53 Pa. C.S. § 8048
Where bonds or notes have been issued pursuant to an assent of the electors given under this subpart, the proceeds thereof shall be kept in a separate account and shall be invested and used only for the cost, including the retirement of notes previously issued for the same project with the proceeds of bonds, of the project for which the assent was obtained unless such purpose is changed as provided in this subpart. Otherwise, the proceeds shall be kept invested and used for the retirement at maturity, or earlier call date, of the fifth or any subsequent stated maturity of the relevant series of bonds or notes, unless the proceeds were previously used to purchase the bonds or notes in the open market or upon tenders at prices not exceeding the principal amount thereof plus accrued and unpaid interest to the date of purchase.
53 Pa.C.S. § 8048