24 Pa. Stat. § 6-609
The amount of funds in any annual estimate by any school district, at or before the time of levying the school taxes, which is set apart or appropriated to any particular item of expenditure, shall not be used for any other purpose, or transferred, except by resolution of the board of school directors receiving the affirmative vote of two-thirds of the members thereof.
No work shall be hired to be done, no materials purchased, and no contracts made by any board of school directors which will cause the sums appropriated to specific purposes in the budget to be exceeded.
Whenever Federal or State funds are made available to school districts, such funds may be expended by the board of school directors for the purposes for which they are made available even though provisions therefor were not made in the annual estimates or budget of such school district. Whenever the General Assembly shall enact a law providing for the levy of taxes within a school district, the revenues from the taxes so levied may be expended by the board of school directors for general school purposes even though provisions therefor were not made in the annual estimates or budget of such school district for the fiscal year within which such law was enacted.
24 P.S. § 6-609