Getty Images For years Republicans have grumbled about the Federal Reserve vastly expanding its influence on the U.S. economy. Now they’ll press Fed Chairwoman Janet Yellen on when the central bank plans to sound the retreat.For years Republicans have grumbled about the Federal Reserve vastly expanding its influence on the U.S. economy. Now they’ll press Fed Chairwoman Janet Yellen on when the central bank plans to sound the retreat. Yellen will testify Wednesday before the House of Representatives and then give a repeat performance in the Senate a day later as part of the bank’s twice-a-year update on the economy. Republicans in control of the House are expected to try to pin her down on when the Fed will start to wind down its massive $4.5 trillion balance sheet. So far the Fed has only said that the process will begin this year.via