Water Hammer occurs when water suddenly changes direction, for example, when you turn off the tap. The momentum change causes pressure waves in the pipes and can be a plumbing nuisance to the point that when pressure is high, it can cause serious pipe damage.
If you have ever been in a home and heard thumping, pounding or vibrating when you turned off a tap, you have witnessed the water hammer effect.
Ensure that the plumber you book is professional and trustworthy, water hammer can be caused by pipework that is not clipped, secured and supported at regular intervals or with inappropriate sized pipe clips.
Water hammer can result from ripples inside open water tanks where a ball / float valve controls the water level -– the ripples are caused by the inflow of water, resulting in the valve floating up and down, repeatedly opening and closing the valve.
This repeated opening and closing of the valve sets up shock waves which reverberate along the pipework causing the water hammer effect. This can be remedied by a metal reinforcing plate fitted on the side of the tank (if the tank is plastic) where the float valve is installed, reducing the flexing of the tank.
Some electrically operated solenoid valves stop the flow of water instantaneously, possibly sending the shock wave through the pipework to cause the water hammer.
Flexible hose attaching the valve to the water supply may be enough to absorb any shock in the pipework.
Preventing air from accumulating in the pipes can help minimise the chances of water hammer. This can be accomplished by using air-relief valves positioned at the high points of the piping system. In areas of relatively flat terrain, these should also be used in the vicinity of the pump discharge, near the middle of the line, and at the downstream end of the line.
Empty pipelines should be filled as slowly as possible to allow entrapped air to escape.