Contractor Pat O’Donnell, president of LoneStar Heating & Cooling of Houston, has begun using a sealant injected into the system for leak control.

One of the biggest challenges in refrigeration equipment is stopping systems from leaking refrigerants into the environment. The newest models are being factory-sealed with special attention to leak tightness. But there is a lot of product in the field with leaks due to aging and even the most modern systems are prone to leak eventually.

All sectors that use refrigeration equipment face the leak control challenge including the food service sector where properly functioning cooling and freezing are vital in terms of food safety and product quality. And restaurant owners want that safety and quality at a reasonable price.

“If more restaurateurs knew their HVACR contractor could seal leaky equipment instead of replacing it, they could save tens of thousands of dollars a year in refrigeration repair costs,” said Baine Brooks, a board member of the Dallas Restaurant Association and a co-owner of TwoRows, which operates five restaurants in Texas.

TwoRows’ service contractor, LoneStar Heating & Cooling of Houston, began using a new sealant technology two years ago when dealing with especially small leaks. A TwoRows’ 10-ton rooftop unit began developing microscopic leaks from galvanic corrosion. Typically a service contractor will recommend replacement, which in this instance would cost $15,000. Another al-ternative would be replacing suspected leaking components for about $5,000 in labor and materials.

LoneStar president Patrick O’Donnell stopped the multiple leaks with a specially formulated liquid that travels with the oil and refrigerant throughout the system. When a leak is detected, the product forms a crystalline structure at the point of leakage, when activated by moisture from the surrounding air. (It is marketed for systems over 5 tons as Super Seal 3 Phase™, manufactured by Cliplight Manufacturing, Toronto.)

The treatment cost less than $500, which saved TwoRows thousands in expected component or unit replacement costs, said O’Donnell. He further said he suspects the aging unit has developed leaks since the treatment, but all have been stopped because the sealant continues to flow throughout the system and plugs leaks as they occur.

In the nine months since treating the rooftop system, he said it hasn’t needed refrigerant and it’s operating efficiently at its original pressures, which helps cut the location’s energy usage.


Restaurant co-owner Rusty Loeffler said the emergence of sealants has lessened his anxiety of refrigeration breakdowns at three of the TwoRows locations, which are brewpub formats. Filtration of the 700 barrels of brews annually and inventory cooling are dependent on the 24/7 operation of each location’s 7.5-ton process chiller. A sudden chiller leak with a long wait for parts could cost a location thousands in lost product, according to Loeffler.

O’Donnell said service technicians either don’t know about the crystalline approach or are content with continually topping off leaking systems with refrigerant every few months. O’Donnell specializes in the repair of ice machines, salad bars, walk-in coolers, rooftop air conditioners, and other refrigeration equipment for major restaurant chains.

“Obviously we can make more money replacing equipment, but not all customers have the cash flow to spontaneously replace a failing unit,” said O’Donnell, who was a service tech for seven years before founding LoneStar 15 years ago. “I’m trying to build business relationships, so customers are delighted when I offer them the option of sealing for a fraction of the replacement cost.”

“We like the money we’ve saved from LoneStar’s techniques, but we’re especially excited about how sealants fit into our ongoing environmental focus,” said Loeffler.

“We’re always incorporating green things such as high-efficiency equipment, cooking fat recycling, automated lighting control, and employee conservation awareness into our operational strategy, so eliminating refrigerant leaks into the environment fits right in.”

In the last three years, O’Donnell has extended the life of more than 25 pieces of refrigeration equipment ranging from ice machines to commercial refrigerators, walk-in coolers, and walk-in freezers by using sealants. O’Donnell claims the sealants are most effective on reach-in/walk-in coolers and rooftop a/c units because they are particularly subject to premature corrosion due to gaseous acids from produce and galvanic action, respectively. Thus, LoneStar has saved clients in equipment replacement, by extending the life of existing equipment by five to 10 years.

“Many techs are worried that anything besides oil and refrigerant in a system will damage the components, but there have been no negative effects to any of the units and zero system failures since introducing the sealant,” said O’Donnell.

TwoRows restaurant is using a leak detector injected as a liquid into the system for some of its maintenance needs.


LoneStar’s first option is to find the leak and fix it with conventional brazing techniques. Leak detection on refrigeration equipment typically requires electronic detectors and/or using soap bubbles to locate the escaping refrigerant.

If a leak is found and it can be repaired conventionally, LoneStar technicians first recover the system’s refrigerant in accordance to EPA regulations. Since moisture is prohibitive in refrigeration systems, a filter-drier is installed at least once during the repair procedure. Next, the technicians bring the system down to a deep vacuum with a vacuum pump to eliminate residual moisture.

If a leak can’t be found or is inaccessible for repair work, LoneStar offers the restaurant manager an option of replacing suspected components or applying the sealant. Since some customers are wary of an unfamiliar technique, LoneStar gives a 30-day service warranty after applying a sealant, which includes refunding one-half the money for the application as long as LoneStar carries out the repair or replacement.

The sealant application has been successful 25 times. On three applications it didn’t work because the hole - which must be 300-microns or smaller for the leak to be plugged - was too large. “The guarantee proves to the customer that I believe in sealants and I’m willing to take on some of the risk of it not working,” said O’Donnell.

Once injected, the sealant remains a liquid and flows throughout the system until the refrigerant leaks from an exit hole. As it escapes, atmospheric moisture hardens it around the exit hole. The remaining sealant in the system continues to flow with the refrigerant and will most likely plug future leaks as they occur unbeknownst to the equipment owner, O’Donnell said.

The contractor said the new repair policy of offering sealants versus equipment replacement is a good avenue for increasing business relationships. While the savings are apparent, customers are also realizing the environmental impact of sealed systems no longer releasing refrigerants into the atmosphere.

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Publication Date:10/01/2007