Opinion ID: 201606
Heading Depth: 3
Heading Rank: 1

Heading: The Robertshaw Unitrol 110

Text: In the early 1950s, Robertshaw learned of serious accidents caused by defects in the Unitrol 110 gas control valve -2- that it manufactured for use on propane water heaters. The problems related to an interlock mechanism, known as the index plate, that was supposed to prevent the reset button from being depressed while the gas cock knob was turned. In 1957, Robertshaw implemented three changes -- a stronger reset button, a thicker index plate, and a new gas cock knob -- to fix these problems. In 1974, Robertshaw notified the Consumer Product Safety Commission (CPSC) of the defect, stating that it had been informed of one fatality and one non-fatal injury. In 1981, the CPSC concluded that Robertshaw had substantially understated the number of incidents; apparently Robertshaw had received 147 liability claims by 1974, including forty-eight deaths and eightynine serious injuries. Robertshaw issued two recall notices under CPSC supervision, one in 1981 and another in 1984. Robertshaw estimated that approximately 1,000 defective controls were in use, primarily on water heaters located in rural areas, such as . . . in vacation or weekend homes. A homeowner could determine if a control was defective by examining the date code on the bottom of the control. According to the recall notices, an alternate method to identify the defective controls was to examine the position of the index pointer relative to the word PILOT -- if it lay under the T it -3- was a pre-1957 defective model, and if it lay between the L and the O, it was a post-1957 model not subject to the recall.1