53 Pa. Stat. § 25899
That the present board of assessors in any such city, or their successors when elected, shall make an assessment of all the subjects of taxation now by law, or which may hereafter be made subject to taxation for city purposes, and they shall take, as the basis of such assessment, the last preceding assessment made by the board of assessors for such city, and shall have power to revise, equalize or alter such assessment by increasing or reducing the valuations and to add to such lists of assessments any subjects of taxation subject to taxation as aforesaid omitted therefrom and fix the taxable valuation, thereof, and it shall be their duty to rectify all errors, and, if necessary for such purpose, require the attendance of citizens before them for examination under oath or affirmation. It shall be their duty to establish without delay, rules and regulations prescribing the mode of appeal to them from any assessment made by them by any person interested therein, and when such assessors shall have finally acted upon such assessments and appeals, an appeal may be taken therefrom to any court of common pleas of the county in which such city is located, whose decision shall be final thereon. Such appeals shall be taken to such court within thirty days after final action by the assessors as aforesaid: Provided, That the said appeal shall not prevent the collection of the taxes complained of, but, in case the same shall be or shall heretofore have been reduced, then the excess collected shall be returned to the person or persons who shall have paid the same: And provided further, that such appeals shall not operate to relieve the appellant from paying accrued interest and penalties on the amount of the assessment as finally established.
53 P.S. § 25899