Unless he expressly contracts otherwise, in writing, a personal representative shall not be personally liable on any written contract which is within his authority as personal representative and discloses that he is contracting as personal representative of a named estate. Any action on such a contract shall be brought against the personal representative in his fiduciary capacity only, or against his successor in such capacity, and execution upon any judgment obtained therein shall be had only against property of the estate.
20 Pa.C.S. § 3331