Abstract: A scroll compressor has a valve normally closed during forward operation of the scroll compressor. Upon reverse rotation, force imbalances allow the valve to open and communicate a chamber downstream of a check valve to a chamber upstream of the check valve. By communicating these two chambers, the detrimental effects of reverse rotation are reduced or eliminated. Two valve embodiments are disclosed. One embodiment also relieves unduly high discharge pressures. In a third embodiment, a pressure relief valve is provided to prevent desirably high pressure ratios or pressure differentials.