A pressure surge or wave caused when a fluid is forced to stop or change direction abruptly is called water hammer. Often it is caused by a valve closing. The pressure wave can cause major problems, including pipe rupture. Using devices such as pulsation dampeners can reduce the effects. If you are having issues with water hammer in your Equilibar fluid control valve, please visit our chatter support page . For a detailed explanation of how to analyze water hammer issues, see this video from Mike Crowley with Fluid Mechanics in the UK.