Con Ed Negotiates With Union As Deadline Nears While New Yorkers try to keep their heads cool during this weekend's heat wave, they may also want to hope that those running the final negotiations between Consolidated Edison and its biggest union do the same. Officials of the union, Local 1-2 of the Utility Workers Union of America, have been threatening to pull their 8,500 members from their jobs as soon as Sunday morning if an agreement on a new contract is not reached before the current one expires at midnight Saturday. But they also have hinted that the company might lock the workers out. As some workers finished their shifts on Friday, they were told to turn in the keys to company cars and trucks and the identification cards that open gates to equipment yards, a spokesman for the union said. The union's president, Harry Farrell, has repeatedly suggested that Con Ed would not be able to keep power flowing to air-conditioners and lights around the city without his members. But Con Ed officials said the utility, which serves New York City and Westchester County, had prepared its managers to step in and operate the power grid and make repairs. "We've been preparing for any eventuality," said Michael Clendenin, a spokesman for Con Ed. If there's a work stoppage, management would operate the gas and electric system. Mr. Clendenin said the company could deploy about 5,000 managers, about half of whom have some experience working in the field. In the interim, he said, some construction projects would be postponed and meter-reading might be curtailed. Representatives of the company and the union met at the Hilton Westchester in Rye Brook on Friday while the temperature in the city reached into the high 90s. Forecasts called for highs above 90 degrees on Saturday and Sunday. Heat waves can test the limits of Con Ed's system, but demand is highest on weekdays, and the weather is expected to become more moderate starting on Monday. Still, Con Ed workers were hoping the heat would help their cause at the bargaining table: on a Facebook page for union members, several posted messages encouraging Mr. Farrell to refuse to concede on wage demands or pension terms. The workers have a traditional pension plan that promises a defined monthly benefit during retirement, but the company has been insisting on converting the pension to what is known as a cash balance plan, which tends to yield lower benefits to older workers. Con Ed stopped offering a defined-benefit pension to new hires in management positions more than a decade ago. But that shift is unacceptable to the union, said one of its spokesmen, John Melia. "There's a feeling that the defined-benefit plan is something that shows that the company is earnest when it says it values its workers," he said. When the union's last contract was about to expire in June four years ago, Gov. David A. Paterson intervened, calling Mr. Farrell and Con Ed's chief executive, Kevin M. Burke, on the last night of the existing contract. At the time, the two sides were still "miles apart" after 10 days of face-to-face negotiations, a union spokesman said then. But after taking a few days to cool off, they resumed talks on the following Tuesday morning and quickly reached an agreement. No such intervention appeared to be coming on Friday afternoon. No elected officials in the city have spoken out about the impending contract expiration. Gov. Andrew M. Cuomo's office did not respond to requests for comment; a spokesman for Mayor Michael R. Bloomberg said the mayor's office was "monitoring the talks."