* G20 vows to refrain from competitive devaluations
* Market awaits further clues on possible Fed easing
* Yen at 15-yr high; euro gains seen capped by options
(Recasts, updates prices, adds detail, comment)
By Steven C. Johnson
NEW YORK, Oct 25 (Reuters) - The dollar fell broadly on Monday as traders sold it on the view that the U.S. central bank was ready to turn on the printing press again next week even as the G20 pledged to shun competitive currency devaluation.
The Federal Reserve is expected to launch a second round of asset purchases at its Nov. 2-3 meeting, a process intended to push down U.S. interest rates and one that would make the dollar less attractive than higher-yielding currencies.
That drove the greenback to a 15-year low against the yen and weakened it against most other major currencies, including the euro and Australian dollar.
Speculation that G20 finance leaders would strike a truce on exchange rate disputes and perhaps even set targets for reducing trade imbalances provided a brief dollar respite last week, but analysts said the lack of any concrete agreement was a green light to keep selling the dollar ahead of Fed easing.
While U.S. Treasury Secretary Timothy Geithner reiterated that the United States supports a strong dollar at the G20 meeting, analysts expected more dollar weakness ahead.
"It is one thing for the Treasury to say that, but then the Fed holds all the ammunition and when it is set to print more money, the dollar will remain a weakened currency," said Jane Foley, senior currency strategist at Rabobank.
BNY Mellon strategist Michael Woolfolk said Fed policy "is on railroad tracks right now and heading in one direction" toward more easing.
The dollar fell to 80.41 yen on trading platform EBS, a 15-year low and within reach of a 79.75 record low. Japan intervened to little avail last month to slow the yen's gains, and traders said chances of more official yen selling would increase if the dollar falls below 80 yen. It was last down 0.8 percent at 80.71 yen.
The euro rose 0.3 percent to $1.3983. Earlier it hit $1.4080 after breaking through resistance at $1.4051 but pared gains after data showed sales of previously owned U.S. homes rose a surprising 10 percent last month.
Traders said the euro may target its recent 8-1/2-month high around $1.4161 this week but said the presence of some large option barriers, including one at $1.4215 set to expire Wednesday, could slow further gains.
That could lead to stronger-than-usual defense of that level with the barrier payout said to be 30 million euros. More typical option payouts are in the 3-5 million euro range.
One trader said real money accounts and trend-following commodity trading advisers were seen buying the euro and the Australian dollar, while another cited buying of the euro and the Australian dollar by Asian accounts.
The Australian dollar surged roughly 1.2 percent to $0.9940, boosted by news that Singapore Exchange will buy Australian bourse operator ASX, and expectations of a rate hike early next month..
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In a Reuters poll earlier this month, U.S. primary dealers projected the size of quantitative easing in a range of $500 billion to $1.5 trillion.
Analysts said that has made it tough to make too much of G20 announcements and agreements on currencies.
Even German Economy Minister Rainer Bruederle took issue on Saturday with what he called a U.S. policy of increasing liquidity, saying it indirectly manipulated exchange rates.
Some investors said there could be some movement toward more flexible exchange rates in the longer term.
Vasileios Gkionakis, macro strategist at Fulcrum Asset Management LLP in London, said the G20 meeting statement "was a touch better" than what people had expected "because at the end of the day, it's the first time that we've got a joint stance as far as FX is concerned.
"From that point of view, he added, "it does provide some tailwinds for gradual appreciation of emerging market currencies against the U.S. dollar."
Gkionakis said a strong growth outlook should continue to boost Asian currencies, with the Singapore dollar, Taiwanese dollar and Korean won all set to benefit. Fulcrum oversees about $900 million in assets.