A leaking chiller in an automotive manufacturing plant left its HVAC/R engineer with two options: a costly production shutdown, or eliminating the leak with a $60 can of refrigeration system sealant.

Shutting down the chiller system, which cools 10,400 gallons of honing oil used in the engine block cutting process at Ford Motor Co's mammoth Essex Engine Plant in Windsor, ON, would run up costs in service and parts, including a reduction in plant productivity. Best-case repair scenario for the V-6 engine production plant was a projected 5-day disassembly of the 24 ton chiller, with hopes that necessary replacement parts would be readily available once the leaking component was found. The worse-case scenario? Waiting one or two weeks for parts, and subsequently renting expensive mobile chillers.

Gerry Miller, the plant's compression equipment engineer, hadn't heard of refrigeration leak sealants prior to the incident, but he was wary of putting any foreign substance in the system.

"I like only refrigerant and oil in my systems, and that's all," said Miller, a 28-year veteran of refrigeration service, "but I had run out of alternatives."

Previous leak detection efforts with electronic leak detection and liquid soaping connections didn't reveal the leak location, but did confirm two realities: 1) the leak was most likely inside the chiller's evaporator in an enclosed tank; and 2) repairing the leak wasn't going to be easy.

To maintain Ford's stringent environmental policies on refrigerant leaks, Miller began preparing a fast-track plan to tear apart the system. Then Paul Appler, a first class power engineer and director of research and development for the HVAC/R division of Toronto-based Cliplight Mfg Corp, suggested using a sealant made especially for refrigeration system leaks.

The relatively new chiller is a 48 ton model with two 25 hp, 24 ton semihermetic reciprocating Carlyle compressors and utilizes Sporlan (St. Louis, MO) filter driers and expansion valves. The system operates with DuPont R-22 refrigerant and Suniso 150-viscosity refrigerant oil by Crompton Corp, Middlebury, CT. The unit supplies 55ºF chilled water to a 50 ton plate heat exchanger that in turn cools the 100ºF-plus honing oil to an ambient 70ºF. Before the repair, the chiller was operating with:

• discharge pressure --195 psig;


• discharge temperature -- 219.2ºF;


• shell temperature -- 212ºF;


• suction pressure -- 40 psig;


• suction temperature -- 77ºF; and


• superheat -- 60 deg.

With his choices limited, Miller invited consultation from Cliplight's A-team of troubleshooters: Appler; chemical engineer Dr. George Cranton; and a field service technician. Since Cliplight HVAC/R sealants were still relatively new, Miller wanted to exercise a controlled methodical approach to their use at the plant. After a thorough analysis by the Cliplight team ensured a clean system, Miller gave the green light. A trial dose of 3 oz of Cliplight's industrial strength sealant, Super Seal 3 Phase™, which is designed for 5 ton and larger systems, was administered by service technician Dave Dunn, owner of Windsor-based Thermo-Dynamics Ltd.

Since the trial dose stopped 80% of the leak without any adverse effects to the refrigeration system components, Miller opted to inject an additional 3 oz dose of sealant. The second injection completely halted the leak, based on system operation statistics:

• discharge pressure -- 208 psig;


• discharge temperature -- 103ºF;


• shell temperature -- 162ºF;


• suction pressure -- 68 psig;


• suction temperature -- 53ºF;


• superheat -- 13 deg.

Miller wanted to wait over one year before declaring that the sealant has completely remedied the problem. However, a recent oil analysis and acid testing revealed a "crystal clear" oil and acid-free sample, he reports.

"If there's going to be a problem, it would have surfaced by now," says Miller. "I'm a believer in refrigeration sealants now."

Paul Appler, Cliplight Mfg's director of R & D, offers these tips when using a refrigeration system sealant:

• The system should leak no more than 14% of its charge over a 4-week period. Such a leak is considered very large and can typically be found by using standard electronic and dye detection methods. However, if the leak is inaccessible for detection, an industrial strength sealant can be successful in leaks of this magnitude.


• Moisture, acid, and any other noncondensable should be removed from the system prior to administering the sealant.


• Systems that have leaked over 17% of their total charge are probably contaminated. Refrigerant recovery is recommended for drying, removing light particulates, and replacing suction and liquid line dryers (where required). The refrigerant can then be reintroduced back into the system if deemed suitable by the technician.


• Systems under 5 tons shouldn't exceed an application of one 3 oz can of sealant. Systems over 5 tons can receive two cans, but separated by a minimum 10-day period. During this intermediate time, system pressure and temperatures should be checked to evaluate the first application's success before adding the second can.

"Sealants are engineered for leaks that go undetected because of their small size and/or intermittent nature," said Appler. "If you can find the leak, fix it. If you can't find it, then use a sealant."