Litigation / Trial Practice A class action lawsuit filed against Goodman Global, Inc., and certain affiliated companies, alleges that central air conditioning units and heat pumps sold under the Goodman® and Amana® brands since 2007 are defective.  In particular, the plaintiff contends in his lawsuit that these units have defective evaporator coils. Evaporator coils are generally located inside a consumer’s home and they are essential to the proper functioning of any central air conditioning system or heat pump.  According to the lawsuit, Goodman and Amana central air conditioning and heat pump systems contain defective evaporator coils that improperly and prematurely leak refrigerant (a.k.a. Freon®).  The defect allegedly renders the systems inoperable because the cooling cycle will not work without refrigerant. Although Goodman sells these units with a warranty, that warranty is limited in a way that provides insignificant protection to owners of the units. 

In particular, the Goodman warranty, by its terms, covers replacement parts, but not the labor costs associated with the replacement.  According to the lawsuit, the result is that, when a defective evaporator coil fails, Goodman provides the owner with a replacement coil, but does not pay to have the old coil removed or the replacement coil installed.  As alleged in the lawsuit, those labor costs typically run in the hundreds of dollars, and in some cases, thousands of dollars.  Thus, in at least some instances, the owner is forced to spend as much or more to replace the defective evaporator coil as the cost to purchase a new Goodman unit. The complaint also alleges that Goodman has known that its units sold since 2007 contained defective evaporator coils, but the company failed to inform consumers about the problem or issue a recall.  Indeed, according to the lawsuit, Goodman continued to tout the quality of its air conditioning systems—claiming they were durable, dependable, and long lasting—even though it was aware that the defective evaporator coils would cause the units to fail prematurely and at rates far above the industry average.

The lead plaintiff in the case acquired his Goodman unit when he purchased his new house in September 2011.  According to the lawsuit, in or about July 2013, after only one summer of use, the unit stopped cooling the plaintiff’s home.  A service technician allegedly found that the unit was low on refrigerant and added four pounds of refrigerant, which immediately leaked out of the system.  After observing this, the technician determined that the evaporator coil was leaking and needed to be replaced.  According to the complaint, the service technician returned the old defective evaporator and replaced it with a new one, charging plaintiff approximately $650 for this service. The civil action was filed in North Carolina state court on behalf of all consumers in North Carolina that purchased a central air conditioning unit or heat pump bearing the trade names Goodman® and Amana® from 2007 to the present. To read a copy of the complaint, click here.Coil corrosion is an expensive problem in the HVAC industry, leading to coil replacement or entire system replacement.

Corrosion results in failure, and is responsible for about 40% of equipment failures in industrial applications, according to CED Engineering.In 2015, subscribers who read this article also: Purchased CoilShine Coil Cleaning SolutionPurchased CoilShine Mold & Mildew InhibitorDownloaded HVAC “Spring Cleaning” ChecklistsAs the authors of an article in Reliable Plant explain, coil corrosion comes in the form of either pitting or formicary deterioration. cover for hvac unitCorrosion may occur as quickly as a few weeks after an installation or it may take up to four years to present itself.what size wire for ac unitPitting corrosion is most often caused by exposure to fluoride or chloride. ac and heating window unitsFluoride is present in municipal water supplies, while chloride is found in a variety of products including snow melt, detergents, cleaners, carpeting and fabrics.

Pitting occurs when chloride or fluoride ions are transported to the metal via condensate. The ions attack the metal, forming pits that form pinholes, causing the coils to leak refrigerant.Formicary corrosion is typically caused by exposure to acetic or formic acids. These acids are present in a host of household products including cleaning solvents, insulation, adhesives, paints, plywood and many other materials. This type of corrosion is not always immediately visible and sometimes presents itself as black or blue-gray deposits. Formicary corrosion creates tunnels within the tubing that result in pinholes forming in the coils, again often leading to a refrigerant leak.Facilities located in more corrosive environments including near saltwater or in industrial sites are particularly prone to experiencing coil corrosion. Other environments that may contribute to a higher amount of corrosive materials being expelled include areas around pools, laundry facilities, water treatment plants, sewers and high traffic areas.

In such highly corrosive areas, coils have been known to fail in less than one year, according to CED Engineering.A potential cause of coil corrosion is Chinese drywall, also known as odorous wallboard. Chinese drywall is also hazardous to your health. According to an article in G3 Environmental & Industrial Hygiene, an environmental and industrial hygiene service company, the drywall was imported from China from 2004 to 2007 and installed in both residential and commercial buildings. The drywall emits sulfur compounds, which corrode metal, including air conditioning coils.The Centers for Disease Control and Prevention confirms that exposure to Chinese drywall can cause certain health problems such as irritated eyes and skin, respiratory problems and headaches. Exposure to this type of drywall can also exacerbate asthma symptoms.You can identify the drywall by looking at the back. It should contain a label with the words: “Made in China,” “China,” or “Knauf.” Some Chinese drywall is not marked.

In that case, metal corrosion including in plumbing, electrical, and natural gas lines, combined with a rotten egg odor may signify a Chinese drywall installationTo combat the problem of coil corrosion, coil manufacturers are applying coatings prior to production. In addition, there are companies offering aftermarket coatings. In a brochure, Aeris Technologies Ltd., a manufacturer of aftermarket coil-protection coatings, explains that the consequences of coil corrosion can include reduced efficiency, unattractive surface deterioration and equipment failure.Additionally, reduced heat rejection may occur, resulting in an increasing compressor temperature and lower cooling capacity, which in turn increases the power usage. Lower cooling capacity means the compressor doesn’t cycle as intended, which means increased power consumption. As systems work harder they become more stressed, experience more breakdowns and have higher maintenance costs. A lower cooling capacity may also mean occupants aren’t very comfortable, resulting in loss of business or productivity.

Preventing coil corrosion is much more effective and cheaper than replacing coils or the entire system.There are basically four types of coil coating materials: polyurethanes, epoxies, fluoropolymers and silanes, according to Reliable Plant. Choose carefully as the wrong coating, especially with aftermarket products, can reduce heat transfer and result in more expensive operating costs. An aftermarket application may affect the manufacturer’s specifications.Thinner coatings have better heat transfer while thicker coatings restrict heat transfer. Hydrophobicity, or how effectively water drains from the coil, can affect heat transfer. Water buildup may also cause mold or mildew growth. The advantages of the four types of coatings differ as to how they resist scratching and corrosion; and heat transfer abilities.Polyurethane is inexpensive, flexible and thin, but it’s not as long-lasting as other coating options. Epoxy is cheap, but it’s usually a thicker coating and can’t be applied in the field;

the coils must usually be shipped to a factory for professional application. Fluoropolymers are highly resistant to acids and solvents, and are inexpensive, but the sprays generally adhere poorly and their effectiveness wanes quickly.Silanes form a thin coating that affects heat transfer very little and they typically last longer than other coatings. But they’re more expensive and proper application is best done by a professional and usually off-site. Each coating type has varying toxicity levels. Technicians applying the coating should wear equipment as specified by OSHA and an appropriate breathing apparatus.Whether coated or not, continuing maintenance of coils is the primary way to combat the effects of corrosion. Twice annual cleaning with an alkaline coil cleaner or ph balanced coil cleaner will clear away any accumulated deposits, keeping coils safe from corrosion but also positively impacting the efficiency of your system.Have you experienced coil corrosion? How did you combat the problem?