In general the IRS can collect past due account balances, say from an audit adjustment for a prior year, from a taxpayer's current refund. While I can't directly speak to when your refund will arrive, in very general terms taxpayers who find themselves in this position receive any amount which exceeds the amount collected within a normal period of time.
So if a taxpayer owed $200 for a prior year and their expected refund was $800 for the current year, they could expect to receive the difference of $600 without a significant delay assuming the return was correct as filed.
Taxpayers will also receive a letter from the IRS explaining why the amount refunded was different from the amount of refund listed on the return within 4 to 6 weeks. This letter will state what tax and tax year the difference, or amount kept from the original refund, was applied to.
