A flush valve for a waste water system comprises a valve including a fluid inlet, a fluid outlet and a main valve element adapted for movement to allow fluid flow between the fluid inlet and the fluid outlet based on a pressure differential across a portion of the main valve element. The valve also includes a vent system comprising a control chamber in flow communication with the fluid inlet of the valve and a vent outlet in flow communication with the fluid outlet of the valve, and a solenoid for venting fluid venting fluid from the control chamber to the fluid outlet. A pressure sensor, such as an electronic pressure transducer, senses the fluid pressure of fluid within the vent system. When a predetermined pressure threshold is reached or exceeded, the solenoid can be energized to release fluid from the control chamber.