Gerber Plumbing Fixtures Corp. announced changes in its top management, with the Gerber family continuing to run the Chicago-based business. Heading the company are Harriet Gerber Lewis, as chairman of the board, her daughter, Ila Lewis, as newly named executive vice-president, and her other daughter, Nancy Lewis Pollack. Other executives include: Jon Deiter, president, Ron Grabski, vice-president of marketing, and Charlie Aranoff and Joe Sell.