Rola-Chem Corp.has issued an advisory for customers who have purchased one of the company’s peristaltic pumps without a chemical controller.

The firm did this after receiving a unit with a compromised timer knob. “This appears to have caused the pump to operate in a continuous mode,” the letter stated.

Last year, the manufacturer settled a lawsuit that involved a similar concern.

In 2008, two residents of a Southern California condominium complex received second-degree burns after using a spa on the property. It was claimed that the chemical feeder, produced by Rola-Chem, had been operating in the “on” position, thereby dumping a large amount of chlorine into the small body of water.

A service technician also named in the lawsuit said he had put the feeder in “timer” mode so the unit would periodically inject a set dosage of sanitizer into the water. He alleged that a defect must have caused it to change modes.

The case was settled, and Rola-Chem never made an admission of liability. However, some came to believe there is a defect in the product. The attorney representing the service firm said he’d heard anecdotal evidence that several such failures had occurred, while the company’s insurance carrier reported receiving a similar claim.

Last month, Rola-Chem issued the letter. According to the advisory, the manufacturer recently examined a failed pump that was more than 10 years old. “Our tests have confirmed that excessive corrosion in the potentiometer is the likely cause of the problem,” the letter stated. “Because this could affect other older Rola-Chem peristaltic pumps, we have issued this advisory letter.”

Rola-Chem recommends that the timer/pot assembly be switched after five years of use. The manufacturer said it would provide replacements free of charge. As an immediate remedy, the letter continued, the minimum necessary amount of chemical should be hooked up to the feeder.

The recommendation doesn’t apply to products being managed by a chemical controller and not utilizing the timer function.