24 Pa. Stat. § 21-2128
The annual estimate of expenses made by the board of public education in each school district of the first class, at or before the time of assessing and levying the annual school tax, shall be certified to the school controller of the district by the secretary of the board. The school controller shall, in a proper book or books kept for that purpose, keep an account with each item of expenditure as therein stated or thereafter changed by the board in the manner herein provided. He shall charge up against each item of such estimate all school orders drawn against the same, at the time they are approved by him, and he shall not permit any such estimate to be overdrawn. He shall furnish to the board of public education a monthly statement showing the original amount of each item of such estimate, the amount paid out thereon, and the balance, if any, on hand. If any item is exhausted he shall promptly notify the board of such fact.
24 P.S. § 21-2128