A flow valve that may act as either an excess flow valve or a pressure relief valve has a seat and a valve body for sealing against the seat. The valve body has an integral spring arm for biasing the valve body towards or away from the seat to seal or open a flow of fluid, and a magnet cooperating with the spring arm to position the body relative to the seat to maintain the body in a first position during a normal flow condition and maintain the body in a second position in an abnormal flow condition.