Abstract: A trip mechanism for a trip valve is made up of a reset lever and a bell crank operatively connected through a guide stem which is guidingly received in a flange portion of the valve housing. A valve stem and the guide stem are slidably connected to the reset lever which is provided with a spring bias which tends to move the reset lever in a valve closing position. When the bell crank and guide stem are in engagement the valve is held open and when the bell crank is subjected to an actuating force the bell crank and guide stem become disengaged causing the valve to close under the spring bias and to remain closed until manually reset.