Conn. Gen. Stat. § 12-514: Excess payments.

If, within three years after the due date of any return, the commissioner determines that any amount, penalty or interest has been paid more than once or has been erroneously or illegally collected or computed, the commissioner shall credit the excess amount collected or paid against any amounts then due and payable from the person under this chapter or any other chapter administered by the commissioner and the balance shall be refunded, upon order of the Comptroller, to the person or his successors, administrators or executors or any other person legally responsible for the conduct of the affairs of the taxpayer.