53 Pa. Stat. § 12394
No money shall be drawn from the city treasury except by due process of law, or upon warrants or checks, signed by the heads of the appropriate departments or by deputies authorized to sign by such department heads or by such other persons as may be designated by ordinance, and countersigned by the city controller. All such warrants or checks shall state the consideration for the same and the particular funds or appropriations to which they are chargeable. The head of each department shall have power to appoint, in writing, one or more deputies to sign warrants or checks, for whose acts he and his sureties shall be responsible. Every written order appointing a deputy to sign warrants or checks under the provisions of this section, shall be filed in the office of the city controller, and the deputy appointed thereby shall have only such power as may specifically conferred by such order.
53 P.S. § 12394