We just had some kitchen renovation done, adding lighting cans to the ceiling. The contractor had to reroute some of the waterlines that were run up there to make room for the lighting fixtures. Only thing is, now the pipes make a kind of loud shudder when the kitchen faucet is turned off. Didn't used to happen. What's the cause of it and what can we do about it?
I think what you have is called air hammer or pipe hammer?, Its common to extend a piece of capped pipe up 12" at the sink plumbing area to make a "air bumper" , ones you buy are mechanical and will eventualy fail. A air bumper I think its called just cushions the shock of turning off the water. Mine are behind the wall and standard to do by a plumber here. You city code dept will tell you if its mandatory or recomended so you wont have to pay to get it fixed. If you see its going to cost you you can still get a permit and they will make him fix anything that fails. Point is you paid for a good functioning job and didnt get one. If a guy missed that I would want everything verified as correct and to code. Getting a permit is always thought of as a wastefull tax by homeowners, im a contractor, people I hire try to rip me off every day and permits and free inspections catch what I miss. A permit gets you free inspections to cover you from being ripped off in the first place. Next job, get a permit and dont pay till it passes, is normal business practice.
Use more pipe straps and add a hammer arrestor. An expansion tank will help to protect valves and pipes. Or, you can learn to turn the water off slowly.
Air chambers...a length of pipe extended some distance above the angle stop location to act as a pressure pulse absorber have a couple shortcomings;
They need to be rather tall to retain useful air space, when they go from atmospheric pressure to system pressure they can lose over 75% of the initial air space depending on system pressure.
the air in the air chamber eventually gets absorbed into the water & the air gap goes away requiring them to "drained" ....an easy process but most homeowners wont do it.
"mechanical" water hammer arrestors do eventually do wear out but the piston style ones made by Sioux are guaranteed for the life of the plumbing system and were tested to verify life beyond 500, cycles without failure and are rated for concealed installation. Despite this guarantee and testing, I prefer to install them such that they can be easily unscrewed and replaced.
air chambers or water hammer arrestors all aim to add "distributed compliance" to the plumbing system; a "soft element" not unlike a car's shock absorber or an energy absorbing bumper.
OP- I would suggest that before you get too heavy handed with the guy who did the work......just give him a call and see what he says about the problem. If he's a stand up guy and you didnt hire him solely on price (did you?) and you didnt beat him down on price as well.......I'd bet that he'll take care of the problem.
If the piping is sealed up into a space with no current access....well, then this might be a bit more problematic.
please let us know how this all resolves
here is is a pretty good discussion of water hammer & the remedies
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scroll down about 1/3 of the page & click on Water Hammer topic
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