I recently had to replace the faucet and sprayer on my kitchen sink. Seemed easy enough and straight forward. The old faucet was original equipment (30 yrs old) and was replaced because it was easier and simpler than repairing the leaking supply hose to the sprayer. I had a “boom” (sticks straight out over the sink with slight angle up) type faucet that I replace with a moen brand goose neck that comes straight up and then arches out over the sink. The problem is that now I have “water hammer” in the faucet. It is not consistent and happens at random times, water temp and pressure (meaning how open the faucet is, not the supply pressure). Why did this happen, how do I fix it(prefer not to install yet another new faucet if possible), or is this just a design flaw inherent in goose neck faucets?
It’s hard to see how changing the shape of the spout could have triggered the onset of water hammer - was it really not there before, at all? Is the actual faucet itself now in a different place (along the line of water travel) than before?
This comes when you turn the tap off, yes? And if you do it slowly, does that help?
As to how to fix it, check out Water Hammer Arrestors.
no it happens when I turn the water on, so maybe water hammer isn’t the correct term. the only thing that is different is the faucet spout and yes, I never had the problem before replacing the faucet. I take that back, the old faucet had the screw type valves (knobs you turn around and around) the new faucet has 1/4 turn (im guessing ball valve like) valves.
I could see it happening with a new faucet if the new one has better seals so it’s shutting off more abruptly OR if any of the mounts that held the copper piping in place were removed or loosened during installation.
Something else to check. Is it just the flexible lines that connect the copper to the faucet rattling around when you shut the water off? Also, if this is the type of faucet where the sprayer and hose is one piece (rather then a separate sprayer off to the side) it could just be that flexing when you shut the water off.
I’d take a look under the sink and see if you can figure out what’s moving when you shut the water off and go from there.
It could just be a matter of (re)securing something that wasn’t loose before. Otherwise you may need to add some arrestors.
ETA, if you’re getting a water hammer sound when you turn the water on, that’s odd. But from the sounds of it, the new faucet is opening and closing faster then the old one so that’s probably the reason.
Something else to try, if the new faucet has a separate sprayer, try holding the sprayer button while you turn the water on (make sure it’s pointed into the sink). If the noise is gone, it’s a bad diverter valve and you’ll probably need to replace the faucet.
Though if it were me, just for kicks, I would unhook the plumbing, turn the water ‘on’ hit the diverter button with the hose pulled all the way up and drain all the water out and give it one more shot before I pulled it all out and went back to the store.
We call it “pipe rattle” here, on or off - off is just more likely due to pressure changes.
Just to be clear, does it happen…
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As soon as you turn it on, or at some point while it’s running?
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With the faucet in general or specifically with the sprayer?
Anecdotal: personally on my own sink, I quite enjoy the “kicK” that happens transitioning between the sprayer and the faucet. I often press and depress the sprayer trigger multiple times for a tiny thrill 
the bend in the goose neck may be torquing the faucet as the water hits the bend and making a noise. open the valve slowly to see if prevents.
flexing hoses especially a single faucet sprayer type can make noise.
sometimes it happens as soon as I turn it on, sometims later, and sometimes several times in a row, its intermitent and inconsistent, except that it never happens when I turn it off. It happens with the faucet, rattles the whole damn spout and I’m worried that it will shorten the lifetime of the thing greatly. yeah I know the sprayer kick you mean, its not as noticeable with the new faucet as it was with the old.
No its not a sprayer/spout combo, my dad just put one of those in his house, now I wish I had I kinda like it.
didn’t mess with the supply lines to the sink except to shut them off and disconnect hoses
Im starting to think maybe it is the gooseneck design, somehow its torquing as you said (the water I mean). eh, I guess if it starts to bother me that much its a good excuse to switch to one of those combo spout/sprayer types,
Thanks everyone, appreciate the input and advice
If the problem is intermittent, I would suspect the problem might be the water pressure. If you have a valve below the sink to cut off supply to the tap, try turning it down slightly and see if that helps.
Try turning the hot side off and seeing if it happens. Then turn hot back on and cold off. Try to isolate the problem.