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In my new house, I did some pipeline testing due to slow hot water flow in various places. This involved turning the mains on and off. One effect I noticed was that the CPVC pipes would buck violently and with a loud thud when I turned the mains water back on.
Had to help my parents with a valve replacement yesterday and noticed they have an expansion tank mounted horizontally (and perpendicular to the vertical mains run) just downstream from the mains valve. Not sure why.
Somewhere I read that an expansion tank eliminates the water hammer effect. I don't think I need this in normal operation--this only happens when I shut off the cold water and drain the pipes. Also there is no backflow preventer and the hot water expands like crazy (I know, I've run the tank without hot/cold hooked up and it pumped a ton of water out as it heated) but the pressure release valve doesn't open in any case, so I assume that the expanding water is just pushing back out the mains and thus I don't need an expansion tank for that purpose.
Are the banging pipes a problem? Or do I just ignore this as it only occurs if my pipes are empty (i.e. shut off mains, release pressure by running washing machine, turn mains back on)?
Had to help my parents with a valve replacement yesterday and noticed they have an expansion tank mounted horizontally (and perpendicular to the vertical mains run) just downstream from the mains valve. Not sure why.
Somewhere I read that an expansion tank eliminates the water hammer effect. I don't think I need this in normal operation--this only happens when I shut off the cold water and drain the pipes. Also there is no backflow preventer and the hot water expands like crazy (I know, I've run the tank without hot/cold hooked up and it pumped a ton of water out as it heated) but the pressure release valve doesn't open in any case, so I assume that the expanding water is just pushing back out the mains and thus I don't need an expansion tank for that purpose.
Are the banging pipes a problem? Or do I just ignore this as it only occurs if my pipes are empty (i.e. shut off mains, release pressure by running washing machine, turn mains back on)?