a Q about water-hammer arrestors and flushometer toilet
I live in a 5-floor, 10-unit self-managed co-op. No "management agency," just a co-op president with lots of power. Built in 1920.
I'm on the 2nd floor; the Prez is on the top floor (5). She said that when we flush our toilet, with its flushometer, that she gets really bad banging. Water hammer, I'm assuming.
Her solution is for all of us who still have the 1920s flushometers to have to replace it with a tank the next time it breaks, instead of simply repairing it. Given that we have an 8" rough-in, I really don't want to go there.
But of course, the water hammer isn't good for the pipes, nor should she have to live with the banging every time we flush.
Apparently this happens on the other side of the building, in the other line of apartments (or else I'd think it came when she did a gut remodel, complete with new pipes, about 13 years ago). She says it's been a while, but I'm thinking it couldn't have been THAT horrible, or she'd have been complaining big-time 16 years ago, when we had middle-of-the-night wakings w/ babies and pregnancies, or right after her remodel, when Kid No. 2 was born.
I haven't had a chance to ask if there's an air cushion that should/could be reinstated. Wouldn't they have known about water hammer, and air cushioning, in 1920, when our bldg was built? And installed something, since the building was full of flushometers? (20 of them in the building originally)
But I'm wondering--would it do any good to install a water-hammer arrestor on the pipes behind our wall?
(I think I can access the pipes *above* the tile through the plaster wall, and then cover it up w/ either a decent skim-coat job, or by hanging the cabinet back up. If I could put the arrestor on the cold-water supply line there, would that help? Not the tallest point in the system, but above the only flushometer in that line.)
How hard is it to install an air cushion for the stack? Would it go on the roof?