Per the IRS:
If I'm eligible for the credit, when will I receive my refund?
We’ll mail you a refund check in 6-8 weeks if you don’t owe tax or other debts we’re required to collect. If we deny the credit, we’ll send you a letter of explanation. If you don't hear from us after 8 weeks, you can call our toll-free line at 800-829-0922 to check the status.
Understanding Your CP09 Notice | Internal Revenue Service (irs.gov)
Also see:
After 'horrendous' year for cash-strapped IRS, taxpayers can expect more delayed refunds (yahoo.com)
