* U.S. service-sector data due at 10 a.m. ET (1500 GMT)
* Nonfarm payrolls on Friday could be hard to parse because of shutdown
* U.S. Treasury quarterly refunding announcement due Wednesday
NEW YORK, Nov 5 (Reuters) - Prices for U.S. Treasuries dipped on Tuesday, giving up gains from the previous session as investors showed their reluctance to break out of recent ranges without greater certainty on the direction of monetary policy in coming months. The Treasuries market is now turning on one central question: When will the U.S. Federal Reserve slow its $85 billion per month bond-buying program? Despite expectations for a September taper, the central bank has instead held firm to its course, although it did take on a more hawkish tinge after its most recent policy meeting last month. "It's just to taper or not to taper," said Wilmer Stith, portfolio manager of the Wilmington Broad Market Bond Fund. "At the end of each day, that's going to be the primary focus." Fed Chairman Ben Bernanke has repeatedly said that the Fed's decision will depend on data showing the health of the world's biggest economy. Other recent Fed speakers have emphasized that message, with three separate Fed officials on Monday suggesting the Fed should only pull back asset purchases on clearer signs of improvement in the economy and should act slowly when it does slow bond buys. Perhaps the most significant upcoming data point for potential policy changes will be Friday's nonfarm payrolls report for the month of October. But that data itself will be problematic, considering that a Congressional impasse shut down most of the federal government for the first half of last month. A weak number, noted Ian Lyngen, senior government bond strategist at CRT Capital Group, "will simply be dismissed as the transitory influence of the government shutdown and civilian furloughs; but on the other hand, if the release comes in above consensus, it will be read as that much stronger given the weight of the shutdown." Recent stronger-than-expected manufacturing data have underscored how hard it will be to judge the shutdown's effect on the economy, although many analysts still worry about a drag on growth. More data are on the way in the week, including data on the U.S. service sector at 10 a.m. ET (1500 GMT) and third-quarter gross domestic product figures on Thursday. But the payrolls figure will be likeliest to guide the market, at least in the short term. Fed policymakers want to see the unemployment rate dropping closer to 6.5 percent from the current 7.2 percent, but economists in a Reuters survey expect that rate to have edged up in October to 7.3 percent. Prices for U.S. benchmark 10-year Treasury notes dipped 8/32 in price on Tuesday to yield 2.631 percent, compared to a yield of 2.6035 percent late on Monday. The U.S. 30-year bond dipped 15/32 in price to yield 3.715 percent, compared to a yield of 3.6943 percent late on Monday. In addition, the U.S. Treasury on Wednesday will issue its quarterly refunding announcement, which will lay out upcoming funding needs.