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The leaking system was in a 400-square-foot walk-in freezer in the commissary of the 186-bed Port Huron (Mich.) Hospital.
Ponke used an electronic leak detector to try to locate the leak. It was finally suspected to be at the piping manifold near the outlet of the 5-ton system’s thermostatic expansion valve. Not only was the leak inaccessible, but there was also an imminent danger of damaging nearby manifold solder joints during any brazing process, according to Ponke, who is one of eight service technicians employed by Watson Brothers Heating & Cooling of Port Huron.
Consequently, Ponke was planning at least one or two full-day’s work to pump down the system of its R-406A refrigerant, replace the manifold, and replace the refrigerant - all for an estimated $2,000. A worse problem was the lack of alternative freezer space for storing the hundreds of pounds of frozen food as well as the possible interruption of the cafeteria’s food service.
“We were looking at either losing all the food or renting a semi-truck trailer freezer at a rate of $1,000 per day, not to mention all the hospital labor of moving the food into it,” said Brian Hase, HVACR systems mechanic at the hospital.
Before dealing with all that, Ponke decided to try a refrigerant sealant that had been recommended by Keith Montville, branch manager of local HVAC distributor, Downriver Refrigeration Supply, Port Huron.
The sealant - brand named Super Seal 3 Phase by Cliplight Mfg., Toronto - is a patented formula of organosilanes that remain in a liquid state with the refrigerant once injected into the refrigeration system. When the refrigerant leaks out of a hole 300 microns or smaller the introduction of atmospheric moisture causes the sealant to crystallize into a hardened bond around the exit point, thus stopping the leak.
PROCEDURESTypically, Ponke would prepare such a system for sealing by checking for leaks with an electronic leak detector and then verifying the leak with soap bubbles. If a leak is found, he tries to repair it conventionally. Next, the filter-drier is changed out to ensure no moisture or particulates are freely circulating in the system. Then the refrigerant is recovered and the entire system is evacuated to 250 to 300 microns. Because the food might have been lost during a pump down and one leak was undetectable and suspected to be inaccessible, Ponke chose to just apply the sealant.
Based on his 25 year’s experience and the fact that the system had developed past leaks in other areas, Ponke believes the unit probably would have developed future leaks if the sealant hadn’t been applied.
“It looked like leaks were going to be a regular occurrence, but now after the application, every-thing has been quiet for over nine months,” Ponke said.
“It’s possible another leak may have already appeared since the repair, but nobody will know because the sealant continues to flow throughout the system plugging leaks as they occur,” said Ponke, who has a long-term service history with the unit including retrofitting it from R-12 to R-406A several years ago.
Since the cooler repair, the hospital has successfully used the sealant, which is designed for systems between 1.5 and 5 tons, on several leaking heat pumps, as well as another product - Super Seal ACR also from Cliplight - on two failing window units.
ANOTHER PROJECTPonke also used the sealant on a 30-year-old walk-in cooler at the local American Legion. With no access to a leaking return line elbow, he was faced with the prospect of removing and bench repairing the evaporator coil. Because of the unit’s age, the piping systems were developing leaks that Ponke found himself fixing almost continuously.
“I told the post commander that if I couldn’t repair the leak, they had to buy a new evaporator coil,” said Ponke. “The commander said they had absolutely no money, so using a sealant was the only option. The approach ended up saving them over $1,000 and kept their food service operating.”
Because of Ponke’s success with sealants, other Watson Bros.’ service techs are considering it based on his recommendation.
“Our service techs have the freedom to try different products to solve on-site problems,” said Dwayne Beem, Watson Bros.’ service manager. As for Ponke, accessible leaks are still repaired conventionally if possible. How-ever, phantom leaks will get the sealant application. “If I had this tool 25 years ago when I started in this business, my life would have been a lot easier,” Ponke said.
For more information, visit www.cliplight.com.
Publication Date: 07/02/2007