If line 12a is under $1, we will send the refund only on written request.
If you want to check the status of your refund, please wait at least 72 hours after the IRS acknowledges receipt of your e-filed return (3 to 4 weeks after you mail a paper return) to do so. But if you filed Form 8379 with your return, allow 14 weeks (11 weeks if you filed electronically). See page 25 for details.
If your refund is large, you may want to decrease the amount of income tax withheld from your pay by filing a new Form W-4. See Income tax withholding and estimated tax payments for 2010 on page 22.