42 Pa.C.S. § 7321.10: Initiation of arbitration.

(a) Notice.--A person initiates an arbitration proceeding by giving notice in a record to the other parties to the agreement to arbitrate in the agreed manner between the parties or, in the absence of agreement, by certified or registered mail, return receipt requested and obtained, or by service as authorized for the commencement of a civil action. The notice must describe the nature of the controversy and the remedy sought.

(b) Lack of notice.--Unless a person objects for lack or insufficiency of notice under section 7321.16 (relating to arbitration process) not later than at the beginning of the arbitration hearing, the person by appearing at the hearing waives any objection to lack of or insufficiency of notice.