(a) General rule.--An action, proceeding or appeal must be commenced within the time specified in or pursuant to this chapter unless, in the case of a civil action or proceeding, a different time is provided by this title or another statute or a shorter time which is not manifestly unreasonable is prescribed by written agreement.
(b) Uniform Commercial Code.--The provisions of Title 13 (relating to commercial code), to the extent that they are inconsistent with this chapter, shall control over the provisions of this chapter.
(c) Equitable matters.--Nothing in this chapter shall modify the principles of waiver, laches and estoppel and similar principles heretofore applicable in equitable matters.