum pumps, and recovery machines,” he said. “This contamination can then be transferred to other pieces of equipment that additives should not be used in. Then, there is the question of refrigerant reclamation: Will reclaim facilities be able to take this stuff out easily?”

Like many issues in the HVAC and refrigeration industries, the questions about leak-stop agents don’t stop at the North American border. Vitor Caçador, an HVAC contractor in the Azores, an autonomous region of Portugal, said he has not used leak-stop agents to date but sometimes wonders if he might be missing out on something great or miraculous.

“I don’t use these products, because I don’t understand the science behind them,” Caçador said. “Information is scarce, and distributors are usually unable to provide me with clear answers to my questions, such as: What’s the science behind leak-stop agents? Are they a permanent solution? How do they work? Do they clog the system in some way? How much is enough? Is the product miscible with the refrigerant and oil? Does it affect the efficiency of the cycle, such as by reducing refrigeration power and increasing current draw?

“I always hear, ‘This works like a charm, everybody’s using it,’ but that answer will not do,” Caçador added. “I understand the science behind conventional leak-repair techniques and will continue to use them. I will not use ad-hoc solutions that sound too good to be true. As we say in Portugal, ‘When the giving is too much, the poor man starts to distrust.’”


The NEWS asked two compressor manufacturers for their views on leak-stop agents.

• Ben Majerus, manager, field systems engineering, Danfoss:

“Danfoss spends extensive engineering time selecting and qualifying our compressor oils. Oil viscosity, miscibility, foaming, and wear properties are some of the key variables that are evaluated to choose the right oil for each refrigerant type. The oil selected is then tested during our engineering qualification of each compressor model to ensure long-term reliability and performance. Our testing is comprised of hundreds of compressors and thousands of hours-of-life testing performed at extreme conditions, so the wear on internal bearing surfaces can be examined. Without testing each of the leak additives, Danfoss cannot guarantee they won’t negatively impact the long-term reliability, so we will not endorse these type of additives. If detected during a warranty claim, it would void our warranty terms.”

• Randy Tebbe, service engineering manager, Emerson Climate Technologies Inc.:

“Creating and maintaining a leak-free refrigerant system is always a goal; however, we have not conducted testing on the vast amount of additives available to approve adding a substance to a refrigerant system that will plug leaks from the inside to achieve that goal. The typical refrigeration or air conditioning system has multiple designed orifices with restriction from cap tubes and thermal expansion devices to injection ports and oil feed holes. Adding a substance intended only to block refrigerant leaks, thereby blocking the orifices, creates a host of potentially negative implications. The substance also brings with it unknown effects on the system’s components, seals, oils, and even manufacturing process fluids over time. Because there are so many unknown effects at this time, Emerson does not approve the use of additives in the presence of refrigerants.”


Cliplight Mfg., a company of Diversitech, introduced its sealants into the HVACR industry more than 15 years ago, and the company says the products are tried, tested, proven to work, and here to stay.

“Super Seal and Super Seal Total have evolved into multifunction tools that not only seal leaks but also eliminate water and contain UV trace dye to find larger leaks,” said Paul Appler, director of research and development.

Appler said major companies, such as Sears Holding, Amtrak, and Ford Motor Co., use Cliplight’s products to service everything from domestic refrigerators to trains (the cooling systems in the passenger cars and kitchens) to plant chillers.

“While good technicians repair most leaks by re-brazing and replacing components, this does nothing to prevent future leaks,” noted Jesse Homenuik, research and development engineer, Cliplight. “Pinhole leaks are time-consuming, often difficult to find, impact compressor life, and decrease performance. While system moisture is a root cause of leaks, it also causes compressors to fail. Sealants save you time and money, reduce call backs, and result in satisfied customers.”

Not all refrigerant leak-stop agents can be counted as the same, added Appler.

“As a contractor, you need to ask the manufacturer three questions: What’s in it, how does it work, and who uses your product? How they answer all three will quickly help you decide if it’s the real McCoy or not,” Appler said.

He suggested looking for sealants that include UV fluorescent dye to help find leaks, moisture eliminators to prevent acid formation, and the capability to seal both present and future leaks for more than a year.

Mike Benack, director of product management, Nu-Calgon, said he views his company’s a/c EasySeal and EasySeal Direct Inject products as valuable tools contractors should add to their tool bags.

“Like any tool, our leak-stop products are designed for use in certain situations,” Benack said. “They’re not meant to replace the traditional method of finding and repairing leaks but more so for fixing leaks that a technician can’t find — the microleaks that contractors would typically fix by topping the system off with a small amount of refrigerant every month or year. They’re really designed to be used in situations where traditional means aren’t practical or as a preventive measure.”

Benack said not all leak-stop agents are created equal, and contractors must pay attention to the active ingredient — and the amount of the active ingredient — contained in the product they’re purchasing.

Regarding the products’ effectiveness and safety, Benack cited Nu-Calgon’s long history in the market.

“EasySeal was launched in July 2009, and although there are still contractors who are skeptical of sealants, we’re confident once they try EasySeal, they’ll find it solves the problem quickly and easily with no issues,” he said. “In addition, EasySeal Direct Inject takes just seconds to install, which adds to the case for using it to fix small, hard-to-find leaks.”

Theresa Lee, AC Leak Freeze product manager, Rectorseal Corp., noted that leak-stop products aren’t designed to seal all leaks.

“If you can hear or see a leak, you need to fix it the traditional way,” she said.

However, for small, hard-to-find leaks, the products work well when used according to the manufacturer’s instructions.

“With polymer-based agents, the system must be free of air and moisture, and that can be difficult to achieve,” she said. “Our products are polymer-free, so, although it’s still not good to have air and moisture in a system, our products won’t react negatively with them.”

Rectorseal promotes its Leak Freeze with Magic Frost SDS as a leak-prevention agent.

“You can put it in when a system is new, and it travels with the oil so it won’t contaminate the refrigerant,” she said. “Once a microleak pops up and the product activates, it will still stay suspended in the oil and look for more microleaks and pinhole leaks.”

Lee noted that although no OEM manufacturers approve leak-stop products, Bristol Compressors Intl. LLC and Fieldpiece Instruments Inc. have tested Rectorseal’s polymer-free products and found they did not harm or damage their systems or tools.

“We continuously run our own tests to ensure our products are safe and effective,” she said.

And, thus, the verdict is in your hands. What decision will you make — or have you made — about leak-stop agents at your company?

Publication date: 4/4/2016

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