The Retirement Savings Contribution credit is a non-refundable credit, which means it will reduce your tax liability, but will not directly add money to your refund. So, if you already have enough deductions/exemptions/other credits, that you do not have a tax liability, then the RSCC will not add anything additional to your refund.
Example of how non-refundable credits work: You have $5,000 in taxable income and a 10% tax rate, which means you have $500 in tax liability. If you have a $1,000 non-refundable credit, then $500 will get applied and bring your tax to 0, but then you lose the other $500. It does not get added into your refund like a refundable credit (i.e the Earned Income Credit).
You can find the credit on line 51 of your Form 1040 and see if it is being applied to your tax liability. If you wish, you can view the limitations of this credit and exactly how it is applied on Form 8880 below. Line 11 and the credit limitation worksheet on page 2 are the relevant sections to the limitation.
You can also view more information about the credit itself and the income limitations at the link below -
