ZURICH, Sept 3 - The Swiss franc traded in narrow ranges early on Monday ahead of the release of Swiss Purchasing Managers Index data that were awaited for more evidence on how the Swiss economic slowdown was progressing. Volume was expected to remain subdued with the U.S. markets closed for a holiday. The dollar was set to move in a range of 1.6630/1.6750 francs, one dealer at a big Swiss bank said, suggesting it would be wise to set up short positions around 1.6725. "As long as the dollar stays below 1.6825 francs it is still set to move lower," he said. Last week's data that showed Swiss inflation slowed in August to a year-on-year rate of 1.1 percent underscored expectations that the Swiss National Bank could ease monetary policy for the second time this year when it unveils its policy framework for the fourth quarter on September 20. The Swiss KOF research institute also said on Friday its leading indicator fell to minus 0.21 in July from a downwardly revised minus 0.07 in June, adding evidence that Swiss growth is slowing.